Older patients are less prone to fast decline of renal function: a propensity-matched study.

Purpose: Despite CKD is common among older patients, and although factors associated with CKD progression have been explored over decades, little is known about the decline of renal function specifically in older individuals.

Methods: We included adult patients with CKD on conservative management in a propensity-score matched study 1:1 older (> 65 year) and young (≤ 65 yr). Factors associated with the slope of the decline of eGFR such as proteinuria, initial eGFR, diabetes, sex, and use of angiotensin-converting enzyme inhibitor/angiotensin receptor block (ACEI/ARB) were analyzed. Inclusion criteria were at least two consultations in the service and an initial eGFR lower than 45 ml/min/m, in the period between January 2012 and December 2017.

Results: Crude analysis of eGFR decline shows a slower progression of older patients when compared to younger patients in both absolute change [- 2.0 (- 4.5, - 1.0) vs. -3.0 (- 7.0, - 1.0) ml/min/1.73m, p < 0.001] and slope of eGFR reduction [- 2.2 (- 4.4, - 1.0) vs. 3.1 (- 6.7, - 1.2)) ml/min/1.73m, p < 0.001]. Patients considered fast progressors (> 5 ml/min/1.73 m/year decline in eGFR) were less likely to be older (35.2% young vs. 22.0% older, p < 0.001). Adjusted logistic multivariate regression confirmed that older patients had less odds ratio of eGFR decline, independently of the presence of proteinuria, diabetes, ACEI/ARB use, sex, baseline eGFR, baseline phosphate and baseline 25(OH) vitamin D.

Conclusion: Older patients present slower CKD progression even after multiple adjustments. This information should be taken into consideration while treating these patients on conservative management and should be kept in mind while planning dialysis start.