University Report: Critical Appraisal of a Cohort Study

This report presents a critical appraisal of the cohort study by Bandstein et al. (2014), which investigated the use of undetectable high-sensitivity cardiac troponin T (hs-cTnT) levels and electrocardiograms (ECG) to rule out myocardial infarction (MI) in the emergency department (ED). The study's methodology, including the selection of a cohort study design, accurate exposure measurement, and a 30-month follow-up period, is evaluated. The report highlights the study's findings, such as the high negative predictive values for MI and mortality in patients with specific hs-cTnT and ECG results. While the study's statistical analysis, presentation of results, and large sample size are noted as strengths, the lack of bias analysis is identified as a limitation. The report also discusses the applicability of the study's findings to different populations and references supporting studies. The critical appraisal is based on the CASP framework, assessing the validity, results, and local applicability of the cohort study.

Running head: CRITICAL APPRAISAL
CRITICAL APPRAISAL
Name of the student:
Name of the University:
Author note:

1CRITICAL APPRAISAL
The purpose of the assignment is to provide a critical appraisal for a cohort study in order
to identify the effectiveness of the evidence and its application in the clinical practice. The
selected study for the assignment is Undetectable High-Sensitivity Cardiac Troponin T Level in
the Emergency Department and Risk of Myocardial Infarction by Bandstein et al., (2014).
The cohort study conducted by Bandstein et al., (2014) has focused on a specific issue
such as evaluation of undetectable (<5 ng/l) high-sensitivity cardiac troponin T level and
electrocardiogram in ruling out myocardial infraction in the ED without the symptoms of
ischemia. The cohort study is type of longitudinal study that recruit a group of people to share
the experience of a specific event for a selected time period and cross section is performed at the
intervals of time to address the research question (Sedgwick, 2014). In this study the researchers
have focused to identify the effectiveness of hs-cTnT and ECG to rule out MI without the sign of
ischemia, thus have recruited patients with chest pain and having at least one hs-cTnT as the
cohort in order to address the research question. Hence it can be said that the selection of cohort
study as the research method is appropriate for the study and the researchers have recruited the
cohort in an effective manner. Exposure was measured accurately for example, patient having at
least one hs-cTnT level were identified and serum creatinine level, undetectable hs-cTnT level
such as level <5 ng/l in combination with myocardial ischemia on ECG with no changes in ST
segment were measured which indicated that the study has measured the required subjective and
objective measurements for expected outcomes. However, lack of identification of confounding
factors such as sensitivity analysis has been found in the study. The study has represented the
follow up of every subject and considered the hazard ratio related to all risk factors of mortality
for the patient with MI in emergency department was calculated in an effective manner which
indicated that the follow up was complete enough and the time period of 30 months is a long

2CRITICAL APPRAISAL
period to reveal the good or bad effect. The result of the study has indicated that the negative
predictive value of MI for the patient with undetectable hs-cTnT level and no evidence of
ischemia changes on ECG within a tome period of 30 months is 99.8% and the negative
predictive value for the death rate of such patients is 100%, which has reflected that patients with
chest pain having hs-cTnT and no symptoms of ischemia on ECG are less susceptible to MI and
death thus they could be discharged from the ED directly. The study has recruited 14636
participants for 30 months in order to derive the result. Adequate statistical analysis was
performed and precise result have been provided by the authors. The presentation of the result,
statistical analysis, effective follow up and positive outcomes have increased the reliability of the
result, however, the study lack the analysis of biasness which is an questionable factor of the
reliability of the result. The study was performed in Sweden which is different from the
population of Saudi Arabia that may create concern regarding the application of the result,
however, the large sample size and satisfactory outcome of the study it may be applicable to the
local population of Saudi Arabia. In addition the findings were supported by other studies for
example study of Cullen, Than & Peacock, (2014) also indicated the similar fact.

3CRITICAL APPRAISAL
Reference:
Bandstein, N., Ljung, R., Johansson, M., & Holzmann, M. (2014). Undetectable High-Sensitivity
Cardiac Troponin T Level in the Emergency Department and Risk of Myocardial
Infarction. Journal Of The American College Of Cardiology, 63(23), 2569-2578. doi:
10.1016/j.jacc.2014.03.017
Cullen, L., Than, M., & Peacock, W. F. (2014). Undetectable hs-cTnT in the emergency
department and risk of myocardial infarction. Journal of the American College of
Cardiology, 64(6), 632-633. https://doi.org/10.1016/j.jacc.2014.03.017
Sedgwick, P. (2014). Retrospective cohort studies: advantages and disadvantages. Bmj, 348,
g1072. https://doi.org/10.1136/bmj.g1072