Burden and correlates of cognitive impairment among hypertensive patients in Tanzania: A cross-sectional study
Authors: Pallangyo Pedro , Mkojera Zabella S , Komba Makrina , Mgopa Lucy R. , Bhalia Smita , Mayala Henry , Wibonela Salma , Misidai Nsajigwa , Swai Happiness J. , Millinga Jalack , Chavala Ester , Kisenge Peter R , Janabi Mohamed 
Published: June 2021

Abstract
Background: The evolution of cognitive impairment of vascular origin is increasingly becoming a prominent health threat particularly in this era where hypertension is the leading contributor of global disease burden and overall health loss. Hypertension is associated with the alteration of the cerebral microcirculation coupled by unfavorable vascular remodeling with consequential slowing of mental processing speed, reduced abstract reasoning, loss of linguistic abilities, and attention and memory deficits. Owing to the rapidly rising burden of hypertension in Tanzania, we sought to assess the prevalence and correlates of cognitive impairment among hypertensive patients attending a tertiary cardiovascular hospital in Tanzania.Methodology: A hospital-based cross-sectional study was conducted at Jakaya Kikwete Cardiac Institute, a tertiary care public teaching hospital in Dar es Salaam, Tanzania between March 2020 and February 2021. A consecutive sampling method was utilized to recruit consented hypertensive outpatients during their scheduled clinic visit. General Practitioner Assessment of Cognition (GPCOG) Score was utilized in the assessment of cognitive functions. All statistical analyses utilized STATA v11.0 software. Pearson Chi square and Student’s T-test were used to compare categorical and continuous variables respectively. Logistic regression analyses were used to assess for factors associated with cognitive impairment. Odd ratios with 95% confidence intervals and p-values are reported. All tests were 2-sided and p<0.05 was used to denote a statistical significance. Results: A total of 1201 hypertensive patients were enrolled in this study. The mean age was 58.1 years and females constituted nearly two-thirds of the study population. About three quarters had excess body weight, 16.6% had diabetes, 7.7% had history of stroke, 5.7% had heart failure, 16.7% had renal dysfunction, 53.7% had anemia, 27.7% had hypertriglyceridemia, 38.5% had elevated LDL, and 2.4% were HIV-infected. Nearly two-thirds of participants had uncontrolled blood pressure and 8.7% had orthostatic hypotension. Overall, 524 (43.6%) of participants had cognitive impairment. During bivariate analysis in a logistic regression model of 16 characteristics, 14 parameters showed association with cognitive functions. However, after controlling for confounders, multivariate analysis revealed ≤primary education (OR 3.5, 95%CI 2.4-5.2, p<0.001), unemployed state (OR 1.7, 95%CI 1.2-2.6, p<0.01), rural habitation (OR 1.8, 95%CI 1.1-2.9, p=0.01) and renal dysfunction (OR 1.7, 95%CI 1.0-2.7, p= 0.04) to have independent association with cognitive impairment. Conclusion: This present study underscore that cognitive decline is highly prevalent among individuals with systemic hypertension. Moreover, our observation suggests that low education, rural life, unemployment status and renal dysfunction interactions with elevated blood pressure has the potential to predict cognitive performance over time. As the effective disease-modifying treatments for cognitive impairment are lacking, these findings imply that several modifiable risk factors including hypertension represents a potentially vital mechanism for prevention or delay of cognitive impairment.