Sodium Intake in Post-Stroke Patients – its Influence on Blood Pressure and Stroke Outcomes In Uganda
MetadataShow full item record
Background. Stroke is one of the leading causes of morbidity and mortality worldwide with developing countries accounting for 85% of global deaths. According to Heart and Stroke Statistics Update (2019), globally 62% of cerebrovascular disease and 49% of ischemic heart disease deaths are attributed to elevated blood pressure. High blood pressure is the largest contributor to stroke-related death in the world. Multiple lines of investigation including genetic, epidemiological and interventional studies have demonstrated consistently a positive relationship between salt intake, blood pressure increment and cardiovascular consequences. The work contained in this study assesses sodium, its impact on BP control and post-stroke outcomes among stroke patients in Uganda’s population. Aim. The overall goal of this doctoral work was to assess 24-hour urine sodium levels as an index of dietary salt consumption in this population and its association with dietary salt knowledge, hypertension and outcomes among post-stroke patients in Uganda. Methods. Studies were conducted among post-stroke patients recruited from the Neurology Outpatient Clinic of Mulago National Referral Hospital to answer three specific objectives. Study 1- Using data from a case- control study conducted between 2015 and 2016, we assessed the influence of sodium consumption and associated knowledge on post-stroke hypertension, using 24-hour urine sodium, a valid measure of dietary salt consumption and a salt knowledge questionnaire. Study 2- Using a cross sectional and convergent parallel mixed methods design, between July 2015 and January 2016, we assessed knowledge, attitudes, and behaviors related to salt consumption decisions after stroke in Uganda’s population. Qualitative responses were analyzed using an inductive approach with thematic analytic procedures. Relationships xv between healthy dietary salt compliance, dietary salt knowledge and participant characteristics were assessed using logistic regression analyses. Study 3- Using a prospective cohort study in which participants were enrolled between August 2016 and August 2017 and followed for up for 12-months following an index stroke, we assessed the associations of the delay between symptom onset and hospital presentation, 24 hour urine sodium excretion, functional status, and other participant characteristics with post stroke mortality and stroke recurrence. Regression and Kaplan–Meier analyses were used to determine the predictive factors and survival at 1-year. Result: High 24-hour urine sodium (>8.5 g/d) was more prevalent among hypertensive post stroke patients than their normotensive counterparts (OR=2.31 95%CI 1.36-3.90; p=0.002). Patients with minimal post-stroke disability who had a choice in determining their diets had higher urine sodium than their more disabled counterparts. Only 43% of the study population had basic dietary salt knowledge, 39% had adequate diet-disease–related knowledge, and 37% had procedural knowledge (report of specific steps being taken to reduce salt consumption). Dietary salt knowledge was similarly poor among hypertensive and normotensive post-stroke patients (p = 0.488) and was not related to education level (p = 0.205). Healthy dietary salt consumption behaviors were associated with basic salt knowledge (p < 0.0001), but no association was found between compliance and salt disease-related knowledge (p = 0.314). Only 20% and 7% of participants obtained health-related salt knowledge from their health facility and educational sources, respectively, whereas a plurality - 44% obtained this information from media personalities. 92% of participants had no understanding of nutrition labels, and only 25% of the study population reported utilizing a viable salt substitute that is potash—an inexpensive salt substitute that is both rich in potassium and low in sodium. xvi Mortality at 1 year was 38.9% with an overall survival probability of 61.1% and mean survival time of 9-months. 18.2% of all study participants had a recurrent stroke. Ischemic strokes, younger age, lower mean time to hospital presentation, higher functional status at the time of admission, higher urine sodium and BP values were independently associated with higher 12 month survival. Mortality hazard rate(s) against urine sodium conformed to a J-curve with increasing mortality at both extreme ends of the urine sodium scale. Conclusion. High salt consumption is an important determinant of hypertension and cardiovascular risk in a post-stroke population. High levels of urine sodium in the population were reflected in higher rates of post-stroke hypertension. The knowledge and understanding of health risks associated with salt was unsatisfactory despite the population being a high cardiovascular risk hypertensive population attending a specialist hypertension clinic. There is a need for increased education and awareness campaigns to increase patients understanding of the health risks associated with high-salt diet High 24-hr urine sodium levels and high preference for dietary salt were more frequent among post-stroke hypertensive patients in Uganda than in their normotensive counterparts. There was, however, no difference in dietary salt knowledge between these stroke hypertensives and non hypertensives groups. Because 18% of the study population had a recurrent stroke, there is a need to improve both primary and secondary stroke prevention. The development of educational strategies that include salt-diet preferences may lead to better blood pressure control in this high-risk population.