Background and Aims

To develop a comprehensive tool to assess medication compliance and its impact on outcomes following percutaneous coronary intervention (PCI).

Methods

This is a single-center, prospective, observational study of 1000 patients discharged following a PCI using drug-eluting stent(s). Clinicodemographic data including socioeconomic status (SES) was collected at baseline and each patient was assessed using the Manipal Scale for Cardiac Drug Compliance (MSCDC) containing 10 questions during follow-up visits at 1, 6, 12 and 18 months. Groups with low, moderate and high compliance (MSCDC scores <1, 1 to 3 and >3 respectively) were compared for the occurrence of major adverse cardiovascular events (MACE).

Results

Mean age of the study population was 56.3±7.5 years, of which 76.1% were males and 52.7% underwent primary PCI. Overall, drug compliance reduced over the course of follow-up from 73.8% having high-MSCDC scores at 6-month to 46.5% at 18-months. Despite guideline-directed therapy, overall MACE rate was high in this study (18.3%) in which 40.7% and 16.0% of the patients belonged to mid and low-SES, respectively.

Low-MSCDC group had a higher 18-month MACE rate compared to moderate- and high-MSCDC groups (28.4%, 22.2% and 16.2% respectively; P=0.009). Paradoxically, high- and mid-SES groups had poorer compliance with medicines compared to low-SES (Low and moderate-MSCDC scores in 29.9%, 24.1% and 21.1% respectively; P=0.006).

Conclusions

Drug non-compliance continues to adversely affects patient outcomes following PCI and does not appear to be related to low SES. Effective strategies like patient education and counselling regarding compliance to therapy is necessary to improve outcomes.