Letters To The Editor

To the Editor: The review by May et al¹ of 3 neglected numbers in the complete blood cell count (CBC) was a good reminder to look more closely at the results of the CBCs we often order in primary care. I was surprised to see no mention of the red cell distribution width in relation to another cardiovascular disorder—obstructive sleep apnea.^2,3 I wonder if the authors would comment on this association?

To the Editor: The review by May et al¹ of 3 neglected numbers in the complete blood cell count (CBC) was a good reminder to look more closely at the results of the CBCs we often order in primary care. I was surprised to see no mention of the red cell distribution width in relation to another cardiovascular disorder—obstructive sleep apnea.^2,3 I wonder if the authors would comment on this association?

To the Editor: The review by May et al¹ of 3 neglected numbers in the complete blood cell count (CBC) was a good reminder to look more closely at the results of the CBCs we often order in primary care. I was surprised to see no mention of the red cell distribution width in relation to another cardiovascular disorder—obstructive sleep apnea.^2,3 I wonder if the authors would comment on this association?

In Reply: We thank Dr. Homler for his question and for highlighting another important disease state, obstructive sleep apnea, in which a high red cell distribution width (RDW) has correlated with disease severity.^1,2 The 2 retrospective studies he mentioned indicated that RDW is negatively correlated with metrics such as oxygen saturation, sleep time, and sleep quality. Interestingly, another retrospective study showed that RDW was significantly higher in patients with concurrent obstructive sleep apnea and cardiovascular disease than in patients with obstructive sleep apnea alone, suggesting that the presence of anisocytosis in obstructive sleep apnea may be due to its link to cardiovascular disease.³

Although we focused on cardiovascular disease in our review, RDW has also shown prognostic significance in many other disorders including ischemic stroke,⁴ pneumonia,^5,6 chronic kidney disease,⁷ and gastrointestinal disorders.⁸ Collectively, these studies indicate that RDW may serve as a red flag for clinicians, raising concern for increased disease severity and potential adverse outcomes. However, further research is needed to determine if and how RDW monitoring should be used to prompt interventions to improve patient outcomes.

In Reply: We thank Dr. Homler for his question and for highlighting another important disease state, obstructive sleep apnea, in which a high red cell distribution width (RDW) has correlated with disease severity.^1,2 The 2 retrospective studies he mentioned indicated that RDW is negatively correlated with metrics such as oxygen saturation, sleep time, and sleep quality. Interestingly, another retrospective study showed that RDW was significantly higher in patients with concurrent obstructive sleep apnea and cardiovascular disease than in patients with obstructive sleep apnea alone, suggesting that the presence of anisocytosis in obstructive sleep apnea may be due to its link to cardiovascular disease.³

Although we focused on cardiovascular disease in our review, RDW has also shown prognostic significance in many other disorders including ischemic stroke,⁴ pneumonia,^5,6 chronic kidney disease,⁷ and gastrointestinal disorders.⁸ Collectively, these studies indicate that RDW may serve as a red flag for clinicians, raising concern for increased disease severity and potential adverse outcomes. However, further research is needed to determine if and how RDW monitoring should be used to prompt interventions to improve patient outcomes.

In Reply: We thank Dr. Homler for his question and for highlighting another important disease state, obstructive sleep apnea, in which a high red cell distribution width (RDW) has correlated with disease severity.^1,2 The 2 retrospective studies he mentioned indicated that RDW is negatively correlated with metrics such as oxygen saturation, sleep time, and sleep quality. Interestingly, another retrospective study showed that RDW was significantly higher in patients with concurrent obstructive sleep apnea and cardiovascular disease than in patients with obstructive sleep apnea alone, suggesting that the presence of anisocytosis in obstructive sleep apnea may be due to its link to cardiovascular disease.³

Although we focused on cardiovascular disease in our review, RDW has also shown prognostic significance in many other disorders including ischemic stroke,⁴ pneumonia,^5,6 chronic kidney disease,⁷ and gastrointestinal disorders.⁸ Collectively, these studies indicate that RDW may serve as a red flag for clinicians, raising concern for increased disease severity and potential adverse outcomes. However, further research is needed to determine if and how RDW monitoring should be used to prompt interventions to improve patient outcomes.

We appreciate the comments and interest of Al-Sharefi and colleagues who highlight the use of glucose-only infusion in the management of hyperkalemia.¹ The incidence of hypoglycemia following hyperkalemia treatment with insulin/dextrose is high and measures to reduce this should be pursued.² However, evidence of the efficacy of glucose-only infusions on lowering potassium in heterogeneous inpatient populations is lacking. The small study by Chothia et al demonstrated potassium lowering efficacy in ten clinically stable patients without diabetes receiving chronic hemodialysis.³ In contrast, multiple observational studies consistently show a clinically significant effect of insulin/dextrose on potassium lowering across different populations.⁴

Importantly, inpatient hyperglycemia is associated with increased morbidity and mortality and occurs in those with preexisting diabetes and also those without, due to stress hyperglycemia from acute illness, medication or nutrition support.⁵ Determining intact insulin sensitivity during acute illness is not straightforward and deciding on the appropriateness of glucose-only hyperkalemia treatment compared with insulin/dextrose would be challenging. With the rising prevalence of diabetes in the inpatient setting (>30% in our study), the number of eligible individuals for glucose-only treatment would be small and does not justify the use of two separate hyperkalemia treatment protocols.

Given the potential life-threatening consequences of hyperkalemia, rapid potassium lowering is a priority. For glucose-only infusions to be applied, there needs to be more convincing evidence across more representative inpatient populations to ensure efficacy.

Disclosures

The authors have nothing to disclose.

We appreciate the comments and interest of Al-Sharefi and colleagues who highlight the use of glucose-only infusion in the management of hyperkalemia.¹ The incidence of hypoglycemia following hyperkalemia treatment with insulin/dextrose is high and measures to reduce this should be pursued.² However, evidence of the efficacy of glucose-only infusions on lowering potassium in heterogeneous inpatient populations is lacking. The small study by Chothia et al demonstrated potassium lowering efficacy in ten clinically stable patients without diabetes receiving chronic hemodialysis.³ In contrast, multiple observational studies consistently show a clinically significant effect of insulin/dextrose on potassium lowering across different populations.⁴

Importantly, inpatient hyperglycemia is associated with increased morbidity and mortality and occurs in those with preexisting diabetes and also those without, due to stress hyperglycemia from acute illness, medication or nutrition support.⁵ Determining intact insulin sensitivity during acute illness is not straightforward and deciding on the appropriateness of glucose-only hyperkalemia treatment compared with insulin/dextrose would be challenging. With the rising prevalence of diabetes in the inpatient setting (>30% in our study), the number of eligible individuals for glucose-only treatment would be small and does not justify the use of two separate hyperkalemia treatment protocols.

Given the potential life-threatening consequences of hyperkalemia, rapid potassium lowering is a priority. For glucose-only infusions to be applied, there needs to be more convincing evidence across more representative inpatient populations to ensure efficacy.

Disclosures

The authors have nothing to disclose.

We appreciate the comments and interest of Al-Sharefi and colleagues who highlight the use of glucose-only infusion in the management of hyperkalemia.¹ The incidence of hypoglycemia following hyperkalemia treatment with insulin/dextrose is high and measures to reduce this should be pursued.² However, evidence of the efficacy of glucose-only infusions on lowering potassium in heterogeneous inpatient populations is lacking. The small study by Chothia et al demonstrated potassium lowering efficacy in ten clinically stable patients without diabetes receiving chronic hemodialysis.³ In contrast, multiple observational studies consistently show a clinically significant effect of insulin/dextrose on potassium lowering across different populations.⁴

Importantly, inpatient hyperglycemia is associated with increased morbidity and mortality and occurs in those with preexisting diabetes and also those without, due to stress hyperglycemia from acute illness, medication or nutrition support.⁵ Determining intact insulin sensitivity during acute illness is not straightforward and deciding on the appropriateness of glucose-only hyperkalemia treatment compared with insulin/dextrose would be challenging. With the rising prevalence of diabetes in the inpatient setting (>30% in our study), the number of eligible individuals for glucose-only treatment would be small and does not justify the use of two separate hyperkalemia treatment protocols.

Given the potential life-threatening consequences of hyperkalemia, rapid potassium lowering is a priority. For glucose-only infusions to be applied, there needs to be more convincing evidence across more representative inpatient populations to ensure efficacy.

Disclosures

The authors have nothing to disclose.

Boughton et al.¹ reported a high incidence of hypoglycemia resulting from glucose-with-insulin (GwI) infusion used to treat acute hyperkalemia. This has been reported by other investigators—particularly in subjects without preexisting diabetes² and resonates with the experiences of clinicians practicing in Internal Medicine or Diabetes.

The authors suggested that patients at risk of hypoglycemia be identified and offered a regimen containing less insulin. However, for subjects without preexisting diagnosis and not at high risk of diabetes, we question the physiological logic and the safety basis for administering insulin.

Infusion of glucose only (GO) to subjects with intact pancreatic function and insulin sensitivity stimulates endogenous insulin secretion in a dose-dependent manner, resulting in a reduction in extracellular fluid potassium with no risk of hypoglycemia.^3,4

It is unclear why GwI historically entered mainstream practice rather than GO, but the rationale may have been based on the potential risks of paradoxical hyperglycemia-mediated hyperkalemia (HMK) being induced by GO. In practice, HMK was only observed in subjects with diabetes.⁵

As there is an ongoing need to reduce the impact of iatrogenic hypoglycemia, revisiting of the prematurely abandoned GO regimen in hyperkalemia management is warranted. Such approach may offer a safe and physiological alternative to GwI in nondiabetic patients with hyperkalemia.

We advocate that GO be prospectively evaluated against GwI for the treatment of hyperkalemia in subjects without diabetes, against the endpoints being noninferiority in respect of efficacy and maintenance of euglycemia in respect of safety.

Disclosures

Nothing to declare.

Boughton et al.¹ reported a high incidence of hypoglycemia resulting from glucose-with-insulin (GwI) infusion used to treat acute hyperkalemia. This has been reported by other investigators—particularly in subjects without preexisting diabetes² and resonates with the experiences of clinicians practicing in Internal Medicine or Diabetes.

The authors suggested that patients at risk of hypoglycemia be identified and offered a regimen containing less insulin. However, for subjects without preexisting diagnosis and not at high risk of diabetes, we question the physiological logic and the safety basis for administering insulin.

Infusion of glucose only (GO) to subjects with intact pancreatic function and insulin sensitivity stimulates endogenous insulin secretion in a dose-dependent manner, resulting in a reduction in extracellular fluid potassium with no risk of hypoglycemia.^3,4

It is unclear why GwI historically entered mainstream practice rather than GO, but the rationale may have been based on the potential risks of paradoxical hyperglycemia-mediated hyperkalemia (HMK) being induced by GO. In practice, HMK was only observed in subjects with diabetes.⁵

As there is an ongoing need to reduce the impact of iatrogenic hypoglycemia, revisiting of the prematurely abandoned GO regimen in hyperkalemia management is warranted. Such approach may offer a safe and physiological alternative to GwI in nondiabetic patients with hyperkalemia.

We advocate that GO be prospectively evaluated against GwI for the treatment of hyperkalemia in subjects without diabetes, against the endpoints being noninferiority in respect of efficacy and maintenance of euglycemia in respect of safety.

Disclosures

Nothing to declare.

Boughton et al.¹ reported a high incidence of hypoglycemia resulting from glucose-with-insulin (GwI) infusion used to treat acute hyperkalemia. This has been reported by other investigators—particularly in subjects without preexisting diabetes² and resonates with the experiences of clinicians practicing in Internal Medicine or Diabetes.

The authors suggested that patients at risk of hypoglycemia be identified and offered a regimen containing less insulin. However, for subjects without preexisting diagnosis and not at high risk of diabetes, we question the physiological logic and the safety basis for administering insulin.

Infusion of glucose only (GO) to subjects with intact pancreatic function and insulin sensitivity stimulates endogenous insulin secretion in a dose-dependent manner, resulting in a reduction in extracellular fluid potassium with no risk of hypoglycemia.^3,4

It is unclear why GwI historically entered mainstream practice rather than GO, but the rationale may have been based on the potential risks of paradoxical hyperglycemia-mediated hyperkalemia (HMK) being induced by GO. In practice, HMK was only observed in subjects with diabetes.⁵

As there is an ongoing need to reduce the impact of iatrogenic hypoglycemia, revisiting of the prematurely abandoned GO regimen in hyperkalemia management is warranted. Such approach may offer a safe and physiological alternative to GwI in nondiabetic patients with hyperkalemia.

We advocate that GO be prospectively evaluated against GwI for the treatment of hyperkalemia in subjects without diabetes, against the endpoints being noninferiority in respect of efficacy and maintenance of euglycemia in respect of safety.

Disclosures

Nothing to declare.

To the Editor: I am an active primary care provider. After reading the update on human papillomavirus (HPV) in the March 2019 issue by Zhang and Batur,¹ I was hoping for some clarification on a few points.

The statement is made that up to 70% of HPV-related cervical cancer cases can be prevented with vaccination. I have pulled the reference² but cannot find supporting data for this claim. Is this proven or optimistic thinking based on the decreased incidence of abnormal Papanicolaou (Pap) test results such as noted in the University of New Mexico HPV Pap registry database³? The authors do cite an additional reference⁴ documenting a decreased incidence of cervical cancer in the United States among 15- to 24-year-olds from 2003–2006 compared with 2011–2014. This study reported a 29% relative risk reduction in the group receiving the vaccine, with the absolute numbers 6 vs 8.4 cases per 1,000,000. Thus, can the authors provide further references to the statement that 70% of cervical cancers can be prevented by vaccination?

The authors also state that vaccine acceptance rates are highest when primary care providers announce that the vaccine is due rather than invite open-ended discussions. At first this shocked me, but then made me pause and wonder how often I do that—and when I do, why. I regularly do it with all the other vaccines recommended by the Advisory Committee on Immunization Practices. When the parent or patient asks for further information, I am armed to provide it. To date, I am struggling to provide data to educate the patient on the efficacy of the HPV vaccine, particularly the claim that it will prevent 70% of cervical cancers. Are there more data that I am missing?

Finally, let me state that I am a “vaccinator”—always have been, and always will be. I discuss the HPV vaccine with my patients and their parents and try to provide data to support my recommendation. However, I am concerned that this current practice regarding the HPV vaccine has been driven by scare tactics and has now turned to “just give it because I say so.” The University of New Mexico Center for HPV prevention reports up to a 50% reduction in cervical intraepithelial neoplasias (precancer lesions) in teens.³ This is exciting information and raises hope for the future successful battle against cervical cancer. I think it is also more accurate than stating to parents and patients that we have proof that we have prevented 70% of cervical cancers. When we explain it in this manner, the majority of parents and patients buy in and, I believe, enjoy and welcome this open-ended discussion.

To the Editor: I am an active primary care provider. After reading the update on human papillomavirus (HPV) in the March 2019 issue by Zhang and Batur,¹ I was hoping for some clarification on a few points.

The statement is made that up to 70% of HPV-related cervical cancer cases can be prevented with vaccination. I have pulled the reference² but cannot find supporting data for this claim. Is this proven or optimistic thinking based on the decreased incidence of abnormal Papanicolaou (Pap) test results such as noted in the University of New Mexico HPV Pap registry database³? The authors do cite an additional reference⁴ documenting a decreased incidence of cervical cancer in the United States among 15- to 24-year-olds from 2003–2006 compared with 2011–2014. This study reported a 29% relative risk reduction in the group receiving the vaccine, with the absolute numbers 6 vs 8.4 cases per 1,000,000. Thus, can the authors provide further references to the statement that 70% of cervical cancers can be prevented by vaccination?

The authors also state that vaccine acceptance rates are highest when primary care providers announce that the vaccine is due rather than invite open-ended discussions. At first this shocked me, but then made me pause and wonder how often I do that—and when I do, why. I regularly do it with all the other vaccines recommended by the Advisory Committee on Immunization Practices. When the parent or patient asks for further information, I am armed to provide it. To date, I am struggling to provide data to educate the patient on the efficacy of the HPV vaccine, particularly the claim that it will prevent 70% of cervical cancers. Are there more data that I am missing?

Finally, let me state that I am a “vaccinator”—always have been, and always will be. I discuss the HPV vaccine with my patients and their parents and try to provide data to support my recommendation. However, I am concerned that this current practice regarding the HPV vaccine has been driven by scare tactics and has now turned to “just give it because I say so.” The University of New Mexico Center for HPV prevention reports up to a 50% reduction in cervical intraepithelial neoplasias (precancer lesions) in teens.³ This is exciting information and raises hope for the future successful battle against cervical cancer. I think it is also more accurate than stating to parents and patients that we have proof that we have prevented 70% of cervical cancers. When we explain it in this manner, the majority of parents and patients buy in and, I believe, enjoy and welcome this open-ended discussion.

To the Editor: I am an active primary care provider. After reading the update on human papillomavirus (HPV) in the March 2019 issue by Zhang and Batur,¹ I was hoping for some clarification on a few points.

The statement is made that up to 70% of HPV-related cervical cancer cases can be prevented with vaccination. I have pulled the reference² but cannot find supporting data for this claim. Is this proven or optimistic thinking based on the decreased incidence of abnormal Papanicolaou (Pap) test results such as noted in the University of New Mexico HPV Pap registry database³? The authors do cite an additional reference⁴ documenting a decreased incidence of cervical cancer in the United States among 15- to 24-year-olds from 2003–2006 compared with 2011–2014. This study reported a 29% relative risk reduction in the group receiving the vaccine, with the absolute numbers 6 vs 8.4 cases per 1,000,000. Thus, can the authors provide further references to the statement that 70% of cervical cancers can be prevented by vaccination?

The authors also state that vaccine acceptance rates are highest when primary care providers announce that the vaccine is due rather than invite open-ended discussions. At first this shocked me, but then made me pause and wonder how often I do that—and when I do, why. I regularly do it with all the other vaccines recommended by the Advisory Committee on Immunization Practices. When the parent or patient asks for further information, I am armed to provide it. To date, I am struggling to provide data to educate the patient on the efficacy of the HPV vaccine, particularly the claim that it will prevent 70% of cervical cancers. Are there more data that I am missing?

Finally, let me state that I am a “vaccinator”—always have been, and always will be. I discuss the HPV vaccine with my patients and their parents and try to provide data to support my recommendation. However, I am concerned that this current practice regarding the HPV vaccine has been driven by scare tactics and has now turned to “just give it because I say so.” The University of New Mexico Center for HPV prevention reports up to a 50% reduction in cervical intraepithelial neoplasias (precancer lesions) in teens.³ This is exciting information and raises hope for the future successful battle against cervical cancer. I think it is also more accurate than stating to parents and patients that we have proof that we have prevented 70% of cervical cancers. When we explain it in this manner, the majority of parents and patients buy in and, I believe, enjoy and welcome this open-ended discussion.

In Reply: We would like to thank Dr. Lichtenberg for giving us the opportunity to clarify and expand on questions regarding HPV vaccine efficacy.

Our statement “HPV immunization can prevent up to 70% of cases of cervical cancer due to HPV as well as 90% of genital warts” was based on a statement by Thaxton and Waxman, ie, that immunization against HPV types 16 and 18 has the potential to prevent 70% of cancers of the cervix plus a large percentage of other lower anogenital tract cancers.¹ This was meant to describe the prevention potential of the quadrivalent vaccine. The currently available Gardasil 9 targets the HPV types that account for 90% of cervical cancers,² with projected effectiveness likely to vary based on geographic variation in HPV subtypes, ranging from 86.5% in Australia to 92% in North America.³ It is difficult to precisely calculate the effectiveness of HPV vaccination alone, given that cervical cancer prevention is twofold, with primary vaccination and secondary screening (with several notable updates to US national screening guidelines during the same time frame as vaccine development).⁴

It is true that the 29% decrease in US cervical cancer incidence rates during the years 2011–2014 compared with 2003–2006 is less than the predicted 70%.⁵ However, not all eligible US females are vaccinated; according to reports from the US Centers for Disease Control and Prevention, 49% of adolescents were appropriately immunized against HPV in 2017, an increase over the rate of only 35% in 2014.⁶ Low vaccination rates undoubtedly negatively impact any benefits from herd immunity, though the exact benefits of this population immunity are difficult to quantify.⁷

In Australia, a national school-based HPV vaccination program was initiated in 2007, making the vaccine available for free. Over 70% of girls ages 12 and 13 were vaccinated, and follow-up within the same decade showed a greater than 90% reduction in genital warts, as well as a reduction in high-grade cervical lesions.⁸ In addition, the incidence of genital warts in unvaccinated heterosexual males during the prevaccination vs the vaccination period decreased by up to 81% (a marker of herd immunity).⁹

In the US, the HPV subtypes found in the quadrivalent vaccine decreased by 71% in those ages 14 to 19, within 8 years of vaccine introduction.¹⁰ An analysis of US state cancer registries between 2009 and 2012 showed that in Michigan, the rates of high-grade, precancerous lesions declined by 37% each year for women ages 15 to 19, thought to be due to changes in screening and vaccination guidelines.¹¹ Similarly, an analysis of 9 million privately insured US females showed that the presence of high-grade precancerous lesions significantly decreased between the years 2007 and 2014 in those ages 15 to 24 (vaccinated individuals), but not in those ages 25 to 39 (unvaccinated individuals).¹² Most recently, a study of 10,206 women showed a 21.9% decrease in cervical intraepithelial neoplasia grade 2 or worse lesions due to HPV subtypes 16 or 18 in those who have received at least 1 dose of the vaccine; reduced rates in unvaccinated women were also seen, representing first evidence of herd immunity in the United States.¹³ In contrast, the rates of high-grade lesions due to nonvaccine HPV subtypes remained constant. Given that progression to cervical cancer can take 10 to 15 years or longer after HPV infection, true vaccine benefits will emerge once increased vaccination rates are achieved and after at least a decade of follow-up.

We applaud Dr. Lichtenberg’s efforts to clarify vaccine efficacy for appropriate counseling, as this is key to ensuring patient trust. Immunization fears have fueled the re-emergence of vaccine-preventable illnesses across the world. Given the wave of vaccine misinformation on the Internet, we all face patients and family members skeptical of vaccine efficacy and safety. Those requesting more information deserve an honest, informed discussion with their provider. Interestingly, however, among 955 unvaccinated women, the belief of not being at risk for HPV was the most common reason for not receiving the vaccine.¹⁴ Effective education can be achieved by focusing on the personal risks of HPV to the patient, as well as the overall favorable risk vs benefits of vaccination. Quoting an exact rate of cancer reduction is likely a less effective counseling strategy, and these efficacy estimates will change as vaccination rates and HPV prevalence within the population change over time.

In Reply: We would like to thank Dr. Lichtenberg for giving us the opportunity to clarify and expand on questions regarding HPV vaccine efficacy.

Our statement “HPV immunization can prevent up to 70% of cases of cervical cancer due to HPV as well as 90% of genital warts” was based on a statement by Thaxton and Waxman, ie, that immunization against HPV types 16 and 18 has the potential to prevent 70% of cancers of the cervix plus a large percentage of other lower anogenital tract cancers.¹ This was meant to describe the prevention potential of the quadrivalent vaccine. The currently available Gardasil 9 targets the HPV types that account for 90% of cervical cancers,² with projected effectiveness likely to vary based on geographic variation in HPV subtypes, ranging from 86.5% in Australia to 92% in North America.³ It is difficult to precisely calculate the effectiveness of HPV vaccination alone, given that cervical cancer prevention is twofold, with primary vaccination and secondary screening (with several notable updates to US national screening guidelines during the same time frame as vaccine development).⁴

It is true that the 29% decrease in US cervical cancer incidence rates during the years 2011–2014 compared with 2003–2006 is less than the predicted 70%.⁵ However, not all eligible US females are vaccinated; according to reports from the US Centers for Disease Control and Prevention, 49% of adolescents were appropriately immunized against HPV in 2017, an increase over the rate of only 35% in 2014.⁶ Low vaccination rates undoubtedly negatively impact any benefits from herd immunity, though the exact benefits of this population immunity are difficult to quantify.⁷

In Australia, a national school-based HPV vaccination program was initiated in 2007, making the vaccine available for free. Over 70% of girls ages 12 and 13 were vaccinated, and follow-up within the same decade showed a greater than 90% reduction in genital warts, as well as a reduction in high-grade cervical lesions.⁸ In addition, the incidence of genital warts in unvaccinated heterosexual males during the prevaccination vs the vaccination period decreased by up to 81% (a marker of herd immunity).⁹

In the US, the HPV subtypes found in the quadrivalent vaccine decreased by 71% in those ages 14 to 19, within 8 years of vaccine introduction.¹⁰ An analysis of US state cancer registries between 2009 and 2012 showed that in Michigan, the rates of high-grade, precancerous lesions declined by 37% each year for women ages 15 to 19, thought to be due to changes in screening and vaccination guidelines.¹¹ Similarly, an analysis of 9 million privately insured US females showed that the presence of high-grade precancerous lesions significantly decreased between the years 2007 and 2014 in those ages 15 to 24 (vaccinated individuals), but not in those ages 25 to 39 (unvaccinated individuals).¹² Most recently, a study of 10,206 women showed a 21.9% decrease in cervical intraepithelial neoplasia grade 2 or worse lesions due to HPV subtypes 16 or 18 in those who have received at least 1 dose of the vaccine; reduced rates in unvaccinated women were also seen, representing first evidence of herd immunity in the United States.¹³ In contrast, the rates of high-grade lesions due to nonvaccine HPV subtypes remained constant. Given that progression to cervical cancer can take 10 to 15 years or longer after HPV infection, true vaccine benefits will emerge once increased vaccination rates are achieved and after at least a decade of follow-up.

We applaud Dr. Lichtenberg’s efforts to clarify vaccine efficacy for appropriate counseling, as this is key to ensuring patient trust. Immunization fears have fueled the re-emergence of vaccine-preventable illnesses across the world. Given the wave of vaccine misinformation on the Internet, we all face patients and family members skeptical of vaccine efficacy and safety. Those requesting more information deserve an honest, informed discussion with their provider. Interestingly, however, among 955 unvaccinated women, the belief of not being at risk for HPV was the most common reason for not receiving the vaccine.¹⁴ Effective education can be achieved by focusing on the personal risks of HPV to the patient, as well as the overall favorable risk vs benefits of vaccination. Quoting an exact rate of cancer reduction is likely a less effective counseling strategy, and these efficacy estimates will change as vaccination rates and HPV prevalence within the population change over time.

In Reply: We would like to thank Dr. Lichtenberg for giving us the opportunity to clarify and expand on questions regarding HPV vaccine efficacy.

Our statement “HPV immunization can prevent up to 70% of cases of cervical cancer due to HPV as well as 90% of genital warts” was based on a statement by Thaxton and Waxman, ie, that immunization against HPV types 16 and 18 has the potential to prevent 70% of cancers of the cervix plus a large percentage of other lower anogenital tract cancers.¹ This was meant to describe the prevention potential of the quadrivalent vaccine. The currently available Gardasil 9 targets the HPV types that account for 90% of cervical cancers,² with projected effectiveness likely to vary based on geographic variation in HPV subtypes, ranging from 86.5% in Australia to 92% in North America.³ It is difficult to precisely calculate the effectiveness of HPV vaccination alone, given that cervical cancer prevention is twofold, with primary vaccination and secondary screening (with several notable updates to US national screening guidelines during the same time frame as vaccine development).⁴

It is true that the 29% decrease in US cervical cancer incidence rates during the years 2011–2014 compared with 2003–2006 is less than the predicted 70%.⁵ However, not all eligible US females are vaccinated; according to reports from the US Centers for Disease Control and Prevention, 49% of adolescents were appropriately immunized against HPV in 2017, an increase over the rate of only 35% in 2014.⁶ Low vaccination rates undoubtedly negatively impact any benefits from herd immunity, though the exact benefits of this population immunity are difficult to quantify.⁷

In Australia, a national school-based HPV vaccination program was initiated in 2007, making the vaccine available for free. Over 70% of girls ages 12 and 13 were vaccinated, and follow-up within the same decade showed a greater than 90% reduction in genital warts, as well as a reduction in high-grade cervical lesions.⁸ In addition, the incidence of genital warts in unvaccinated heterosexual males during the prevaccination vs the vaccination period decreased by up to 81% (a marker of herd immunity).⁹

In the US, the HPV subtypes found in the quadrivalent vaccine decreased by 71% in those ages 14 to 19, within 8 years of vaccine introduction.¹⁰ An analysis of US state cancer registries between 2009 and 2012 showed that in Michigan, the rates of high-grade, precancerous lesions declined by 37% each year for women ages 15 to 19, thought to be due to changes in screening and vaccination guidelines.¹¹ Similarly, an analysis of 9 million privately insured US females showed that the presence of high-grade precancerous lesions significantly decreased between the years 2007 and 2014 in those ages 15 to 24 (vaccinated individuals), but not in those ages 25 to 39 (unvaccinated individuals).¹² Most recently, a study of 10,206 women showed a 21.9% decrease in cervical intraepithelial neoplasia grade 2 or worse lesions due to HPV subtypes 16 or 18 in those who have received at least 1 dose of the vaccine; reduced rates in unvaccinated women were also seen, representing first evidence of herd immunity in the United States.¹³ In contrast, the rates of high-grade lesions due to nonvaccine HPV subtypes remained constant. Given that progression to cervical cancer can take 10 to 15 years or longer after HPV infection, true vaccine benefits will emerge once increased vaccination rates are achieved and after at least a decade of follow-up.

We applaud Dr. Lichtenberg’s efforts to clarify vaccine efficacy for appropriate counseling, as this is key to ensuring patient trust. Immunization fears have fueled the re-emergence of vaccine-preventable illnesses across the world. Given the wave of vaccine misinformation on the Internet, we all face patients and family members skeptical of vaccine efficacy and safety. Those requesting more information deserve an honest, informed discussion with their provider. Interestingly, however, among 955 unvaccinated women, the belief of not being at risk for HPV was the most common reason for not receiving the vaccine.¹⁴ Effective education can be achieved by focusing on the personal risks of HPV to the patient, as well as the overall favorable risk vs benefits of vaccination. Quoting an exact rate of cancer reduction is likely a less effective counseling strategy, and these efficacy estimates will change as vaccination rates and HPV prevalence within the population change over time.

To the Editor: I read with great interest the article “Aleukemic leukemia cutis” by Abraham et al,¹ as we recently had a case of this at my institution. The case is unique and quite intriguing; however, I found the pathologic description confusing and imprecise.

The authors state, “The findings were consistent with leukemic T cells with monocytic differentiation.”¹ This is based on their findings that the tumor cells expressed CD4, CD43, CD68, and lysozyme. However, the cells were negative for CD30, ALK-1, CD2, and CD3.

First, I must contest the authors’ claim that “the cells co-expressed T-cell markers (CD4 and CD43)”: CD4 and CD43 are not specific for T cells and are almost invariably seen on monocytes, especially in acute monoblastic/monocytic leukemia (AMoL; also known as M5 in the French-American-British classification system).^2,3 Therefore, the immunophenotype is perfect for an AMoL, but since there was no significant blood or bone marrow involvement and it was limited to the skin, this would best fit with a myeloid sarcoma, which frequently has a monocytic immunoprofile.^3,4

Additionally, this would not be a mixed-phenotype acute leukemia, T/myeloid, not otherwise specified, as that requires positivity for cytoplasmic CD3 or surface CD3, and that was conspicuously absent.⁵ Therefore, the appropriate workup and treatment should have essentially followed the course for acute myeloid leukemia,⁴ which is unclear from the present report as there is no mention of a molecular workup (eg, for FLT3 and NPM1 mutations). This would, in turn, have important treatment and prognostic implications.⁶

The reason for my comments is to bring to light the importance of exact pathologic diagnosis, especially when dealing with leukemia. We currently have a host of treatment options and prognostic tools for the various types of acute myeloid leukemia, but only when a clear and precise pathologic diagnosis is given.⁵

To the Editor: I read with great interest the article “Aleukemic leukemia cutis” by Abraham et al,¹ as we recently had a case of this at my institution. The case is unique and quite intriguing; however, I found the pathologic description confusing and imprecise.

The authors state, “The findings were consistent with leukemic T cells with monocytic differentiation.”¹ This is based on their findings that the tumor cells expressed CD4, CD43, CD68, and lysozyme. However, the cells were negative for CD30, ALK-1, CD2, and CD3.

First, I must contest the authors’ claim that “the cells co-expressed T-cell markers (CD4 and CD43)”: CD4 and CD43 are not specific for T cells and are almost invariably seen on monocytes, especially in acute monoblastic/monocytic leukemia (AMoL; also known as M5 in the French-American-British classification system).^2,3 Therefore, the immunophenotype is perfect for an AMoL, but since there was no significant blood or bone marrow involvement and it was limited to the skin, this would best fit with a myeloid sarcoma, which frequently has a monocytic immunoprofile.^3,4

Additionally, this would not be a mixed-phenotype acute leukemia, T/myeloid, not otherwise specified, as that requires positivity for cytoplasmic CD3 or surface CD3, and that was conspicuously absent.⁵ Therefore, the appropriate workup and treatment should have essentially followed the course for acute myeloid leukemia,⁴ which is unclear from the present report as there is no mention of a molecular workup (eg, for FLT3 and NPM1 mutations). This would, in turn, have important treatment and prognostic implications.⁶

The reason for my comments is to bring to light the importance of exact pathologic diagnosis, especially when dealing with leukemia. We currently have a host of treatment options and prognostic tools for the various types of acute myeloid leukemia, but only when a clear and precise pathologic diagnosis is given.⁵

To the Editor: I read with great interest the article “Aleukemic leukemia cutis” by Abraham et al,¹ as we recently had a case of this at my institution. The case is unique and quite intriguing; however, I found the pathologic description confusing and imprecise.

The authors state, “The findings were consistent with leukemic T cells with monocytic differentiation.”¹ This is based on their findings that the tumor cells expressed CD4, CD43, CD68, and lysozyme. However, the cells were negative for CD30, ALK-1, CD2, and CD3.

First, I must contest the authors’ claim that “the cells co-expressed T-cell markers (CD4 and CD43)”: CD4 and CD43 are not specific for T cells and are almost invariably seen on monocytes, especially in acute monoblastic/monocytic leukemia (AMoL; also known as M5 in the French-American-British classification system).^2,3 Therefore, the immunophenotype is perfect for an AMoL, but since there was no significant blood or bone marrow involvement and it was limited to the skin, this would best fit with a myeloid sarcoma, which frequently has a monocytic immunoprofile.^3,4

Additionally, this would not be a mixed-phenotype acute leukemia, T/myeloid, not otherwise specified, as that requires positivity for cytoplasmic CD3 or surface CD3, and that was conspicuously absent.⁵ Therefore, the appropriate workup and treatment should have essentially followed the course for acute myeloid leukemia,⁴ which is unclear from the present report as there is no mention of a molecular workup (eg, for FLT3 and NPM1 mutations). This would, in turn, have important treatment and prognostic implications.⁶

The reason for my comments is to bring to light the importance of exact pathologic diagnosis, especially when dealing with leukemia. We currently have a host of treatment options and prognostic tools for the various types of acute myeloid leukemia, but only when a clear and precise pathologic diagnosis is given.⁵

In Reply: We greatly appreciate our reader’s interest and response. He brings up a very good point. We have reviewed the reports and discussed it with our pathologists. On page 85, the sentence that begins, “The findings were consistent with leukemic T cells with monocytic differentiation” should actually read, “The findings were consistent with leukemic cells with monocytic differentiation.” The patient was appropriately treated for acute myeloid leukemia.

In Reply: We greatly appreciate our reader’s interest and response. He brings up a very good point. We have reviewed the reports and discussed it with our pathologists. On page 85, the sentence that begins, “The findings were consistent with leukemic T cells with monocytic differentiation” should actually read, “The findings were consistent with leukemic cells with monocytic differentiation.” The patient was appropriately treated for acute myeloid leukemia.

In Reply: We greatly appreciate our reader’s interest and response. He brings up a very good point. We have reviewed the reports and discussed it with our pathologists. On page 85, the sentence that begins, “The findings were consistent with leukemic T cells with monocytic differentiation” should actually read, “The findings were consistent with leukemic cells with monocytic differentiation.” The patient was appropriately treated for acute myeloid leukemia.

To the Editor: Regarding the article about a man with rapidly progressive pleural effusion by Zoumot et al in the January 2019 issue,¹ there was some inconsistency between the teaching points and the actions taken.

Question 1 asked what was the most likely cause of the patient’s pleuritic chest pain. Pulmonary embolism was an unlikely diagnosis, given the patient’s presentation and his normal D-dimer level, which the text acknowledges, but then proceeds to state that computed tomographic angiography of the chest was done anyway.

After pleural effusion was diagnosed, question 2 asked what was the best management strategy for the patient at that time. The best management strategy was to give oral antibiotics with close follow-up because the patient was at low risk of a poor outcome, but he was advised to be admitted for intravenous antibiotics anyway.

I’m not quite sure of the point of the didactic exercise when actions are not consistent with the analytic rationale for testing and treatment.

To the Editor: Regarding the article about a man with rapidly progressive pleural effusion by Zoumot et al in the January 2019 issue,¹ there was some inconsistency between the teaching points and the actions taken.

Question 1 asked what was the most likely cause of the patient’s pleuritic chest pain. Pulmonary embolism was an unlikely diagnosis, given the patient’s presentation and his normal D-dimer level, which the text acknowledges, but then proceeds to state that computed tomographic angiography of the chest was done anyway.

After pleural effusion was diagnosed, question 2 asked what was the best management strategy for the patient at that time. The best management strategy was to give oral antibiotics with close follow-up because the patient was at low risk of a poor outcome, but he was advised to be admitted for intravenous antibiotics anyway.

I’m not quite sure of the point of the didactic exercise when actions are not consistent with the analytic rationale for testing and treatment.

To the Editor: Regarding the article about a man with rapidly progressive pleural effusion by Zoumot et al in the January 2019 issue,¹ there was some inconsistency between the teaching points and the actions taken.

Question 1 asked what was the most likely cause of the patient’s pleuritic chest pain. Pulmonary embolism was an unlikely diagnosis, given the patient’s presentation and his normal D-dimer level, which the text acknowledges, but then proceeds to state that computed tomographic angiography of the chest was done anyway.

After pleural effusion was diagnosed, question 2 asked what was the best management strategy for the patient at that time. The best management strategy was to give oral antibiotics with close follow-up because the patient was at low risk of a poor outcome, but he was advised to be admitted for intravenous antibiotics anyway.

I’m not quite sure of the point of the didactic exercise when actions are not consistent with the analytic rationale for testing and treatment.