To better understand melasma, it is important for researchers to find groups of patients with confirmed disease for future clinical study. A recent for researchers interested in conducting retrospective studies of this patient population.
“Overall, our results support the validity of using the ICD-10 code for melasma to identify patients with a diagnosis of melasma for future studies,” Nicholas Theodosakis, MD, PhD, of the department of dermatology at Massachusetts General Hospital, Boston, and colleagues wrote in their research letter. “Despite some variability in diagnostic confidence, most patients were ultimately classified as moderately or highly likely to have a true diagnosis of melasma.”
Dr. Theodosakis and colleagues evaluated data from 5,322 adult patients in the Mass General Brigham Research Patient Data Registry between October 2015 and January 2021 who had an encounter that used the ICD-10 code for melasma (L81.1). The researchers then validated the ICD-10 code by examining the medical records of 300 patients (5.6%), confirming that melasma was the clinician’s favored diagnosis and that the patient met secondary diagnostic criteria. Confidence was rated in categories of “low confidence,” “moderate confidence,” “high confidence,” and “maximum confidence” based on secondary criteria such as hyperpigmentation of the face and upper body, hormone-related therapy exposure before diagnosis, pregnancy history, and dermatologist-confirmed diagnosis.
The patients who had their medical records examined for confirmed melasma were primarily women (285 patients; 95.0%) and were a mean 48.4 years old at diagnosis.
Of those in the validation cohort, melasma was the preferred diagnosis for clinicians of 291 patients (97.0%), while 274 patients (91.3%) had secondary diagnostic criteria of hyperpigmentation of the face and upper body and 252 patients (84.0%) had received a diagnosis from a dermatologist. Other less common secondary diagnostic criteria of the patient group were a history of having received hormone-related therapy before a melasma diagnosis (148 patients; 49.3%) and a history of pregnancy (168 patients; 56.0%). Based on identification of secondary diagnostic criteria, confidence in melasma diagnosis was high for 208 patients (69.3%), moderate for 61 patients (20.3%), and low for 31 patients (10.3%).
Dr. Theodosakis and colleagues noted their study was limited by its retrospective nature and the presence of a small validation cohort. “Despite these limitations, our findings provide a framework for identifying cohorts to evaluate the clinical course and treatment of melasma,” the authors concluded.
One of the authors reported relationships with companies including AbbVie, Acom, Boehringer Ingelheim, Concert, Digital Diagnostics, and Eli Lilly in the form of personal fees, equity, royalties and/or licensing, or medical advisory board positions outside the submitted work; another author reported being an advisory board member and consultant for and receiving honoraria from Incyte, Castle Biosciences, Galderma, and Sanofi outside the submitted work. The other authors reported no relevant conflicts of interest.