Different measures applied to the same patient suggest different levels of adherence. Adherence may be underestimated by MEMS and overestimated by pill count and interview. A summary measure combining several measures is more strongly related to a clinical response, but more practical measurement methods are needed for clinical use.

Nearly all patients' adherence levels were suboptimal, demonstrating the critical need for programs to assist patients with medication taking. Interventions that assess and treat substance abuse and incorporate adherence aids may be particularly helpful and warrant further study.