Using Administrative Claims Data to Estimate Virologic Failure Rates among Human Immunodeficiency Virus–Infected Patients with Antiretroviral Regimen Switches

Objective. To develop and validate a claims signature model that estimates proportions of HIV-infected patients in administrative claims databases who switched combination antiretroviral therapy (cART) regimens because of virologic failure. Methods. The authors used an HIV-specific registry (development data set) to develop logistic regression models to estimate odds of virologic failure among patients who switched cART regimens. Models were validated in a sample of administrative claims with laboratory values (validation data set). The final model was applied to an application data set as a worked example. Results. There were 1691, 1073, and 3954 eligible patients with cART switches in the development, validation, and application data sets, respectively. In the development data set, virologic failure before a switch was observed 21.8% of the time. Failure more likely caused the regimen switch among patients who were treatment experienced, had been receiving their baseline regimen for > 180 days, had ≥ 2 or more physician visits within 90 days, had > 1 HIV RNA or CD4 cell count test within 30 days, had any resistance test within 180 days, or had a change in regimen type. The final model had good discriminatory ability (C = 0.885) and fit (Hosmer-Lemeshow P = 0.8692). Failure was estimated to occur in 18.9% (v. 18.6% observed) of switches in the validation data set and 13.8% in the application data set. Conclusions. This claims signature model allows payers to use claims data to estimate virologic failure rates in their patient populations, thereby better understanding plan costs of failure.