Objectives: Non-lactate strong ion difference (SID) has been shown to be associated with predictors of mortality in intensive care unit. However, the existence of any association between non-lactate SID (nlSID) and all cause, cardiovascular and cancer mortality has not been explored before in community dwelling US adults.
Methods: In a nationally representative cross-sectional survey of the US non-institutionalized population, all adult participants (≥20 years of age) using National Health and Nutrition Examination Survey data (1999-2010) combined with National Death Index for mortality status through December 2011. Cox proportional hazard models were built to estimate the hazard ratios for cardiovascular, cancer, and all-cause mortality for each unit increase in non-lactate SID. The models were adjusted for demographic and confounder variables.
Results: In the study population the mean (SD) age was 49.6 (18.4) years. Of the study population, 31,475 (91.5%) were alive and 2,893 (8.4%) died during the mean (SD) follow-up period of 5.5 (3.5) years. In univariate regression model using nlSID as continuous variable, we found 2% (unadjusted hazard ratio, HR=1.02; 95% CI, 1.004-1.05) increase in all-cause but not in cardiovascular and cancer mortality (HR=1.03; 95% CI, 0.99-1.08, HR=1.01; 95% CI, 0.97-1.06). After adjusting for potential confounders, we found 7% (adjusted HR=1.07; 95% CI, 1.04-1.10), 5% (HR=1.05; 95% CI, 1.00-1.11) and 7% (HR=1.07; 95% CI, 1.02-1.12) increase in all-cause, cardiovascular, and cancer mortality.
Conclusions: A high nlSID is associated with an increase in cardiovascular, cancer and all-cause mortality and may be a prognostic indicator of mortality in general adult population. These findings may provide a point of reference for further studies.
Keywords: NHANES; acid-base; all-cause mortality; non-lactate strong ion difference.