Overall and cause-specific mortality among patients diagnosed with gastric precancerous lesions in Sweden between 1979 and 2014: an observational cohort study.

ABSTRACT

BACKGROUND: The Correa's cascade, encompassing chronic non-atrophic gastritis, atrophic gastritis, intestinal metaplasia, and dysplasia, represents the well-recognized pathway for the development of non-cardia gastric cancer. Population-based studies on all-cause and cause-specific mortalities among patients with gastric lesions in Correa's cascade are scarce. METHODS: We compiled a cohort of 340 744 eligible patients who had undergone endoscopy with biopsy for non-malignant indications during the period 1979-2011, which was followed up until 2014. Standardized mortality ratios (SMRs) with 95% confidence intervals (CIs) provided estimation of the relative risk, using the general Swedish population as reference. Cox regression model was used to estimate hazard ratios (HRs) of death for internal comparison. RESULTS: A total of 306 117 patients were included in the final analysis, accumulating 3,049,009 person-years of follow-up. In total 106,625 deaths were observed during the study period. Compared to the general population, excess risks of overall mortality were noted in all subgroups, with SMRs ranging from 1.11 (95% CI 1.08-1.14) for the normal mucosa group to 1.54 (95% CI 1.46-1.62) for the dysplasia group. For cause-specific mortalities, mortality from gastric cancer gradually increased along Correa's cascade, with excess risk rising from 105% for patients with chronic gastritis to more than 600% for the dysplasia group. These results were confirmed in the comparison with the normal mucosa group. For non-cancer conditions, increased death risks were noted for various diseases compared to the general population, especially among patients with more severe gastric precancerous lesions. But the results were confirmed only for "infectious diseases and parasitic diseases", "respiratory system diseases", and "digestive system disease", when using the normal mucosa group as reference. CONCLUSIONS: Increased mortality from gastric cancer suggests that early recognition and intervention of gastric precancerous lesions probably benefit the patients. Excess mortality due to non-cancer conditions should be interpreted with caution, and future studies are warranted.