Impact of Pill Burden on Adherence, Risk of Hospitalization, and Viral Suppression in Patients with HIV Infection and AIDS Receiving Antiretroviral Therapy.

STUDY OBJECTIVE

To evaluate the impact of pill burden on outcomes in patients with human immunodeficiency virus (HIV) infection and acquired immune deficiency syndrome (AIDS) receiving antiretroviral therapy (ART) as a single-tablet regimen (STR) or multiple-tablet regimen (MTR).

DESIGN

Retrospective cohort study.

DATA SOURCES

South Carolina Medicaid medical and pharmacy paid claims data were obtained from the South Carolina Revenue and Fiscal Affairs Office; laboratory data were obtained from the South Carolina Department of Health and Environmental Control.

PATIENTS

A total of 2174 patients covered by South Carolina Medicaid who were dispensed a complete ART STR (580 patients) or MTR (1594 patients) lasting at least 60 days between January 1, 2006, and December 31, 2013.

MEASUREMENTS AND MAIN RESULTS

Outcomes were ART adherence; risk of, time to, and total number of hospitalizations; and viral load suppression. Patients were followed from the index date (start date of their complete ART regimen) until the earliest date of one of the following: treatment discontinuation; treatment switch from MTR to STR, or vice versa; end of study period; last date of Medicaid eligibility; or death. Differences in outcomes were evaluated by using bivariate χ(2) and Wilcoxon rank sum tests, as well as multivariate regression models controlling for covariates measured during a 6-month baseline period. The STR and MTR cohorts were, on average, similar in terms of age at index date, Charlson Comorbidity Index score, sex, drug abuse, and mental health diagnoses, but they differed significantly in racial composition, index year of regimen, previous treatment, baseline viral load, and CD4 measures. The bivariate analysis revealed that the STR cohort was more adherent (p<0.0001), had a lower risk of hospitalization (p=0.0076), and had a higher proportion of patients with viral suppression (64.5% vs 49.5%, p<0.0001). In addition, multivariate regression models revealed that the STR cohort was more adherent and was associated with a lower risk of hospitalization (hazard ratio 0.71, 95% confidence interval 0.59-0.86), but no significant difference in viral load suppression was noted between the STR and MTR cohorts.

CONCLUSION

The STR was associated with higher adherence rates and a lower risk of hospitalization (both in the adjusted and unadjusted analyses) in South Carolina Medicaid patients with HIV infection and AIDS. A higher proportion of patients in the STR cohort had viral suppression during the follow-up period in the unadjusted analysis compared with the MTR cohort; however, no significant difference in viral suppression was observed when controlling for adherence.