Prevalence of Hyponatremia Amongst Patients with Heart Failure in Two Sub-Saharan Hospitals: Cross-sectional Study

<i>Background</i>: Hyponatremia is a very frequent abnormality amongst patients with Heart failure (HF) and significantly increases the morbidity and length of hospital stays amongst these patients. There is limited data on the epidemiology of this condition in sub-Saharan countries like Cameroon. This study therefore seeks to estimate the prevalence of hyponatremia amongst patients admitted for HF in 2 university hospitals in Cameroon. <i>Methods</i>: A hospital-based retrospective cross-sectional study was conducted in two University Hospital in Yaounde; Cameroon on patient files of patients admitted for HF from January 2021 to January 2022. A total of 107 participants were included using exhaustive sampling. Data were obtained from the patients’ medical records and analyzed using SPSS version 23.0. Frequencies were expressed as percentage (%) and continuous variables were presented as mean ± standard deviation. Comparison of categorical variables was done using the Chi-square tests. <i>Results</i>: A total of 184 patients were admitted for HF decompensations in the study period. Of these, 132 files were available but only 107 patient files met inclusion criteria. The female sex predominated in this study (55.1%) with a sex ratio (M/F) of 0.77. The majority of patients in this study were elderly patients with a mean age of 61.3±17.1 years and the age range of 70 years and above being the most frequent (31.8%). The prevalence of hyponatremia in this study was 32.7% dominated by mild hyponatremia (22.4%) followed by moderate (5.6%) and severe (2.8%) hyponatremia. The mean serum sodium level was 36.98 ± 5.24 mEq/l with extreme values of 122.0mEq/l and 148mEq/l. More than half of the participants in this study had a previous diagnosis of hypertension (53.3%) while 16.3% had diabetes mellitus. The most common etiologies for HF in our study were hypertensive cardiopathy (43.9%) and dilated cardiopathies (32.7%). Ischemic cardiopathies made up only 9.3% of etiologies in this study. 64.5% of participants were classified as NYHA class IV on admission. The predominant clinical manifestations at admission were dyspnea (92.5%) followed by pedal edema (76.6%) and pulmonary congestion (54.2%). One tenth of patients presented in a state of cardiogenic shock (10.3%). 45.8% of participants presented an anemia on complete blood count (Hb<12g/dl) while 38.3% had renal dysfunction (eGFR<60ml/min/1.73m<sup>2</sup>). <i>Conclusion</i>: Hyponatremia is very frequent amongst patients admitted for HF affecting about a third of patients. Despite this high prevalence, the vast majority of cases are mild with very few patients presenting with severe hyponatremia.