The Burden of Hyponatremia and 30-day Outcomes among Adults Admitted with Stroke at a Large Tertiary Teaching Hospital in Northwestern Tanzania

Johari Katanga ¹ Igembe Nkandala ¹ Joshua Ngimbwa ² Lilian Andrew Mwamba ³ Innocent Kitandu Paul ¹ Sospeter Berling ¹ Gladness Xavier ¹ Matilda K Basinda ¹ Sophia Kagoye ⁴ Karim Mahawish ⁵ Sarah Shali Matuja ^1*

• ¹ Catholic University of Health and Allied Sciences (CUHAS), Bugando, Tanzania
• ² Aga Khan University, Dar es Salaam, Tanzania
• ³ Department of Internal Medicine Jinzhou Medical University, China, Jinzhou City, China
• ⁴ Mwanza Research Centre, National Institute of Medical Research (Tanzania), Dar es Salaam, Tanzania
• ⁵ Counties Manukau District Health Board, Auckland, Auckland, New Zealand

The most frequent electrolyte derangement in adults with stroke is hyponatremia, which is associated with increased morbidity, mortality, and prolonged hospital stay. The study aimed to investigate the incidence of hyponatremia and 30-day outcomes among adults admitted with stroke at a large tertiary teaching hospital in Northwestern Tanzania.Methods: This cohort study recruited adults presenting with first-ever stroke (as defined by the World Health Organization) between November 2023 to May 2024. Data was collected on demographics, the degree of neurological impairment at admission using the National Institutes of Health Stroke Scale (NIHSS), laboratory workup including sodium levels on admission and the modified Rankin Scale was used to assess stroke outcomes. We used the modified Poisson and Logistic regression to examine factors associated with hyponatremia and 30-day outcomes respectively.Results: A total of 167 adults were enrolled, of which 56.9% (n=95) were female with a median age of 60 years (IQR 40-74) and 71.2% (n=119) had hypertension and heart failure. The incidence of hyponatremia was 29.3% (n=49) and among these, 53% (n=26) had mild severity hyponatremia. Factors associated with hyponatremia were: use of mannitol on admission ], p-value<0.001) and increasing NIHSS (aRR 1.03 [95%CI 1.00-1.06], p-value<0.05). There were no differences in 30-day mortality (38.3% Vs 36.7%, p=0.79) between those with and without hyponatremia respectively. The presence of leukocytosis was independently associated with 30-day mortality (aOR=2.7 [95% CI 1.39-5.36], p=0.004) and the median length of hospital stay was significantly higher in those with hyponatremia compared to those without: 7 days (IQR 4-9) vs 5 days (IQR 3-9), p=0.032.Hyponatremia is prevalent among adults with stroke in Northwestern Tanzania, associated with increased stroke severity, probable infections and prolonged hospital stays. The high prevalence of 3 hypertension and heart failure underscores the need for targeted preventive strategies. Early detection and appropriate management of hyponatremia are essential to improve stroke outcomes in this region.