Progression of CKD in Patients with and without Hyperkalemia

Jill Davis, MS, and colleagues conducted a study to compare rates of progression of chronic kidney disease (CKD) between patients with and without hyperkalemia. The researchers reported results of the study during a poster session at Kidney Week 2019 in a poster titled Hyperkalemia and Progression of CKD.

Inclusion criteria included ≥18 years of age with CKD stages 3-4 and one or more estimated glomerular filtration rate (eGFR) measurements at baseline (6 months prior to the index date) and during the study period (up to 5 years post index date). Eligible patients were identified using electronic medical records from the US Research Action for Health Network (2012-2018). CKD stage was identified using diagnostic codes or eGFR measurement.

The study examined two separate outcomes: (1) progression to CKD stage 5 and (2) ≥10 unit decline in eGFR. Following adjustment for baseline eGFR, demographic characteristics, relevant comorbidities, and treatment use, Kaplan-Meier analyses and multivariable Cox models were performed. Sensitivity analyses were preformed adjusting for albumin-creatinine ratio (ACR), stratifying by baseline CKD stage, and excluding patients with baseline acute kidney injury (AKI).

Compared with patients without hyperkalemia (n=36,764; mean age 72.7 years), those with hyperkalemia (n=9220; mean age 72.3 years) had higher rates of CKD stage 4 (33.9% vs 9.7%), heart failure (31.7% vs 15.0%), and AKI (33.8% vs 11.5%), and a higher ACR value (393.9 mg/g vs 154.4 mg/g).

During the 5-year study period, 16.7% of patients in the hyperkalemia group progressed to CKD stage 5, compared with 3.7% of those in the non-hyperkalemia group. In the hyperkalemia group, 31.7% of patients had a decline in eGFR of ≥10 units, compared with 17.0% of patients in the non-hyperkalemia group (both comparisons log-rank P<.001).

In Cox models, patients with versus without hyperkalemia had a statistically significant higher risk of CKD progression to CKD stage 5 (adjusted hazard ratio [aHR], 2.20; 95% confidence interval [CI], 2.02-2.38; P<.001) and eGFR decline (aHR, 2.40; 95% CI, 2,28-2.52; P<.001). Following adjustment for ACR, stratification by baseline CKD stage, or exclusion of patients with AKI, results of Cox models were consistent with those prior to adjustment.

The researchers said, “Even after adjusting for relevant comorbidities and treatments, hyperkalemia was significantly associated with higher risk of progression to CKD stage 5 and eGFR decline among patients with CKD stage 3-4. Associations were robust in all sensitivity analyses.”

Source: Davis J, Done N, Chamberlain CX, et al. Hyperkalemia and progression of CKD. Abstract of a poster presented during the American Society of Nephrology Kidney Week 2019 (Abstract FR-PO654), November 9, 2019, Washington, DC.