Association Between a Self-Rated Health Question and Mortality in Young and Old Dialysis Patients: A Cohort Study

Thong, Melissa S.Y.; Kaptein, Adrian A.; Benyamini, Yael; Krediet, Raymond T.; Boeschoten, Elisabeth W.; Dekker, Friedo W.; Netherlands Cooperative Study on the Adequacy of Dialysis (NECOSAD) Study Group,

doi:10.1053/j.ajkd.2008.04.001

« Previous Next »American Journal of Kidney Diseases
Volume 52, Issue 1 , Pages 111-117, July 2008

Association Between a Self-Rated Health Question and Mortality in Young and Old Dialysis Patients: A Cohort Study

Melissa S.Y. Thong, MSc
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands
- Address correspondence to Melissa S.Y. Thong, MSc, Department of Clinical Epidemiology, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands.
Adrian A. Kaptein, PhD
- Department of Medical Psychology, Leiden University Medical Center, Leiden, The Netherlands
Yael Benyamini, PhD
- Bob Shapell School of Social Work, Tel Aviv University, Tel Aviv, Israel
Raymond T. Krediet, MD, PhD
- Department of Nephrology, Academic Medical Center, University of Amsterdam, Amsterdam
Elisabeth W. Boeschoten, MD, PhD
- Hans Mak Institute, Naarden, The Netherlands.
Friedo W. Dekker, PhD
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands
Netherlands Cooperative Study on the Adequacy of Dialysis (NECOSAD) Study Group

Received 31 July 2007; accepted 2 April 2008. published online 30 May 2008.

Background

Self-rated health (SRH) has been shown to predict mortality in large community-based studies; however, large clinical-based studies of this topic are rare. We assessed whether an SRH item predicts mortality in a large sample of incident dialysis patients beyond sociodemographic, disease, and clinical measures and possible age interaction.

Study Design

Prospective cohort study.

Setting & Participants

1,443 predominantly white patients from 38 dialysis centers in The Netherlands participating in the Netherlands Cooperative Study on the Adequacy of Dialysis-2 between 1997 and 2004.

Predictor

SRH score completed at 3 months after the start of dialysis therapy (baseline).

Outcomes & Measurements

Cox proportional hazards model estimated the association between SRH and all-cause mortality. Interaction of SRH with age (<65 and ≥65 years) was examined in an additive model.

Results

Mean age of patients was 59.6 ± 14.8 years, with 61% men and 69% married/living together. Mean follow-up was 2.7 ± 1.8 years. Deaths per SRH group in the multivariate analyses sample: excellent/very good (9 of 63 patients; 14.3%), good (148 of 473 patients; 31.3%), fair (194 of 508 patients; 38.2%), and poor (45 of 71 patients; 63.4%). Patients with poor, fair, or good health ratings had a greater mortality risk than those with excellent/very good health ratings (adjusted hazard ratio [HR_adj], 3.56; 95% confidence interval [CI], 1.71 to 7.42; HR_adj, 2.09; 95% CI, 1.06 to 4.12; HR_adj, 1.87; 95% CI, 0.95 to 3.70, respectively) independent of a range of risk factors. No age interaction with SRH was found.

Limitations

Although the SRH-mortality association remained strong despite extensive adjustments, unknown residual confounding could still exist.

Conclusion

SRH is an independent predictor of mortality in incident dialysis patients. Patients with poor SRH in both age strata had a significantly increased risk of mortality even after controlling for demographic and clinical confounders. Patient self-assessment of health can be an invaluable and economical complement to clinical measures in risk assessment.

Index Words: Self-rated health, mortality, dialysis, age interaction