Combined influence of depression and low-grade inflammation on mortality in peritoneal dialysis patients

BACKGROUND: The relationship between depression and systemic inflammation as risk factors for mortality is not well understood and requires further investigation. METHODS: Patients undergoing continuous ambulatory peritoneal dialysis (CAPD) between July 01, 2015 to December 31, 2019, were analyzed and followed up until December 31, 2020. According to their status of depression (PHQ-9 score ≥ 5) and low-grade inflammation (hs-CRP level ≥ 3 mg/L), patients were divided into four groups (G1, without depression, nor inflammation; G2, with depression, without inflammation; G3, with inflammation, without depression; G4, with both depression and inflammation). We performed Kaplan–Meier and multivariable Cox proportional analyses of mortality for the combined influence of depression and systemic inflammation in this cohort. RESULTS: During the mean follow-up of 36.3 ± 14.8 months, 73 deaths were recorded in 358 participants. Compared with patients in group G1, patients in group G2 and G3 carried 137% {hazard ratio (HR): 2.37, 95% confidence interval (CI): 1.06—5.23, p = 0.035} and 140% (HR: 2.40, 95% CI: 1.01—5.69, p = 0.048) higher risk of mortality. Patients in group G4 (with both depression and inflammation) showed the highest risks of all-cause mortality with 276% higher mortality risk (HR: 3.76, 95% CI: 1.73—8.15, p = 0.001), respectively. CONCLUSION: The combined of depression and inflammation is associated with all-cause mortality in peritoneal dialysis patients, suggesting a need for further study of depression and low-grade inflammation in PD patients and potential relationship between them.