Quality of life and kidney function in CKD patients: a longitudinal study

Background: In chronic kidney disease (CKD), a declining glomerular filtration rate (GFR) leads to physiological and psychosocial burdens that impair quality of life (QoL). However, this relationship has been mainly investigated in cross-sectional studies and a limited number of longitudinal studies that reported contrasting results. Objective and methods: This longitudinal study included 582 patients with Stages 2-5 CKD. QoL was assessed using the Kidney Disease Quality of Life (KDQOL™) instrument at baseline and annually for 3 years. GFR was estimated using the MDRD equation, the equation recommended by guidelines that were contemporary to the study cohort. We analysed the relationship between repeated measures of QoL and GFR using unadjusted and adjusted mixed linear models (MLMs). Results: The cohort had a mean age of 61 ± 12 years, with 60% males and 33% diabetics. Baseline eGFR was 36±13 ml/min/1.73 m2. Physical and mental component summary scores of QoL were 43.5 and 45.1, respectively. In MLM analyses adjusted for potential confounders, a 10 ml/min/1.73 m² decrease in eGFR was significantly associated with reductions in physical (β = -0.60, P =. 016) and mental (β = -0.52, P =. 045) component summary scores over the follow-up period. The physical functioning and role limitation physical health subcomponents of QoL were primarily responsible for these associations. Conclusions: This longitudinal study shows that declining kidney function is associated with deteriorating QoL in CKD patients independently of other factors. These findings support the current KDIGO recommendation that regular monitoring of QoL should be incorporated into clinical practice to improve patient outcomes.