Objective: To study persistence and adherence with the use of common antihypertensive (AHT) medications.
Design, setting and participants: Longitudinal assessment of Pharmaceutical Benefit Scheme claim records covering the period January 2004 to December 2006. We analysed a 10% random sample of all Australian long-term health concession card holders who had been commenced on an angiotensin II receptor antagonist (A2RA), an angiotensin-converting enzyme inhibitor (ACEI) and/or a calcium channel blocker (CCB), but for whom no AHT medication had been dispensed in the previous 6 months.
Main outcome measures: Proportion of patients failing to fill a second prescription; median persistence time with medication (ie, non-cessation of therapy); persistence with medication over 33 months; median medication possession ratio (MPR, defined as the proportion of prescribed medication actually consumed by patients persisting with treatment).
Results: The database yielded information relating to 48 690 patients prescribed AHT medication. Nineteen per cent of patients failed to collect a second prescription. The median persistence time was 20 months. The data were little different from the population average with respect to A2RAs or ACEIs, but persistence was 57% poorer with respect to CCBs (log-rank P < 0.001) (28% of patients prescribed CCBs failed to collect a second prescription; median persistence time, 7 months). There were differences in persistence between individual drugs in the respective classes, the best outcomes being with candesartan and telmisartan (A2RAs; 10%-20% better), perindopril (ACEI; 25% better) and lercanidipine (CCB; 25% better). Median MPRs were generally around 100%, indicating that most patients who collected prescriptions also showed good adherence to treatment regimens.
Conclusion: There is an ongoing problem of poor persistence with commonly used AHT medications. This may represent a diminished opportunity for cardiovascular disease prevention.