Propensity score analysis exploring the impact of smoking and drinking on the prognosis of patients with oral cancer

Abstract Background To explore the effect of smoking and drinking on survival of patients with oral cancer by comparing the characteristics and survival of nonsmoking and nondrinking (NSND) patients in contrast to smoking and/or drinking (SD) patients. Methods This prospective study including 1165 patients with oral cancer was conducted in Fujian, China from January 2005 to January 2019. The patients were categorized to two groups, the NSND group and SD group. We compared overall survival and disease‐specific survival between the two groups using the Kaplan‐Meier method and Cox proportional hazards regression before and after propensity score matching (PSM) to explore the effect of smoking and drinking on the prognosis of patients with oral cancer. Results NSND patients accounted for 55.45% (646 patients) of all the patients with oral cancer. SD patients with oral cancer tended to be older and mainly are male (98.46%) and with more advanced disease status. There are trends toward both higher risk of all‐cause death (HR = 1.678; 95% CI: 1.086‐2.594) and oral cancer specific death (HR = 1.632; 95% CI: 1.044‐2.552) in SD patients with oral cancer before PSM. After PSM, the association is still significant, with adjusted HR of 1.897 (95% CI: 1.138‐3.165) for all‐cause death and adjusted HR of 1.764 (95% CI: 1.043‐2.983) for oral cancer‐specific death. Additionally, PSM can improve the HR value and result in a stronger association. Conclusions Social and clinical characteristics of NSND patients differed from SD patients with oral cancer. SD patients with oral cancer have higher all‐cause mortality and oral cancer‐specific mortality than NSND patients.