Self-rated health as a predictor of survival among patients with advanced cancer.

Abstract

Evidence is emerging about the strong predictive relationship between self-rated health (SRH) and survival, although there is little evidence on palliative populations where an accurate prediction of survival is valuable. Thus, the relative importance of SRH in predicting the survival of ambulatory patients with advanced cancer was examined. SRH was compared to clinical assessments of performance status, as well as to quality-of-life measures. By use of a prospective cohort design, 181 patients (76% response rate) with advanced cancer were recruited into the study, resurveyed at 18 weeks, and observed to record deaths. The average age of patients was 62 years (SD = 12). The median survival time was 10 months. SRH was the strongest predictor of survival from baseline. Also, a Cox regression comparing changes in SRH over time yielded hazard ratios suggesting the relative risk (RR) of dying was greater for fair ratings at 18 weeks (approximately 3 times) compared with consistent good or better ratings; the RR was even greater (4.2 and 6.2 times) for poor ratings, especially when ratings were poor at baseline and 18 weeks (31 times). Improvement in SRH over time yielded the lowest RR. SRH is valid, reliable, and responsive to change as a predictor of survival of advanced cancer. These qualities suggest that SRH should be considered as an additional tool by oncologists to assess patients. Similarly, health managers could use SRH as an indicator of disease severity in palliative care case mix. Finally, SRH could provide a key to help us understand the human side of disease and its relationship with medicine.