Non-adherence to cardiovascular pharmacotherapy in Iraq assessed using 8-items Morisky questionnaire and analysis of dried blood spot samples

Abstract

The study evaluated the non-adherence to selected cardiovascular medications, atenolol, atorvastatin, bisoprolol, diltiazem, lisinopril, simvastatin and valsartan in Iraqi patients by applying a standardized Morisky questionnaire (8-MMAS) and by measuring therapeutic drug concentrations in dried blood spots (DBS) analyzed by liquid chromatography - high resolution mass spectrometry (LC-HRMS). Sixty-nine patients, on continued use of one or more of the selected drugs, were evaluated. The questionnaire showed that 21.7% of participants were non-adherent whereas DBS analysis showed that 49.3% were non-adherent to their medications. No significant correlation between medication non-adherence and gender was detected, but adherence was negatively correlated with the number of medications in the regimen. The 8-items questionnaire was unable to differentiate non-adherence to multiple medications in the prescribed pharmacotherapy regimens. DBS is an alternative to conventional methods to monitor non-adherence objectively. Agreement between the two approaches was weak (Kappa =0.269, p-value 0.05).