Haematology Watch

Haematology Watch, Vol 1, Issue 1.


How to read medical literature: A check list

 Dr. Mehmood-ul-Hasan

General Articles:

I.              In the Abstract section

A.            Is the study, if properly designed and analyzed, important and worth knowing about?

B.              If the results are statistically significant, do they also have clinical significance?

II.            In the Introduction section

A.            Why is the study needed?

B.            *What is the purpose of the study?

C.           What has been done before, and how does this study differ? (This information may be in the Discussion section.)

D.           *What is the population to which the study findings apply? Does the location of the study have relevance? Is the time period covered by the study appropriate? (This information may be in the Method section.)

III.           In the Method section

A.            *What design is used in the study (clinical trial, cohort, case-control, cross-sectional, case-series)?

B.            *What are the criteria for inclusion and exclusion of subjects? What limitation results?

C.           *How are subjects chosen or recruited? Randomly? If not, are they representative of the population? (How are subjects assigned in a trial?)

D.           *Is there a control group? If so, how is it chosen?

E.            How are patients followed up? Who are the drop outs, and how many are there?

F.            How is data quality ensured? Response rates? Reliability (second party review)? Compliance?

G.           What are the independent variables (or factors) studied, and what are the dependent variables (outcome or response variables)? Are they clearly defined?

H.           *Do the authors explain or give a reference to any unusual method used in the study?

I.              *Are the statistical methods  used in the study specified in sufficient detail?

J.            *Is there a statement about the sample size or power? Statements on power are essential in a negative study.

K.            In a multicenter trial, what is the number of centers involved, and what methods of quality assurance are used?

IV.          In the result section

A.    *Do the results relate to research questions and the purpose of the study?

B.    Do the statistical tests answer the research questions? Are all relevant outcomes reported?

C.   *Are actual values reported ( eg, means, standard deviations, proportions), not just the results of statistical tests? In paired designs, is the magnitude and range of differences reported?

D.   Are many comparisons made or many statistical tests performed?

E.    *Are groups similar on baseline measures? If not, were appropriate analyses done to take differences into consideration?

F.    Are appropriate graphics used to present results clearly?

V.            In conclusion and discussion section (s)

A.    *Are the questions posed in the study adequately addressed?

B.    *Are the conclusions justified from the data? Do the authors extrapolate beyond the data?

C.   Are shortcomings of the study addressed and constructive suggestions given for future research?


Clinical Trials

A.    Is the number of therapies considered appropriate?

B.    *Is the choice of control appropriate?

C.   *Were the patients randomized, and if so, how? If not:

1.    How were patients selected for the study to avoid selection biases?

2.    If historical controls were used, were methods and criteria the same for the experimental group, and were cases and controls compared on prognostic factors?

D.   *Was a powerful analysis done to determine sample size?

E.    Was the study protocol adequately described?

F.    *Were there multiple endpoints? Were subgroup analyses performed and, if so, reported appropriately? Were repeated measures made over time, and if so, how were they analyzed?

G.   *Were there censored observations, and if so, how were they analyzed?


Cohort Studies

A.    *Are the patients representative of the population to which the findings are to be applied?

B.    Is there evidence of volunteer bias?

C.   *Was there adequate follow-up time?

D.   Were there few dropouts or patients lost to follow-up?


Cross-Sectional and Survey Studies

A.    If a survey, were questions posed an unbiased manner?

B.    *Was the sample randomly selected in an appropriate manner?

C.   *Were efforts made to ensure a good response rate or to minimize the occurrence of missing data?

D.   *Were reliability (reproducibility) and validity reported?


Case-Control Studies

A.    Were records of cases and controls reviewed blindly?

B.    *How were possible selection biases controlled?

C.   How were possible measurement biases controlled?


Decision Analysis Studies

A.    Is the outcome clearly defined with criteria for assessment?

B.    Is there any evidence of circular reasoning (using findings as both predictors and criteria)?

C.   Was the outcome assessed blindly?

D.   *Was information on the false-positive rate or specificity given in addition to information on sensitivity?

E.    *If predictive values were given, was the dependence on prevalence emphasized?


Meta-Analysis or Review Studies

A.    *Do the authors specify how the literature search was conducted, and was an effort made to reduce publication bias?

B.    *Were the criteria for inclusion and exclusion of studies clearly stated?

C.   If significant findings were concluded, did the authors specify the number of additional negative studies that would be needed to eliminate the observed significance?

 *:Highly Important

(Basic & Clinical Biostatistics, 2nd edition by Beth Dawson-Saunders, Robert G. Trapp, p. 278-80)