Antiretroviral therapy adherence, medication use, and health care costs during 3 years of a community pharmacy medication therapy management program for Medi-Cal beneficiaries with HIV/AIDS.

BACKGROUND

The types of pharmacist-provided medication therapy management (MTM) services provided to patients with human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) and the effects of MTM on medication adherence and patient outcomes have only recently begun to be studied. Although available studies suggest that patients receiving MTM services have better antiretroviral therapy (ART) adherence and outcomes, only 1 study has examined a large group of patients with HIV/AIDS, and none has examined adherence or outcomes for more than 1 year. A pilot program conducted by the California Department of Health Care Services (DHCS) and Medi-Cal (California's Medicaid program) provided an opportunity to examine ART adherence and outcomes in a large patient population receiving MTM services in community pharmacies over 3 years.

OBJECTIVES

To examine an HIV/AIDS pharmacy MTM compensation pilot program over a 3-year period (2005- 2007) in a sample of Medi-Cal beneficiaries by describing the associations between use of pilot pharmacies and (a) adherence to ART regimens; (b) medication utilization, including number and type of ART medication regimens and use of contraindicated ART regimens; (c) occurrence of opportunistic infections; and (d) all-cause pharmacy and medical costs.

METHODS

This was a cohort study examining Medi-Cal pharmacy and medical claims data (2005-2007) for patients with HIV/AIDS who were served by pilot pharmacies versus other (nonpilot) pharmacies. The study groups, pilot and nonpilot pharmacy patients with HIV/AIDS, consisted of Medi-Cal beneficiaries aged 18 years or older as of January 1, 2005, who were continuously enrolled from January 1, 2004, through December 31, 2007, and who received both a diagnosis of HIV/AIDS and at least 1 ART pharmacy claim during both the index period (2004) and the study period (January 1, 2005, through December 31, 2007). Pilot pharmacy patients were identified as having filled 50% or more of their ART prescriptions each year at 1 of the 10 pilot pharmacies. Patients for whom comprehensive medication data were not available, including those enrolled in managed care plans and/or Medicare, were excluded. Adherence was defined as a medication possession ratio (MPR) of 80%-120% and excess medication fills as MPR greater than 120%. Logistic regression was used to investigate the factors associated with adherence. Comparisons were made between groups using bivariate statistics (Pearson chi-square for categorical variables and t-tests for continuous variables). For comparisons of costs, generalized linear models were used including predictor variables for age, gender, and race/ethnicity. RESEARCH RESULTS: The study sample consisted of 2,234 patients meeting the study inclusion criteria. The proportion of study patients receiving the majority of their prescription medications (ART plus non-ART) at pilot pharmacies was 19.7% in 2005 and increased to 27.6% in 2006 and 28.1% in 2007. The demographic profile of pilot pharmacy patients was similar to that of patients receiving medications at nonpilot pharmacies, except that pilot pharmacies had a higher proportion of Latino patients (e.g., 19.7% vs. 14.9% in 2007, respectively, P = 0.006). A greater percentage of pilot than nonpilot pharmacy patients were adherent to their ART medication regimens (e.g., 2007: 69.4% vs. 47.3%, respectively, P < 0.001). After controlling for age, gender, and ethnicity/race in logistic regression analysis, use of a pilot pharmacy (odds ratio [OR] = 2.74, 95% CI = 2.44-3.10) was the most important factor associated with likelihood of adherence. Each year, pilot pharmacy patients were more likely than nonpilot pharmacy patients to remain on a single type of ART regimen (e.g., 2007: 71.7% vs. 49.1%, respectively, P < 0.001) and less likely to have excess fills (e.g., 2007: 12.9% vs. 35.5%, respectively, P < 0.001) and to use contraindicated regimens (e.g., 2007: 8.9% vs. 12.2%, respectively, P = 0.027). The percentages of patients experiencing opportunistic infections were similar between groups each year, approximately 35% (P = 0.809-0.945). In the generalized linear model analyses, the between-group differences in predicted mean (standard error [SE]) total health care costs per patient were not significantly different in any year (e.g., 2007: $38,983 [$1,023] vs. $38,856 [$633], respectively, P = 0.915). In each year, predicted non- ART medication costs were approximately 30%-40% greater in the pilot pharmacy than nonpilot pharmacy group (e.g., 2007: $10,815 [$538] vs. $8,190 [$252], respectively, P < 0.001); however, predicted expenditures for inpatient services were significantly lower (e.g., 2007: $3,083 [$293] vs. $5,186 [$300], respectively, P < 0.001). Payment from the DHCS Medi-Cal program for MTM services was approximately $1,000 per pilot pharmacy patient per year.

CONCLUSIONS

Over a 3-year period, patients at pilot pharmacies consistently had higher medication adherence rates, were more likely to remain on a single type of ART regimen throughout the year, had fewer excess fills, and used fewer contraindicated regimens than nonpilot pharmacy patients. There were no significant differences in mean total cost per patient per group, and the additional MTM services payment added less than 3% to the total cost.