DIURETIC THERAPY – STILL NUMBER 1 REASON FOR HYPONATREMIA

Abstract

Objective: Hyponatremia is the most common electrolyte imbalance in hospitalized patients. Up to 35% of patients develop hyponatremia during hospitalization. Hypertension is also common in hospitalized patients with prevalence rates up to 72%. We aimed to study the main causes of hyponatremia in hospitalized patients and to investigate the association between hyponatremia and hypertension in this population. Design and method: We included consecutive patients admitted to our hospital between March 2019 and August 2021, with the diagnosis of hyponatremia. We retrospectively analyzed the electronic health records and we collected demographic data, clinical and paraclinical data, hyponatremia etiology and associated comorbidities. We conducted comparative analysis between group without hypertension (Group 1) versus group with hypertension (Group 2). Results: The study population included 397 patients (mean age 71 ± 12 years old, 50,9 % women) with hyponatremia (4,9% of total admissions to our department in the specified period of time) -40,6% mild and 59,4% moderate-severe hyponatremia. The main causes of hyponatremia were diuretic use (37,7%), SARS-COV2 infection (17,1%), NYHA class IV heart failure (12,5%), SARS-COV2 infection associated with diuretic use (10,3%). 21,9% of patients had chronic treatment with psychotropic medication (antidepressants or antipsychotics), 8,6% of patients had chronic treatment with antiepileptic drugs The majority of patients in the study population had hypertension (68,3%). Patients in the hypertensive group were older (72 ± 11 vs 67 ± 15 years old, p<0,001). Mean sodium at hospital admission was lower in group 2 (125,9 vs 127,8 p = 0,01). Hyponatremic encephalopathy was more common in group 2 (15,9% vs 4,0%, p = 0,001). Diuretic use was also more prevalent in hypertensive group (56,3% vs 31,0%, p<0,001). Loop diuretic use was similar between groups (38,5%-Group 1 vs 32,5% - Group 2, p = 0,47), but thiazide-like diuretic use was more common in Group 2 (46,8% vs 20,5%, p = 0,003). Conclusions: The most common etiology of hyponatremia in the internal medicine department of an emergency hospital was diuretic use. Hypertension was associated with older age, lower sodium at hospital admission, hyponatremic encephalopathy and thiazide-like diuretic use in this population.