Comorbidity and survival among women with ovarian cancer: evidence from prospective studies

The relationship between comorbidity and ovarian cancer survival has been controversial so far. Therefore, we conducted a meta-analysis to summarize the existing evidence from prospective studies on this issue. Relevant studies were identified by searching the PubMed, EMBASE, and ISI Web of Science databases through the end of January 2015. Two authors independently performed the eligibility evaluation and data abstraction. Random-effects models were used to estimate summary hazard ratios (HRs) and 95% confidence intervals (CIs) for overall survival. Eight prospective studies involving 12,681 ovarian cancer cases were included in the present study. The summarized HR for presence versus absence of comorbidity was 1.20 (95% CI = 1.11-1.30, n = 8), with moderate heterogeneity (I(2) = 31.2%, P = 0.179). In addition, the summarized HR for the highest compared with the lowest category of the Charlson's comorbidity index was 1.68 (95% CI = 1.50-1.87, n = 2), without heterogeneity (I(2) = 0%, P = 0.476). Notably, a significant negative impact of comorbidity on ovarian cancer survival was observed in most subgroup analyses stratified by the study characteristics and whether there was adjustment for potential confounders. In conclusion, the findings of this meta-analysis suggest that underlying comorbidity is consistently associated with decreased survival in patients with ovarian cancer. Comorbidity should be taken into account when managing these patients.