Health-Related Quality of Life according to Renal Function: Results from a Nationwide Health Interview and Examination Survey

Abstract

Background: Most studies on health-related quality of life (HRQoL) in chronic kidney disease (CKD) focus on patients with end-stage kidney disease although they represent a small proportion of patients with CKD. We aimed to analyze HRQoL according to glomerular filtration rate (GFR) categories in a population-based sample of adults living in Germany.

Methods: Data from the German health interview and examination survey conducted from 2008 to 2011 were used. Participants with valid interview and examination data aged 40-79 years were included (n = 5,159). Serum creatinine levels were used to calculate estimated GFR via the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. We classified kidney function in GFR categories according to the Kidney Disease Improving Global Outcomes Initiative (KDIGO) guidelines on CKD: G1 (high): ≥90 mL/min/1.73 m2, G2 (normal): 60-89 mL/min/1.73 m2, G3a (mildly decreased): 45-59 mL/min/1.73 m2, G3b (moderately decreased): 30-44 mL/min/1.73 m2, G4/5 (severely decreased/end-stage kidney disease): <30 mL/min/1.73 m2. HRQoL was evaluated with the Short Form Health Survey (SF-36). Different multivariate linear and logistic regression models were used to analyze the association of HRQoL with GFR categories.

Results: Overall, 5.9% had a GFR <60 mL/min/1.73 m2 (corresponding to categories G3a, G3b, and G4/5). Compared to category G2 linear regression showed a decline in physical HRQoL in categories G3a (-2.34, p = 0.004), G3b (-5.37, p = 0.009), and G4/5 (-4.82, p = 0.117). No decline in mental HRQoL was detected with increasing GFR categories. Categories G3a to G4/5 were significantly associated with a low perceived general state of health (G3a: odds ratio [OR] = 2.03, p = 0.001; G3b: OR = 3.01, p = 0.009; G4/5: OR = 8.70, p = 0.016) when compared to category G2.

Conclusion: In a representative sample of adults living in Germany, both physical HRQoL and the perceived general state of health are already significantly reduced in category G3a.

Keywords: Chronic kidney disease; Glomerular filtration rate; Health-related quality of life; Short form health Survey-36.