Association of hyponatremia with in-hospital outcomes in infective endocarditis: A 5-year review from an Indian Intensive Care Unit

Hyponatremia is commonly noted with cardiovascular disorders, but its role in infective endocarditis (IE) is limited to being a marker of increased morbidity in IE patients with intravenous drug use. This was a 5-year retrospective review from an Indian Intensive Care Unit (ICU). Patients >18 years with IE and available serum sodium levels were included in the study. Pediatric and pregnant patients were excluded from the study. Hyponatremia was defined as admission sodium <135 mmol/L. Detailed data were abstracted from the medical records. Primary outcomes were need for invasive mechanical ventilation, ICU length of stay, and in-hospital mortality. Secondary outcomes included development of acute kidney injury, acute decompensated heart failure (ADHF), acute respiratory distress syndrome, stroke, and severe sepsis in the ICU. Two-tailed P < 0.05 was considered statistically significant. Between January 2010 and December 2014, 96 patients with IE were admitted to the ICU with 85 (88.5%) (median age 46 [34.5-55] years, 51 [60.0%] males) meeting our inclusion criteria. The comorbidities, echocardiographic, and microbiological characteristics were comparable between patients with hyponatremia (56; 65.9%) and eunatremia (29; 34.1%). Median sodium in the hyponatremic cohort was 131 mmol/L (127.25-133) compared to the eunatremic cohort 137 mmol/L (135-139) (P < 0.001). The primary outcomes were not different between the two groups. Hyponatremia was associated more commonly with ADHF (12 [21.4%] vs. 0; P = 0.007) during the ICU stay. Hyponatremia is commonly seen in IE patients and is not associated with worse hospital outcomes. ADHF was seen more commonly in the hyponatremic patients in comparison to those with eunatremia.