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SAN DIEGO – A simple scoring system surpassed thermal imaging for diagnosing lower extremity cellulitis in a head-to-head, single-center comparison in 67 patients.
The ALT-70 score – which tallies points for asymmetry, leukocytosis, tachycardia, and age of at least 70 years – produced a positive predictive value for lower-extremity cellulitis (LEC) of 80.4% and a negative predictive value of 90.9%, compared with values of 75.5% and 57.1%, respectively, for thermal imaging when researchers applied both methods to 67 patients, said David G. Li, a clinical research fellow in the department of dermatology at Brigham and Women’s Hospital, Boston, where the study was conducted.
The senior author of Mr. Li’s report, Arash Mostaghimi, MD, director of the inpatient consultation service, department of dermatology at Brigham and Women’s, was also lead investigator for the team of dermatology researchers – from his center and from Massachusetts General Hospital in Boston – who recently devised the ALT-70 scoring system for diagnosing LEC (J Amer Acad Dermatol. 2017 April;76[4]:618-25.e2).
The four-item survey can generate a score of 0-7, with a score of 0-2 suggesting need for additional monitoring, a score of 3-4 initiating a dermatology consult, and a score of 5-7 triggering immediate treatment for cellulitis, Mr. Li said. The 2017 review of ALT-70 showed that among 259 patients, those with a score of 0-2 had an 83% likelihood of having pseudocellulitis, while patients with a score of 5-7 had an 82% likelihood of having true cellulitis.
The current study enrolled 67 patients who had a presumptive diagnosis of LEC while in the emergency department or inpatient wards during a 7-month period. In addition to undergoing blinded assessment by both thermal imaging and by ALT-70 scoring, all patients also underwent blinded assessment by a board-certified dermatologist, who provided the definitive diagnosis. The attending dermatologists determined that 46 of the patients had true LEC and 21 patients did not.
The calculated sensitivity of ALT-70 was 97.8%, compared with 87.0% for thermal imaging. Specificity was 47.6% for ALT-70 and 38.1% for thermal imaging, Mr. Li reported at the annual meeting of the American Academy of Dermatology.
He also presented an analysis of the results when he combined both methods, with a positive on both assessments required to produce a positive LEC diagnosis. This resulted in a positive predictive value of 86.7%, slightly higher than the 80.4% from ALT-70 alone, but the combination produced a negative predictive value of 68.2%, substantially less than the 90.9% rate with ALT-70 alone. This demonstrated the “marginal benefit” from combining the two methods, he said.
In a receiver operating characteristic curve analysis, in which the area under the curve (c-statistic) reflects a diagnostic test’s validity, ALT-70 produced a c-statistic of 0.85, thermal imaging had a c-statistic of 0.63, and when combined, the c-statistic was 0.88.
Mr. Li called for validation of the findings using larger and different patient populations.
He had no reported disclosures.
SOURCE: Li DG et al. AAD 18, Abstract 6744.
SAN DIEGO – A simple scoring system surpassed thermal imaging for diagnosing lower extremity cellulitis in a head-to-head, single-center comparison in 67 patients.
The ALT-70 score – which tallies points for asymmetry, leukocytosis, tachycardia, and age of at least 70 years – produced a positive predictive value for lower-extremity cellulitis (LEC) of 80.4% and a negative predictive value of 90.9%, compared with values of 75.5% and 57.1%, respectively, for thermal imaging when researchers applied both methods to 67 patients, said David G. Li, a clinical research fellow in the department of dermatology at Brigham and Women’s Hospital, Boston, where the study was conducted.
The senior author of Mr. Li’s report, Arash Mostaghimi, MD, director of the inpatient consultation service, department of dermatology at Brigham and Women’s, was also lead investigator for the team of dermatology researchers – from his center and from Massachusetts General Hospital in Boston – who recently devised the ALT-70 scoring system for diagnosing LEC (J Amer Acad Dermatol. 2017 April;76[4]:618-25.e2).
The four-item survey can generate a score of 0-7, with a score of 0-2 suggesting need for additional monitoring, a score of 3-4 initiating a dermatology consult, and a score of 5-7 triggering immediate treatment for cellulitis, Mr. Li said. The 2017 review of ALT-70 showed that among 259 patients, those with a score of 0-2 had an 83% likelihood of having pseudocellulitis, while patients with a score of 5-7 had an 82% likelihood of having true cellulitis.
The current study enrolled 67 patients who had a presumptive diagnosis of LEC while in the emergency department or inpatient wards during a 7-month period. In addition to undergoing blinded assessment by both thermal imaging and by ALT-70 scoring, all patients also underwent blinded assessment by a board-certified dermatologist, who provided the definitive diagnosis. The attending dermatologists determined that 46 of the patients had true LEC and 21 patients did not.
The calculated sensitivity of ALT-70 was 97.8%, compared with 87.0% for thermal imaging. Specificity was 47.6% for ALT-70 and 38.1% for thermal imaging, Mr. Li reported at the annual meeting of the American Academy of Dermatology.
He also presented an analysis of the results when he combined both methods, with a positive on both assessments required to produce a positive LEC diagnosis. This resulted in a positive predictive value of 86.7%, slightly higher than the 80.4% from ALT-70 alone, but the combination produced a negative predictive value of 68.2%, substantially less than the 90.9% rate with ALT-70 alone. This demonstrated the “marginal benefit” from combining the two methods, he said.
In a receiver operating characteristic curve analysis, in which the area under the curve (c-statistic) reflects a diagnostic test’s validity, ALT-70 produced a c-statistic of 0.85, thermal imaging had a c-statistic of 0.63, and when combined, the c-statistic was 0.88.
Mr. Li called for validation of the findings using larger and different patient populations.
He had no reported disclosures.
SOURCE: Li DG et al. AAD 18, Abstract 6744.
SAN DIEGO – A simple scoring system surpassed thermal imaging for diagnosing lower extremity cellulitis in a head-to-head, single-center comparison in 67 patients.
The ALT-70 score – which tallies points for asymmetry, leukocytosis, tachycardia, and age of at least 70 years – produced a positive predictive value for lower-extremity cellulitis (LEC) of 80.4% and a negative predictive value of 90.9%, compared with values of 75.5% and 57.1%, respectively, for thermal imaging when researchers applied both methods to 67 patients, said David G. Li, a clinical research fellow in the department of dermatology at Brigham and Women’s Hospital, Boston, where the study was conducted.
The senior author of Mr. Li’s report, Arash Mostaghimi, MD, director of the inpatient consultation service, department of dermatology at Brigham and Women’s, was also lead investigator for the team of dermatology researchers – from his center and from Massachusetts General Hospital in Boston – who recently devised the ALT-70 scoring system for diagnosing LEC (J Amer Acad Dermatol. 2017 April;76[4]:618-25.e2).
The four-item survey can generate a score of 0-7, with a score of 0-2 suggesting need for additional monitoring, a score of 3-4 initiating a dermatology consult, and a score of 5-7 triggering immediate treatment for cellulitis, Mr. Li said. The 2017 review of ALT-70 showed that among 259 patients, those with a score of 0-2 had an 83% likelihood of having pseudocellulitis, while patients with a score of 5-7 had an 82% likelihood of having true cellulitis.
The current study enrolled 67 patients who had a presumptive diagnosis of LEC while in the emergency department or inpatient wards during a 7-month period. In addition to undergoing blinded assessment by both thermal imaging and by ALT-70 scoring, all patients also underwent blinded assessment by a board-certified dermatologist, who provided the definitive diagnosis. The attending dermatologists determined that 46 of the patients had true LEC and 21 patients did not.
The calculated sensitivity of ALT-70 was 97.8%, compared with 87.0% for thermal imaging. Specificity was 47.6% for ALT-70 and 38.1% for thermal imaging, Mr. Li reported at the annual meeting of the American Academy of Dermatology.
He also presented an analysis of the results when he combined both methods, with a positive on both assessments required to produce a positive LEC diagnosis. This resulted in a positive predictive value of 86.7%, slightly higher than the 80.4% from ALT-70 alone, but the combination produced a negative predictive value of 68.2%, substantially less than the 90.9% rate with ALT-70 alone. This demonstrated the “marginal benefit” from combining the two methods, he said.
In a receiver operating characteristic curve analysis, in which the area under the curve (c-statistic) reflects a diagnostic test’s validity, ALT-70 produced a c-statistic of 0.85, thermal imaging had a c-statistic of 0.63, and when combined, the c-statistic was 0.88.
Mr. Li called for validation of the findings using larger and different patient populations.
He had no reported disclosures.
SOURCE: Li DG et al. AAD 18, Abstract 6744.
REPORTING FROM AAD 18
Key clinical point: The ALT-70 score surpassed thermal imaging for diagnosing lower-extremity cellulitis.
Major finding: Positive and negative predictive values were 80.4% and 90.9% for ALT-70 and 75.5% and 57.1% for thermal imaging.
Study details: A single-center study with 67 patients.
Disclosures: Mr. Li had no disclosures.
Source: Li DG et al. AAD 18, Abstract 6744.