Risk for hyperkalaemia during long-term treatment with angiotensin-converting enzyme inhibitors in insulin-dependent type 2 diabetics in relation to the GFR

Background and objective: The risk for hyperkalaemia during therapy with an giotensin-converting enzyme inhibitors is especially increased in the elder ly diabetic because of a decrease in glomerular filtration rate (GFR), as w ell as the occurrence of hyporeninaemic hypoaldosteronism. We evaluated the risk for hyperkalaemia under long-term angiotensin-converting enyzme inhib ition in 86 insulin-dependent type 2 diabetic patients in relation to their GFR. Patients and methods: We compared the influence of a 3 to 6 months long tre atment with angiotensin-converting enzyme inhibitors on the serum potassium levels, the creatinine clearance and the urinary albumin excretion in insu lin-dependent type 2 diabetic patients with an initial creatinine clearance < 50 ml/min/ 1.73m(2) (n=15, age 66 +/- 6 years) and greater than or equal to 50ml/min/1.73 m(2) respectively(n=71, age 61 +/- 10 years). In addition , we also investigated the influence on the metabolic control and the blood pressure values in both groups of patients. Results: In the patients with creatinine clearance 50ml/min/ 1.73 m(2) the mean potassium level increased from 4.3 +/- 0.2 to 4.6 +/- 0.4 mmol/l (P < 0.01), while the incidence of a potassium level > 5 mmol/I was 17%. In the group with a creatinine clearance < 50 ml/min/1.73m(2) the potassium level rose from 4.5 0.2 to 5.0 +/- 0.4 mmol/l (P < 0.01). The incidence of potass ium levels > 5 mmol/l was 66% (P < 0.01). In both patient groups the creati nine clearances did not change significantly during angiotensin-converting enzyme inhibition, and the urinary albumin excretion as well as the HbA(1c) values and blood pressure showed only a tendency towards a decrease. Conclusion: Long-term treatment with angiotensin-converting enzyme inhibito rs in insulin-dependent type 2 diabetic patients leads to a significant inc rease in serum potassium. The incidence of hyperkalaemia with potassium lev els > 5 mmol/l is significantly higher in the patients with initial creatin ine clearance < 50m/l min/1.73 m(2). Severe hyperkalaemia with potassium le vels > 6 mmol/l was not observed.