Original investigations
Pathogenesis and treatment of kidney disease and hypertension
Quality of life in Chronic Kidney Disease (CKD): A cross-sectional analysis in the Renal Research Institute-CKD study

https://doi.org/10.1053/j.ajkd.2004.12.021Get rights and content

Background: Health-related quality of life (QOL) is an important measure of how disease affects patients’ lives. Dialysis patients have decreased QOL relative to healthy controls. Little is known about QOL in patients with chronic kidney disease (CKD) before renal replacement therapy. Methods: The Medical Outcomes Study Short Form-36 (SF-36), a standard QOL instrument, was used to evaluate 634 patients (mean glomerular filtration rate [GFR], 23.6 ± 9.6 mL/min/1.73 m2 [0.39 ± 0.16 mL/s/1.73 m2]) enrolled in a 4-center, prospective, observational study of CKD. SF-36 scores in these patients were compared with those in a prevalent cohort of hemodialysis (HD) patients and healthy controls (both from historical data). QOL data also were analyzed for correlations with GFR and albumin and hemoglobin levels in multivariable analyses. Results: Patients with CKD had higher SF-36 scores than a large cohort of HD patients (P < 0.0001 for 8 scales and 2 summary scales), but lower scores than those reported for the US adult population (P < 0.0001 for 7 of 8 scales and 1 of 2 summary scales). Patients with CKD stage 4 had lower QOL scores than patients with CKD stage 5, although differences were not significant. Hemoglobin level was associated positively with higher mental and physical QOL scores (P < 0.05) in all individual and component scales except Pain. Conclusion: SF-36 scores were higher in this CKD cohort compared with HD patients, but lower than in healthy controls. GFR was not significantly associated with QOL. Hemoglobin level predicted both physical and mental domains of the SF-36. Longitudinal studies are needed to define at-risk periods for decreases in QOL during progression of CKD.

Section snippets

Study design and subjects

The Renal Research Institute-CKD (RRI-CKD) Study is an ongoing multicenter (University of Michigan, Albany Medical Center, New Haven, and University of North Carolina), prospective, observational study of adult patients with moderate to advanced CKD. The details of study design have been published elsewhere12 and are summarized here. Patients were recruited from the outpatient nephrology clinics at these sites by a study coordinator. The main inclusion criterion was a GFR of 50 mL/min/1.73  m2

Results

The 634 patients enrolled in the RRI-CKD study had significantly impaired renal function; mean GFR was 23.6 ± 9.6 mL/min/1.73 m2. The majority of patients had stages 3 (n = 151) and 4 (n = 360) CKD according to the National Kidney Foundation-Kidney Disease Outcomes Quality Initiative classification of chronic kidney disease.20 One hundred eighteen patients with stage 5, or “kidney failure,” were not receiving renal replacement therapy at the time of enrollment.

Baseline QOL data were available

Discussion

Patients with CKD in this study had QOL scores measured by means of the SF-36 that were significantly higher than those of HD patients, but lower than those of a general population. Using SF-36 QOL scores to evaluate the magnitude of any individual patient’s symptoms is not straightforward.22 SF-36 scores represent surrogate markers of the impact of an individual patient’s symptoms on his or her QOL.23 One way to evaluate the magnitude of difference in scores is by considering variation from a

Acknowledgment

The authors thank their patients for taking the time to fill out the QOL questionnaires and the Study Coordinators and Research Assistants for their hard work and patience during patient recruitment. The following deserve special mention: Laura Davidson, Bonnie Welliver, Rita Aouad, Christine Kehrer, Susan Reimann, Kerri Briesmiester (University of Michigan); Kathy Lambeth, Melissa Caughey (University of North Carolina); Diane Delmonico, Nancy Sutter, Susan Rauch (Albany Medical College);

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Supported in part by a grant from the Renal Research Institute, New York, NY, and Amgen Inc, Thousand Oaks, CA.

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