Therapy Adherence and Highly Active Antiretroviral Therapy: Comparison of Three Sources of Information

Patient adherence, a critical component in the management of HIV, has become a behavioral problem since the advent of HAART. Failure to adhere to a therapeutic regimen can dilute beneficial effects of the drugs and cause the emergence of drug-resistant strains of HIV. A central limitation to studying adherence to HAART is that often researchers have to rely on self-reported measures of adherence, which tend to overestimate.

The current study combines information on adherence from several sources: patients' self reports, perception of adherence reported by the patients' designated most significant others, evaluation of adherence by the physicians in charge of treatment, and HIV-1 RNA levels.

Investigators gathered data from 86 participants in the French- and Flemish-speaking areas of Belgium. The study used variables based on the health belief model, a value-expectancy theory that views behavior as a function of the subjective value of an outcome and the subjective expectancy that a specific action will result in the outcome. To improve the explanatory power of the health belief model, the authors also measured adherence-specific social support, and satisfaction with the patient-provider relationship.

The researchers found that the best results for explaining adherence were those reported by the medical staff in charge of treatment. Perception of barriers to following the complicated treatment regimen was the most important predictor of adherence. The impact of received benefits was the second most important predictor. Doctors noted that patients who report high benefits from the regimen were more compliant. Female patients also showed to be more compliant than males. Adherence varied with the complexity of the treatments. More complex treatments resulted in lower adherence. Contrary to expectations, the authors found that a higher satisfaction with the doctor-patient relationship, as reported by medical staff, resulted in lower adherence.

Adherence reported by the participants had only one significant predictor, perceived self-efficacy. Respondents with high self-efficacy reported fewer missed doses of medication. None of the variables as seen by respondents' most significant other had a significant impact on adherence. The study found older participants to have higher viral load levels, and lower levels of viral particles in the blood of respondents reporting high levels of perceived benefits in following HAART therapy.

"We did find that the health belief model is able to explain a considerate amount of the variation in adherence as reported by the medical staff," the authors noted. "Benefits and barriers are related to adherence. We also found for HIV-1 RNA levels that perceived barriers were significant."

Since little is currently known about the long-term outcomes of HAART, the researchers suggested that adherence could become more stringent as treatment effects stabilize over time and benefits become more visible.

"While this study has limitations related to sample size, statistical power, and missing data, nonetheless, we strongly believe that relying on and combining different sources of information on therapy adherence will sharpen our insights into the complex process of adherence and produce more effective therapeutic outcomes," the researchers concluded.

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