EVALUATION OF MICROALBUMINURIA IN THE DIAGNOSIS OF NEPHROPATHY AMONG ADULT HYPERTENSIVES IN PLATEAU STATE SPECIALIST HOSPITAL, JOS

                                                         Summary

Background: Hypertension is one of the commonest causes of non-communicable diseases in

Nigeria and it is also one of the commonest risk factors for chronic kidney disease (CKD). Evaluating microalbuminuria which is a predictor of CKD is crucial to early prevention of this scourge considering the high prevalence rate of CKD in Nigeria (8-10%).

Purpose: To evaluate microalbuminuria in the diagnosis of nephropathy (CKD) among adult hypertensives in Plateau State specialist hospital (PSSH), Jos with a view of recommending dipstick urinalysis in early screening of renal disease.

Methodology: A hospital based cross-sectional descriptive study was performed from January to

March 2013 at the GOPD and MOPD of PSSH. A total of 152 hypertensive patients (47 males and 105 females) without a history of pre-existing kidney diseases participated in the study. A pretested questionnaire was used for collecting data on demographics, family and social history, disease information, social information and clinical characteristics. Anthropometric measurements such as: weight (kg), height (m), waist circumference (cm), hip circumference (cm), Waist/Hip ratio; Body Mass Index (BMI) (Kg/m²) were determined among respondents. A spot early morning urine samples were collected for dipstick urinalysis using Dirui H11 MA strips and those positive were quantitatively estimated for urinary albumin creatinine ratio (UACR). The data analysis was done using EPI info version 3.5.1 August 13, 2008 software Computation (CDC Atlanta Georgia, USA). A 95% confidence interval was used in this study and a P-value of less than 0.05 was considered significant.  Information obtained was represented in frequencies and percentages.  Mean and standard deviation were calculated for quantitative data. Pearson Chi square was used to determine the association between qualitative variables. Multiple logistic regressions were used to determine the risk factors associated with microalbuminuria.

Results: A total of 152 hypertensive patients, 47 (30.9%) males and 105 (69.1%) females were randomly selected by balloting from patients attending the GOPD/MOPD of PSSH. The mean age of the respondents was 55.38 ± 12.77years and the mean systolic and diastolic blood pressure was 140.00 ± 27.72mmHg and 90.00 ± 16.11mmHg respectively. Microalbuminuria was found in 90 subjects (59.2%) using dipstick (M11 Dirui), out of which 81 of them (90.0%) were confirmed using UACR, giving a prevalence of 53.3%.  Nine risk factors (age, BMI, WHR, SBP, DBP, alcohol consumption, cigarette smoking duration of hypertension and habitual intake of analgesics/herbs were considered simultaneously in a multiple logistic regression, after  adjusting for confounding variables, the only independent determinant of elevated UACR/CKD was systolic blood pressure (SBP). P < 0.004, 95% CI: 1.0116-1.0643.

Conclusion:  In Plateau State Specialist Hospital, microalbuminuria which is a predictor of nephropathy among hypertensives was common. Systolic blood pressure was the independent determinant risk factor for microalbuminuria (UACR). Majority of the respondents with CKD were detected using the microalbumin dipstick and were further confirmed by the UACR. The dipstick (M11 Dirui) was easy to perform and cheaper than the UACR.

TABLE OF CONTENTS

Title Page……………………………………………………………………………..i

Declaration……………………………………………………………………………ii

Certification…………………………………………………………………………..iii

Dedication……………………………………………………………………………iv

Acknowledgement……………………………………………………………………v

Table of contents……………………………………………………………………...vi

List of tables and figures………………………………………………………..…….x

Abbreviations………………………………………………………………………….xi

Summary………………………………………………………………………………xiv

CHAPTER ONE

1.0 Introduction………………………………………………………………………..1

1.1 Background of the study…………………………………………………………..1

1.2 Statement of the problem………………………………………………………….7

1.3 Definitions and classification of chronic kidney disease (CKD), hypertension,

microalbuminuria and proteinuria…………………………………………….............10

1.4 Rationale for the study…………………………………………………………….11

1.5 Aim and objectives of the study…………………………………………………..12

1.5.1 Aim of the study…………………………………………………………………12

1.5.2 Objectives of the study………………………………………………………….13

CHAPTER TWO

2.0 Literature review…………………………………………………………………..14

2.1 Brief historical background of proteinuria/ microalbuminuria…………................14

2.2 Overview of hypertension………………………………………………………..15

2.2.1 Epidemiology of hypertension………………………………………………….15

2.2.2 Risk factors for hypertension……………………………………………………16

2.3 Epidemiology of chronic kidney disease………………………………………….18

2.3.1 Microalbuminuria in essential hypertension……………………………………..19

2.4 Prevalence of microalbuminuria among hypertensives……………………………19

2.5 Risk factors for microalbuminuria (CKD)…………………………………………21

2.5.1 Age……………………………………………………………………………….22

2.5.2 Gender…………………………………………………………………………… 22

2.5.3 Race….……………………………………………………………………………22

2.5.4 Hypertension as a risk factor for microalbuminuria………………………………22

2.5.5 Diabetes mellitus as a risk factor for microalbuminuria…………………………..24

2.5.6 Cardiovascular disease as a risk factor for microalbuminuria…………………… 25

2.5.7 Smoking as a risk factor for microalbuminuria…………………………………...26

2.5.8 Alcohol intake and microalbuminuria…………………………………………….26

2.5.9 Physical exercise and microalbuminuria………………………………………….27  

2.5.10 Microalbuminuria and its relations with serum lipid abnormalities in newly

diagnosed hypertensives……………………………………………………………….28

2.5.11 Socio-economic status as risk factor for microalbuminuria……………………..28

2.5.12 Association between obesity and microalbuminuria…………………………….28

2.6 Mechanisms of microalbuminuria in hypertensives………………………………...31

2.7 Diagnosis of nephropathy using microlabuminuria (dipstick) and UACR………..32

2.7.1 Dipstick urine testing-haematuria………………………………………………..33

2.7.2 Dipstick urine testing- proteinuria………………………………………………..34

2.7.3 Microalbumnuria (dipstick) and microalbuminuria (UACR)…………………….36

2.8 Treatment of nephropathy among hypertensive patients in primary care…………..38

2.8.1 Lifestyle modifications in slowing the progression of CKD in hypertensives……38

2.8.2 Blood pressure control…………………………………………………………....40

2.8.3 Lowering blood pressure using drugs…………………………………………….42

2.8.4 Reducing proteinuria using drugs………………………………………………...43

2.8.5 Reducing the risk of cardiovascular disease………………………………………44

2.8.6 Reducing microalbuminuria using drugs………………………………………….45

2.9 Prevention of hypertensive nephropathy……………………………………………46

2.9.1 Public awareness campaign………………………………………………………..46

2.9.2 Provision of information to patients by primary care providers about kidney

disease…………………………………………………………………………………..46

CHAPTER THREE

3.0 Materials and method……………………………………………………………….50

3.1 Background to the study area………………………………………………………50

3.2 Study population……………………………………………………………………51

3.3 Study design………………………………………………………………………..51

3.4 Sample size calculation …………………………………………………………….51

3.5 Sampling method…………………………………………………………………...52

3.6 Ethical clearance and informed consent……………………………………………53

3.7 Selection criteria…………………………………………………………………....53

3.7.1 Inclusion criteria………………………………………………………………….53

3.7.2 Exclusion criteria…………………………………………………………………53

 

3.8 Materials…………………………………………………………………………..54

3.9 Pre-testing of instruments for data collection……………………………………..55

3.10 Method of data collection………………………………………………………..55

3.11 Method of data analysis…………………………………………………………..60

CHAPTER FOUR

4.0 Results………………………………………………………………………………61

4.1 Sociodemographic characteristics of the respondents……………………………..61

4.2 Disease characteristics of the respondents………………………………………….64

4.3 Social information of the respondents……………………………………………...66

4.4 Clinical characteristics of respondents……………………………………………..68

4.5 Investigation results of respondents……………………………………………….69

CHAPTER FIVE

5.0 Discussion…………………………………………………………………………..79

5.1 Prevalence of microalbuminuria among respondents………………………………79

5.2 Sociodemograhics…………………………………………………………………..80

5.3 Risk factors for microalbuminuria…………………………………………………..84

5.4 Association between obesity and microalbuminuria among respondents………….85

5.5 Confirmation of nephropathy using UACR among respondents positive on the

microalbuminuria (dipstick)……………………………………………………………87

5.6 Conclusion…………………………………………………………………………88

5.7 Limitations of the study…………………………………………………………...88

5.8 Recommendations…………………………………………………………………89             REFERENCES.....……………………………………………………………………90

                                                 CHAPTER ONE

1.0 INTRODUCTION

1.1 BACKGROUND OF THE STUDY

The magnitude of the problem of Chronic Kidney Disease (CKD) or nephropathy is enormous, and the prevalence of kidney failure is rising. Currently, CKD is emerging as a worldwide public health problem.¹ There is an ongoing discussion in Europe on whether screening for renal disease is sensible and cost-effective, be it universal screening or targeted screening in specific segments of the general population. Of course, screening for renal disease makes sense, not only with respect to prevention or slowing progression to end-stage renal disease, but quantitatively even more so with respect to prevention of cardiovascular complications.²

The World Health Report of 2002 and Global Burden of Disease Project Reports showed that diseases of the kidneys and urinary tract contribute to the global burden of diseases-with approximately 850, 000 deaths every year.³ Though, patients with End Stage Renal Disease (ESRD) represent a small group of the total European countries population, (0.02% in UK and 0.06% in Italy), dialysis costs absorb 0.7–1.8% of the health-service budget.⁴ In the United States, the expenditure on ESRD was estimated to double in the year 2010 to more than US$28 billion.⁴

Similar figures are lacking in Africa and indeed, Nigeria.⁴ The exact prevalence rate of CKD in Nigeria is not known. However, hospital based data in Nigeria have reported prevalence rates expressed as ratios of hospital admissions of between 1.6 and 8%.⁵ Chronic kidney disease affects approximately 10% of adult population in western world and 8-10% of hospital admissions in

South-East Nigeria.^1,6 In the United States, the incidence of ESRD continues to grow increasingly at a rate of 8–10%, with about 220,000 patients presently undergoing dialysis, 80,000 living with functioning renal transplant and about two million people in various stages of chronic renal failure. There are less detailed analyses for trends in Europe and Japan, but the data available indicate a similar pattern to that in the USA.⁵ End stage renal disease disproportionately affects people in developing countries like Nigeria as well as ethnic and racial minorities in the United States. Data from the United State Renal Data System (USRDS) Annual Report demonstrates that African Americans make up to 29% of the ESRD cases and yet represent only 12% of the United States population,⁵ with predominance in males than females. Similar gender differences have been documented among Nigerians.⁵ In the United States (US), the average age of CRF patients was 58 in 1999 and 62 in 1998, reflecting the increasingly available renal replacement therapy. While the average age of CRF patients among Nigerians lies between the third and the fourth decades.⁵ That is, CKD epidemiology in Sub- Saharan Africa including Nigeria mostly affects younger adults in their economically productive years; unlike in the developed world where middle aged and elderly populations are affected.⁷

High blood pressure (HBP) is a common disease globally. It is a major risk factor for chronic renal failure, cardiovascular disease, stroke, and peripheral vascular disease. Although there is no recent concise data on prevalence of HBP in Nigeria, however, it was estimated that about 17 to 20% or more of adult Nigerians have HBP.⁸  In the US, diabetes mellitus and hypertension are the two leading causes of CRF, while hypertension and chronic glomerulonephritis top the list in the tropics (including Nigeria).⁵ In fact, hypertension and glomerulonephritis are regarded as the major causes of CKD in Sub-Saharan Africa; other causes include diabetes mellitus and family history of CKD. In Scotland however, chronic pyelonephritis and chronic glomerulonephritis are of equal aetiological significance.⁷ Hypertension is a major risk factor for chronic kidney disease by causing direct damage to the small blood vessels in the nephrons.⁹ Renal dysfunction is a common finding in patients with hypertension and is associated with an increased risk for cardiovascular events (CVEs),^10,11 as well as with progression to ESRD.¹² It has been pointed out that cardiovascular risk progressively increases as renal function declines and that it is already significantly elevated at the earliest stages of renal damage.¹³ The Task force for the management of arterial hypertension of the European Society of Hypertension (ESH) and the European Society of Cardiology (ESC) published updated guidelines in 2007 in relation to microalbuminuria. These guidelines stated that microalbuminuria is an essential component in the assessment of organ damage and routine testing for microalbuminuria should be performed in all people with hypertension (>140/90 mmHg).¹⁴  To maximize risk reduction, physicians must aim for a blood pressure lower than 130/80 mmHg in those with albuminuria and hypertension. In 2009, a reappraisal of the 2007 guidelines placed a much stronger emphasis on the prognostic value of

microalbuminuria and proteinuria in the context of organ damage.¹⁴

Worldwide, the incidence of ESRD is increasing, resulting in an increased need for long-term renal replacement therapy (RRT).¹⁵ The timely commencement of renoprotective therapy, which consists predominantly of lowering blood pressure and reducing albuminuria or proteinuria, may slow progression of chronic kidney disease to ESRD. Because many individuals are unaware of having CKD, screening may be necessary.¹⁵ Moreover, identifying individuals with CKD is necessary for the purpose of treating the associated health problems with CKD such as increased risk for CVD, anaemia, and renal osteodystrophy.^15,16 Different screening strategies for detection of CKD have been proposed.¹⁷ Some advocate targeted screening of populations that are at increased risk for CKD, such as patients known with hypertension or diabetes.^18,19 Others have suggested screening in the general population;²⁰ (although, it is not yet clear how many patients may benefit from the screening). Identifying the predictor of overt kidney disease such as microalbuminuria is of utmost importance to limit the burden of renal and cardiovascular morbidity especially among hypertensive patients.²¹ Microalbuminuria screening is a critical step toward primary prevention of renal disease, which allows damage to be discovered while therapy is still effective. Since primary prevention is now the hallmark of renal medicine; it is also regarded as a hallmark of the reversible stage of nephropathy.²¹ It is well known that increasing microalbuminuria/ albuminuria predicts the progression of renal disease and also an early marker and risk factor of cardiovascular disease; myocardial infarction, stroke and premature deaths not only in diabetes but also in the non-diabetic hypertensive subjects.²²

Hypertension is one of the most prevalent conditions found in the general outpatient department of Plateau State Specialist Hospital. Screening for microalbuminuria is now being considered as an essential component in the assessment of subclinical organ damage because its detection is easy and relatively inexpensive and cost-effective.²² However, reliable data about epidemiology of microalbuminuria in non-diabetic hypertensive patients and its association with cardiovascular and renal morbidity are limited.²²

This study was carried out to evaluate microalbuminuria in the early diagnosis of nephropathy amongst adult hypertensives attending the general outpatient department of Plateau State Specialist Hospital, Jos. Furthermore, the diagnostic test method was based on antibody-based dipstick, which would be confirmed using urinary albumin creatinine ratio (UACR) in subjects who had tested positive with the primary screening (dipstick). The results from this study would provide us with a precise prevalence of microalbuminuria amongst hypertensives. Also, factors associated with elevated urinary albumin excretion (microalbuminuria) such as age, sex, smoking status, BMI, Waist/Hip ratio, duration of hypertension and blood pressure control, habitual intake of analgesics and herbs would be identified in this population.²³

A study was carried out in the departments of cardio-nephrology and Internal Medicine, University of Genoa, Genoa, Italy to evaluate the role of microalbuminuria as a predictor of Chronic Renal Insufficiency (CRI) in patients with hypertension.¹³ It was revealed that baseline microalbuminuria was associated with an increased risk for developing CRI, cardiovascular events and cardio-renal events. Microalbuminuria remained significantly related to CRI and cardio-renal events even after adjustment for several baseline covariates. Microalbuminuria is an independent predictor of renal and cardiovascular complications in patients with essential hypertension.¹³ In fact, apart from screening a targeted group e.g. hypertensives or diabetics for renal disease, some studies have advocated screening the general population. However, the main question was, is it cost effective? It is unknown whether screening for albuminuria in the general population identifies individuals at increased risk for renal disease or accelerated loss of renal function. This study revealed that albuminuria was associated with increased renal risk: the higher the level of albuminuria, the higher the risk of need for renal replacement therapy and the more rapid renal function decline.¹³ Restricting screening to high-risk groups (e.g., known hypertensives, diabetics, cardiovascular disease patients, and elderly people) reduced the sensitivity of the test only marginally but failed to identify 45% of individuals with micro and macroalbuminuria.

Screening for albuminuria identifies patients at increased risk for progressive renal disease, 40 to 50% of whom were previously undiagnosed or untreated. The question still remains, is screening the general public for renal disease cost-effective or not?²⁴

The upsurge in incidence and prevalence of CKD in both developed and developing Nations has necessitated a renewed interest in global CKD prevention. Although CKD management is consuming a huge proportion of health care finances in developed countries, it is contributing significantly to mortality and decreased life expectancy in developing countries.^1,6 Appropriate management should preferably involve a multifaceted approach targeting the control of hypertension, dyslipidaemia, proteinuria, obesity and smoking which have been identified as intervention strategies for preventing progression of renal diseases.²⁵ Pre-employment urinalysis screening and health education will go a long way in educating, increasing awareness and preventing the deleterious complications of uncontrolled hypertension. There is the need to embark on a massive health education campaign and screening of the study populace for early detection of kidney diseases.²⁵

According to the American Academy of Family Physicians in 2004, Family physicians have the opportunity to screen at-risk patients, identify affected patients, and ameliorate the impact of chronic kidney disease by initiating early therapy and monitoring disease progression.⁹ Family physicians and general practitioners have an advantage over nephrologists in screening for nephropathy because they make regular contacts with potential chronic kidney disease and cardiovascular disease patients at an early stage.^9,27 Upon diagnosis of hypertension, patients with microalbuminuria should be advised on²⁸ lifestyle modifications such as regular exercise, intake of high fibre diets, low salt-intake and weight reduction in overweight and obese patients. Pharmaceutical interventions using ACE inhibitors or angiotensin receptor blockers (ARBs) should be recommended when the lifestyle modifications fail. Studies have shown that the ACE inhibitors such as captopril, lisinopril, ramipril effectively reduce microalbuminuria in patients with hypertension, type II diabetes, or both.²⁸

The President of International Society of Nephrology, Jan J Weening in 2005 said “We know now that simple testing for albuminuria is extremely efficient as an early indicator of renal malfunction.

It is essential that systematic screening programs for high-risk patients (hypertension, diabetes) are begun immediately and it will be advisable to extend this to the public at large as a second step”²⁹

1.2 STATEMENT OF THE PROBLEM

Chronic kidney disease (CKD) or nephropathy is a serious public health problem associated with increasing prevalence rates, rising healthcare costs, and high rates of mortality from co-morbid conditions.³⁰ In 2008, the United States Renal Data System (USRDS) reported an estimated 33 million Americans (16 percent of the population), have kidney disease. Approximately 550,000 patients are undergoing dialysis or have had a kidney transplant to sustain life.³⁰ In 2008, 88,620 people died of kidney failure; and Medicare costs reached $59.4 billion and almost $26.8 billion for CKD and EndStage Renal Disease (ESRD) respectively.³⁰ Also, in Nigeria, CKD is a common cause of morbidity and mortality.⁵ A study done at a Family practice clinic of Wesley Guild hospital, Ilesa, Nigeria, from August 2005 to January 2006; where 250 general populace were screened for CKD using spot UACR (Microalbustix^TM strips) and serum creatinine concentration revealed that 113 of the 250 subjects (45.2%) had pathologic albuminuria at the initial screening while 31(12.4%) had persistent albuminuria three months later. Significant risk factors for CKD in the study were increasing age, elevated blood pressure, history of diabetes mellitus, habitual intake of analgesics and herbs, and an abnormal waist-hip-ratio. The study showed that the prevalence of CKD was high and its association with modifiable and non-modifiable risk factors was demonstrated. Therefore, Family physicians have a unique opportunity to identify and address these factors in their patients. Routine screening for microalbuminuria in family practice clinics is indicated to reduce the burden of renal disease in the population.³¹ Another study reported a prevalence of 19.9% of undetected renal diseases in a rural populace in Nigeria.³¹ Also, study done in the South-West Nigeria, reported a prevalence rate of 1.6-8% (CKD) in a hospital based data.

The incidence of ESRD is increasing Worldwide at an annual rate of 8%, far in excess of the annual population growth rate of 1.3%.¹⁹ A similar study carried out in the North Eastern part of Nigeria in 2006, on the prevalence of impaired kidney function in hospitalized hypertensive patients in Maiduguri discovered that 45.5% of the patients had elevated serum creatinine.³² Therefore, proactive community based preventive measures and early detection of hypertension

and kidney damage at the primary care levels is urgently needed.³²

Hypertension is second only to diabetes as the most common cause of CKD and end-stage renal disease (ESRD). African Americans have more severe and higher rates of hypertension, lower rates of blood pressure control which culminate in a huge burden of renal disease, cardiovascular disease and premature deaths.^33,34 According to the new report from World Health Organization (WHO) published in September 2011, cardiovascular diseases (CVDs) remain the leading cause of death and disability in the world. Non-communicable diseases accounted for more than 36 million deaths in 2008 with CVDs responsible for 48% of these deaths, cancers 21%, chronic respiratory diseases 12%, and diabetes mellitus 3%. Over 80% of CVD deaths occur in low- and middle-income countries like Nigeria. Although, a large proportion of CVDs is preventable, they continue to rise mainly because preventive measures are inadequate and it has been projected that by year 2030; almost 23.6 million people will die from CVDs.³⁵ Similarly, majority of CVD deaths in low income countries occur in individuals less than 60 years of age.^35,36 These premature deaths have grave economic and social implications. Interestingly, while actions to reduce blood pressure are having an impact on overall CVD mortality in high-income countries, there is worsening of CVD risk profiles in most developing regions of the world.³⁷ In sub-Saharan Africa, the prevalence of CVDs has reached near epidemic proportions with systemic hypertension (SH) being the main driver of cardiovascular complications.³⁸ Whereas SH was said to be rare in Africans in the first half of the twentieth century, current evidences have shown it affects between 30 and 60% of Africans.³⁹ It is the commonest cause of heart failure, stroke, and kidney disease from many studies in Africa.^38,39 The heart disease mortality rate is 50% higher, the stroke mortality rate is 80% higher, and the incidence of hypertension-related end-stage renal disease is 320% higher or six times more common in African Americans than in the whites.⁴⁰ A study carried out on hypertension-related admissions and their outcome at the Abubakar Tafawa Balewa University Teaching Hospital (ATBUTH) Bauchi, North-East Nigeria; showed a prevalence of 23.7% of total admissions, where there was an excess of mortality associated with SH complications (42.9%).

Stroke was the commonest, and it accounted for 44.4% of cases. Stroke had the highest mortality (39.3%), followed by chronic kidney disease (36.6%); hypertensive emergencies (30.9%) and hypertensive heart failure had the lowest intra-hospital mortality (27.5%). In conclusion, SHrelated admissions were common among medical admissions in Bauchi, Nigeria and were associated with high mortality. Therefore, community interventions that promote early diagnosis and reduction of cardiovascular and renal risk profiles were urgently needed.⁴⁰

A study carried out in Ido-Ekiti in 2011 found a high prevalence of microalbuminuria (32%) among hypertensives, using microalbuminuria as a predictor of renal disease. It was recommended that screening for microalbuminuria should be part of the routine investigations of patients with high blood pressure on follow up.⁸ Microalbuminuria occurred in 11-40% of persons with hypertension in America; the prevalence increasing with age and duration of hypertension.⁴¹ However, microalbuminuria had been reported in 6.1% of men and 9.7% of women in the general population in the United States with diabetes, hypertension, cardiovascular disease or elevated creatinine. while European studies reported a five to seven percent prevalence of microalbuminuria in the general population, and studies done in Pakistan in 2010, had shown that microalbuminuria occurred in about 30% of patients with mild or moderate hypertension.⁴¹ It is therefore, a clarion call for family physicians to screen at risk patients for renal disease when in contact with such patients in the clinics, wards or elsewhere. Just a dipstick will make the difference.

1.3 DEFINITIONS AND CLASSIFICATION OF CHRONIC KIDNEY DISEASE (CKD), HYPERTENSION, MICROALBUMINURIA AND PROTEINURIA

American National Kidney Foundation defines chronic kidney disease (CKD) as either kidney damage (decreased kidney function) or a Glomerular Filtration Rate (GFR) of less than 60mls per minute per 1.73m² for at least three months.¹ According to the International Society of Nephrology (ISN), CKD can be defined as kidney damage or GFR < 60 ml/min/1.73m² for 3 months; kidney damage is defined by structural or functional abnormalities of the kidney, with or without decreased GFR, manifest by either pathologic abnormalities or markers of kidney damage, including abnormalities in the composition of the blood or urine, or abnormalities in imaging tests.

Kidney damage can be ascertained by the presence of microalbuminuria. The ISN definition of CKD was accepted internationally.¹ The study used the urine markers (microalbuminuria) to diagnose early kidney damage amongst hypertensives.

Chronic kidney disease can be classified based on cause as: Diabetic, hypertensive, glomerular, tubulo-interstitial, vascular or cystic kidney disease.¹ A widely adopted classification of chronic kidney disease was developed by the American National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF KDOQI tm).^4,42 The KDOQI classification system should be used to stage patients with chronic kidney disease as follows: Stage 1-Kidney damage with normal/raised GFR (≥90 ml/min/1.73m²), Stage 2-Kidney damage with mild decrease in GFR (6089 ml/min/1.73m²), Stage 3A- Moderately lowered GFR (45-59 ml/min/1.73m²), Stage 3B-

Moderately lowered GFR (30-44 ml/min/1.73m²), Stage 4-Severely lowered GFR (15-29 ml/min/1.73 m²), Stage 5- Kidney failure (end-stage renal disease) (< 15 ml/min/1.73 m²). In order to diagnose stages 1 and 2 CKD, additional evidence of kidney damage must be present, such as microalbuminuria/proteinuria.

Hypertension, being a major cause of CRF, can be defined as blood pressure (BP) = systolic/diastolic ≥140/90 mmHg taken on two different occasions at least six hours apart, according to the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of high blood pressure (JNC 7).³⁴ Therefore blood pressure is being classified into: Normal (< 120/80 mmHg), Pre-hypertension (120-139/80-89 mmHg), Stage 1

(140-159/90-99 mmHg), Stage2 (≥ 160/100 mmHg).³⁴

Hypertension can either be primary or secondary. Primary or essential hypertension is defined as that without an identifiable cause and it makes up 95% of hypertensive cases. While secondary hypertension has an identifiable cause and accounts for five percent.⁴³

According to the 2011 International Society of Nephrology (ISN), microalbuminuria is defined as urinary albumin concentration of 30–300 mg/l in a spot urine (especially early morning).⁴⁴ Or a 24 hour urinary albumin excretion rate of 30-300mg (20-200 microgram/min); or urinary albumin: creatinine ratio (UACR) of 2.5-30mg/mmol in Men, 3.5-30 mg/mmol in Women on 2-3

occasions.²⁸ While proteinuria is defined as albumin: creatinine ratio of > 30mg / mmol or albumin concentration > 200 mg/L.²⁸ 

1.4 RATIONALE FOR THE STUDY

Majority of previous studies were focused on the screening for nephropathy in type II diabetes using semi-quantitative method to determine microalbuminuria. However, fewer recent studies were on hypertension considering the significant effect of this disease on the kidney. A high number of hypertensive patients who have on-going chronic kidney disease were not detected early but later seen with end stage renal failure in the tertiary hospital is worrisome. Family physicians will play a pivotal role of screening these patients early and ensure appropriate treatment modalities (such as lifestyle modifications, ACE inhibitors). In Nigeria, there is paucity of information and research work on the prevalence of microalbuminuria in hypertensive patients, hence, prompting the study as the case in Singapore. Screening for microalbuminuria may prove to be useful in early risk assessment and prevention of renal diseases in hypertensive patients in Plateau State Specialist Hospital, Jos-Nigeria.

This study will help the family physicians to identify patients at risk early and prevent complications of hypertension (such as nephropathy, cardiovascular and cerebrovascular accidents). It will help the family physician to ascertain early the renal status of hypertensive patients. Family physicians will be recommended to use the semi-quantitative(dipstick) method (Dirui H11 MA) in screening for renal disease in primary care setting-GOPD (because it is cheap, easy to perform and quick) instead of the quantitative method which is difficult to perform and is expensive. It will help the family physician to give health education and counsel clients on primary prevention of hypertension.

This study will also contribute to fill-in the research gap and enrich the pool of knowledge and also assist the individual participants with abnormal test results by modifying their lifestyle. It will also lay the foundation for more prospective studies exploring the role of dipstick in screening for microalbuminuria amongst hypertensive patients in Jos and beyond.

1.5 AIM AND OBJECTIVES OF THE STUDY

1.5.1 AIM OF THE STUDY

To evaluate microalbuminuria in the diagnosis of nephropathy among adult hypertensive patients in Plateau State Specialist hospital Jos, with a view of recommending the use of microalbuminuria (dipstick) by Family physicians in early screening of renal disease in hypertensives and to deter the progression to chronic renal disease.

 

 

1.5.2 OBJECTIVES OF THE STUDY

1. To determine the prevalence of microalbuminuria amongst hypertensive patients in Plateau State specialist hospital
2. To determine the risk factors for microalbuminuria in hypertensive patients seen at Plateau State Specialist hospital
3. To determine the association between BMI, Waist/ Hip ratio and microalbuminuria amongst hypertensive patients
4. To confirm nephropathy using UACR in those who were positive on microalbuminuria (dipstick).

 

EVALUATION OF MICROALBUMINURIA IN THE DIAGNOSIS OF NEPHROPATHY AMONG ADULT HYPERTENSIVES IN PLATEAU STATE SPECIALIST HOSPITAL, JOS

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