A Risk Model to Predict Statin Non-Adherence Following an Acute Coronary Syndrome.

BACKGROUND

Patients at risk of statin non-adherence are often not identified during hospital admission with an acute coronary syndrome (ACS).

METHODS

In 19,942 patients hospitalised for ACS, statin dispensing was determined from the national pharmaceutical dispensing database. A risk score for non-adherence was developed from a multivariable Poisson regression model of associations between risk factors and the statin Medication Possession Ratio (MPR) <0.8 6-18 months after hospital discharge.

RESULTS

Statin MPR was <0.8 in 4,736 (24%) patients. MPR <0.8 was more likely in patients with a history of cardiovascular disease (CVD) (RR 3.79, CI 95% 3.42-4.20) and those without known CVD (RR 2.25, 95% CI 2.04-2.48) who were not taking a statin on ACS admission, compared to patients with low density lipoprotein (LDL) cholesterol <2 mmol/L who were on a statin. For patients taking a statin on admission, higher LDL was associated with MPR <0.8 (≥3 versus <2 mmol/L, RR 1.96, 95%CI 1.72-2.24). Other independent risk factors for MPR <0.8 were age <45 years, female, disadvantaged ethnic groups, and no coronary revascularisation during the ACS admission. The risk score, which included nine variables, had a C-statistic of 0.67. MPR was <0.8 in 12% of 5,348 patients with a score ≤5 (lowest quartile) and 45% of 5,858 patients with a score ≥11 (highest quartile).

CONCLUSION

A risk score generated from routinely collected data predicts statin non-adherence in patients hospitalised with ACS. This may be used to target inpatient and outpatient interventions to improve medication adherence.