|Year : 2019 | Volume
| Issue : 4 | Page : 558-565
Prevalence and determinants of depression among patients with hypertension: A cross-sectional comparison study in Ghana and Nigeria
AD Ademola1, V Boima2, AO Odusola3, F Agyekum4, CE Nwafor5, BL Salako1
1 Department of Paediatrics, Faculty of Clinical Sciences, College of Medicine, University of Ibadan, PMB 5017, Ibadan, Oyo State, Nigeria
2 Department of Medicine and Therapeutics, School of Medicine and Dentistry, University of Ghana, P.O. Box 4236, Accra, Ghana
3 Department of Community Health and Primary Health Care, Lagos State University Teaching Hospital, PMB 21005, Lagos, Nigeria
4 Department of Medicine, Korle Bu Teaching Hospital, P.O. Box 77, Accra, Ghana
5 Department of Medicine, University of Port Harcourt Teaching Hospital, Port Harcourt, PMB 6173, Rivers State, Nigeria
|Date of Acceptance||13-Jan-2019|
|Date of Web Publication||11-Apr-2019|
Dr. V Boima
School of Medicine and Dentistry, University of Ghana, P.O. Box 4236, Accra
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Despite evidence linking depression to poor blood pressure (BP) control and increased hypertension-related morbidity and mortality, there is paucity of data about depression among patients with hypertension in sub-Saharan Africa. We assessed factors associated with depression among patients with hypertension in Ghana and Nigeria. Subjects and Methods: Patients with hypertension were recruited from four hospitals: In Ghana, Korle Bu Teaching Hospital (n = 120), and in Nigeria, the University of Port Harcourt Teaching Hospital, the Lagos State General Hospital, and the University College Hospital Ibadan (n = 237). Demographic, socioeconomic, psychosocial, and clinical factors which predicted depression among the study cohort were assessed by logistic regression. Depression and beliefs about medications were assessed with the Patient Health Questionnaire (PHQ-9) and the Beliefs about Medication Questionnaire, respectively. Depression was regarded as PHQ-9 score >4. Results: The mean ages of the Ghanaian and Nigerian cohort were 57.0 ± 13.7 years (58.3% female) and 56.4 ± 12.9 years (57.0% female), respectively. Prevalence of depression was 41.7% and 26.6% among the Ghanaian and Nigerian cohorts, respectively. Significant predictors of depression in the Nigerian cohort were age in years [OR 0.97 (0.95–0.99)], concern about medications [OR 1.15 (1.03–1.30)], and poor BP control [OR 2.06 (1.09–3.88)]. Young age was the only independent predictor of depression in the Nigerian cohort. In the Ghanaian cohort, none of the factors significantly predicted depression. Conclusion: Prevalence of depression is high among patients with hypertension in Ghana and Nigeria. Screening and treatment of depression among patients with hypertension in Ghana and Nigeria may have important implications for improving outcomes.
Keywords: Depression, Ghana, hypertension, Nigeria
|How to cite this article:|
Ademola A D, Boima V, Odusola A O, Agyekum F, Nwafor C E, Salako B L. Prevalence and determinants of depression among patients with hypertension: A cross-sectional comparison study in Ghana and Nigeria. Niger J Clin Pract 2019;22:558-65
|How to cite this URL:|
Ademola A D, Boima V, Odusola A O, Agyekum F, Nwafor C E, Salako B L. Prevalence and determinants of depression among patients with hypertension: A cross-sectional comparison study in Ghana and Nigeria. Niger J Clin Pract [serial online] 2019 [cited 2019 Apr 23];22:558-65. Available from: http://www.njcponline.com/text.asp?2019/22/4/558/255922
| Introduction|| |
Hypertension is a significant public health problem and a major cause of morbidity and mortality, accounting for 6% of all deaths worldwide., Prevalence ranges between 20% and 50% in most countries. Similar to global rates, the burden of hypertension in Nigeria and Ghana is increasing with prevalence of 20.8–36.6% and 25.7–32.8%, respectively., Population-based surveys indicate that the lifetime prevalence of depression ranges from 10% to 15%. The population-based World Mental Health Survey Initiative carried out in Nigeria reported 3.1% and 1.1% as the lifetime and 12-month prevalence of major depression, respectively. In Ghana, the World Health Organization study on global aging and adult health reported a prevalence of 6.7% for mild depression among adults 50 years and older. Compared to the general population, depression is more prevalent among patients with chronic diseases, such as hypertension, and is often associated with poor outcomes, poor quality of life, and increase utilization of health-care resources.,,,,, Among hypertensive patients, depressive symptoms have been associated with poor blood pressure (BP) control.
Despite the evidence linking depression to poor BP control and increased hypertension-related morbidity and mortality, there is paucity of data on the burden of depression among patients with hypertension in sub-Saharan Africa. In Nigeria, the prevalence of major depression among patients with hypertension in two studies were 26.7% and 6.2%., Factors associated with major depression, documented in one of the studies, were lack of education, being unmarried, and being unemployed. In Ghana, depression was found in 10.5% of patients with hypertension, but the factors that were associated with depression among patients with hypertension were not described. Our study was conducted to address gaps in the prevalence of depression among patients with hypertension or the factors that predict hypertension in Nigeria and Ghana.
The purpose of this study was twofold. First, to determine the prevalence of depression and second to determine the demographic (age, gender, and marital status), socioeconomic (level of education, employment status, and income), psychosocial (knowledge of hypertension, beliefs about need for medication, and concerns about medication), and clinical (BP control) factors that predict depression among patients with hypertension who receive care in four selected hospitals in Ghana and Nigeria.
| Subjects and Methods|| |
This cross-sectional study was conducted both in Ghana at the Korle Bu Teaching Hospital (n = 120 participants), and in Nigeria, at the University of Port Harcourt Teaching Hospital (n = 73 participants), the Lagos State General Hospital (n = 79 participants), and the University College Hospital Ibadan (n = 85 participants). Participant recruitment took place at the specialist, medical, and/or general outpatient clinics of the participating institutions between April and September 2013.
Eligibility criteria for participation in this study included age 18 years or older, diagnosis of hypertension, treatment with an antihypertensive medication for at least 12 months, and those that granted written informed consent to participate in the study. Hypertension was defined as systolic BP ≥140 mmHg and/or diastolic BP ≥90 mmHg or patients who were already on treatment for hypertension. Study questionnaires and other data collecting instruments were the same across all sites and were administered by the investigators and trained research assistants. Consecutive patients satisfying the inclusion criteria at each site were recruited into the study.
The main outcome variable was depression, and it was assessed with the Patient Health Questionnaire 9 (PHQ-9). The PHQ-9 is a 9-item scale with nine criteria on which the diagnosis of the DSM-IV depressive disorder is based. It has previously been validated in large studies, and also has previously been used in Ghana and Nigeria., The total score for the PHQ-9 ranges from 0 to 27 and scores of 0–4, 5–9, 10–14, 15–19, and 20–27 represent none to minimal, mild, moderate, moderately severe, and severe depression, respectively. In the present study, we classified scores of more than 4 as having depression. The PHQ-9 score ≥10 has a sensitivity of 88% and a specificity of 88% for major depression. The independent variables included demographic and socioeconomic characteristics (age, gender, ethnicity, education, occupation, and monthly income). Occupation was recorded as employed or unemployed/retired. Monthly income was grouped as ≤100, 101–300, and >301 USD. Beliefs about medication were assessed using the Beliefs about Medication Questionnaire. Knowledge about hypertension was assessed using a 17-item knowledge questionnaire which was adapted from previous studies.,, BP was measured with validated automatic BP monitor (OMRON M6 Comfort), after 10 min rest, in arm of seated patients three times at 1-min intervals following standard BP measurement guidelines.,, The average of the last two readings were recorded and BP control was defined as systolic BP <140 mmHg and diastolic BP <90 mmHg. Information regarding comorbidities was extracted from the patient's case records and referred to the documentation of other diagnoses apart from hypertension that will usually require long-term management. Marital status was grouped as married and others. “Others” referred to those who were single, separated, divorced, or widowed.
Continuous variables were summarized as mean (±SD), when the variables were normally distributed; otherwise, they were summarized as median and interquartile range. Categorical variables were summarized as proportions. Missing values were excluded from the denominator. In order to determine the prevalence of depression, we assessed the proportion of the study population with PHQ-9 score >4. For analysis by site, we grouped the Nigerian cohort from all three study sites together and determined factors associated with depression separately for the Ghanaian cohort and in the Nigerian cohorts. We compared continuous variables using the Student t-test. We compared ranked score that was not normally distributed using Mann–Whitney U test. We determined factors associated with depression using the Chi-squared test and bivariate logistic regression. Evaluation of selected covariates as potential confounding variables was carried out by using the stepwise binary logistic regression backward elimination (likelihood ratio). Variables were introduced into the model as demographic (age, gender, and marital status), socioeconomic (educational status, employment status, and income), psychosocial (knowledge of hypertension, beliefs about need for medication, and concerns about medication), and clinical factors (BP control). The reference groups for categorical variables in the logistic regression models were male for gender, married for marital status, senior secondary school/more than 3 years of secondary school education for educational status, being employed for employment status, >301 USD per month for income, and control for BP control. Statistical significance was considered as P value <0.05. The statistical analysis was done using the International Business Machines Statistical Package for the Social Sciences (IBM SPSS) v 23 software (IBM Corp., Armonk, N.Y., USA).
Ethical approval for the study was obtained from the Ethical and Protocol Review Committee of the University of Ghana Medical School, the University of Ibadan/University College Hospital Ibadan Ethics Committee, and the University of Port-Harcourt Teaching Hospital Ethics Committee.
| Results|| |
We enrolled 357 subjects, of which 57.4% were men. Two-thirds of the study participants were recruited from the three Nigerian sites. Characteristics of study participants by cohort are presented in [Table 1]. There were significant differences between Ghanaian and Nigerian patients in medical insurance, comorbidity, beliefs about need for medication, knowledge about hypertension, BP control, educational status, occupation, and depression [Table 1]. The mean age of participants from Ghana was 57 ± 13.7 years, with 58.3% being female, 60.1% of the participants had educational level of junior secondary or below. About one-fifth of the participants from Ghana were either unemployed or retired, and about half of the participants earned about 101–300 USD per month. Diabetes mellitus accounted for 43.9% of the comorbidities. The prevalence of depression was 41.7% with mild, moderate, moderately severe, and severe depression categories as 26.7%, 8.3%, 3.3%, and 3.3%, respectively. PHQ-9 score ≥10 was present in 14.9% of the patients. BP was controlled in 27.7% of the participants [Table 1].
Similarly, in the Nigerian cohort, the mean age was 56.4 ± 12.9 years, and 57% were women [Table 1]. About three quarter of participants had junior secondary education or below, and about a third were either unemployed or retired. About half (46.6%) earned >301 USD per month. Diabetes mellitus accounted for 50.5% (n = 48) of the comorbidities in the Nigerian cohort. The prevalence of depression was 26.6% with mild, moderate, moderately severe, and severe depression in 19.4%, 3.8%, 2.5%, and 0.4% of the participants, respectively. PHQ-9 score ≥10 was present in 6.7% of the patients. Forty percent had controlled BPs [Table 1].
Distribution of the study population characteristics by depression status is shown in [Table 2]. Depression was more prevalent in the cohort from Ghana than in the Nigerian cohort (P = 0.01).
|Table 2: Factors associated with depression among patients with hypertension in Ghanaian and Nigerian sites|
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Results of bivariate analysis for predictors of depression are presented in [Table 3]. Poor BP control and concern about medications were significantly associated with depression in the Nigerian cohort: OR 2.06 (1.09–3.88) and 1.15 (1.03–1.30), respectively. Younger age was also significantly associated with depression in the Nigerian cohort with every 1-year increment in age resulting in a 3% decrease in the odds of depression [Table 3].
|Table 3: Bivariate logistic regression for depression among hypertensives by site|
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In stepwise logistic regression analysis, younger age was an independent predictor of depression in the Nigerian cohort in all the models. Model 1 included age, gender, marital status, and a constant; model 2 included age, marital status, and a constant; whereas model 3 included age and a constant. Model 1 explained 7.3% of the variance in this cohort, whereas models 2 and 3 explained 6.3% and 4.9% of the variance in the Nigerian cohort, respectively [Table 4].
|Table 4: Stepwise logistic regression for the prediction of depression among patients with hypertension in Ghana and Nigeria by demographic, socioeconomic, psychosocial, and blood pressure control factors|
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In the Ghanaian cohort, the stepwise logistic regression analysis did not yield any variable that was significantly associated with depression [Table 4].
| Discussion|| |
In this study, the prevalence of depression among patients with hypertension in Ghana and Nigeria was 41.7% and 26.6%, respectively. In the Nigerian cohort, depression was associated with younger age, concerns about medications, and poor BP control. Stepwise logistic regression indicated that younger age was the only independent predictor of depression in the Nigerian cohort. In the Ghanaian cohort, however, there was no significant relationship between depression and any of the studied factors.
The prevalence of depression among patients with hypertension in the cohort from Nigeria was much greater than the prevalence of 6.2% for major depression that was noted among hospital-based patients with hypertension in Lagos. However, this difference was most likely attributable to the inclusion of patients with mild depression in our study cohort. When the subset of patients in the index study with PHQ-9 score of ≥10 is considered, the proportion of patients with major depression in our study is 6.7% which is comparable to the finding by Oshodi et al. in Lagos. However, the 6.7% approximate prevalence of major depression in our study is much less than the 26.6% prevalence of major depression reported among hospital-based patients with hypertension in a teaching hospital in Eastern Nigeria. Possible reasons for the differences may be genetic or environmental factors, but more studies are needed.
The prevalence of depression among patients with hypertension in the cohort from Ghana was 41.7% and much higher than 10.5% derived from a previous hospital-based Ghanaian study. About 80% of the patients in the previous study had been on management for hypertension for ≥10 years, whereas about 70% of the Ghanaian cohort in our study had been on treatment for hypertension for less than 10 years. Our findings suggest that depression may be more common in Ghanaian patients who have been on treatment for less than 10 years. The Ghanaian study however noted a high prevalence of anxiety (56%) and stress (20%) among patients with hypertension.
Ordinarily, one would expect that the proportion of patients with hypertension who have depression in Ghana and Nigeria will be similar; our study however indicates that that the prevalence of depression among patients with hypertension in Ghana is much higher than in Nigeria. Population rates of depression rates are known to differ worldwide and depression prevalence has been noted to vary between countries and within regions., Differences in depression prevalence are associated with factors which include substantive factors (i.e., genetic and environmental factors) and methodological approaches (i.e., different diagnostic criteria, sampling techniques, etc.). It has also been noted that while the use of the same diagnostic criteria, as in our study, may permit immediate comparability, the validity of the construct being measured may be reduced. In addition, country-specific differences in response patterns to surveys on mental health may contribute to variability., These factors may have contributed to the higher prevalence of depression in the Ghanaian cohort, but more studies are needed.
In the Nigerian cohort, patients with depression were significantly younger than patients without depression both in the unadjusted and adjusted models. The finding is similar to the observation that depression was associated with younger age among out-patients with heart failure in the United States of America. Indeed, in a review of depression in the general population from different countries, it was observed that in six high-income countries and Brazil, depression was more common in the younger age group; in two high income and five low-to-middle-income countries, there was no significant association between depression and age, but in India and Ukraine, young age was associated with low risk. Our observation of younger age for patients with depression in our study is however different from a previous observation in the Nigerian general population. Gureje et al. observed that increasing age was associated with higher estimates for positive responses to screening questions for major depression episodes and lifetime disorders among respondents who screened positive. Our study was however hospital based, focused on patients with hypertension, and included patients with mild depression; these might have contributed to the differences between our findings and the Nigerian general population. Our data suggest that younger Nigerian patients are less likely to adjust well to the diagnosis of hypertension and are more likely to have depression than older patients with hypertension.
Our study noted an association between concerns about medication and depression in the cohort from Nigeria. In a similar vein, a study from Northern Ireland reported significant bivariate association between depression and concerns about medications among patients with hypertension. We are not aware of any study from sub-Saharan Africa that has assessed the relationship between concern about medications and depression in patients with hypertension.
Poor BP control was associated with depression among hypertensives in the cohort from Nigeria. Association between poor BP control and depression has been variably reported in the literature.,, Similarly, depression has been independently associated with development of hypertension, but reports are inconsistent.,,, In addition, depression has been associated with risk and mortality from cardiovascular disease and stroke among patients with hypertension.,,
Findings in our study suggest that younger age mediated the relationship between poor BP control and concern about medication and depression among patients with hypertension in the Nigerian cohort. It also suggests that attention should be focused on managing depression among younger patients with hypertension in the Nigerian cohort. Treatment of depression may contribute to improved well-being and reduction of risks for cardiovascular disease morbidity and mortality among hypertensive patients in West Africa. Further studies are however needed to identify factors which predict depression, especially among Ghanaian patients with hypertension.
Our study however has several limitations including the cross-sectional nature which means causality could not be assessed. Additionally, our study was conducted mainly in tertiary institutions which may not be representative of the general population. In addition, we did not compare the prevalence of depression among patients with hypertension and age, sex, and socioeconomic matched controls which might have made it easier to directly elicit the contribution of hypertension to depression. The centers that were selected for this study may not represent all the ethnic, socioeconomic, and geographic factors in the two countries that influence depression in patients with hypertension. We also did not document the antihypertensive medications that the patients were taking, as some of these medications may be associated with depression. Our data however suggest a high prevalence of depression among patients with hypertension in Ghana.
| Conclusion|| |
We found a high prevalence of depression among patients with hypertension in Ghana and Nigeria. The prevalence of depression in the Ghanaian cohort was higher than that in the Nigerian cohort. In Nigeria, younger age, concerns about medication, and poor BP control were associated with depression in bivariate analysis. In the adjusted model, only younger age was retained as independent predictor of depression. More studies are needed to identify factors which predict depression in Nigeria and Ghana. Improving mental health screening and treatment may have important implications for morbidity and mortality among hypertensive patients in West Africa.
Financial support and sponsorship
The authors thank Cardiovascular Research Training Institute (Fogarty International Center Grant no. 5D43TW009140) for training and funding support.
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]