Incidence of toxic epidermal necrolysis and Stevens-Johnson Syndrome in an HIV cohort: an observational, retrospective case series study.

BACKGROUND The incidence of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) has been reported to be between 0.95 and 1 per 1000 individuals with AIDS. Accessibility to a cohort of individuals with HIV with known drug exposure (including drug, dose, and time of exposure) and collection of adverse-event information may provide an opportunity to determine an incidence rate of SJS and TEN. OBJECTIVE The primary objective of this analysis was to determine the incidence of confirmed SJS and TEN in a cohort of Canadian HIV patients who were receiving HIV and HIV-related medications. STUDY DESIGN This was a retrospective analysis of an HIV cohort. PATIENT POPULATION The Ontario HIV Treatment Network (OHTN) cohort population was eligible for this analysis. METHODS A search of the OHTN database was conducted to determine whether cases with a diagnosis of SJS or TEN were included. Search terms included 'TEN,' 'SJS,' 'epidermal necrolysis,' and 'erythema multiforme.' All SJS and TEN cases recorded in the OHTN database between January 1995 and August 2008 were obtained. Diagnostic criteria for SJS and TEN were established and two reviewers examined the medical records to confirm the SJS or TEN diagnosis. Drug exposure and utilization were documented. Incidence rates for the entire cohort were calculated. RESULTS Seventeen cases over seven OHTN study sites were identified from an approximate cohort sample size of 3700. There were 15 men (88%). The mean ± SD age was 51.6 ± 11.3 years and time since HIV diagnosis was 16.1 ± 4.4 years. Only one patient reported experiencing a previous SJS or TEN episode. Of the 17 cases, clinical experts diagnosed five cases as true SJS and/or TEN, two cases were labeled as indeterminant, and the remaining cases were considered not SJS or TEN. Among the confirmed cases, drugs taken included nevirapine, trimethoprim/sulfamethoxazole (cotrimoxazole), stavudine (d4T), and clarithromycin. CONCLUSIONS The incidence of SJS and/or TEN was 5-7 per 3710 or approximately 1-2 per 1000 individuals in this cohort with HIV. Careful diagnosis of this adverse event is required for an accurate measure of incidence and to avoid false inflation of the incidence.