Special Report Diuretics and diabetes incidence—an appeal against the reluctance to prescribe a medication that is safe and proven A. Siebenhofer*†, K. Jeitler*‡, I. Rakovac§ and K. Horvath* *Department of Internal Medicine, Medical University of Graz, Graz, Austria, †Institute for General Practice, Goethe University, Frankfurt am Main, Germany, ‡Institute for Medical Informatics, Statistics and Documentation, Medical University of Graz, Graz, Austria and §Institute of Medical Technologies and Health Management, Joanneum Research Forschungsgesellschaft mbH, Graz, Austria Accepted 21 July 2009 Abstract The publication of the scientific report of the Institute for Quality and Efficiency in Health Care (IQWiG) in Germany on the ‘Comparative evaluation of the benefits and harms of different antihypertensive drug classes [diuretics, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, calcium-channel blockers and angiotensin II (AT-II) blockers] as first- choice therapy for patients with essential hypertension’ raised an enormous public debate, particularly as diabetes incidence was not judged to be a patient-relevant outcome. In this assessment, the overall view of the patient-relevant results was that diuretics can be used as first-line antihypertensive treatment. Diabetes incidence is highest with diuretics, but minimal differences in fasting plasma glucose of  0.28 mmol / l are magnified by the transformation of continuous blood glucose values into categorical data: with the establishment of thresholds, the diagnosis of diabetes depends on being above a certain blood glucose value. The protective cardiovascular effects of diuretics do not seem to be reduced in hypertensive patients who develop new-onset diabetes during treatment. Since blood pressure control is often worse, detection, treatment and control should be urgently improved. The debate on antihypertensive agents is mainly of scientific interest and has only minor clinical relevance for everyday patient care. Diabet. Med. 27, 130–135 (2010) Keywords diabetes incidence, diuretics Abbreviations ACE, angiotensin-converting enzyme; ALLHAT, Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial; AT-II, angiotensin II; CHD, coronary heart disease; CI, confidence interval; HbA 1c , glycated haemoglobin; HR, hazard ratio; IQWiG, Institute for Quality and Efficiency in Health Care; OR, odds ratio; SHEP, Systolic Hypertension in the Elderly Program; UKPDS, UK Prospective Diabetes Study Background Epidemiological studies have shown a clear positive association between blood glucose levels and increased microvascular and macrovascular morbidity and mortality risk, even below diagnostic threshold levels of diabetes [1–3]. The risk for cardiovascular morbidity or mortality is 2- to 4-fold higher in patients with diabetes mellitus in comparison with non-diabetic patients [4–7]. Furthermore, patients with arterial hypertension have a higher risk per se of developing diabetes mellitus [8]. Therefore, to minimize diabetes risk, guidelines recommend avoiding antihypertensive treatments which increase diabetes risk [9,10]. Diuretics in particular increase plasma glucose and have the highest incidence of diabetes in comparison with other first-line drugs. The lowest incidence is with angiotensin II (AT-II) blockers, where the risk is almost halved, followed by angiotensin-converting enzyme (ACE) inhibitors, calcium- channel blockers and placebos. For beta-blockers, the odds ratio is close to 1.0 [11], This is one of the reasons why many physicians refrain from prescribing these antihypertensive agents, both for diabetic and non-diabetic patients. Another major reason is the extensive promotion of other, more expensive antihypertensive agents. Despite the recommendation provided by the Joint National Committee on Prevention, Detection, Correspondence to: Andrea Siebenhofer, MD, Institute for General Practice, Goethe University, Theodor-Srern-Kai 7, D-60590, Frankfurt am Main, Germany. E-mail: siebenhofer@allgemeinmedizin.uni-frankfurt.de DIABETICMedicine DOI: 10.1111/j.1464-5491.2009.02821.x ª 2010 The Authors. 130 Journal compilation ª 2010 Diabetes UK. Diabetic Medicine, 27, 130–135