Moderating Effect of Country of Residence in Predicting Adherence to Treatment Among Black Adults Diagnosed with Hypertension

Abstract

Background: Uncontrolled hypertension (HTN) is the major global risk factor for cardiovascular diseases (CVD). Black individuals have worse cardiovascular health outcomes than their racial counterparts. High incidences of HTN-related strokes, heart failure, and chronic kidney diseases are prevalent in Black communities. Long-term adherence to HTN treatment is efficacious in hypertension control but challenged by psychosocial factors and the asymptomatic nature of HTN. Purpose: This research aims to assess if the country of residence moderates the relationship between adherence and each of its potential predictors in Black adults with HTN residing in the United States and Nigeria. Methodology: This is a secondary data analysis of two studies conducted in New York and southeast Nigeria (n=226). Data were analyzed using SPSS Statistical software Version 27. Descriptive differences in adherence and predicting variables, bivariate analyses for significant predicting variables within each sample, and general linear model analyses with plots for country of residence interaction effects were conducted. Results: The mean ages of the US and Nigerian samples were 57.3 ± 11.9 years (70.9% female) and 46.6 ± 8.9 years (67.1% female), respectively. Significant differences (p <.05) were noted between levels of adherence, age, self–efficacy, illness perception, annual income, and herbal use. Adherence was significantly associated (p < .05) with social support, self-efficacy, provider-patient communication, depressive symptoms, herbal use, employment, and income status within the Nigerian sample. Adherence was significantly associated with depressive symptoms and income status within the US sample. The interaction of country of residence with illness perception, social support, self-efficacy, and provider-patient communication significantly predicted adherence but not for the other variables. Interestingly, there was an opposite relationship between illness perception and adherence between the two samples. Conclusions: The country of residence moderated the relationship between adherence and illness perception, social support, self-efficacy, and provider-patient communication. These findings have clinical, cultural, and policy implications. Understanding the similarities and differences between the US and Nigeria will help clinicians working with Black patients and tailor interventions to meet the unique needs of this population. Future studies and culturally relevant strategies to improve HTN treatment adherence could target factors unique to hypertensive patients’ country of residence.