Relationships of serum osmolality with cardiovascular disease and mortality risk: A retrospective cohort study of the National Health and Nutrition Examination Surveys database

Aim The relationship of serum osmolality with cardiovascular disease (CVD) is unclear. Serum osmolality calculated by sodium (Na), potassium (K), glucose, urea nitrogen and other indicators has been proposed to replace the complex and high cost directly measured plasma osmolality (pOsm). Herein, we aimed to investigate the association of calculated serum osmolality with CVD in adults, and further assess the mortality risk in patients with CVD. Methods In this retrospective cohort study, data of 28,715 adults were extracted from the National Health and Nutrition Examination Surveys (NHANES) database in 2007-2018. We explored the association of serum osmolality with CVD in adults using weighted univariate and multivariate logistic regression analyses, and further investigated relationship of serum osmolality with all-cause mortality in patients with CVD through weighted Cox regression analyses. The evaluation indexes were odds ratios (ORs), hazard ratios (HRs) and 95% confidence intervals (CIs). These relationships were also explored in subgroups of age, gender, stroke, cancer, hypertension, and diabetes mellitus (DM). Results A total of 2,415 (6.75%) individuals had CVD, and 706 (24.40%) of them died from all-cause. After adjusting for covariates respectively, we found that current dehydration (serum osmolality >300 mmol/L) was associated with both high odds of CVD (OR=1.26, 95%CI: 1.02-1.57) and high risk of all-cause mortality (OR=1.41, 95%CI: 1.13-1.75). In addition, the relationships between current dehydration and CVD were also significant in ≥60 years old, male, non-stroke, non-cancer, hypertension, and non-DM subgroups (all P<0.05). Conclusion Serum osmolality is important for adults especially when they at dehydration status, which may be associated with potential risk of CVD. Besides, patients with CVD should also pay more attention to the current dehydration to reduce the risk of mortality.