Regional variation in the prescribing for diabetes and use of secondary preventative therapies in Ireland

PURPOSE: To compare the prescribing of secondary preventative therapies for patients with both insulin-dependent diabetes mellitus (IDDM) and non-insulin-dependent diabetes mellitus (NIDDM) in the eight health board regions of Ireland. METHODS: We utilized data from the national general medical services (GMS) prescribing database to examine the variability of prescribing for diabetes and associated secondary therapies between regions in those aged 45 years or more. Age-sex standardized prescribing rates of six secondary preventative therapies (aspirin, beta-blockers, statins, ACE inhibitors, angiotensin receptor (AT2) antagonists, and fibrates) were calculated for each region. RESULTS: Variations exist between regions for treated NIDDM (1.5-fold) and IDDM (1.5-fold). Wide variations were observed between regions for prescribing of secondary preventative therapies with the highest variability observed for statin prescribing (1.5- to 1.6-fold) and for AT2 antagonist prescribing (2.0-fold) in NIDDM patients. In those with NIDDM, men were more likely to receive aspirin OR=1.26 (1.21--1.31), ACE inhibitors 1.14 (1.101.18), and fibrates OR=1.55 (1.23--1.96) than women and those aged over 75 years were less likely to receive statins OR=0.60 (0.56--0.65) and fibrates OR=0.25 (0.17--0.37) than those aged 45--74. Similar results were also shown for patients with IDDM. CONCLUSIONS: The results suggest that access to secondary preventative therapy in diabetes patients is not equitable across regions, gender, and age in Ireland. While much of the variability remains unexplained, it may be due to differences in screening and health promotion between regions, prescriber uncertainty, variability in clinical need, or may be derived from a socioeconomic disparity among regions.