Polypharmacy and Risk of Antiretroviral Drug Interactions Among the Aging HIV-Infected Population

BACKGROUND

Among aging HIV-infected adults, polypharmacy and its consequences have not been well-described.

OBJECTIVE

To characterize the extent of polypharmacy and the risk of antiretroviral (ARV) drug interactions among persons of different ages.

DESIGN AND PARTICIPANTS

Cross-sectional analysis among patients within the HIV Outpatient Study (HOPS) cohort who were prescribed ARVs during 2006–2010.

MAIN MEASURES

We used the University of Liverpool HIV drug interactions database to identify ARV/non-ARV interactions with potential for clinical significance.

KEY RESULTS

Of 3,810 patients analyzed (median age 46 years, 34 % ≥ 50 years old) at midpoint of observation, 1,494 (39 %) patients were prescribed ≥ 5 non-ARV medications: 706 (54 %) of 1,312 patients ≥ 50 years old compared with 788 (32 %) of 2,498 patients < 50 years. During the five-year period, the number of patients who were prescribed at least one ARV/non-ARV combination that was contraindicated or had moderate or high evidence of interaction was 267 (7 %) and 1,267 (33 %), respectively. Variables independently associated with having been prescribed a contraindicated ARV/non-ARV combination included older age (adjusted odds ratio [aOR] per 10 years of age 1.17, 95 % CI 1.01–1.35), anxiety (aOR 1.78, 95 % CI 1.32–2.40), dyslipidemia (aOR 1.96, 95 % CI 1.28–2.99), higher daily non-ARV medication burden (aOR 1.13, 95 % CI 1.10–1.17), and having been prescribed a protease inhibitor (aOR 2.10, 95 % CI 1.59–2.76). Compared with patients < 50 years, older patients were more likely to have been prescribed an ARV/non-ARV combination that was contraindicated (unadjusted OR 1.44, 95 % CI 1.14–1.82), or had moderate or high evidence of interaction (unadjusted OR 1.29, 95 % CI 1.15–1.44).

CONCLUSIONS

A substantial percentage of patients were prescribed at least one ARV/non-ARV combination that was contraindicated or had potential for a clinically significant interaction. As HIV-infected patients age and experience multiple comorbidities, systematic reviews of current medications by providers may reduce risk of such exposures.