Risk for hypertension and heart failure linked to high normal serum sodium and tonicity in electronic medical records.

Background And Aims: Population aging is fueling an epidemic of age-related chronic diseases. Managing risk factors and lifestyle interventions have proven effective in disease prevention. Epidemiological studies have linked markers of poor hydration with higher risk of chronic diseases and premature mortality. Many individuals do not adhere to recommended hydration levels and could benefit from improved hydration habits. Our study evaluates the use of electronic medical records to confirm the relationship between inadequate hydration and the risk of chronic diseases, which may inform hydration-focused interventions in general healthcare.

Methods: We analyzed 20-year electronic medical records for 411,029 adults from Israel's Leumit Healthcare Services. Hydration status was assessed using serum sodium and tonicity. We included adults without significant chronic diseases or water balance issues, defined as having normal serum sodium (135-146 mmol/l) and no diagnosis of diabetes. We used Cox proportional hazards models, adjusted for age, to assess the risk of developing hypertension and heart failure.

Results: Our findings showed an increased risk of hypertension with elevated serum sodium levels: a 12% rise for the 140-142 mmol/l group and 30% for levels above 143 mmol/l (HR1.30, 95%CI:1.26-1.34). Tonicity over 287 mosmol/kg was associated with a 19% increased risk of hypertension (HR1.19, 95%CI:1.17-1.22). The risk of heart failure also increased, reaching 20% for sodium levels above 143 mmol/l (HR1.20,95%CI:1.12-1.29) and 16% for tonicity above 289 mosmol/kg (HR1.16, 95%CI: 1.10-1.22). The association between sodium and hypertension was observed across genders, while the risk of heart failure was more pronounced in females. Within the healthy Leumit cohort, 19% had serum sodium levels within the 143-146 mmol/l range, and 39% were in the 140-142 mmol/l range.

Conclusions: Data analysis from electronic medical records identified a link between serum sodium of 140 mmol/l and above and increased risk of hypertension and heart failure in the general Israeli population. Identifying individuals with high-normal sodium values in healthcare records could guide improvements in hydration habits, potentially leading to better health outcomes.