Calcium Antagonists Risk-Benefit and Blood Pressure Control in Diabetes: Review of Literature and Drug Utilization Profile

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Authors
Fenarese A, De RM, Monesi G, Joppi R, Battistutta C, Monesi L, Tognoni G
Abstract
Introduction: Results from recent RCT and observational studies demonstrated a poor risk-benefit of Calcium Antagonist in hypertensive persons -with type 2 diabetes. These results confirm the favourable role of angiotensin-converting enzyme (ACE) and the effectiveness of beta-blockers and diuretics low doses. A literature review and a survey of calcium antagonists prescription in 9 Italian Local Health Units diabetic population were conduct

Objectives: 1. To assess the knowledge and to define the correct approach to antihypertensive therapy in type 2 diabetes. 2. To analyze the pharmacoepidemiological profile of cardiovascular drugs prescribed to diabetic patients in general practice.

Methods: A MEDLINE search of articles published between 1996 and 1998 using the terms diabetes, hypertension, calcium antagonists was conducted. The drug utilization study included the population of 9 Local Health Units of Veneto in the Norm-East of Italy (1,873,827 inhabitants) participating to the AKNO Project who received prescription medications free of charge, as part of the national health care program (SSN), during 1996. The cohort of patients were identified by prescriptions for insulin and oral antidiabetics (more than 4 boxes/year). The selection of controls to examine the concurrent therapies (mean to check diabetes complications) was done under the design of a "case-control" study. Controls were identified among the patients who hadn't taken antidiabetic drugs; their number was twice the number of cases, with same gender, age and general practitioner. Statistical analysis was performed primarily to assess the prevalence of drug-treated diabetes and compare me proportions of concurrent therapies in the patients with and without diabetes (cases and controls). The drug utilization data were expressed as number of defined daily doses (DDO) related to 1,000 subjects.

Results: The literature analysis highlight that, in diabetic hypertensive patients, the incidence of fatal and non fatal cardiovascular events was significantly higher in those receiving calcium antagonists compared with those receiving angiotensin-converting enzyme (ACE) and diuretics low doses. Particularly the UKPDS Study confirmed the ACE-inhibitors role and provided similar effectiveness of beta-blockers. The drug utilization survey documented in the 40-64 year-old class me following results: - The general consumption of cardiovascular agents (which show micro and macroangiopathic complications) was double in diabetic patients compared to controls; - The calcium antagonists use was double in the cases as well; - 21,979 DDD/1000 diabetic patients/year of calcium antagonists and 29,152;

Discussion: DDD/1000 diabetic patients/year of ACE-inhibitors respectively were prescribed. Systematic reviews and drug utilization studies have to become integrated with the aim of bridging me gap between research and practice.