Critical Appraisal Report: CLRS90027 Principles of Clinical Research

This report presents a critical appraisal of two research papers focusing on the effects of yoga interventions on breast cancer survivors. The first paper, by Derry et al. (2015), investigates the impact of Hatha yoga on cognitive complaints, while the second paper, by Kiecolt-Glaser et al. (2014), assesses yoga's influence on inflammation, fatigue, and mood changes. Both studies utilized randomized controlled trials with breast cancer survivors, comparing a yoga intervention group to a control group. The appraisal evaluates the study designs, comparison groups, circumstances, methods, and follow-up procedures. It examines the association between exposure and outcome, including statistical significance and confidence intervals, and the calculation of risk estimates. The report also discusses the strengths and limitations of each study, such as sample size, retention rates, and the absence of active control groups. The findings suggest that yoga may have positive effects on cognitive function, inflammation, and fatigue in breast cancer survivors, but further research with larger sample sizes and more comprehensive methodologies is needed.

Running head: CRITICAL APPRAISAL
Critical Appraisal
Name of the Student
Name of the University
Author Note

1CRITICAL APPRAISAL
Aim of the researches:
Aim of the first research paper (Derry et al., 2015) is to compare Hatha yoga
intervention between trial group and wait-list control group of survivors of breast cancer to
reduce cognitive complaints through randomized trial group. Aim of the second paper
(Kiecolt-Glaser et al., 2014) is to assess the impact of yoga in reducing inflammation, fatigue
and mood changes through randomized controlled trial.
Comparison groups:
The papers contain comparison groups which are trial group undergoing Hatha yoga
intervention after surviving from breast cancer and a wait-list control group who have not
received the yoga intervention and are selected randomly to be waiting.
Circumstances and methods:
In the first paper, selections of 200 random breast cancer survivors from breast
cancer groups, clinics and physicians and through announcement in the community. The
women of trial group was reported to be participating in the 12-week yoga intervention
whereas the control group refrained from participating in yoga intervention with time. The
trial group and the control group after 3 months follow-up were asked to fill up
questionnaires and give blood samples with morning fast. In the second research paper, 200
participants of age 27-76 years comprising of breast cancer stage 0 to stage IIIa survivors
who had completed their intervention for cancer 3 years back and surgery 2 months back
were enlisted. Breast cancer groups, community and web-based announcements, and
references from oncologists was used. Similar to the first research paper the trial group was
assigned to participate in yoga and the control group participants were asked to refrain from
joining yoga.

2CRITICAL APPRAISAL
Follow-up:
The follow up for the second research was sufficiently complete and the authors
followed the CONSORT diagram to assess the participants follow-up intervention and
screening them throughout the randomization but follow up was not 100% (Consort-
statement.org., 2020). The follow up was done for both the trial and the control group which
showed that analysis at the end of intervention contained 96% of participants in trial group
whereas 90% in the control group during follow up intervention. The first research provided
no clear follow-up data.
Association between exposure and outcome:
Both papers did not calculate relative risk, hazard risk and odd-ratio between the
exposure and the outcome. However the strength of association between the yoga practice
and cognitive problems after 3 months of follow-up intervention were significantly higher
with a p-value less than 0.05 (p<0.001). Since it was a randomized trial study, it does not
include odd-ratio measure. 95% CI was considered where the population size was within the
interval (Walsh et al., 2014). In the second study, the association between yoga practice and
outcome measures that is inflammation, fatigue and mood was statistically significant and
stronger association was found for both groups between yoga and fatigue (p =0.19), and
vitality (p =0.016, p =0.0045) but lower significance of association between yoga and
depression (p >0.2) for both the trial and control group. It was also observed that during the 3
months follow-up, gradual increasing exposure led to the decrease in proinflammatory
cytokine production- IL-1(p = 0.3), IL-6 (p = 0.1) but not for TNF-α (p >0.5).
Calculation for exposure/outcome
The calculations for exposure/control event rates, ARR, NNT, RR, RRI was not
provided for both the researches. The baseline study was used in the first study. Breast

3CRITICAL APPRAISAL
Cancer Prevention Trial (BCPT) Cognitive Problems scale as show in table 1 was used for
the participants to report their cognitive problems (Sandler, Petersen, Steinberg, Ganz, &
McCloskey, 2018).
Table 1:
Contrast
BCPT cognitive
scale score
Inference
(association
between exposure
and outcome in
both groups)
p-value
Yoga vs wait-list immediately post-intervention
of breast cancer
0.250 Not significant
Yoga vs wait-list after 3 months follow up 0.003 Significant
Follow up for 3 months immediately after
intervention in yoga group
0.291 Not significant
Follow up for 3 months immediately after
intervention in wait-list control group
.071 Not significant
The second research measured fatigue via multidimensional fatigue symptom
inventory-short form, questionnaire for assessing duration and frequency of activity,
immunological assays for checking proinflammatory cytokines in both groups, and
characteristics of cancer across the randomized groups using chi-square and t-test. The group
effects on primary outcome is given below in table 2.
Table 2:
Outcome (at 3 months post
treatment and follow-up
by yoga)
p-value for group effect Inference
Fatigue 0.002 significant

4CRITICAL APPRAISAL
Energy scale 0.01 significant
Depression 0.15 Not significant
TNF-α 0.068 Not significant
IL-6 0.056 Not significant
IL-1 0.19 Not significant
Estimate of risk:
The studies had no risk ratio therefore 95% CI was not estimated. First study
describes the BCPT Cognitive Scale scores revealing the analysis where 95% CI range was
not specific for most of the contrast and is deviated from the mean difference. But one
contrast was specific- yoga vs wait-list at 3-month follow up (95% CI = 0.11 to 0.51 and
mean difference =0 .31). In the second paper it was observed that range for 95% CI in
outcome of yoga on inflammatory cytokine IL-1 at 3 months post-treatment has a huge
difference even when it was statistically significant (p =0.03) therefore the outcome was not
specific(Greenland et al., 2016).
Exposure duration:
The exposure in the researches was found to be before the onset of outcome. The
exposure for the first study was for 12-weeks and twice a week for trial group as well as
control group and the exposure frequency increased gradually. Whereas in the second paper
the randomized trial was conducted for 3 months with exposure given for 90 minutes in two
days a week and outcome measured in trial group and wait-list control group.

5CRITICAL APPRAISAL
Dose- response gradient:
A dose-response magnitude of the exposure gradient was observed in both the studies
where the frequency of yoga practice decreased cognitive complaints of the women in the
first study and reduced production of inflammatory cytokines and fatigue in the second study.
Dechallenge-rechallenge:
There is no use of the dechallenge-rechallenge strategy in both the studies because the
outcome of administration or withdrawal or re-administration of a drug or medication and
then is considered as a medical testing protocol which is not relevant to the exposure used in
the studies that are yoga (Sardella & Belcher, 2018).
Strengths and limitations:
The strengths of both the papers include reduction of using confounding factors,
randomized selection, precise administration of intervention and easy measurement of
outcome and interpretation. The limitations of both the studies is the small sample size, loss
of retention factor and incomplete exposure in some individuals leading to reduction in the
sample size and changes during analysis. In the first study, women had kept no track of their
daily yoga practice during the intervention period, impact of yoga on cognitive function not
clear and loss of objective measurement of cognitive function. In the second study, yoga
group was not compared to an active control group which lead to non-specific benefits of
intervention and inclusion criteria omitted the symptoms of mood changes.

6CRITICAL APPRAISAL
References:
Consort-statement.org. (2020). Consort - The CONSORT Flow Diagram. Retrieved from
http://www.consort-statement.org/consort-statement/flow-diagram
Derry, H. M., Jaremka, L. M., Bennett, J. M., Peng, J., Andridge, R., Shapiro, C., . . . Kiecolt-
Glaser, J. K. (2015). Yoga and self-reported cognitive problems in breast cancer
survivors: a randomized controlled trial. Psycho-oncology, 24(8), 958-966.
doi:10.1002/pon.3707
Greenland, S., Senn, S. J., Rothman, K. J., Carlin, J. B., Poole, C., Goodman, S. N., &
Altman, D. G. (2016). Statistical tests, P values, confidence intervals, and power: a
guide to misinterpretations. European Journal of Epidemiology, 31(4), 337-350.
doi:10.1007/s10654-016-0149-3
Kiecolt-Glaser, J. K., Bennett, J. M., Andridge, R., Peng, J., Shapiro, C. L., Malarkey, W.
B., . . . Glaser, R. (2014). Yoga's impact on inflammation, mood, and fatigue in breast
cancer survivors: a randomized controlled trial. Journal of clinical oncology : official
journal of the American Society of Clinical Oncology, 32(10), 1040-1049.
doi:10.1200/JCO.2013.51.8860
Sandler, K. A., Petersen, L., Steinberg, M. L., Ganz, P. A., & McCloskey, S. A. (2018).
Identifying Survivorship Needs Among Women with Breast Cancer after Receiving
Radiation Therapy. International Journal of Radiation Oncology • Biology • Physics,
102(3), e604-e605. doi:10.1016/j.ijrobp.2018.07.1659
Sardella, M., & Belcher, G. (2018). Pharmacovigilance of medicines for rare and ultrarare
diseases. Therapeutic Advances in Drug Safety, 9(11), 631-638.
doi:10.1177/2042098618792502
Walsh, M., Srinathan, S. K., McAuley, D. F., Mrkobrada, M., Levine, O., Ribic, C., . . .
Devereaux, P. J. (2014). The statistical significance of randomized controlled trial
results is frequently fragile: a case for a Fragility Index. Journal of Clinical
Epidemiology, 67(6), 622-628. doi:https://doi.org/10.1016/j.jclinepi.2013.10.019