Self-rated health supersedes patient satisfaction with service quality as a predictor of survival in prostate cancer

BACKGROUND We have previously reported that higher patient satisfaction (PS) with service quality is associated with favorable survival outcomes in a variety of cancers. However, we argued that patients with greater satisfaction might be the ones with better self-rated health (SRH), a recognized predictor of cancer survival. We therefore investigated whether SRH can supersede patient satisfaction as a predictor of survival in prostate cancer. METHODS Nine hundred seventeen prostate cancer treated at four Cancer Treatment Centers of America(®) hospitals between July 2011 and March 2013. PS was measured on a 7-point scale ranging from "completely dissatisfied" to "completely satisfied". SRH was measured on a 7-point scale ranging from "very poor" to "excellent". Both were dichotomized into two categories: top box response (7) versus all others (1-6). Patient survival was the primary end point. Cox regression was used to evaluate the association between PS and survival controlling for covariates. RESULTS The response rate for this study was 72%. Majority of patients (n = 517) had stage II disease. Seven hundred eighty-seven (85.8%) patients were "completely satisfied". Three hundred nineteen (34.8%) patients had "excellent" SRH. There was a weak but significant correlation between satisfaction and SRH (Kendall's tau b = 0.18; p < 0.001). On univariate analysis, "completely satisfied" patients had a significantly lower risk of mortality (HR = 0.46; 95% CI: 0.25-0.85; p = 0.01). Similarly, patients with "excellent" SRH had a significantly lower risk of mortality (HR = 0.25; 95% CI: 0.11-0.58; p = 0.001). On multivariate analysis, SRH was found to be a significant predictor of survival (HR = 0.31; 95% CI: 0.12-0.79; p = 0.01) while patient satisfaction was not (HR = 0.76; 95% CI: 0.40-1.5; p = 0.40). CONCLUSIONS SRH supersedes patient satisfaction with service quality as a predictor of survival in prostate cancer. SRH should be used as a control variable in analyses involving patient satisfaction as a predictor of clinical cancer outcomes.