Abstract
Gastrointestinal diseases pose a significant challenge to global public health, with depression being prevalent among patients. Depression may influence disease prognosis through mechanisms such as the gut-brain axis. However, the specific impact of depression on nursing and all-cause mortality risk and its potential nonlinear relationship remains unclear. This study utilized publicly available data from the National Health and Nutrition Examination Survey from 2011 to 2018, including 4071 eligible participants. Gastrointestinal diseases and depression status were assessed through self-reported questionnaires, and covariates such as age, sex, body mass index, history of diabetes, and alcohol consumption were collected. Multivariate Cox regression analysis was used to evaluate the association between depression and all-cause mortality in patients with gastrointestinal diseases, with visualization via Kaplan-Meier survival curves. Additionally, restricted cubic spline analysis was performed to explore the nonlinear relationship between depression scores and mortality risk, while receiver operating characteristic curve analysis assessed the predictive value of related indicators. Patients with gastrointestinal diseases exhibited significant differences compared to non-patients in terms of depression scores, socioeconomic status, body mass index, alcohol consumption, and diabetes prevalence (P < .05). Multivariate Cox regression showed that depression significantly increased the mortality risk in patients with gastrointestinal diseases (hazard ratio = 7.96, 95% CI: 3.26-19.47, P < .001). Restricted cubic spline analysis revealed a nonlinear relationship between depression scores and mortality risk, with a pronounced cumulative effect of higher depression severity on mortality (nonlinearity test P < .001). Receiver operating characteristic curve analysis demonstrated that depression scores were a robust predictor of mortality risk, with an area under the curve of 0.734 (95% CI: 0.665-0.887). Depression significantly increases the mortality risk in patients with gastrointestinal diseases, particularly in those with high depression scores. Psychological health management and comprehensive intervention strategies are essential for improving patient outcomes.