Self-reported Morisky 8 item medication adherence scale to statins concords with pill count method and correlates with serum lipid profile parameters and Serum HMGCoA Reductase levels

Abstract

ABSTRACTBackgroundIt is imperative that non-compliance to statins be identified and addressed to optimize the clinical benefit of statins. Patient self-reporting methods are convenient to apply in clinical practice but need to be validated.ObjectiveWe studied the concordance of a patient self-report method, MMAS (Morisky eight item medication adherence scale) with pill count method in measuring adherence to statins and their correlation with extended lipid profile parameters and serum HMGCoA-R (hydroxymethylglutaryl coenzyme A reductase) enzyme levels.MethodsMMAS and pill count method were used to measure the adherence to statins in patients on statins for any duration. Patients were subjected to estimation of extended lipid profile and serum HMGCoA-R levels at the end of 3 months follow-up.ResultsOut of a total of 200 patients included in the study, 117 patients had low adherence (score less than 6 on MMAS) whereas 65 and 18 patients had medium (score 6 to less than 8) and high adherence (score of 8) respectively. Majority of patients who had low adherence to statins by MMAS were nonadherent by pill count method yielding concordance of 96.5%. Medium or high adherence to statins by MMAS method had concordance of 89.1% with pill count method. The levels of total cholesterol, low density lipoprotein-cholesterol, apolipoprotein B and HMGCoA-R were significantly negatively correlated with compliance measured by pill count and MMAS with similar correlation coefficients. HMGCoA-R levels demonstrated a plateau phenomenon with levels being 9-10 ng/ml when compliance to statin therapy was greater than 60% by pill count and greater than 6 on Morisky scale.ConclusionIn conclusion, MMAS and pill count methods showed concordance in measuring adherence to statins. These methods need to be explored further for their interchangeability as surrogates for biomarker levels.