Hyperkalaemia in people with diabetes: occurrence, risk factors and outcomes in a Danish population-based cohort study.

AimsTo examine the incidence, risk factors and clinical outcomes of hyperkalaemia in people with diabetes in a real-world setting. MethodsUsing Danish health registries, we identified a population-based cohort of people with first-time drug-treated diabetes, in the period 2000-2012. First, the cumulative incidence of hyperkalaemia, defined as first blood test with potassium level >5.0 mmol/l after diabetes treatment initiation, was ascertained. Second, in a case-control analysis, risk factors were compared in people with vs without hyperkalaemia. Third, clinical outcomes were assessed among individuals with hyperkalaemia in a before-after analysis, and among people with and without hyperkalaemia in a matched cohort analysis. ResultsOf 68 601 individuals with diabetes (median age 62 years, 47% women), 16% experienced hyperkalaemia (incidence rate 40 per 1000 person-years) during a mean follow-up of 4.1 years. People who developed hyperkalaemia had a higher prevalence of chronic kidney disease [prevalence ratio 1.74 (95% CI 1.68-1.81)], heart failure [prevalence ratio 2.35 (95% CI 2.18-2.54)], use of angiotensin-converting enzyme inhibitors [prevalence ratio 1.24 (95% CI 1.20-1.28)], use of spironolactone [prevalence ratio 2.68 (95% CI 2.48-2.88)] and potassium supplements [prevalence ratio 1.59 (95% CI 1.52-1.67)]. In people with diabetes who developed hyperkalaemia, 31% were acutely hospitalized within 6 months before hyperkalaemia, increasing to 50% 6 months after hyperkalaemia [before-after risk ratio 1.67 (95% CI 1.61-1.72)]. The 6-month mortality rate after hyperkalaemia was 20%. Compared with matched individuals without hyperkalaemia, the hazard ratio for death was 6.47 (95% CI 5.81-7.21). ConclusionsOne in six newly diagnosed people with diabetes experienced a hyperkalaemic event, which was associated with severe clinical outcomes and death.