Quality of life in predialysis end-stage renal disease patients at the initiation of dialysis therapy. The NECOSAD Study Group.

OBJECTIVE: To assess health-related quality of life (QL) in a group of Dutch predialysis end-stage renal disease (ESRD) patients prior to the initiation of dialysis, and to compare QL between patients with different intended initial dialysis treatments.
DESIGN: In a prospective cohort study, demographic, clinical, and QL data were obtained from Dutch adult patients who were consecutively enrolled from 27 different centers 0 - 4 weeks prior to the beginning of their chronic dialysis treatment. PATIENTS: Of the 301 patients who completed the QL questionnaires (of a possible 337 enrolled patients), 152 intended to start with hemodialysis (pre-HD) and 149 patients with peritoneal dialysis (pre-PD). MAIN OUTCOME MEASURE: Perceived QL of pre-HD and pre-PD patients. Quality of life was assessed with two generic health assessment instruments: the SF-36 and the EuroQol.
RESULTS: After correction for group differences, pre-HD patients scored consistently, but not significantly, lower for all separate dimensions of the SF-36 and the overall health score of the EuroQol compared to pre-PD patients. However, analyzing the dimensions of the SF-36 together, adjusted for case-mix, pre-HD patients scored significantly lower than pre-PD patients. Mean difference was 6.5 points (p = 0.04).
CONCLUSION: Multivariate adjustment for known case-mix differences at the start of dialysis therapy was not sufficient to adjust for all patient selection effects on QL. Consequently, published QL comparisons between HD and PD in nonrandomized cohort studies should be interpreted with caution. Assessment of QL just before start of dialysis therapy and subsequent adjustment for baseline values may be the only valid alternative for randomized studies.