Prevalence and factors associated with hyponatraemia among patients aged sixty years and above with heart failure attending Mulago National Referral Hospital

Abstract

Patients with heart failure are predisposed to electrolyte abnormalities especially the older population. The most common electrolyte abnormality among these patients is hyponatraemia which is mostly dilution hyponatraemia. It is a common electrolyte disturbance found in older patients especially among those who are hospitalized, on medicines and with comorbidities. It can be prevented and treated through strategies aimed at controlling the precipitating factors. Hyponatraemia is associated with increased length of stay in hospital and loss of independence among older patients with both acute and chronic heart failure. The prevalence and factors associated with hyponatraemia among older patients with heart failure are unknown in Uganda. Objectives: The objectives of the study were; To determine the prevalence of hyponatraemia among patients aged 60 years and above with heart failure attending Mulago National Referral Hospital. To describe the factors associated with hyponatraemia among patients aged 60 years and above with heart failure attending Mulago National Referral Hospital. Methodology This was a cross-sectional study conducted at Mulago National Referral Hospital between August 2013 and March 2014. Patients aged 60 years and over with predominantly acute decompensated heart failure were consecutively recruited from the cardiology ward, cardiac clinic and Uganda Heart Institute. A questionnaire was completed by the principal investigator or research assistant through an interview for those meeting the eligibility criteria. Laboratory investigations including serum sodium, urine sodium, serum osmolality, plasma osmolality, fasting blood sugar and fasting lipid profile were done. The data were analyzed using STATA version 12.0 Analysis software. Results: A total of 211 elderly patients (mean age 71.3±7.7) with a clinical diagnosis of heart failure were recruited into the study. The majority of the patients were females (n=130, 61.6%).The prevalence of hyponatraemia was 24.2% (51/211).Of these 27/51(52.9%) had mild hyponatraemia, 12/51(23.5%) had moderate hyponatraemia and 12/51(23.5%) had severe hyponatraemia. Vomiting and use of loop diuretics were identified as independent factors associated with hyponatraemia among elderly patients with heart failure. Conclusion: The prevalence of hyponatraemia among elderly patients with heart failure was relatively high (24.2%). The patients who presented with vomiting from any cause and with history of use of loop diuretics were more likely to have hyponatraemia. Therefore, clinicians should have a high index of suspicion of hyponatraemia among elderly patients with heart failure. These findings justify the need of regular monitoring of serum sodium and discontinuation of offending drugs should a patient develop hyponatraemia. A study about the quantity of salt intake among elderly patients with heart failure should be done.