Young HIV-Infected Adults Are at Greater Risk for Medication Nonadherence

Stephen L. Becker, MD; Christopher M. Dezii, RN, MBA; Beth Burtcel, PharmD; Hugh Kawabata, MA; Sally Hodder, MD

Disclosures
In This Article

Discussion

Adherence is essential in achieving the goals of therapy in patients with HIV infection. We found that rates of NRTI adherence and persistence are poor overall, and even worse in young patients, in a study population of Medicaid recipients who were new to HIV therapy. Medicaid is the largest single payer of direct medical services for people living with HIV/AIDS in the United States, serving 55% of patients, suggesting that this work is relevant and generalizable.[8] The overall adherence rate of 53.0% during the course of 1 year is similar to the 58.2% rate of adherence to NRTI therapy observed by McNabb and colleagues[9] in an inner-city treatment-experienced population during a 3-month period.

Numerous studies have confirmed the importance of adherence with regard to the outcomes of therapy. It has been shown that successful suppression of HIV with HAART requires a high adherence rate, in excess of 90% of doses.[10,11] Low-Beer and colleagues[12] found that ≥ 95% adherence, as measured by pharmacy dispensing data, is associated with a high rate of virologic success (HIV-1 RNA < 500 copies/mL). As therapy adherence decreased, virologic success rates fell sharply. In addition, the development of drug resistance and therapeutic failure has been attributed to nonadherence.[13]

Several studies have concluded that 60% to 70% of patients are adherent to antiretroviral therapy at least 80% of the time.[14,15] In our study, the proportion of individuals with adherence of 80% or better was approximately 26%, which is comparable to the proportion (34%) reported by Laine and colleagues[16] in a claims-based analysis of pregnant HIV-infected women.

We did not observe a consistent association between sex and adherence, but increased age was associated with increased rates of adherence in this study. However, the literature suggests that demographic characteristics are not reliable predictors of adherence.[17] Of interest, stratification of the population by rate of adherence revealed a consistent representation across all of the strata representing adherence rates below 80%, suggesting a wide variation in patients' ability to overcome the obstacles to adherence. This would suggest that the commitment to addressing and designing programs to improve adherence should not be partial.[18] Comprehensive programs addressing all known barriers to adherence such as complex drug regimens, psychosocial issues, and patient-belief systems, to name a few, may be required to maximize adherence rates.

The lowest rates of adherence and persistence were observed in the youngest subjects (18-24 years), indicating a need for intensive and ongoing adherence interventions and monitoring to help facilitate maximum response to therapy in this group. Although adherence rates were poor throughout the study population, the youngest group is at the highest risk for nonadherence.

Our analysis of persistence, which reflects how long patients would remain on therapy on a practical basis, suggests that nonadherent behaviors are manifested early in the course of therapy. A significant proportion of patients fail to refill their prescriptions within 60 days of the initial prescription, indicating the importance of addressing adherence issues early in therapy, or before it is initiated.

There are inherent limitations associated with the use of prescription refills to measure adherence, such as the inability to assess the relationship between timing of doses and duration of drug action. However, this limitation may be somewhat mitigated by the fact that adherence assessed by prescription refill is a highly specific measure that allows the identification of individuals who cannot be taking sufficient medication to attain a treatment goal.[3]

In conclusion, our results suggest that nonadherence can be a critical issue during the first year following initiation of therapy in treatment-naive individuals, and especially among the youngest patients.

Stephen L. Becker, MD, has received grants for clinical research, received grants for educational activities, and served as an advisor or consultant for Agouron Pharmaceuticals, Boehringer Ingelheim Corporation, Bristol-Myers Squibb Co., Gilead Sciences, and GlaxoSmithKline.

Christopher M. Dezii, RN, MBA; Beth Burtcel, PharmD; Hugh Kawabata, MA; and Sally Hodder, MD, are all employees of Bristol-Myers Squibb Co.

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