In chronic disease, nationwide data show poor adherence by patients to medication and by physicians to guidelines.

Purpose: It is widely acknowledged in small studies that provider variation from evidence-based care guidelines and patient medication nonadherence lead to less than optimal health outcomes, increasing costs, and higher utilization. The research presented here aims to determine the prevalence of patient adherence to a medication regimen and provider adherence to guidelines for a variety of chronic conditions, using nationally representative data.

Design: A retrospective analysis of administrative claims data from a large national insurer was conducted.

Methodology: The study examined multiple quality indicators exemplifying evidence-based medicine and medication adherence for several chronic conditions. Medication possession ratio (MPR) determined patient adherence. Using EBM Connect software created by Ingenix, we measured adherence to guidelines by applying a series of clinical rules and algorithms.

Principal Findings: Adherence to the evidence-based practice guidelines examined in this study averaged approximately 59 percent, while patient medication nonadherence rates for all the conditions studied averaged 26.2 percent, with a range of 11 percent to 42 percent. Physician adherence to guidelines was highest in the prescribing of inhaled corticosteroids for persistent asthma. Ironically, medication adherence rates for inhaled corticosteroids were the worst identified. The best medication adherence rate was observed in patients with hypertension.

Conclusion: Like earlier studies, this analysis finds that poor adherence is common across the nation and across common chronic conditions.