Background: Knowing whether risk factors for mortality differ in dialysis patients who survive longer and the strengths of these risk factors for mortality change over time would assist physicians in making better prognostic judgments.
Study design: Prospective cohort study.
Setting & participants: 1,041 incident dialysis patients treated in 81 clinics (mean follow-up, 3.1 years).
Predictor: A parsimonious set of risk factors (older age, white race, unemployed status, comorbidity, ever smoking, decreased systolic blood pressure, and decreased serum albumin level) chosen from several available demographic, clinical, and laboratory variables.
Outcomes & measurements: Long-term (4+ years) survival and mortality over yearly intervals of follow-up, examined in logistic regression and Cox proportional hazards analyses.
Results: All baseline risk factors were associated with a decreased chance of surviving 4+ years, even after adjustment for confounders. Increased age was a strong and independent risk factor for mortality over all yearly intervals; comorbidity, smoking, and decreased blood pressure were early risk factors; low albumin level and unemployed status were intermediate risk factors; and white race was a late risk factor. When risk factors were updated with time, low albumin level and severe comorbidity became significant risk factors over most intervals.
Limitations: Lack of some follow-up data and inability to rule out residual confounding or make causal inference based on results.
Conclusion: Long-term survivors on dialysis therapy may have different risk factors for mortality than patients in earlier phases of end-stage renal disease (eg, race versus blood pressure); other risk factors may be constant over time (eg, age, comorbidity, and albumin level). Such information may help guide physicians in making prognostic judgments for individual patients with particular dialysis vintages.