High risks of all-cause and cardiovascular deaths in apparently healthy middle-aged people with preserved glomerular filtration rate and albuminuria: A prospective cohort study

Background The reason why coexistence of preserved estimated glomerular filtration rate (eGFR) and albuminuria contributes to a high risk of death and which cause of death increases all-cause mortality have not been elucidated. Methods A total of 16,759 participants aged 40 to 69 years with normal or mildly reduced eGFR (45-119 ml/min/1.73 m²) were enrolled and divided into six groups (group 1, eGFR: 90-119 without albuminuria; group 2, eGFR: 90-119 with albuminuria; group 3, eGFR: 60-89 without albuminuria (reference); group 4, eGFR: 60-89 with albuminuria; group 5, eGFR: 45-59 without albuminuria; group 6, eGFR: 45-59 with albuminuria) based on GFR estimated by using the CKD-EPI study equation modified by a Japanese coefficient and albuminuria (urine albumin-creatinine ratio ≥ 30 mg/g). Outcomes included all-cause death (ACD), cardiovascular death (CVD) and neoplasm-related death (NPD). Multivariable-adjusted mortality rate ratios (RR) and their 95% confidence intervals (CIs) in the groups were estimated by Poisson's regression analysis. Results The highest risk of ACD (RR (95% CIs): 3.95 (2.08-7.52)), CVD (7.15 (2.25-22.7)) and NPB (3.25 (1.26-8.38)) was observed in group 2. Subjects in group 2 were relatively young and had the highest levels of body mass index, blood pressure and HbA_1c and the highest prevalence of diabetes and metabolic syndrome. Conclusion Coexistence of preserved eGFR and albuminuria increases risks for ACD, CVD and NPD. Relatively young metabolic persons having both preserved eGFR and albuminuria should be considered as a very high-risk population.