Epidemiology of hyperkalemia in CKD patients under nephrological care: a longitudinal study

Hyperkalemia is a potential life-threatening condition among chronic kidney disease (CKD) patients. Available estimates of the burden of this alteration in CKD are mainly derived from large administrative databases. Since K measurements in patients in these databases are often dictated by clinical reasons, longitudinal studies including pre-planned measurements of potassium independently of clinical complication/symptoms may produce more reliable estimates of the frequency and the risk factors underlying hyperkalemia in CKD patients. We estimated the prevalence and the incidence of hyperkalemia in a longitudinal study in 752 stages 2–5 CKD patients lasting 3 years and including up to seven pre-planned assessment of key biochemical measurements including K. At baseline, 203 out of 752 patients (27%) had serum K > 5.0 mM/L and 33% had acidosis (HCO3 ≤ 22 mmol/L). Among those without hyperkalemia at baseline (n = 549), 284 patients developed this alteration across the 3-year follow-up. The point prevalence of hyperkalemia rose from 27% (baseline) to 30% (last visit) (P = 0.001). In a multivariate model, hyperkalemia at baseline [odds ratio (OR):7.29, 95% CI 5.65–9.41, P