Social determinants of health and all-cause or cardiovascular mortality in chronic kidney disease: insights from 1999-2018 US National Health and Nutrition Examination Survey

Unfavorable social risk profile has been identified as a fundamental driver for disparate mortality rate. This study aimed to determine the association between social determinants of health (SDOH) and all-cause or cardiovascular disease (CVD) mortality in patients with chronic kidney disease (CKD). Data from adult participants with CKD and available information on SDOH were collected from the 1999-2018 US National Health and Nutrition Examination Survey. SDOH was calculated based on eight factors, including employment, poverty-income ratio, food security, education level, access to healthcare, health insurance, housing instability, and marital status. Cox proportional hazard regression analysis, restricted cubic spline analysis and subgroup analysis were performed. 5,420 participants (mean age 58.13 years, 43.04% men) were analyzed, including 729, 1,713, 1,849 and 1,129 with a SDOH of ≤ 2, 3-4, 5-6, and 7-8, respectively. Over a median follow-up of 92 months, 1,923 (742 CVD-related) deaths occurred. Compared to the reference group (SDOH of 7-8), the hazard ratios and 95% confidence intervals for those with a SDOH of 5-6, 3-4, and ≤ 2 were 1.25 (1.06-1.48), 1.51 (1.26-1.81) and 2.00 (1.54-2.60), respectively, for all-cause mortality, and 1.38 (1.08-1.77), 1.43 (1.09-1.89), and 1.78 (1.15-2.77), respectively, for CVD mortality. Restricted cubic spline analysis indicated linear dose-response relationships between SDOH levels and all-cause or CVD mortality. The association between SDOH and mortality was more pronounced in men than in women. Lower SDOH levels are independently associated with higher all-cause and CVD mortality rates among US adults with CKD, especially in men.