Objective: To observe the level of blood sodium in patients hospitalized for heart failure with water-sodium retention treated with loop diuretics and risk factors of low blood sodium.

Methods: We selected 1 378 acute decompensated heart failure patients who visited Anzhen Hospital, and they are treated with loop diuretics, 259 patients with weight loses more than 1 kg in one week was enrolled in the final analysis, and divided into 3 groups: Group A (weight reduction between 1-3 kg), Group B (weight reduction between 3-5 kg) and Group C (weight reduction over 5 kg). Blood sodium, creatinine and uric acid were compared among groups and risk factors of low blood sodium were analyzed.

Results: Blood sodium was similar before and post loop diuretics treatment in Group A, and reduced in group B ((138.28 ± 3.73) mmol/L vs. (139.34 ± 3.66) mmol/L, P < 0.05) and in Group C((137.60 ± 4.07) mmol/L vs. (139.44 ± 4.12) mmol/L, P < 0.05). Forty-six (17.8%) patients developed hyponatremia post loop diuretics treatment. Duration of loop diuretics use was the independent risk infector for hyponatremia (OR = 1.191, 95%CI 1.010-1.385).

Conclusions: Loop diuretics use is safe for treating hospitalized patients for heart failure with water-sodium retention and the risk of developing hyponatremia is low. Duration of loop diuretics use is the independent risk factor of hyponatremia.