Abstract
Introduction: Although the prevalence of chronic kidney disease (CKD) is increasing in the aging population, the clinical relevance of the CKD definition (glomerular filtration rate [GFR] <60 mL/min/1.73 m2) in older populations remains debatable. We investigated the clinical outcomes in older populations with mildly to moderately decreased GFR (45–59 mL/min/1.73 m2, CKD stage 3A). Methods: A total of 7,789,242 participants aged ≥40 years with estimated GFR (eGFR) ≥45 mL/min/1.73 m2 in national health screening examination from 2012 to 2017 were included in this retrospective cohort study using the Korean National Health Insurance Service database. The main outcomes included kidney failure, cardiovascular disease (CVD), and all-cause death. Cox regression hazard models were used to estimate the hazard ratios. Results: The proportion of participants with eGFR 45–59 mL/min/1.73 m2 was 10.0% and 16.3% in the old (65–74 years) and very old (75≥ years) groups, respectively. Mildly to moderately decreased eGFR was associated with a higher risk of kidney failure, CVD, and all-cause death compared with eGFR 60–89 mL/min/1.73 m2 in the old and very old groups, regardless of proteinuria (adjusted hazard ratio [95% confidence interval] in the very old group without proteinuria: kidney failure 3.048 [2.495–3.722], CVD 1.103 [1.066–1.142], and all-cause death 1.172 [1.144–1.201]). Conclusion: Mildly to moderately decreased eGFR was associated with an increased risk of kidney failure, CVD, and all-cause death in the older population, regardless of proteinuria, suggesting the importance of appropriate monitoring and management in this population.
Plain Language Summary
Chronic kidney disease (CKD) is diagnosed when the glomerular filtration rate (GFR) falls below 60 mL/min/1.73 m2. While it is normal for GFR to decrease with age, this threshold remains important for diagnosing CKD in older adults. Our research shows that even people aged 75 and older with a GFR between 45 and 59 mL/min/1.73 m2 (CKD stage 3A) have higher risks of kidney failure, myocardial infarction or stroke, and death. This suggests that it may be reasonable to define CKD using a GFR below 60 mL/min/1.73 m2 even in older adults. Therefore, older adults with slightly reduced GFR need regular checkups and careful management to prevent complications. Despite the natural decline of GFR with aging, defining CKD as a GFR below 60 mL/min/1.73 m2 helps ensure that older adults with mildly to moderately decreased GFR are properly monitored and managed to prevent serious health issues and improve overall quality of life.
