Human immunodeficiency virus (HIV) treatment is complicated by antiretrovirals prone to clinically significant drug interactions (CSDIs). Objectives were to examine relationships of patient and medication characteristics and provider training level with CSDIs in an outpatient HIV clinic. A clinical pharmacist reviewed medication lists of randomly selected adult HIV-positive patients on antiretrovirals for accuracy and presence of a CSDI, defined as grade C, D, or X using Lexicomp software. Characteristics were compared between patients with and without CSDIs by χ2 tests for categorical variables and t tests for continuous variables. Associations between these parameters and CSDIs (presence vs absence) were evaluated by logistic regression. Associations between provider type (infectious disease physician [IDMD], infectious disease fellow [Fellow], and nurse practitioner [NP]) and number of CSDIs per patient, and provider response to being informed of a CSDI were analyzed by χ2 tests.
Of 107 records reviewed, 405 CSDIs were identified in 83 (76%) patient records. Clinically significant drug interaction presence was associated with older age, increased medications, protease inhibitor-based regimen, and medication list inaccuracies. Patients with and without CSDIs did not differ in sex, race, HIV viral load, or nonnucleoside reverse-transcriptase inhibitor regimen. Older age (odds ratio [95% confidence interval], 3.53 [1.21–11.64]) and a protease inhibitor-based regimen (odds ratio [95% confidence interval], 8.49 [2.18–46.07]) were associated with having a CSDI. Fellows were more likely to report being unaware of CSDIs than IDMDs and NPs and to request additional information versus IDMDs and NPs. These findings suggest that providers may benefit from involving a pharmacist to identify and educate about CSDIs.