The prevalence of undiagnosed cognitive impairment and prevalence of undiagnosed depressive ...

277 Pages·2013·3.59 MB·English

The prevalence of undiagnosed cognitive impairment
and prevalence of undiagnosed depressive mood in
over 60’s with type 2 diabetes in a Thai community:
a cross-sectional study

Supaporn Trongsakul

A thesis submitted in fulfilment of the requirements

for the degree of Doctor of Philosophy

School of Allied Health Professions

Faculty of Medicine and Health Sciences

University of East Anglia

2013

© This copy of the thesis has been supplied on condition that anyone who consults it
is understood to recognise that its copyright rests with the author and that no
quotation from the thesis, nor any information derived therefrom, may be published
without the author’s prior, written consent.
Abstract

Type 2 diabetes is a lifelong disease and a major health problem in Thai older
people. Declining cognitive function and depressive mood can potentially present a
barrier to self-care management. To date, there is no primary research data of
cognitive impairment related to diabetes in Thailand, particularly in primary care
settings which are the first important place for health care service in Thai
community. This study contributes to the estimated prevalence of undiagnosed
cognitive impairment and undiagnosed depressive mood in Thai older people with
type 2 diabetes. In order to promote an early detection of cognitive impairment, a
Thai version of Mini-Cog, a brief cognitive screening test for using in primary care
settings was developed.

A cross-sectional study design was conducted in a group of older diabetic patients
aged 60 and over in the primary care settings of San-sai district, Chiang Mai,
Thailand. Overall 556 participants were recruited and the following screening tests
were applied on them: Mini-Cog Thai version, Mini-Mental State Examination
(MMSE) Thai 2002, and the depressive mood screening test of Thai Geriatric
Depression Scale (TGDS).

The study shows the prevalence of Thai older people with type 2 diabetes who
were probably undiagnosed with cognitive impairment to be 65.4% (95% CI
59.7%, 70.7%) for Mini-Cog, and 12.4% (95% CI 9.0%, 16.7%) for MMSE Thai
2002. The prevalence of people who were probably undiagnosed with depressive
mood by TGDS is shown to be 19.4% (95% CI 15.2%, 24.4%). Logistic regression
has been used to identify the associated characteristics of cognitive impairment and
the associated characteristics of depressive mood. Using Mini-Cog, age, education,
BMI and HDL were found to have effects on cognitive impairment. While using
MMSE Thai 2002, only the effect of age and education were associated with
cognitive impairment. The associated factor with depressive mood was
retinopathy.

The differences of prevalence rate and associated characteristics between the two
cognitive screening tests are probably due to the different foci on cognitive domain
tests. Mini-Cog may be more sensitive in detecting an earlier stage of cognitive
impairment better than MMSE Thai 2002. Mini-Cog Thai version shows a good
inter-rater reliability (K=0.8, p<0.001, 95% CI 0.54, 1.06).

This study encourages health care providers’ awareness of cognitive decline and
depressive mood that may affect self-care diabetes. Mini-Cog Thai version might
be used as a brief cognitive screening tool in primary care settings.

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Acknowledgements

I would like to express my gratitude to many people who have helped me through
the completion of this PhD thesis. This would have been impossible without the
assistance and guidance of the following people.

I would like to acknowledge the Ministry of Science and Technology, Thailand
and Mae Fah Luang University of the scholarship to carry out this PhD thesis in
the United Kingdom.

I am thankful to my supervisory team: Dr. Jane Cross, Dr. Rod Lambert and Dr.
Allan Clark for their advice and constructive comments on my study and writing.
In addition to my supervisory team, I would like to thank Dr.Barbara Richardson
and Dr. Ketan Dhatariya, my panel committee, for their helpful comments at the
beginning of the study.

I would like to thank Dr. Nahathai Wongpararan, Dr. Peeraya Munkhetvit, Dr.
Somporn Sungkarat, Nichar Gregory, Tina Wray for their assistance for translating
and developing Mini-Cog Thai version.
I am grateful to all of my participants and health care staff at primary care settings
and hospital in San-sai district, for their participation and assistance in my study.
I would also like to thank my Thai, Iranian and British friends in Norwich for their
support and encouragement throughout this PhD journey.
Special thanks go to my friends in Thailand, Budsaba-Surasak Laopanichkul,
Thanyalak Kaewmuang, Oranuch Nampaisan and Thitima Suklerttrakul for their
endless friendship. Also thanks to Buddhist Society of Western Australia team, and
Aj.Brahm in particular, for sharing dhamma talks that inspired me with a positive
thinking.
Last but not least, my PhD thesis is dedicated to my mother, Ampa Trongsakul for
her greatest love and support at all times. Thank you for being a role model for
strength and patience.

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List of Contents

Abstract............................................................................................................. ii
Acknowledgements......................................................................................... . iii
List of Contents............................................................................................... iv
List of Tables................................................................................................... x
List of Figures.................................................................................................. xiii
Abbreviations and acronyms......................................................................... . xiv
Chapter 1: Introduction
1.1 Background and significance of this study............................................ 1
1.2 Definition of cognitive impairment and mild cognitive impairment..... 3
1.3 Type 2 diabetes, cognitive impairment and depressive mood:
a potential linkage................................................................................. . 4
1.3.1 Type 2 diabetes and cognitive impairment……………………. 4
1.3.2 Type 2 diabetes and depressive mood…………………………. 5
1.3.3 Depressive mod and cognitive impairment…………………….. 5
1.4 Cognitive function and depressive mood: Impact for diabetes self-care 7
1.5 The importance of the early detection of cognitive impairment and
depressive mood……………………………………………………… 7
1.6 An overview of Thailand……………………………………………… 8
1.6.1 Thailand profile………………………………………………….. 8
1.6.2 Overview of health care structure in Thailand…………………… 9
1.6.3 Overview of Thai ageing population……………………………. 11
1.7 The burden and gap problem of diabetes care in Thailand…………… 12
1.8 Structure of thesis…………………………………………………….. 15
1.9 Summary……………………………………………………………… 17
Chapter 2: Literature review
2.1 Reviews studies of the prevalence of cognitive impairment and
depressive mood .................................................................................. . 18
2.1.1 Method…………………………………………………………. 19
2.1.2 Results………………………………………………………….. 20

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List of Contents (continued)

2.2 Contribution of other factors on cognitive impairment in type 2
Diabetes……………………………………………………………… 38
2.3 Summary …………………………………………………………….. 42
Chapter 3: Cognitive screening test in Thailand and choice of the
screening tests
3.1 Cognitive screening tests in Thailand.................................................. .. 43
3.1.1 Mini-Mental State Examination (MMSE) Thai 2002…………. . 43
3.1.2 Thai Mental State Examination (TMSE)…………………......... 46
3.1.3 Chula-test………………………………………………………. 46
3.1.4 Clock drawing test-Chula (CDT-Chula)……………………….. 47
3.1.5 Informant Questionnaire for Cognitive Decline in theE lderly
(IQCODE)………………………………………………………. 47
3.2 Limitation of using existing screening tools in primary care settings. .. 51
3.3 Choice of screening test in the current study....................................... . 52
3.3.1 Cognitive screening tests 52
3.3.1.1 Cognitive screening tests which specific for primary
care setting…………………………………………..... . 52
3.3.1.2 Mini-Cog ………………………………………………. 53
3.3.2 Depressive mood screening test………………………………. . 54
Thai Geriatric Screening Test (TGDS)………………………… 54
3.4 Summary………………………………………………………………. 55
Chapter 4: Development of Mini-Cog Thai version
4.1 Background and development of Mini-Cog...................................... . 57
4.2 Development of the Thai version of Min-iCog................................. 59
4.3 Summary.......................................................................................... . 63
Chapter 5: Study Protocol
5.1 Research questions…………………………………………………. 65
5.2 Research objectives…………………………………………………. 66
5.3 Research design…………………………………….......................... 67
5.4 Sample size………………………………………………………….. 68
5.5 Research setting and target population……………………………... 70

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List of Contents (continued)

5.6 The criteria of the participants……………………………………….. 72
5.6.1 Inclusion criteria…………………………………………………. 72
5.6.2 Exclusion criteria………………………………………………… 73
5.7 Study instruments and outcome measure............................................. 75
5.7.1 Cognitive screening tests……………………………................. 75
- Mini-Cog……………………………………………………… 75
- Mini-mental State Examination (MMSE) Thai 2002………… 75
5.7.2 Depression screening test…………………………………….... 76
-Thai Geriatric Screening Test (TGDS)……………………….. 76
5.8 Study plans and processes…………………………………………… 76
5.8.1 Pilot study……………………………………………………… 76
5.8.2 Main study……………………………………………………… 76
5.9 Data collection………………………………………………………… 77
5.10 Statistics analysis……………………………………………………. 78
5.11 Ethical approval……………………………………………………… 78
5.12 Ethical considerations……………………………………………….. 78
5.13 Summary…………………………………………………………….. 79
Chapter 6: Pilot study
6.1 What is a pilot study………………………………………………...... 81
6.2 Objectives of the pilot study………………………………………….. 81
6.3 Setting and population………………………………………………… 82
6.4 Sample size……………………………………………………………. 82
6.5 Procedure……………………………………………………………… 83
6.6 Measure outcomes…………………………………………………….. 83
6.6.1 Inter-rater reliability of Mini-Cog………………………………. 83
6.6.2 Concurrent validity……………………………………………… 84
6.7 Data analysis………………………………………………………….. 84
6.8 Ethical approval……………………………………………………….. 85
6.9 Ethical considerations…………………………………………………. 85
6.10 Results……………………………………………………………….. 86
6.11 Discussion…………………………………………………………… 91

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List of Contents (continued)

6.12 Summary…………………………………………………………….. 95
Chapter 7: Methodology
7.1 Summary of the necessary changes for the study protocol……………. 96
7.2 Area of the study………………………………………………………. 99
7.3 Study population and sampling procedures…………………………… 101
7.4 Ethical issues and considerations……………………………………… 101
7.5 Identification and recruitment of the participants……………………... 103
7.6 Recruitment and training of the research assistant……………………. 103
7.7 Data collection for the main study…………………………………….. 104
7.8 Data analysis and statistical procedures………………………………. 105
7.8.1 preparing the data for analysis…………………………………... 105
7.8.2 Analysis the data by using inferential statistics…………………. 105
7.9 Summary………………………………………………………………. 110
Chapter 8: Results
8.1 Inter-rater reliability of Mini-Cog, MMSE Thai 2002 and the TGDS... 111
8.2 Participant recruitment………………………………………………… 117
8.3 Demographic characteristic data of the participants…………………... 119
8.4 Prevalence study………………………………………………………. 124
8.5 Comparison of the prevalence of cognitive impairment and depressive 125
mood between the groups with and without HbA1c test……………….
8.6 Characteristics associated with cognitive impairment and depressive
Mood…………………………………………………………………… 121
8.6.1 Association between the predictors and cognitive impairment by
Mini-Cog………………………………………………………… 128
8.6.2 Association between the predictors and cognitive impairment by
MMSE Thai 2002……………………………………………….. 133
8.6.3 Association between the predictors and depression by TGDS….. 137
8.7 Relationship between cognitive impairment and depressive mood
(controlling potential confounders)…………………………………… 142

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List of Contents (continued)

8.8 Comparison of the results (by cut-off scores) of cognitive and
depressive mood screening tests between good and poor glycaemic
control (HbA1c) groups………………………………………………… 145
8.9 Summary……………………………………………………………….. 146
Chapter 9: Discussion
9.1 The characteristics of the groups with and without HbA1c test……… 148
9.1.1 Living arrangement……………………………………………… 148
9.1.2 Clinical characteristics………………………………………….. 149
9.2 The prevalence of possibly cognitive impairment and depressive
mood…………………………………………………………………. 152
9.2.1 The prevalence of possible cognitive impairment by Mini-Cog
and MMSE Thai 2002…………………………………………. 152
9.2.2 The prevalence of possible depressive mood by TGDS………. 157
9.3 Predictors associated with possible cognitive impairment and
depressive mood……………………………………………………… 158
9.3.1 Major predictors associated with possible cognitive impairment.. 158
9.3.2 The major predictor of depression……………………………… 163
9.4 Correlation between cognitive impairment and depressive mood……. 165
9.5 Correlation between Mini-Cog and MMSE Thai 2002……………….. 166
9.6 Cognitive impairment and depressive mood withthe degree of good
and poor glycaemic control (HbA1c)…………………………………. 168
9.7 Summary……………………………………………………………… 169
Chapter 10: Summary and Recommendations
10.1 Overall summary…………………………………………………….. 171
10.2 Strength and limitations of the study………………………………… 172
10.2.1 Strengths of the study………………………………………… 172
10.2.2 Limitations of the study……………………………………… 173
10.3 Clinical implication…………………………………………………. 176
10.3.1 Implication of Mini -Cog…………………………………….. 176

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List of Contents (continued)

10.3.2 Implication for clinical and health care professionals………. 178
10.4 Implication for future research …………………………………….. 181
10.5 Summary…………………………………………………………… 182
References………………………………………………………………….. 184
Appendices…………………………………………………………………. 202
Appendix A: Ethical approval and the permission document……………. 203
Appendix B: Translation of Mini-Cog…………………………………… 208
Appendix C: Information Sheet and Consent forms……………………… 225
Appendix D: Instruments of the study……………………………………. 233
Appendix E: Participant recording form and code of variables…………… 252
Appendix F: Tests of normality and multicollinearity of data ……………. 258

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List of Tables

Table 1.1: Level of health care system in Thailand: administrative level,
population size, level of care and provider in Thailand…………….. 10
Table 2.1: Summary of the studies on the prevalence of related cognitive
impairment in type 2 diabetes........................................................... 27
Table 2.2: Summary of the studies on the prevalence of depressive mood in
type 2 diabetes Selection criteria for reviewed articles...................... 32
Table 3.1: Summary of the cognitive screening tools used in Thailand with
some advantages and disadvantages.................................................. 49
Table 6.1: Raw data scores of CDT in Mini-Cog Thai version from the
researcher and expert, a pilot study in sample of 32 older people
with type 2 diabetes in Nong-han primary care centre, San-sai
district............................................................................................... 87
Table 6.2: 32 participants are scored by the researcher and expert for Mini-
Cog. 0 (zero) denotes the participants with incorrectly drawn clock,
2(two) denotes the participants are classified with correctly drawn
clock.................................................................................................. 88
Table 6.3: Pearson correlation coefficients between the scores of Mini-Cog
Thai version and MMSE Thai 2002................................................. 88
Table 6.4: Demographic and clinical characteristics of the participants in pilot
study................................................................................................... 89
Table 7.1: Summary of the differences between the pilot and the main
study................................................................................................... 99
Table 8.1: Raw data scores of Mini-Cog Thai version, MMSE Thai 2002 and
TGDS between the researcher and the RA in a sample of 21 older
people with type 2 diabetes in the main study..................................... 112

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