PATTERN OF PRE-HYPERTENSION AND ITS ASSOCIATED RISK FACTORS IN ADULT OBESE PATIENTS ATTENDING THE GENERAL OUTPATIENT CLINIC OF FEDERAL MEDICAL CENTRE, OWERRI.
Background: Hypertension (HBP), a sustained elevation in the blood pressure of an individual above that which is considered normal, is an important health issue in the developed and developing nations. It has been referred to as a “silent killer” because it often has no detectable symptoms while causing continuous and progressive damage to vital (target) organs in the body. Most hypertensive patients go through a stage termed pre-hypertension defined as systolic BP (SBP) of 120-139mmHg and/or diastolic (DBP) of 80-89mmHg in adults 18 years and above.
It emphasizes the risk associated with BP in this range and focuses on the need for increased clinical and public health attention since individuals with pre-hypertension are at increased risk of developing clinical hypertension compared with people of lower BP levels. Many disorders such as HBP occur with greater risk in obese people. Data has shown association of obesity with HBP, DM and dyslipidaemia under the umbrella disorder called metabolic syndrome.11 This shows that obesity and HBP frequently co-exist and may point to common lifestyle practices associated with metabolic syndrome.
Aim: This study was designed to assess the pattern of pre-hypertension and its associated risk factors among adult obese patients attending the General Out-patient Clinic (GOPC) of Federal Medical Centre, (FMC) Owerri, with a view to recommending measures for early detection, management and ultimate reduction in the burden of HBP among the study population.
Materials and methods: This was a hospital based cross-sectional study involving 384 obese patients that were consecutively recruited. The study lasted for three months. Relevant data on demographic features and risk factors of pre-hypertension were obtained using 384 pre-tested, interviewer administered questionnaires while the anthropometric indices, blood pressure and plasma lipid profile were done using standard clinical measurements. Data was analyzed using
Statistical Package for Social sciences version 15.
Results: Majority of the subjects were females (68.0%) with a male to female ratio of 1: 2.1, belonged to 50-59 years (25.5%) age group, were civil servants (38.6%), Ibos (94.0%), Christians (92.2%), married (75.8%), of middle socio-economic class (82.3%) and had tertiary level of education (85.7%). The prevalence of pre-hypertension among the study population was 43.0%. Total Cholesterol ( لا 2 = 24.91, p < 0.0001), High Triglyceride level (لا2 = 16.65, p < 0.0001), Low HDL-C (لا2=62.62, p< 0.0001), elevated LDL-C (لا2 = 19.3, p < 0.0001), cigarette smoking (لا2 = 57.13, p < 0.0001) and inadequate physical activity (لا2 = 76.51, p < 0.0001) were associated risk factors of pre-hypertension on bivariate analysis.
Conclusion: This study has demonstrated a more common pattern of combined systolic and diastolic pre-hypertension with a considerable prevalence among adult obese patients in an African community. It also showed a direct relationship between pre-hypertension and obesity. Dyslipidaemia, cigarette smoking and inadequate physical activity were noted to have significant association with pre-hypertension on bivariate analysis.
The study recommended routine screening of the obese patients for pre-hypertension and a comprehensive health education on healthy lifestyle practice such as regular physical activity for its prevention.
TABLE OF CONTENTS
Title Page i
Dedication iv Acknowledgement v
Table of contents vi
List of abbreviations and acronyms vii
List of tables ix
List of appendices x
Chapter one: Introduction 3
Chapter two: Literature review 12
Chapter three: Materials and methods 35
Chapter four: Results 49
Chapter five: Discussion 67
Limitations of study 75
CHAPTER ONE INTRODUCTION
Non-communicable diseases (NCDs) such as hypertension (HBP), diabetes mellitus (DM) and obesity have received global attention in the last two decades. These conditions which in the early 80s either attracted minimal attention in sub-Saharan Africa or were termed “Whiteman’s sickness” have grown so much in significance that within a span of just about twenty years, the health statistics in Nigeria and other parts of sub-Saharan Africa have been dramatically altered by them. Obesity, which was socially and culturally acceptable among Nigerians, hence not regarded as a medical problem, is now widely recognized as a rapidly growing health risk globally.1 This has been attributed to the change in lifestyle with abandonment of the traditional high fiber diet and active lifestyle for diet rich in excess calories, saturated fat and sedentary lifestyle.2 As a result, NCDs notably hypertension (HBP), diabetes mellitus (DM) and obesity have emerged
global pandemics and major causes of morbidity and mortality in the world.3,4
Whereas a lot of studies, advocacy and funding with free screening and treatment are on-going on a wide scale for communicable diseases such as HIV/AIDS, tuberculosis among others in Nigeria and Africa, little can be said about this for NCDs. Non-communicable diseases are implicated for rising morbidity and mortality in Africa, and carry great concern for the future. The incidence and prevalence of obesity have increased significantly during the past two decades and this trend is said to be rising, not just in the developed nations but also in the developing world.2 In Nigeria, a prevalence rate of 16.3% and 14% have been reported for obesity in Okirika and Port-Harcourt respectively, both in Rivers state.5
Obesity is an emerging problem in segments of sub-Saharan African society particularly where lifestyles are becoming urbanized and westernized. It is reported to be associated with increased risk of premature death, heart disease, HBP and DM.6-8 Many disorders occur with greater risk in obese people, the most important being HBP, type 2 DM and dyslipidaemia.6,9 Data had shown association of obesity with HBP, DM and dyslipidaemia under the umbrella disorder called metabolic syndrome.10 This showed that obesity and HBP frequently co-exist and may point to common lifestyle practices associated with metabolic syndrome.
Hypertension (HBP), a sustained elevation in the blood pressure of an individual above that which is considered normal, is an important health issue not just in the developed nations but also in the developing countries of the world including those of sub-Saharan Africa11. It is a significant public health challenge today because of its worldwide occurrence coupled with being the most important modifiable
risk factor for cardiovascular, cerebrovascular and renal diseases12,13.It has been referred to as a “silent killer” because it often has no symptoms while causing continuous and progressive damage to vital (target) organs in the body.HBP is the leading global risk for mortality, being responsible for about 7.5 million deaths annually (13% of total), and it is the fifth leading contributor to the global burden of disease accounting for about 57million disability-adjusted life years (DALYs)14.
Blood pressure levels are continuously related to the risk of developing cardiovascular disease15,16. The risk of mortality from cardiovascular and cerebrovascular events doubles for every 20/10mmHg increase in blood pressure above 115/75mmHg17. This continuous relationship between the level of blood pressure and cardiovascular risk makes any numerical definition and classification of hypertension arbitrary15,16. Previously, the blood pressure threshold for defining hypertension was 160/95mmHg, however, more recently, several guidelines have set the blood pressure threshold for defining hypertension at 140/90mmHg15-17. Hypertension is therefore defined as a systolic blood pressure of140 mmHg or greater and/or a diastolic blood pressure of 90 mmHg or greater in subjects who are not taking anti-hypertensive medications15.
Hypertension has a worldwide occurrence and it is estimated that it presently affects as many as one billion persons globally17.The reported prevalence of hypertension varies widely in the various parts of the world, as low as 3.4% in rural Indian men and as high as 72.5% in Polish women12. While the prevalence in the developed nations appears to be stabilizing or even declining in the past decade, the prevalence in the developing world has been on the increase12.The increase in the prevalence of hypertension in sub-Saharan Africa is believed to be due to rapid epidemiologic transitions brought about by economic development, industrialization, urbanization and changing lifestyle factors11.
Several risk factors for essential hypertension have been identified and they include older age, a positive family history of hypertension, diabetes, heavy alcohol intake, obesity, excessive dietary salt intake,
sedentary lifestyle, cigarette smoking as well as hyperlipidaemia18,19.
Data from observational studies involving more than 1 million individuals had shown that death from both ischaemic heart disease and stroke increase progressively and linearly from levels as low as 115mmHg systolic and 75mmHg diastolic blood pressures upwards.20The increase risks are present in individuals ranging from 40 to 89 years age. For every 20mmHg systolic or 10mmHg diastolic increase in blood pressure (BP), there is a doubling of mortality, from both ischaemic heart disease and stroke. In addition, longitudinal data obtained from the Framingham Heart Study have indicated that BP values between 130-139/ 85-89 mmHg are associated with a more than two fold increase in relative risk from CVD as compared with those whose BP levels are below 120/80mmHg.21
In view of the inherent dangers of high BP, the seventh report of the Joint National Committee on prevention, detection, evaluation and treatment of high BP (JNC 7) in 2003, defined a new category, termed Pre-hypertension, as systolic BP (SBP) of 120-139mmHg and/or diastolic (DBP) of 80-89mmHg in adults 18 years and above.17
The purpose of defining this category or stage was to emphasize the excess risk associated with BP in this range and to focus on the increased clinical and public health attention and prevention.17
According to JNC 7, individuals with pre-hypertension are at increased risk of developing clinical hypertension compared with people of lower BP levels17.
Evidence supporting pre-hypertensive state abound22-26 and chief among them is the longitudinal Framingham heart study which showed that BP in the pre-hypertensive range preceded the diagnosis of hypertension in 90% of subjects aged greater or equal to 55 years.26
The increase in the prevalence of DM, HBP and obesity in African communities is attributable to the drastic lifestyle changes accompanying urbanization and modernization as aforementioned. Unfortunately prospective approaches to this burden and possible preventive strategies have been partly hindered by scarcity of data on NCDs in Africa. Studies on NCDs (prevalence, pattern of disease, aetiopathogenesis and complications) in Nigeria and Africa as a whole are limited despite the fact that they are major health problems. Indeed Africa is experiencing one of the most rapid demographic and epidemiological transitions in the world history characterized by the tremendous rise in the burden of NCDs.3
The relationship between HBP and obesity is well established. Obesity is an important modifiable risk factor for the development of HBP.18,19
In sub-Saharan Africa, it is estimated that NCDs deaths were one-third of communicable disease deaths in 1990 and that by 2020 they will be roughly equal.3 Thus, even in the poorest African countries where communicable diseases predominate, NCDs have emerged substantial causes of morbidity and mortality in adults especially in urban areas.
In view of this, the Federal Government of Nigeria in 1988 established an Expert Committee on NCDs with the main objective of identifying risk factors involved in these disease conditions and formulating suitable programmes for early detection and effective control.27
1.2 STATEMENT OF THE PROBLEM AND PROBLEM ANALYSIS
In the last couple of years, there has been an increase in the number of hypertensive patients that present to the General Out-patient Clinic (GOPC) of the Federal Medical Centre, Owerri. Many of these patients presented with varied co-morbidities, with multiple complications of hypertension including cerebrovascular accidents, heart failure, myocardial infarction, and end stage renal disease. These complications contributed significantly to deaths due to medical illnesses in the hospital. A sizeable number of these complications are preventable through early detection and adoption of healthy lifestyles which could reduce the BP, decrease the rate of progression of BP to hypertensive levels with age, or prevent hypertension entirely. Moreover, the increased urbanization and incessant adoption of Westernized lifestyles in addition to the dramatic surge in the number of fast food restaurants in Owerri, in the recent past and its possible implications on blood pressure, are critical public health challenges. This trend is worrisome considering the influence of junk food on cardiovascular health.
Pre-hypertension is a recognized risk factor for overt hypertension and has been associated with an increased risk of myocardial infarction, stroke, heart failure, and cardiovascular death. These are clinical scenarios that are of great concern to the family physician because of their long-term impact on health. The increasing incidence of heart failure and strokes, which are notable complications of hypertension in our locality, have not only reduced the quality of life of the affected individuals but also placed a huge burden on the health care facilities28-33.
Despite the importance of this new BP category and the rising BP levels in many sub-Saharan African countries, limited studies to date have assessed pre-hypertension in Nigeria34,35-40. Recent evidence suggests that BP levels and hypertension rates in Nigeria are among the highest in Africa. The increased prevalence of hypertension in Nigeria is consistent with the higher levels of stroke
and CVD mortality28-33. This ugly trend needs to be checked in order to decrease the incidence and overall cardiovascular morbidity and mortality associated with increasing levels of blood pressure. The long-term benefits of targeting individuals with pre-hypertension with lifestyle modifications may be greater for low-income countries like Nigeria, where activities aimed at controlling clinical hypertension have to compete with many other pressing health challenges like malaria, `tuberculosis, and HIV/AIDS. This study was conceptualized and carried out to determine the pattern of pre-hypertension and its associated risk factors among adult obese patients attending the GOPC of the Federal Medical Centre, Owerri.
1.3 JUSTIFICATION FOR THE STUDY
It is common knowledge that one of the major obstacles to the control of blood-pressure-related diseases in low and middle income countries is the dearth of appropriate primary healthcare services, which in the Nigerian context is compounded by the lack of political will on the part of policy makers to reasonably implement or fund healthcare programmes. This trend is worrisome and has been worsened by the persisting interaction between poverty, ignorance and disease, which abound in our environment. This again brings to light one of the key challenges facing the delivery of primary healthcare services in our setting and the need for primary prevention of hypertension cannot be overemphasized.
In view of the rising prevalence of hypertension and the great burden it imposes on the healthcare system and families in Nigeria, identification and monitoring of individuals with blood pressures that are within the pre-hypertensive range remains worthwhile. This study will provide the prevalence rate, pattern and associated risk factors of pre-hypertension in adult obese patients attending the General Out-patient Clinic of the Federal Medical Centre, Owerri. Such knowledge would help health care providers to address the modifiable behavioural risk factors of prehypertension such as cigarette smoking and inadequate physical activity.
This study will afford the participants the opportunity of knowing their blood pressure reading in numbers, not just in words, as this has been identified as the first step in preventing and/or controlling high blood pressure. Knowing the BP reading in numbers will help to assess what the individual needs to do to lower the risks of developing future health problems. It will also afford the opportunity to alert individual patients and the clinician that early action can prevent serious health consequences later. The study will also provide the opportunity to educate patients and their families concerning healthy lifestyles including the need to change one's lifestyles such as losing weight if overweight, increasing physical activity, avoiding cigarette smoking and reducing salt intake, which have been shown to prevent the progressive rise in blood pressure and even lower it. It will also impact positively on the awareness level of the study participants and the public, a key step to prevention and control of high blood pressure, which is an important public health problem.
Studies have shown that pre-hypertension is common. Progression of pre-hypertension to fullblown hypertension has been commonly documented. The management of hypertension and its complications are common medical problems confronting the family physician. Improving the awareness level of patients on pre-hypertension and motivating patients towards adoption of healthy behavioural lifestyle changes are capable of halting progression from pre-hypertension to hypertension or even preventing it. The implication is that the scarce resources spent on antihypertensive drugs annually and the associated cardiovascular morbidity and mortality would be less. Furthermore, the doctor–patient ratio which is a critical factor related to quality healthcare delivery in sub-Saharan Africa would be positively impacted on as fewer patients with hypertension or its complications will present to the family physician for work-up. This has the potential of optimizing healthcare as the work load of family physicians would reduce and more time given to patients and their families for counselling and education.
1.4 AIM AND OBJECTIVES
To assess the pattern of pre-hypertension and its associated risk factors among adult obese patients attending the General Out Patient Clinic of Federal Medical Centre, Owerri with a view to recommend measures for early detection, management and ultimate reduction in the burden of hypertension.
- To determine the socio-demographic characteristics of the study population.
- To determine the prevalence of pre-hypertension among the study population.
- To determine the association between pre-hypertension and lipid profile pattern of the study population.
- To determine the association between pre-hypertension and behavioural activities such as cigarette smoking, physical activity and alcohol consumption in the study population.
PATTERN OF PRE-HYPERTENSION AND ITS ASSOCIATED RISK FACTORS IN ADULT OBESE PATIENTS ATTENDING THE GENERAL OUTPATIENT CLINIC OF FEDERAL MEDICAL CENTRE, OWERRI.