INTRODUCTION
Acne has approximately an 85-90% lifetime prevalence, however the duration of the condition is not well characterized.1,2 Understanding the duration of the disease and healthcare utilization for the disease can help set expectations for how long treatment is required. The information can be used for health management planning as well as educating patients, which helps improve adherence.3 This study examined the duration of healthcare resources use among patients with acne, using electronic medical records from a large academic hospital.
METHODS
After receiving IRB approval, the Wake Forest Baptist Hospital Transitional Data Warehouse was queried for dermatology visits linked with an ICD-9 diagnosis code of 706.1 between January 1, 2009 and November 15, 2012. The average duration of time spent visiting a dermatologist for an acne treatment was calculated by taking the difference in days between the earliest and latest visits over this period, and 95% confidence intervals were calculated. Kaplan Meier analyses were used to describe how long subjects remained in the treated cohort overall and by most intensive treatment prescribed: topical products, non-isotretinoin oral products, or isotretinoin. For the Kaplan Meier survival curve for all patients referring to a dermatologist for acne treatment, 95% confidence intervals and 95% equal precision bands were generated. Median times to treatment discontinuation were reported for each treatment group. Kaplan Meier survival curves by most intensive treatment prescribed were generated and compared using a Log-Rank test. Subjects were considered right-censored if their last visit was within the last three months of the study period. Data were analyzed using SAS 9.2 (SAS Institute Inc., Cary, NC).
RESULTS
A total of 3,664 patients had at least one dermatology visit resulting in an acne diagnosis. Of these patients, 1,860 had one visit and 1,804 had multiple visits. For patients with multiple visits, the mean duration between visits was 0.78 year (286 days) with a 95% confidence interval of 0.75-0.82 year (273-299 days). One hundred sixty-three (9%) of the multiple-visit patients were right-censored. Twenty-five percent ceased visiting a dermatologist in 0.27 year, 50% in 0.51 year, and 75% in 1.01 year (Figure 1).
An acne medication prescription was mentioned in 785 records. For single-visit patients, 90, 132, and 13 were correspondingly prescribed topical, non-isotretinoin oral, or isotretinoin medication. For multi-visit patients, 79, 243, and 228 patients were respectively prescribed topical treatments, oral medications excluding isotretinoin, and isotretinoin as the most intensive therapy. Median treatment durations were 0.73 year for the topical group, 1.03 year for the oral medication group, and 0.54 year for the isotretinoin group (Figure 2). Patients not pre-
