TOPLINE:

The International Classification of Diseases (ICD) 10 code L80 demonstrated high accuracy for identifying vitiligo, with a positive predictive value (PPV) of 95% for single code use and 99% with at least one code combined with treatment data.

METHODOLOGY:

• To validate the diagnostic accuracy of the ICD-10 code for vitiligo, researchers identified 3454 records from the Mass General Brigham Research Patient Data Registry between January 2017 and January 2025, using four strategies: one or more L80 codes, at least two codes within 6 months, at least two codes within 12 months, and one or more codes plus at least one standard vitiligo treatment.
• They randomly reviewed records of 300 individuals; 285 had confirmed vitiligo (mean age, 48.2 years; 52.6% women). Investigators confirmed vitiligo cases using clinician documentation that listed vitiligo as the preferred diagnosis, and this confirmation served as the reference standard.
• Among confirmed cases, diagnostic confidence was graded as high when patients met three or more predefined secondary criteria, moderate when they met two criteria, and low when they met zero to one criterion. The predefined secondary criteria included typical lesion morphology, use of vitiligo-specific therapies, documented disease activity or progression, diagnosis by a dermatologist, and absence of melanocytes on biopsy.

TAKEAWAY:

• At least one single L80 code showed a PPV of 95% for confirmed vitiligo.
• Requiring at least two codes within 6 or 12 months of the initial diagnosis increased the PPV to 98%.
• Combining at least one code with treatment yielded a PPV of 99%.
• Among 285 confirmed cases, diagnostic confidence was high in 73.3%, moderate in 20.4%, and low in 6.3% of cases.

IN PRACTICE:

Compared with a previously reported ICD-9-based study, which found a PPV for vitiligo of 33.7% (and 85.5% when combined with treatment data), “our ICD-10-based algorithms demonstrated consistently higher PPVs,” the study authors wrote. “This likely reflects improved specificity of ICD-10 coding for vitiligo, which uses a dedicated diagnostic code (L80) rather than the broader dyschromia category used in ICD-9,” they added.

SOURCE:

The study was led by Debby Cheng, Department of Dermatology, Massachusetts General Hospital, Boston, and was published online on October 1 in JAMA Dermatology.

LIMITATIONS:

The study was limited by its single-region data collection and modest sample size.

DISCLOSURES:

The authors did not report any funding information. Several study authors reported receiving honoraria, personal fees, and consulting fees from Arcutis Biotherapeutics, Alterome Therapeutics, Boehringer Ingelheim, Galderma, Eli Lilly and Company, Pfizer, Regeneron, Sanofi, and several other companies. One author also reported being a member of the scientific advisory board for the American Vitiligo Research Foundation. Additional disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.