Abstract
BACKGROUND: Hyponatremia is the most common electrolyte imbalance, however the prognostic significance of hyponatremia in peripartum cardiomyopathy (PPCM) remains unclear. AIM: To assess the prognostic significance of hyponatremia in PPCM patients. METHODS: We consecutively recruited patients with PPCM from 14 sites in Nigeria and followed them up for a median of 18 months. Serum sodium was measured at baseline, and patients with hyponatremia (< 135 mmol/L) were compared with those with normal sodium levels. Cox proportional hazards regression models were developed to identify factors associated with all-cause mortality. RESULTS: Of the 191 PPCM patients recruited, 90 (47.1%) had hyponatremia at presentation. All-cause mortality among the hyponatremic patients (24/90; 26.7%) was significantly higher than among patients with normal serum sodium (7/101; 6.9%) (P-value < 0.001). In the Cox proportional hazards regression model, hyponatremia was independently associated with an increased risk of all-cause mortality [hazard ratio: 3.18 (95% confidence interval: 1.35-7.52; P = 0.008)], as were hypotension (systolic blood pressure < 100 mmHg) [2.22 (1.03-4.79); P = 0.043] and left ventricular ejection fraction (LVEF) < 25% [3.14 (1.47-6.73), P = 0.003]. CONCLUSION: Hyponatremia was common in our cohort of PPCM patients, and was independently associated with a threefold increased risk for all-cause mortality. Hypotension and a LVEF below 25% at presentation were also independent predictors of mortality.