Two-Year Changes in Diabetic Kidney Disease Phenotype and the Risk of Heart Failure: A Nationwide Population-Based Study in Korea

BACKGROUND: Diabetic kidney disease (DKD) is a risk factor for hospitalization for heart failure (HHF). DKD could be classified into four phenotypes by estimated glomerular filtration rate (eGFR, normal vs. low) and proteinuria (PU, negative vs. positive). Also, the phenotype often changes dynamically. This study examined HHF risk according to the DKD phenotype changes across 2-year assessments. METHODS: The study included 1,343,116 patients with type 2 diabetes mellitus (T2DM) from the Korean National Health Insurance Service database after excluding a very high-risk phenotype (eGFR <30 mL/min/1.73 m(2)) at baseline, who underwent two cycles of medical checkups between 2009 and 2014. From the baseline and 2-year eGFR and PU results, participants were divided into 10 DKD phenotypic change categories. RESULTS: During an average of 6.5 years of follow-up, 7,874 subjects developed HHF. The cumulative incidence of HHF from index date was highest in the eGFR(low)PU(–) phenotype, followed by eGFR(nor)PU(+) and eGFR(nor)PU(–). Changes in DKD phenotype differently affect HHF risk. When the persistent eGFR(nor)PU(–) category was the reference, hazard ratios for HHF were 3.10 (95% confidence interval [CI], 2.73 to 3.52) in persistent eGFR(nor)PU(+) and 1.86 (95% CI, 1.73 to 1.99) in persistent eGFR(low)PU(–). Among altered phenotypes, the category converted to eGFR(low)PU(+) showed the highest risk. In the normal eGFR category at the second examination, those who converted from PU(–) to PU(+) showed a higher risk of HHF than those who converted from PU(+) to PU(–). CONCLUSION: Changes in DKD phenotype, particularly with the presence of PU, are more likely to reflect the risk of HHF, compared with DKD phenotype based on a single time point in patients with T2DM.