Association of high-risk comorbidity with overall survival among patients with gastric cancer and its sex-specific differences in China: a retrospective observational cohort study

Abstract Background Concomitant diseases often occur in cancer patients and are important in decision-making regarding treatments. However, information regarding the prognostic relevance of comorbidities for mortality risk is still limited among Chinese gastric cancer (GC) patients. This study aimed to investigate the association between comorbidities and 3-year mortality risk. Methods This retrospective study enrolled 376 GC patients undergoing radical gastrectomy at the Affiliated Zhongshan Hospital of Dalian University from January 2011 to December 2019. Demographic and clinicopathological information and treatment outcomes were collected. Patients were divided into low-, moderate- and high-risk comorbidity groups based on their Charlson Comorbidity Index (CCI) and age-adjusted CCI (ACCI) scores. Kaplan-Meier survival and Cox regression analyses were used to examine 3-year overall survival (OS) and mortality risk for each group. Results The median follow-up time was 43.5 months, and 40.2% (151/376) of GC patients had died at the last follow-up. There were significant differences in OS rates between ACCI-based comorbidity groups (76.56; 64.51; 54.55%, log-rank P = 0.011) but not between CCI-based comorbidity groups (log-rank P = 0.16). The high-risk comorbidity group based on the ACCI remained a significant prognostic factor for 3-year OS in multivariate analysis, with an increased mortality risk (hazard ratio [HR], 1.99; 95% CI, 1.15–3.44). Subgroup analysis revealed that this pattern only held for male GC patients but not for female patients. Conclusion The present study suggested that high-risk comorbidities were significantly associated with a higher mortality risk, particularly in Chinese male GC patients. Moreover, the ACCI score was an independent prognostic factor of long-term mortality.