(CCB), beta-blockers (BB), angiotensin-converting enzyme inhibitors (ACEI) and angiotensin receptor blocker (ARB). The type of antihypertensive to be recommended depends on the patient’s health status, co-morbidities, treatment for other conditions being received, and the known side effects of the class of drugs.73 Recommended guidelines advocate a step ladder approach for therapy starting with thiazide diuretic alone or in combination with CCB, before addition of ACEI/ARB, BB or aldosterone agonist. The second medication can be added
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before or at maximization of the first drug, or started as fixed-dose combination. At each step of the treatment ladder, lifestyle and medication reinforcement are required to reach goal blood pressure.47
There are proven benefits of drug treatment of hypertension in the elderly with reduction in morbidity and mortality as shown by the hypertension in the very elderly trial (HYVET) study.74 Thiazide diuretics are recommended as first line drugs as monotherapy or in combination with CCB or ACEI/ARB in blacks.39, 47 This recommendation is based on the finding of volume dependence (salt and water) in blacks with hypertension.40 A landmark study has shown proven benefits of thiazide diuretics in reduction of heart failure, cerebrovascular events and combined cardiovascular outcomes in blacks when compared with CCB and ACEI/ARB.47It was also found to be generally well tolerated in blacks, but not to be surpassed in preventing the cardiovascular complications of hypertension.
Angiotensin receptor blockers have fewer side effects when compared with ACEIs and are better tolerated. The Telmisartan Randomised Assessment Study in, A. C. E. intolerant subjects with cardiovascular Disease (TRANSCEND), a randomized controlled trial of about 6000 patients, specifically studied the use of ARBs in patients unable to tolerate ACE inhibitors and concluded that they can be safely given to patients who had side effects from ACE inhibitors.75 The Study on Cognition and Prognosis in the elderly (SCOPE) described sustained blood pressure reduction and improved health-related quality of life with candesartan-based treatment, which is an angiotensin receptor blocker.76
McHugh et al. in a meta-analysis of multiple randomized control trials showed that beta-blockers should not be first line for hypertension in patients above 60 years, unless in the
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presence of compelling indications like previous myocardial infarction, heart failure or atrial fibrillation.77 This is because when compared to other antihypertensive drugs like ACE inhibitors, ARB and CCB, beta-blockers were inferior in reducing cardiovascular outcomes and even had higher risk of stroke, myocardial infarction and death in older patients.
Alpha blockers, centrally acting alpha-agonists and vasodilators are to be avoided in the elderly because of their unfavourable side effects such as postural hypotension.47
45 2.1.7. Complications of hypertension
Hypertension rarely causes symptoms in the early stages and many people go undiagnosed until complication sets in. People with untreated or uncontrolled hypertension are often at risk of developing complications directly associated with the disease. Adequate blood pressure control can however prevent or delay the onset of target organ damage in patient with hypertension. The major target-organ complications of hypertension include left ventricular hypertrophy, diastolic dysfunction, congestive heart failure, ischemic heart disease, stroke, retinopathy and renal failure.33
Nelissen et al. in a cross-sectional study on target organ damage among hypertensive non-pregnant adults in two rural communities in North-central Nigeria observed a high prevalence of 32% target organ damage in the hypertensive adults, with hypertension severity as a strong determinant.78 The study evaluated both hypertensive non-pregnant adults and non- hypertensive non-pregnant adults.
In North-east Nigeria, Kolo et al. in a study on hypertension-related admissions and outcomes, reported stroke in 44.4% of cases with it causing mortality in 39.3%, followed by chronic kidney disease in 36.6%; hypertensive emergencies in 30.9% and hypertensive heart failure in 27.5%.79 The above being a hospital-based study had prevalence of target organ damage as the patients were admitted for these complications.
Oladapo et al. in a study on the prevalence and pattern of target organ damage and associated clinical conditions in 415 hypertensive individuals in a rural community in South-western Nigeria, observed the following: evidence of target organ damage in 43.1%, cardiovascular disease in 10.8%, Left ventricular hypertrophy in 27.9%, atrial fibrillation in 16.4%, microalbuminuria in 12.3% and overt proteinuria in 15.3%, stroke in 6.3%, heart failure in
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4.6%, retinopathy in 2.2%, ischaemic heart disease in 1.7% and peripheral vascular disease in 3.6% of patients.80 The study population were adults aged 18-64 years living in a rural community. The association between increasing age and target organ damage was not elucidated in the study, however, target organ damage was significantly higher in those with severe hypertension and diabetes mellitus.80 Ayodele et al. also studied pattern of target organ damage among adults with treated hypertension in an outpatient clinic in South-western Nigeria and found left ventricular hypertrophy in 31%, heart failure in 10.8%, chronic kidney disease in 18.2% and stroke in 8.9% of the patients.81
In South-east Nigeria, hypertension with its complications accounted for 69.6% of the cardiovascular system in-patient admissions, with congestive cardiac failure in 26.5% of cases.
The case fatality rate of hypertension with its related complications was 42.9% in the study.82 The high figures recorded in this study could be because the patients requiring admission would have had cardiac-related emergencies, and were not healthy subjects as would have been seen in out-patient clinic or within the community.
Apart from the above hypertension-related complications in Nigerians, risk factor from coronary artery disease was as high as 53% of cases and hypertensive retinopathy was responsible for 4.6% to 13% of retinal disease over the past five decades (1970-2011) in a review study in Nigeria.36