The synergistic effect of depression and moderate chronic kidney disease on the all-cause and cardiovascular disease mortality among adults: a retrospective cohort study

Background The relationship between the coexistence of depression and moderate chronic kidney disease (CKD) and mortality is unclear. We aimed to investigate whether there is a synergistic effect of depression and moderate CKD on the all-cause and cardiovascular disease (CVD) mortality among adults. Methods We studied 24,412 participants from the National Health and Nutrition Examination Survey 2005-2014 with a mortality follow-up assessment in 2015. Four groups were created based on depression and CKD status: Group 1, no depression and no CKD; Group 2, depression present and no CKD; Group 3: no depression and CKD present; Group 4: depression present and CKD present. Moderate CKD was defined as an estimated glomerular filtration rate of 15-59 mL/min/1.73 m(2) (Stage 3-4) or one-time urine albumin-to-creatinine ratio >= 30 mg/g. Depression was defined as the 9-item Patient Health Questionnaire score of 10 or more. Cox proportional hazards regression models were used to calculate the multivariate-adjusted hazard ratios (HRs) of death for Group 4 with other groups. Results Over a mean follow-up of 5.8 years, 1783 deaths were documented, including 338 deaths from CVD. The HR for all-cause mortality in Group 4 was 3.62 (95% CI: 2.69-4.87), 2.99 (1.92-4.66), and 1.75 (1.29-2.37) when compared with Group 1, 2, and 3, respectively. The HR for CVD mortality in Group 4 was 3.89 (1.68-9.00), 1.90 (0.86-4.21), and 1.97 (1.17-3.32) when compared with Group 1, 2, and 3, respectively. Conclusions There might be a synergistic effect of depression and moderate CKD on all-cause mortality. Moreover, depression might increase the risk of CVD mortality in individuals with moderate CKD.