Trends in co-prescribing of angiotensin converting enzyme inhibitors and angiotensin receptor blockers in Ireland.

Abstract

(i) To examine the trends in co-prescribing of angiotensin converting enzyme inhibitor (ACEI) and angiotensin-II receptor blocker (ARB) therapy and (ii) to examine the influence of major clinical trials (CALM, COOPERATE, VALIANT and ONTARGET) on co-prescribing.

The Irish HSE-Primary Care Reimbursement Services database was used to identify patients ≥16 years old co-prescribed ACEIs and ARBs between January 2000 and April 2009 (n= 266 554 prescriptions). The rate of prescribing per 1000 general medical services (GMS) scheme population was calculated for each month. Patients with diabetes, hypertension, heart failure and ischaemic heart disease were also identified by prescribing of certain medications. A linear trend test was used to examine prescribing trends. Logistic regression was used to examine prescribing according to patient characteristics. The effects of the major trials on prescribing were examined using segmented regression analysis for 12 months pre- and post-trials.

There was a significant linear trend in overall ACEI and ARB co-prescribing over the study period (P < 0.001). Rate of co-prescribing in January 2000 and April 2009 was 0.16 and 5.72, per 1000 eligible population, respectively. Those 45-64 years old (OR = 2.88, 95% confidence interval (CI) 2.71, 3.06) and ≥65 years (OR = 2.52, 95% CI 2.36, 2.68) were more likely to receive dual therapy compared with those <45 years old. Those with hypertension (OR = 8.85, 95% CI 8.45, 9.27), diabetes (OR = 4.10, 95% CI 3.97, 4.23) and heart failure (OR = 1.78, 95% CI 1.72, 1.84) were more likely to receive dual therapy compared with the general population. Significant increases in prescribing were observed only after the CALM (P= 0.03) and VALIANT (P= 0.007) trials.

Increased co-prescribing of ACEIs and ARBs was observed in Ireland during 2000-09. Prescribing patterns did not appear to be affected by results from major trials.