Persistence with a single pill versus two pills of amlodipine and atorvastatin: the Australian experience, 2006–2010

OBJECTIVE: To study patient persistence on therapy for hypertension and dyslipidaemia using a single-pill combination compared with a two-pill approach. DESIGN AND SETTING: Post-hoc observational assessment of Pharmaceutical Benefits Scheme claim records covering the period April 2005 to March 2010. PARTICIPANTS: A 10% random sample of Australian long-term concession card holders was analysed. The patients studied had commenced on either amlodipine and atorvastatin as two individual pills, or a single pill containing both amlodipine and atorvastatin (AA), with neither combined approach having been dispensed to them in the previous 6 months. MAIN OUTCOME MEASURES: The proportions of patients failing to fill their first repeat prescription after 1 month or failing to persist with treatment at 12 months, and the median persistence time (MPT) were measured. RESULTS: Of 4146 patients prescribed the AA single pill, 11% failed to fill the first repeat prescription and 33% had ceased treatment by 12 months (MPT, 35 months). Of 6204 patients prescribed amlodipine and atorvastatin as two pills, 23% failed to fill the first repeat prescriptions and 59% had ceased treatment by 12 months (MPT, 7 months). In a multivariate model, cessation of single-pill therapy increased by 165% if there was no prior therapy, but only increased by 48%-55% if there was no prior therapy with a calcium channel blocker or statin. MPT on the single pill was 8 months in those without prior antihypertensive therapy, but was ≥ 37 months in those with any prior antihypertensive therapy. CONCLUSION: A single-pill combination drug is associated with superior long-term persistence compared with two-pill therapy in the management of hypertension and dyslipidaemia.