Prevalence of Hyperkalemia in Diabetic and Non-Diabetic Patients with Chronic Kidney Disease: A Nested Case-Control Study.

BACKGROUND: Hyperkalemia is a potentially life-threatening disorder, usually complicating chronic kidney disease (CKD). Factors superimposed to reduced renal function are further elevating hyperkalemia risk, but their contribution is not fully elucidated. This study aimed to compare the prevalence of hyperkalemia in diabetic and non-diabetic patients with CKD.

METHODS: This is a nested case-control study of 180 type-2 diabetic and 180 non-diabetic patients with CKD followed in a Nephrology outpatient clinic, matched for gender, age and estimated glomerular filtration rate. Type-1 diabetes or end-stage renal disease patients were excluded. Prevalence of hyperkalemia was defined as potassium >5 mEq/l or use of sodium polystyrene sulfonate, and further by potassium >5, ≥5.2 and ≥5.5 mEq/l. It was calculated in both groups in whole and CKD stages separately. Univariate and multivariate logistic regression analysis were conducted to identify factors associated with hyperkalemia.

RESULTS: The prevalence of hyperkalemia was higher in diabetic CKD patients (27.2 vs. 20%, p = 0.107) and remained around 30% higher with all secondary definitions used, but never reached statistical significance. In Stage 2, no difference was noted (8.7 vs. 17.4%, p = 0.665); in Stage 3, it was significantly higher in diabetics (28.6 vs. 17.5%, p = 0.036); and in Stage 4, it was equally high in both groups (35.5 vs. 32.3%, p = 0.788). In multivariate analysis, Stage 4 CKD (OR 4.535, 95% CI 1.561-13.173), use of angiotensin-converting enzyme inhibitors (ACEIs; OR 2.228, 95% CI 1.254-3.958) and smoking (OR 2.254, 95% CI 1.218-4.171) were independently associated with hyperkalemia.

CONCLUSIONS: Diabetes mellitus was found to elevate the prevalence of hyperkalemia only in CKD Stage 3 patients (moderately impaired renal function). Advanced CKD at Stage 4 and ACEIs are major determinants of hyperkalemia occurrence.