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 (R) 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.