Risk Factor Characterization of Ischemic Stroke Subtypes Among West Africans.

BACKGROUND AND PURPOSE: To identify the qualitative and quantitative contributions of conventional risk factors for occurrence of ischemic stroke and its key pathophysiologic subtypes among West Africans. METHODS: The SIREN (Stroke Investigative Research and Educational Network) is a multicenter, case-control study involving 15 sites in Ghana and Nigeria. Cases include adults aged ≥18 years with ischemic stroke who were etiologically subtyped using the A-S-C-O-D classification into atherosclerosis, small-vessel occlusion, cardiac pathology, other causes, and dissection. Controls were age- and gender-matched stroke-free adults. Detailed evaluations for vascular, lifestyle, and psychosocial factors were performed. We used conditional logistic regression to estimate adjusted odds ratios with 95% CI. RESULTS: There were 2431 ischemic stroke case and stroke-free control pairs with respective mean ages of 62.2±14.0 versus 60.9±13.7 years. There were 1024 (42.1%) small vessel occlusions, 427 (17.6%) large-artery atherosclerosis, 258 (10.6%) cardio-embolic, 3 (0.1%) carotid dissections, and 719 (29.6%) undetermined/other causes. The adjusted odds ratio (95% CI) for the 8 dominant risk factors for ischemic stroke were hypertension, 10.34 (6.91-15.45); dyslipidemia, 5.16 (3.78-7.03); diabetes, 3.44 (2.60-4.56); low green vegetable consumption, 1.89 (1.45-2.46); red meat consumption, 1.89 (1.45-2.46); cardiac disease, 1.88 (1.22-2.90); monthly income $100 or more, 1.72 (1.24-2.39); and psychosocial stress, 1.62 (1.18-2.21). Hypertension, dyslipidemia, diabetes were confluent factors shared by small-vessel, large-vessel and cardio-embolic subtypes. Stroke cases and stroke-free controls had a mean of 5.3±1.5 versus 3.2±1.0 adverse cardio-metabolic risk factors respectively (P<0.0001). CONCLUSIONS: Traditional vascular risk factors demonstrate important differential effect sizes with pathophysiologic, clinical and preventative implications on the occurrence of ischemic stroke among indigenous West Africans.

May Measurement Month 2019: an analysis of blood pressure screening results from Nigeria.

The aim of this study is to estimate the frequency of undetected hypertension across the six geopolitical zones of Nigeria. We conducted an opportunistic screening of adults aged at least 18 years in the month of May 2019. Participants were recruited by trained volunteers using the May Measurement Month protocol. Blood pressure (BP) was measured using validated digital and mercury sphygmomanometers. We defined hypertension as BP ≥140/90 mmHg or the use of BP-lowering medication. A total of 3646 participants (52.8% females) with a mean age of 44.5 ± 15.7 years were screened. Hypertension was present in 39.2% of the participants but only 55. 4% of these were on antihypertensive medications. Only 46.8% hypertensives who were on medications had their BP controlled (<140/90 mmHg). Previous history of hypertension in pregnancy, alcohol intake and smoking were associated with increased mean systolic and diastolic BPs. The frequency of Nigerians with hypertension is high while only about half of those on antihypertensive medications are controlled. A multi-pronged approach to reduce the burden of hypertension is needed.

May Measurement Month 2018: an analysis of blood pressure screening results from Nigeria.

Hypertension remains the dominant cardiovascular risk factor worldwide. May Measurement Month (MMM) is an annual global programme of the International Society of Hypertension aimed at screening for undetected hypertension in the general population. We report the outcome of MMM 2018 in Nigeria. An opportunistic screening of adults aged at least 18 years was conducted in the six geopolitical zones of Nigeria in the month of May, 2018. Screening for hypertension was done by trained volunteers with the use of validated digital and mercury sphygmomanometers following the MMM protocol. Hypertension was defined as blood pressure (BP) ≥140/90 mmHg or the use of BP-lowering medication. There were 6398 participants (53.0% female) with a mean (SD) age of 41.7 (15.0) years. Hypertension was present in 36.4% of the participants with 51.1% of the hypertensives aware of their status, 41.8% on medication, of whom 43.1% were controlled. Overall, only 18.0% of all hypertensive participants had their BP under control. The proportion with hypertension is high, and awareness, treatment, and control rates are low. Concerted efforts are needed to improve awareness and treatment of hypertension in Nigeria in order to reduce the high rate of complications associated with uncontrolled BP.

Heart rate variability on antihypertensive drugs in black patients living in sub-Saharan Africa.

BACKGROUND: Compared with Caucasians, African Americans have lower heart rate variability (HRV) in the high-frequency domain, but there are no studies in blacks born and living in Africa. METHODS: In the Newer versus Older Antihypertensive agents in African Hypertensive patients trial (NCT01030458), patients (30-69 years) with uncomplicated hypertension (140-179/90-109 mmHg) were randomized to single-pill combinations of bisoprolol/hydrochlorothiazide (R) or amlodipine/valsartan (E). 72 R and 84 E patients underwent 5-min ECG recordings at randomization and 8, 16 and 24 weeks. HRV was determined by fast Fourier transform and autoregressive modelling. RESULTS: Heart rate decreased by 9.5 beats/min in R patients with no change in E patients (- 2.2 beats/min). R patients had reduced total (- 0.13 ms²; p = 0.0038) and low-frequency power (- 3.6 nu; p = 0.057), higher high-frequency (+ 3.3 nu; p = 0.050) and a reduced low- to high-frequency ratio (- 0.08; p = 0.040). With adjustment for heart rate, these differences disappeared, except for the reduced low-frequency power in the R group (- 4.67 nu; p = 0.02). Analyses confined to 39 R and 47 E patients with HRV measurements at all visits or based on autoregressive modelling were confirmatory. CONCLUSION: In native black African patients, antihypertensive drugs modulate HRV, an index of autonomous nervous tone. However, these effects were mediated by changes in heart rate except for low-frequency variability, which was reduced on beta blockade independent of heart rate.

Rationale and design of the Newer Versus Older Antihypertensive Agents in African Hypertensive Patients (NOAAH) trial.

BACKGROUND: Sub-Saharan Africa experiences an epidemic surge in hypertension. Studies in African Americans led to the recommendation to initiate antihypertensive treatment in Blacks with a diuretic or a low-dose fixed combination including a diuretic. We mounted the Newer versus Older Antihypertensive Agents in African Hypertensive Patients (NOAAH) trial to compare in native African patients a fixed combination of newer drugs, not involving a diuretic, with a combination of older drugs including a diuretic. METHODS: Patients aged 30-69 years with uncomplicated hypertension (140-179/90-109 mmHg) and two or fewer associated risk factors are eligible. After a 4-week run-in period off treatment, 180 patients will be randomized to once daily bisoprolol/hydrochlorothiazide 5/6.25 mg or amlodipine/valsartan 5/160 mg. To attain and maintain blood pressure below 140/90 mmHg during 6 months of follow-up, the doses of bisoprolol and amlodipine in the combination tablets will be increased to 10 mg/day with the possible addition of α-methyldopa or hydralazine. NOAAH is powered to demonstrate a 5-mmHg between-group difference in sitting systolic pressure with a two-sided p-value of 0.01 and 90% power. NOAAH is investigator-led and complies with the Helsinki declaration. RESULTS: Six centers in four sub-Saharan countries started patient recruitment on September 1, 2010. On December 1, 195 patients were screened, 171 were enrolled, and 51 were randomized and followed up. The trial will be completed in the third quarter of 2011. CONCLUSIONS: NOAAH (NCT01030458) is the first randomized multicenter trial of antihypertensive medications in hypertensive patients born and living in sub-Saharan Africa.

Impact of Operational Definitions on the Predictors and Prevalence of Asthma Estimates: Experience from a University Students' Survey and Implications for Interpretation of Disease Burden.

BACKGROUND: Inconsistent operational definitions during asthma surveillance can lead to inaccurate estimation of disease burden and formulation of health policy. This study aimed to evaluate the impact of different definitions on the prevalence estimates and predictors of asthma among university students in Ilorin, Nigeria. The secondary aim was to compare level of agreement of the different definitions. METHODS: This cross-sectional study was carried out from June to August 2015. The European Community Respiratory Health Survey (ECRHS) questionnaire was self-administered by 1485 students. Asthma diagnosis was based on five definitions used in previous studies in the country. These were ECRHS, International Study of Asthma, Allergies in Childhood (ISAAC), Probable, Modified ECRHS and Modified Probable asthma definitions. RESULTS: The prevalence rates varied from 10.4 to 24.1% depending on the definition. Prevalence obtained by using ECRHS definition significantly differed from estimates by other definitions (Z score ≥ 1.96 p<0.0001) except modified probable asthma. Identified predictors of asthma varied from five to six depending on the definition, and their strength also differed by definition. Regardless of the definition, reported nasal allergy, skin allergy, family history of nasal allergy, asthma and parental smoking were the predictors of asthma. The Kappa statistics demonstrated a fair to almost perfect association between the ECRHS and other asthma definitions (Kappa = 0.334-0.841, p < 0.001). CONCLUSION: The prevalence rates and predictors of asthma are affected by operational definitions. Researchers need to adopt a uniform definition for accurate estimation of disease burden, international comparison of result and formulation of prevention policy.

Costs and Cost-Effectiveness of Hypertension Screening and Treatment in Adults with Hypertension in Rural Nigeria in the Context of a Health Insurance Program.

BACKGROUND: High blood pressure is a leading risk factor for death and disability in sub-Saharan Africa (SSA). We evaluated the costs and cost-effectiveness of hypertension care provided within the Kwara State Health Insurance (KSHI) program in rural Nigeria. METHODS: A Markov model was developed to assess the costs and cost-effectiveness of population-level hypertension screening and subsequent antihypertensive treatment for the population at-risk of cardiovascular disease (CVD) within the KSHI program. The primary outcome was the incremental cost per disability-adjusted life year (DALY) averted in the KSHI scenario compared to no access to hypertension care. We used setting-specific and empirically-collected data to inform the model. We defined two strategies to assess eligibility for antihypertensive treatment based on 1) presence of hypertension grade 1 and 10-year CVD risk of >20%, or grade 2 hypertension irrespective of 10-year CVD risk (hypertension and risk based strategy) and 2) presence of hypertension in combination with a CVD risk of >20% (risk based strategy). We generated 95% confidence intervals around the primary outcome through probabilistic sensitivity analysis. We conducted one-way sensitivity analyses across key model parameters and assessed the sensitivity of our results to the performance of the reference scenario. RESULTS: Screening and treatment for hypertension was potentially cost-effective but the results were sensitive to changes in underlying assumptions with a wide range of uncertainty. The incremental cost-effectiveness ratio for the first and second strategy respectively ranged from US$ 1,406 to US$ 7,815 and US$ 732 to US$ 2,959 per DALY averted, depending on the assumptions on risk reduction after treatment and compared to no access to antihypertensive treatment. CONCLUSIONS: Hypertension care within a subsidized private health insurance program may be cost-effective in rural Nigeria and public-private partnerships such as the KSHI program may provide opportunities to finance CVD prevention care in SSA.

A survey on doctors' knowledge and attitude of treating chronic pain in three tertiary hospitals in Nigeria.

BACKGROUND: Chronic non-cancer pain (CP) is one of the most common complaints that bring patients to the hospital. When pain persists, people move from doctor-to-doctor seeking for help, thus the burden of CP is huge. This study, therefore was aimed at assessing attitude and knowledge of doctors in three teaching hospitals in Nigeria to CP. MATERIALS AND METHODS: Structured questionnaire was administered to doctors practicing at the University of Ilorin Teaching Hospital, Usmanu Danfodio University Teaching Hospital and University of Maiduguri Teaching Hospital. Responses were graded on maximum scale of five. RESULTS: Of the 410 doctors who participated in study, 79.7% were men. Their years of practice varied from 1 year to 20 years (mean SD = 4.5 ± 1.7 years). Close to 58% of participants were resident doctors, 36.4% medical officers and 8.6% consultants. Only 23.3% of participants had basic medical or postgraduate training on pain management. The physicians' mean goal of treating CP in patients was 3.7 ± 1.1, compared to 4.0 ± 1.1 in close relative and 4.1 ± 0.9 for doctors'-self pain. Only 9.5% of doctors use opioids for CP compared to 73% who use Nonsteroidal anti-inflammatory drugs (NSAIDs). Few doctors (23%) use ≥2 drugs to treat CP. Doctors were indifferent on the appropriateness of patients with CP to request for additional analgesics (mean score = 3.1 + 1.4). Doctors' self-rated knowledge of CP was 1.8 ± 0.7 compared to 4.1 ± 0.9 for acute and 0.8 ± 0.3 for cancer pains (P = 0. 003). CONCLUSION: Incorporation of pain management into continuing medical education could help improve observed deficiency in doctors' knowledge of pain treatment which resulted from lack of basic medical education on pain.

Left ventricular structure and function in black normotensive type 2 diabetes mellitus patients.

BACKGROUND: Relationship between type 2 DM and cardiovascular disease (CVD) is well known, with CVD being the most common cause of mortality in diabetics. Significant myocardial injury before overt CVD in DM can be identified early using echocardiography. This study therefore aimed at evaluating left ventricular structure and function of patients with type 2 DM. MATERIALS AND METHODS: One hundred and fifty adult type 2 DM patients were recruited with 150 age- and sex-matched controls. Patients and subjects with systemic hypertension, pregnancy, sickle cell disease and structural heart disease were excluded from the study. Participants were evaluated clinically; had anthropometric parameters and electrocardiogram taken. Echocardiograms were obtained according to the American Society of Echocardiography (ASE) recommendations. RESULTS: Mean age of the patients (55.4 ± 11.6 years) was similar to that of the control (54.2 ± 9.6 years) (P=0.348) and the duration of DM was 4.53 years. Left ventricular (LV) systolic function was normal in both groups but was higher in patients than controls (ejection fraction=70.3 ± 10.7% and 64.4 ± 9.4%, P =0.001 respectively). The prevalence of LV diastolic dysfunction (LVDD) was 72% in the patients compared with 6% in controls (P=0.001). Patients' age, body weight, duration of DM, LV mass index and left atrial dimension were positive correlates of LVDD while patients' age, weight and left atrial dimension were independent predictors of LVDD. CONCLUSION: There is high prevalence of alterations in LV structure and function in normotensive type 2 DM; and there is a need for early intervention to prevent overt LV dysfunction.

Progress report on the first sub-Saharan Africa trial of newer versus older antihypertensive drugs in native black patients.

BACKGROUND: The epidemic surge in hypertension in sub-Saharan Africa is not matched by clinical trials of antihypertensive agents in Black patients recruited in this area of the world. We mounted the Newer versus Older Antihypertensive agents in African Hypertensive patients (NOAAH) trial to compare, in native African patients, a single-pill combination of newer drugs, not involving a diuretic, with a combination of older drugs including a diuretic. METHODS: Patients aged 30 to 69 years with uncomplicated hypertension (140 to 179/90 to 109 mmHg) and ≤2 associated risk factors are eligible. After a four week run-in period off treatment, 180 patients have to be randomized to once daily bisoprolol/hydrochlorothiazide 5/6.25 mg (R) or amlodipine/valsartan 5/160 mg (E). To attain blood pressure <140/<90 mmHg during six months, the doses of bisoprolol and amlodipine should be increased to 10 mg/day with the possible addition of up to 2 g/day α-methyldopa. RESULTS: At the time of writing of this progress report, of 206 patients enrolled in the run-in period, 140 had been randomized. At randomization, the R and E groups were similar (P ≥ 0.11) with respect to mean age (50.7 years), body mass index (28.2 kg/m(2)), blood pressure (153.9/91.5 mmHg) and the proportions of women (53.6%) and treatment naïve patients (72.7%). After randomization, in the R and E groups combined, blood pressure dropped by 18.2/10.1 mmHg, 19.4/11.2 mmHg, 22.4/12.2 mmHg and 25.8/15.2 mmHg at weeks two (n = 122), four (n = 109), eight (n = 57), and 12 (n = 49), respectively. The control rate was >65% already at two weeks. At 12 weeks, 12 patients (24.5%) had progressed to the higher dose of R or E and/or had α-methyldopa added. Cohort analyses of 49 patients up to 12 weeks were confirmatory. Only two patients dropped out of the study. CONCLUSIONS: NOAAH (NCT01030458) demonstrated that blood pressure control can be achieved fast in Black patients born and living in Africa with a simple regimen consisting of a single-pill combination of two antihypertensive agents. NOAAH proves that randomized clinical trials of cardiovascular drugs in the indigenous populations of sub-Saharan Africa are feasible.

Relationship between left ventricular diastolic function and geometric patterns in Nigerians with newly diagnosed systemic hypertension.

BACKGROUND: It is not known whether abnormalities of left ventricular diastolic function are influenced by the various cardiac geometric patterns in Nigerians with newly diagnosed systemic hypertension. OBJECTIVE: To evaluate the relationship between the parameters of left ventricular diastolic function and the geometric patterns in this group of patients. METHODS: Two-dimensional, guided M-mode echocardiography including Doppler was performed in 150 consecutive, newly diagnosed hypertensive individuals and normotensive controls aged between 35 and 74 years. Left ventricular mass index and relative wall thickness were used to classify the hypertensive individuals into four geometric patterns, and the pulsed-wave Doppler parameters obtained were used to categorise the abnormalities of diastolic function. RESULTS: Four left ventricular geometric patterns were identified: 23 (15.3%) had normal left ventricle geometry, 33 (22%) had concentric remodelling, 37 (24.7%) were found to have eccentric hypertrophy, and concentric hypertrophy occurred in 57 (38%) of the hypertensive individuals. Left ventricular diastolic dysfunction occurred more in hypertensives with concentric left ventricular geometric pattern. Increased left ventricular mass index and relative wall thickness were found to be associated with the mitral E-wave, E/A ratio and pulmonary venous flow S-wave in the hypertensives (p < 0.001). CONCLUSION: In newly diagnosed Nigerian hypertensives, the abnormalities in left ventricular diastolic function varied between the different left ventricular geometric patterns, being worst in those with concentric geometry.