Quantifying the effects of diuretics and beta-blockers on glycaemic control in diabetes mellitus - a systematic review and meta-analysis
Hirst J, Farmer A, Feakins B, Aronson J, Stevens R.
Although there are reports that beta-adrenoceptor antagonists (betablockers) and diuretics can affect glycaemic control in people with diabetes mellitus, there is no clear information on how blood glucose concentrations may change and by how much. We report results from a systematic review to quantify the effects of these antihypertensive drugs on glycaemic control in adults with established diabetes. Methods: We systematically reviewed the literature to identify randomised controlled trials in which glycaemic control was studied in adults with diabetes taking either beta-blockers or diuretics. We combined data on HbA1c and fasting blood glucose using fixed-effects meta-analysis. Results: From 3864 papers retrieved, we found 10 studies of beta-blockers and 12 studies of diuretics to include in the meta-analysis; one study included both comparisons, totalling 21 included reports. Beta-blockers increased fasting blood glucose concentrations by 0.64 mmol/l (95%CI 0.24 to 1.03) and diuretics by 0.77 mmol/l (95%CI 0.14 to 1.39) compared with placebo. Effect sizes were largest in trials of non-selective beta-blockers (1.33, 95%CI 0.72 to 1.95) and thiazide diuretics (1.69, 95%CI 0.60 to 2.69). Beta-blockers increased HbA1c concentrations by British Pharmacological Society British Journal of Clinical Pharmacology British Journal of Clinical Pharmacology 0.75% (95%CI 0.30 to 1.20) and diuretics by 0.24% (95%CI −0.17 to 0.65) compared with placebo. There was no significant difference in the number of hypoglycaemic events between beta-blockers and placebo in three trials. Conclusions: Randomised trials suggest that diuretics and non-selective beta-blockers increase fasting blood glucose and HbA1c concentrations in patients with diabetes by moderate amounts. These data will inform prescribing and monitoring of beta-blockers and diuretics in patients with diabetes.