The relationship between kidney function and quality of life among community-dwelling adults varies by age and filtration marker

Abstract

Background

The impact of a diminished level of kidney function on the well-being of an older individual is poorly understood. We sought to determine the association between estimated glomerular filtration rate (eGFR) and overall quality of life (QoL) among older adults.

Methods

Cross-sectional analysis of 4293 participants from the Irish Longitudinal Study on Ageing, a population-based study of community-dwelling adults ≥50 years of age. We used multivariable negative binomial regression to model the relationship between categories of cystatin C eGFR (eGFR _cys) or creatinine eGFR (eGFR _cr) and the number of QoL deficits from the Control, Autonomy, Self-realization and Pleasure (CASP-19) scale, a holistic measure of QoL among older adults (range 0–57). We further explored this relationship across age strata.

Results

Median age was 61 [interquartile range (IQR) 55–68] years, 53% were female, mean (SD) CASP-19 score was 44.8 (7.4) and median eGFR _cys was 81 (IQR 68–93) mL/min/1.73 m ². After multivariable adjustment, participants with eGFR _cys <45 mL/min/1.73 m ² had 14% greater QoL deficits {incidence rate ratio 1.14 (95% confidence interval 1.03–1.25)] relative to the reference group (eGFR _cys ≥90 mL/min/1.73 m ²). This relationship appeared linear across eGFR _cys categories and was more pronounced in younger (50–64 years) compared with older participants (65–74 or ≥75 years). There was no substantive relationship between eGFR _cr and CASP-19.

Conclusions

Cystatin C but not creatinine eGFR was associated with clinically modest declines in QoL among a large sample of community-dwelling older adults. This relationship varied by age, suggesting that a diminished eGFR contributes little to overall QoL beyond middle age in this population.