Association between Depression and Type 2 Diabetes: A Critical Appraisal

This research paper critically appraises the association between depression and type 2 diabetes. It examines three research papers with different designs and provides recommendations for future research. The findings suggest that there is a significant link between diabetes and depression, highlighting the need for effective treatment options.

Running head: HEALTH CARE
Health care
Name of the student:
Name of the University:
Author’s note

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Introduction:
Diabetes is one of the highly prevalent diseases, whose global burden has increased
significantly in the 21st century. According to Bădescu et al. (2016), one in every 11 adults
suffers from diabetes globally. In addition, depression is a high common and serious mental
health condition with adverse impact on daily life and long term health outcome. Depression has
a significant impact on behaviour, emotion and cognition of an individual. People diagnosed
with diabetes are at risk of developing type 2 diabetes and anxiety in patients with diabetes is one
of the main causes behind presence of depression, worsening prognosis of diabetes and poor
compliance to treatment and quality of life. It also increases the risk of mortality in patient
(Verma et al., 2017). Hence, due to this issue, examining the association between diabetes and
depression is considered important. The main purpose of this research is to find links or
association between depression and type 2 diabetes. This has been done by critical appraisal of
three research papers with three different research designs related to the research topic. This
paper will give an insight into the method used to search for the three articles and the results
obtained by critical appraisal of the papers using the CASP checklist. The report will also
provide discussion on the possibility of bias, chance and confounding factors in each paper and
give recommendations to improve the methodology in future research.
Methodology:
Search strategy:
The main research question for the project was ‘What is the association between
depression and diabetes?’. To find relevant papers related to the research question, the search for
peer reviewed full-text article was done in CINAHL and PUBMED. Both of these databases are

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highly used database that published research in the field of nursing, biomedical and health care.
The key search terms that was used for search process includes ‘diabetes’, ‘depression’, ‘major
depressive disorder’ and ‘type 2 diabetes’. This search term was used during basic search
process. To further advance the search process, the above key words were combined with
Boolean operators ‘AND’ to retrieve most relevant article related to the research question. Based
on the study purpose, as link between both depression and anxiety was necessary, the search
terms were combined in the following ways:
 depression AND diabetes
 major depressive disorder and type 2 diabetes
Inclusion and exclusion criteria:
The search process was also guided by inclusion and exclusion criteria which were as
follows:
 Only articles published with the past five years needs to be taken in the research. The
articles published before 2014 needs to be excluded
 Only those paper were selected which used cohort, cross-sectional, randomized
controlled trial or case controlled trial as the study design. Secondary research design
using literature review or systematic review needs to be excluded.
 Research articles published in English language needs to be taken in the review.
 The research must report about both depression and anxiety symptom in research
participant
 There is no criteria for taking any specific sample group for the study. All types of
sample group including elderly, young adults and children can be included in the review.

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Results:
Results for cohort study design by Meng et al. (2018):
Statement Answers Justifications
Did the study address a
clearly focused issue?
Yes The aim of the study and justification has been clearly
stated with details about the population group and
research outcome.
Was the cohort recruited in
an acceptable way?
Yes The study had a defined population group and
diversity in the population was considered
Was the exposure
accurately measured to
minimise bias?
Unclear There was no intervention to be tested. However,
research variables related to presence of diabetes and
depression were identified.
Was the outcome
accurately measured to
minimise bias?
Yes Subjective and objective measurements were well
defined using evidence based tool whose internal
consistency and validity was discussed too.
Have the authors identified
all important confounding
factors?
No Recording data from medical record can contribute to
confounding or risk of bias
Have they taken account
of the confounding factors
in the design and/or
analysis?
Yes Confounding factor was considered during selection of
research tools and data collection process
Was the follow up of
subjects complete enough?
Yes It had adequate follow up period and no lost to follow
up case
Was the follow up of Yes The follow for the Chinese cohort was done for 8

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subjects long enough? years.
Do you believe the results? Yes The result is valid as consistency element and
influence of confounding factor has been considered
Can the results be applied
to the local population?
No The health care system currently may differ compared
to the time when the result was done.
Do the results of this study
fit with other available
evidence?
Yes The findings are consistent with past research outcome
Result for case control study design by Islam et al. (2015):
Statement Answers Justification
Did the study address a
clearly focused issue?
Yes The study has clear research objective and clear
research aim
Did the authors use an
appropriate method to
answer their question?
Yes The matched case-controlled study design is
appropriate to answer the research question as the
purpose of research is to determine the exposure to
the risk factor of interest in two groups of
individuals particularly the control and the cases
group (Lewis, 2015). The author of this study also
aimed to evaluate the exposure of diabetes on risk of
depression in individuals.
Were the cases recruited in Yes Validity factor and time period was considered.

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an acceptable way? However, no power calculation was done
Were the controls selected
in an acceptable way?
Yes For each index case, controls were taken which
matched for age, sex and area of residence
Was the exposure
accurately measured to
minimise bias?
Yes Both subjective and objective data was used to
evaluate exposure thus reducing risk of biases in
study result.
Aside from the
experimental intervention,
were the groups treated
equally?
Unclear No equal treatment required according to research
aim
Have the authors taken
account of the potential
confounding factors in the
design and/or in their
analysis?
Yes Validity element was considered in choice of tool
such as WHO criteria for diabetes diagnosis and
translation of interview questionnaire
Do you believe the results? Yes The study finding is reliable as appropriate sample
size and data collection techniques have been used
to study findings.
Can the results be applied
to the local population?
No It cannot be applied to local population as no long
follow up was done and self reported data was
collected for risk of diabetes.
. Do the results of this study
fit with other available
evidence?
Yes The finding is consistent with other research
evidence

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Result for case control study design by Akpalu et al. (2018):
Statement Answers Justification
Did the study address a
clearly focused issue?
Yes The study had clear focused question as outcome
of interest, research variables and population
group was well-defined
Was the cohort recruited in
an acceptable way?
Yes Appropriate recruitment method as both sample
size calculation and power analysis was done
Was the exposure
accurately measured to
minimise bias?
Yes The focus on objective data minimized any risk of
bias
Was the outcome
accurately measured to
minimise bias?
Yes Validated tool was used to conduct screening for
patient at risk of depression
Have the authors identified
all important confounding
factors?
Yes All possible confounding factors were considered
Have they taken account of
the confounding factors in
the design and/or analysis?
Yes Validitty of measurement tool was done, sample
size was considered and power calculation was
done.
Was the follow up of
subjects complete enough?
No Details related to follow up is missing
Was the follow up of
subjects long enough?
Unclear Lack of any data in this area
Do you believe the results? Yes Both objective and subjective data has been used
to confirm the findings thus eliminating chance of

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biases
Can the results be applied
to the local population?
Yes It cannot be applied as the research was done only
in a single tertiary hospital
Do the results of this study
fit with other available
evidence?
Yes The findings are consistent with other relevant
research papers.
Discussion:
Based on the evaluation of study findings, certain areas of risk and need for future
research has been found. The following table for each study gives an insight into possible
strategies to further improve the methodology:
Statement (Refer
to statement in
results)
Answers Justification for improvement in methodology for the
study by Meng et al. (2018)
1. Yes No improvement needed
2. Yes The cohort was selected from CKB study. This can be further
improved by recruiting cohort at current time instead of from
any past research data
3. Unclear Based on research aim, the identify of diabetes cases could
have been done by HbA1c testing. This would have helped to
estimate severity of the condition
4. Yes The study could be improved by collecting more data related
to quality of life in patient with depression
5. No Instead of using medical record to identify diabetes, active

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screening in target setting is needed in future research
Yes Impact of sociodemographic factors on study results can be
considered in future research
7 Yes No improvement needed in this area
8. Yes There is no risk of bias in this area
9. Yes The result is valid. However future research can focus on the
evaluation of treatment for depressive episode in diabetes
patient.
10. No The health care system currently may differ compared to the
time when the result was done. Hence, there is a need to
validate the finding in Chinese population
11. Yes More recently published research papers can be considered to
understand suitability of the research evidence.
Statement (Refer
to statement in
results)
Answers Justification for improvement in methodology for the
study by Islam et al. (2015)
1. Yes No improvement needed
2. Yes The researcher used a much improved research method and
no improvement needed
3. Unclear There is need for power calculation
4. Yes The influence of socioeconomic factors on results should be
considered in future research
5. No No improvement needed

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6. Yes The data analysis was of high quality with no bias
7 Yes As significant treatment effect was not found, this area needs
to be reevaluated in future research
8. Yes No improvement
9. Yes Future research should focus on the evaluation of treatment
for depressive episode in diabetes patient.
10. No Due to retrospective analysis, bias may occur. Future
research needs to be done in Chinese population
11. Yes More recently published research papers can be considered to
understand suitability of the research evidence.
Statement (Refer
to statement in
results)
Answers Justification for improvement in methodology for the
study by Akpalu et al. (2018)
1. Yes No improvement needed
2. Yes High quality recruitment method selected and no further
improvement required
3. Yes Focus on objective data minimize any risk of bias
4. Yes Evidence based tool was used and it is appropriate for
screening
5. Yes No improvement needed
6. Yes no bias as all confound factors at critical point of research
considered
7 No Long follow up needed in future research

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8. No Loss to follow up must be considered
9. Yes Future research should focus on the evaluation of treatment
for depressive episode in diabetes patient.
10. No Future research needs to be done in multiple center to
enhance generalisability
11. Yes No change needed
Conclusion:
From the critical appraisal of research paper, it has been identified that diagnosis of
diabetes is associated with significant risk of depression. The critical appraisal of research paper
gives the implication that diabetes and depression are interlinked as burden of diabetes increased
risk of depression. There is a need to identify effective treatment option so that diabetes people
can have good physical as well as mental health.

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References:
Akpalu, J., Yorke, E., Ainuson-Quampah, J., Balogun, W., & Yeboah, K. (2018). Depression and
glycaemic control among type 2 diabetes patients: a cross-sectional study in a tertiary
healthcare facility in Ghana. BMC psychiatry, 18(1), 357.
Bădescu, S. V., Tătaru, C., Kobylinska, L., Georgescu, E. L., Zahiu, D. M., Zăgrean, A. M., &
Zăgrean, L. (2016). The association between Diabetes mellitus and Depression. Journal
of medicine and life, 9(2), 120–125.
Islam, S. M. S., Ferrari, U., Seissler, J., Niessen, L., & Lechner, A. (2015). Association between
depression and diabetes amongst adults in Bangladesh: a hospital based case–control
study. Journal of global health, 5(2)
Lewis, S. (2015). Qualitative inquiry and research design: Choosing among five
approaches. Health promotion practice, 16(4), 473-475.
Meng, R., Liu, N., Yu, C., Pan, X., Lv, J., Guo, Y., ... & Pan, A. (2018). Association between
major depressive episode and risk of type 2 diabetes: A large prospective cohort study in
Chinese adults. Journal of affective disorders, 234, 59-66.
Verma, S. K., Luo, N., Subramaniam, M., Sum, C. F., Stahl, D., Liow, P. H., & Chong, S. A.
(2017). Impact of depression on health related quality of life in patients with diabetes.