prevalence of thyroid dysfunction in ambulant patients with type 2 diabetes attending diabetes ...

52 Pages·2014·0.89 MB·English

PREVALENCE OF THYROID DYSFUNCTION IN AMBULANT
PATIENTS WITH TYPE 2 DIABETES ATTENDING DIABETES
CLINICS AT KENYATTA NATIONAL HOSPITAL

DISSERTATION SUBMITTED IN PART FULFILLMENT OF THE REQUIREMENTS FOR
THE AWARD OF THE DEGREE OF MASTER OF MEDICINE IN INTERNAL MEDICINE
OF THE UNIVERSITY OF NAIROBI

DR. ROSSLYN NGUGI (SHO INTERNAL MEDICINE) - H58 /63770/2010
MBChB (UoN)
DECLARATION
This Research proposal is my original work and has not been presented for a degree at any other
university.

Signed…………………………………………….DATE…………………………..

PRINCIPAL INVESTIGATOR,
DR ROSSLYN NGUGI,
RESIDENT, DEPARTMENT OF CLINICAL MEDICINE AND THERAPEUTICS.

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SUPERVISORS’ APPROVAL

This research proposal has been submitted with the approval of my supervisors, namely:

PROF. C.F. OTIENO
Associate professor
Department of Clinical Medicine and Therapeutics,
University of Nairobi.
SIGNED………………………………………………………DATE…………………………

DR. RITESH PAMNANI
MBBS, Dip Clinical Pathology, M.D (path)
Lecturer,
Department of Human Pathology.
University of Nairobi.
SIGNED………………………………………………………DATE…………………………

PROF. C. KIGONDU
Thematic Head unit of Clinical Chemistry
Department of Human Pathology
SIGNED………………………………………………………DATE…………………………

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ACKNOWLEDGMENT

I give thanks to God for having brought me this far in good health and all that I am.
I appreciate my supervisors Prof C.F Otieno, Prof C. Kigondu, Dr .R. Pamnani for their
unrelenting support, critical review and commitment throughout every stage of my study.
I thank all my research assistants who worked tirelessly and assisted me in data collection.
I would like to thank Kenyatta National Hospital staff at theDiabetes clinic for their assistance
and to the clients who graciously accepted to participate in my study.
I would like to thank staff of Immunology laboratory in their assistance in conducting
biochemistry investigations.
Finally, I am grateful to my family, friends and colleagues for their constant encouragement and
motivation.

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TABLE OF CONTENTS
DECLARATION........................................................................................................................... ii
SUPERVISORS’ APPROVAL ................................................................................................... iii
ACKNOWLEDGMENT ............................................................................................................. iv
LIST OF TABLES ...................................................................................................................... vii
LIST OF FIGURES ................................................................................................................... viii
LIST OF ABBREVIATIONS ..................................................................................................... ix
ABSTRACT ................................................................................................................................... x
1.0 INTRODUCTION................................................................................................................... 1
1.1 LITERATURE REVIEW ................................................................................................... 2
1.2EPIDEMIOLOGY ............................................................................................................... 2
1.2.1 BURDEN OF DIABETES MELLITUS......................................................................... 2
1.2.2 PREVALENCE OF THYROID DYSFUNCTION ........................................................ 2
1.2.3 PREVALENCE OF THYROID DYSFUNCTION IN TYPE 2 DIABETICS ............... 3
1.3 EFFECT OF DIABETES ON THYROID FUNCTION .................................................. 4
1.4 EFFECT OF HYPERTHYROIDISM ON GLYCEMIC STATUS ................................ 4
1.5 EFFECT OF HYPOTHYROIDISM ON GLYCEMIC STATUS .................................. 5
1.6 EFFECT OF THYROID DYSFUNCTION ON OTHER ORGAN SYSTEMS ............ 7
1.6.1 EFFECT OF HYPOTHYROIDISM ............................................................................. 8
1.6.2 EFFECT OF HYPERTHYROIDISM ............................................................................ 9
1.7 EFFECT OF DRUGS ON THYROID FUNCTION ........................................................ 9
1.8 OUTCOME OF TREATMENT OF THYROID DYSFUNCTION ........................... 10
2.0 STUDY JUSTIFICATION ................................................................................................... 11
3.0 RESEARCH QUESTION .................................................................................................... 11
4.0 OBJECTIVES ....................................................................................................................... 12
4.1 BROAD OBJECTIVE .................................................................................................. 12
5.0 METHODOLOGY ............................................................................................................. 12
5.1 STUDY SITE .................................................................................................................. 12
5.2 STUDY POPULATION ................................................................................................. 12
5.3 STUDY DESIGN ............................................................................................................ 12
5.4 SAMPLE SIZE ............................................................................................................... 12
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5.5 SAMPLING METHOD .................................................................................................. 13
5.6 CASE DEFINITION ......................................................................................................... 13
5.6.1 TYPE 2 DIABETES – .................................................................................................... 13
5.6.2 THYROID HORMONE REFERENCE RANGES ..................................................... 13
5.7 INCLUSION AND EXCLUSION CRITERIA ............................................................... 14
5.7.1 INCLUSION CRITERIA ............................................................................................. 14
5.7.2 EXCLUSION CRITERIA ............................................................................................ 14
5.8 SCREENING AND RECRUITMENT AND CONSENTING ...................................... 15
5.9 PROCEDURES ................................................................................................................. 15
5.9.1 CLINICAL EXAMINATION ...................................................................................... 15
5.9.2 LABORATORY METHODS ....................................................................................... 15
5.10 QUALITY ASSURANCE ............................................................................................... 16
5.11 STUDY VARIABLES AND DEFINITIONS ................................................................ 17
5.11.1 INDEPENDENT VARIABLES ................................................................................. 17
5.11.2 DEPENDENT VARIABLES ..................................................................................... 17
5.12 DATA MANAGEMENT AND ANALYSIS ................................................................. 17
5.13 STUDY ADMINISTRATION ........................................................................................ 18
5.14 ETHICAL CONSIDERATIONS ................................................................................... 18
6.0 RESULTS .............................................................................................................................. 19
7.0 DISCUSSION .................................................................................................................... 28
8.0 CONCLUSION .................................................................................................................. 32
9.0 LIMITATIONS ................................................................................................................. 32
10.0 RECOMMENDATIONS ................................................................................................ 32
11.0 REFERENCES .................................................................................................................... 33
12.0 APPENDICES ..................................................................................................................... 39
APPENDIX 1: DATA ABSTRACTION TOOL ................................................................... 39
APPENDIX 2: BUDGET ........................................................................................................ 41

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LIST OF TABLES
Table 1: Studies of prevalence of Thyroid dysfunction in patients with type 2 diabetes 3
Table 2: Interaction between thyroid disease and Diabetes Mellitus. 7
Table 3: Assay of thyroid hormones. 13
Table 4: Analysis and Interpretation of thyroid hormones. 14
Table 5: Sociodemographic characteristics of patients with type 2 Diabetes 20
Table 6: Clinical parameters of patients with type 2 Diabetes 21
Table 7: Medication used by study patients with type 2 Diabetes 24
Table 8: History of thyroid disease & management of thyroid disease in patients with type
diabetes 24
Table 9: Clinical evaluation for thyroid dysfunction in study participants 26
Table 10: Thyroid function tests results in patients with type 2 Diabetes. 26

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LIST OF FIGURES
Figure 1: Thyrotoxicosis effect on glucose homeostasis 5
Figure 2: Hypothyroidism effect on glucose homeostasis 6
Figure 3: Relationship between serum TSH and cholesterol 6
Figure 4: Results of study participants 19
Figure 5: Age distribution of patients with type 2 Diabetes 22
Figure 6: Duration of Diabetes Mellitus in study participants 23
Figure 7: Assessment of BMI of patients with type 2 Diabetes 25
Figure 8: Prevalence of thyroid dysfunction of patients with type 2 Diabetes 27

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LIST OF ABBREVIATIONS
BMI Body Mass Index.
CVD Cardiovascular disease.
ELISA Enzyme Linked Immunosorbent Assay.
FFA Free Fatty acids.
FT3 Free Triiodothyronine.
FT4 Free Thyroxine.
GAD Glutamic Acid Decarboxylase.
GLUT-2 Glucose Transporter type 2.
GLUT-4 Glucose Transporter type 4.
HTN Hypertension.
IR Insulin Resistance.
KNH Kenyatta National Hospital.
NHANES National Health and Nutritional Examination Survey.
PI Principal Investigator.
rT3 Reverse Triiodothyronine.
TSH Thyroid Stimulating Hormone.
TRH Thyroid Releasing Hormone.
T2DM Type 2 Diabetes Mellitus
UON University of Nairobi
US United States.
WHO World Health Organisation.

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ABSTRACT
Background
Thyroid disease and Diabetes are two common endocrinopathies found in the general population.
Thyroid disease is a pathological state which can adversely affect Diabetes control and
contribute to negative patient outcomes. Hyperthyroidism contributes to hyperglycemia while
hypothyroidism contributes to episodes of hypoglycemia. This not only impedes management of
Type 2 Diabetes but also worsens metabolic control. However, uncontrolled diabetes on the
other hand has been shown to impair TSH response to TRH which normalizes with improvement
in glycemic control
Objectives
To determine the prevalence and patterns of thyroid dysfunction in patients with Type 2 Diabetes
Mellitus.
Methodology
This was a cross-sectional descriptive survey of participants who were over the age of 30 years
selected from patients with type 2 Diabetes attending outpatient diabetes clinics. Systematic
random sampling was done on patients meeting the inclusion criteria.A sample size of 180 was
obtained. Consenting participants’ had their demographic data and medical history collected by
use of structured pre-tested questionnaires and a physical examination was done thereafter. This
was followed by drawing of venous blood samples for assessment of, i.e. TSH & fT4. Assays for
thyroid hormones were done using specific antibodies and enzyme markers for specific thyroid
hormones using Enzyme Linked Immuno Sorbent Assay technology. (ELISA)
Results
In this study, majority of the patients were female (62.4%), with a mean age of 59 years and had
a mean duration of 9.5 years with diabetes mellitus. Those with a previous diagnosis of thyroid
dysfunction were about 10.6% and 22.7% had a positive family history of thyroid dysfunction.
The prevalence of thyroid dysfunction in patients with type 2 Diabetes was found to be 61%, of
which subclinical hypothyroidism was the most predominant type at 58%. No patient was found
to have evidence of overt hyperthyroidism.

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