Validating the diagnostic code for acne in a tertiary care dermatology centre

Abstract

Background: Administrative databases provide valuable patient data and are used to conduct population-based studies. However, no studies have been conducted to validate the codes for dermatological conditions.

Objective: To evaluate the validity of ICD 9 code 706 for acne.

Methods: This was a retrospective chart review of patients seen in dermatology clinics at Sunnybrook Health Sciences Centre between March 1 and May 31, 2013. The billing code for a clinic visit was compared to the diagnosis documented in the medical chart.

Results: There were 4,248 participants; 201 with an ICD-9 code of acne. This code had a PPV and sensitivity with 95% confidence intervals (CI) of 84.58% (78.67-89.13%) and 86.29% (80.51-90.62%), respectively. The specificity was 99.20% (98.86-99.45%).

Conclusions: We showed that ICD-9 code 706 can be used to accurately identify patients with acne in a dermatology setting. This information can be applied to future epidemiologic studies.

Keywords: acne; diagnostic code; validity.