CASP-Case-Control-Study-Checklist-2018 fillable form PDF

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Download CASP-Case-Control-Study-Checklist-2018 fillable form PDF

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ntr ol St udy Con tro Stu Checkli klist: CASP Chec kli st: 11 questions to help you make sense of a Case Co

How to use th is ap pr this appr praa isal too tooll : Three broad issues need to be considered when appraising a case control study: Are the results of the study valid? (Section A) What are the results? (Section B) Will the results help locally? (Section C) The 11 questions on the following pages are designed to help you think about these issues systematically. The first three questions are screening questions and can be answered quickly. If the answer to both is “yes”, it is worth proceeding with the remaining questions. There is some degree of overlap between the questions, you are asked to record a “yes”, “no” or “can’t tell” to most of the questions. A number of italicised prompts are given after each question. These are designed to remind you why the question is important. Record your reasons for your answers in the spaces provided. About ut:: These checklists were designed to be used as educational pedagogic tools, as part of a Abo ut workshop setting, therefore we do not suggest a scoring system. The core CASP checklists (randomised controlled trial & systematic review) were based on JAMA 'Users’ guides to the medical literature 1994 (adapted from Guyatt GH, Sackett DL, and Cook DJ), and piloted with health care practitioners. For each new checklist, a group of experts were assembled to develop and pilot the checklist and the workshop format with which it would be used. Over the years overall adjustments have been made to the format, but a recent survey of checklist users reiterated that the basic format continues to be useful and appropriate. Referenc nciing: we recommend using the Harvard style citation, i.e.: Critical Appraisal Skills Programme (2018). CASP (insert name of checklist i.e. Case Control Study) Checklist. [online] Available at: URL. Accessed: Date Accessed. ©CASP this work is licensed under the Creative Commons Attribution – Non-CommercialShare A like. To view a copy of this license, visit http://creativecommons.org/licenses/by-ncsa/3.0/ www.casp-uk.net

Critical Appraisal Skills Programme (CASP) part of Oxford Centre for Triple Value Healthcare Ltd www.casp-uk.net

Paper for appraisal and reference: Section A: Are the results of the trial valid? 1. Did the study address a clearly focused issue?

Yes Can’t Tell No

HINT: An issue can be ‘focused’ In terms of • the po pulation studied • Whether the study tried to detect a beneficial or harmful effect • the risk factors studied

Comments: The study was clearly aimed at colorectal cancer association with lifestyles

behaviours such as diet, smoking, alcohol, physical activity while taking into account the family history, weight and presence of conditions such as diabetes.

2. Did the authors use an appropriate method to answer their question?

Yes Can’t Tell No

HINT: Consider • Is a case control study an appropriate way of answering the question under the circumstances • Did it address the study question

Comments: The case control study was appropriate for the comparison of people with

and without colorectal cancer to determine the effects of the above mentioned.

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Is it worth continuing?

3. Were the cases recruited in an acceptable way?

Yes Can’t Tell No

Comments:

All cases were recruited after histopathological confirmation (which is one of the highest degrees of accuracy for colorectal cancer). Patients with pre-existing malignancies before CRC were also excluded ensuring all cases reflected the study of CRC and findings were not influenzed by other means

4. Were the controls selected in an acceptable way?

Yes Can’t Tell No

Comments: Controls were matched by the age and gender to the patients. Controls were selected from the same medical facility with conditions such as inguinal hernia, varicose veins, necrotizing fasciitis and diabetic foot. All of which are independent of the study factors such as diet, smoking and alcohol consumption. If multiple eligible controls were found they were randomly selected. Controls were representative of the study population however the control numbers had been less to be generalised to the entire population (based on population of India) but that was not the aim of this study.

HINT: We are looking for selection bias which might compromise validity of the findings • are the cases defined precisely • were the cases representative of a defined population (geographically and/or temporally) • was there an established reliable system for selecting all the cases • are they incident or prevalent • is there something special about the cases • is the time frame of the study relevant to disease/exposure • was there a sufficient number of cases selected • was there a power calculation

HINT: We are looking for selection bias which might compromise the generalisability of the findings • were the controls representative of the defined population (geographically and/or temporally) • was there something special about the controls • was the non-response high, could non-respondents be different in any way • are they matched, population based or randomly selected • was there a sufficient number of controls selected

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5. Was the exposure accurately measured to minimise bias?

Yes Can’t Tell No

Comments: The questionnaires prepared for initial analysis was validated by an expert. After this in-depth face-face interviews were conducted with the appropriate candidates where the behavioral traits were assessed in accordance to the risk factors. Alcohol consumption was assessed as based on the WHO STEPwise approach whereby the consumption pattern was converted to grams per day. Physical activity was measured based on international physical activity questionnaire-short version where it was converted to mins\day. For dietary 29 food items were used and broken down to 7 levels of consumption taking into account vegetarians and non-veg. All these measures provide and accurate and standardized approach to the risk-factos which do not vary between the different participants of the research.

HINT: We are looking for measurement, recall or classification bias • was the exposure clearly defined and accurately measured • did the authors use subjective or objective measurements • do the measures truly reflect what they are supposed to measure (have they been validated) • were the measurement methods similar in the cases and controls • did the study incorporate blinding where feasible • is the temporal relation correct (does the exposure of interest precede the outcome)

HINT: List the ones you think might be important, that the author may have missed • genetic • environmental • socio-economic

6. (a) Aside from the experimental intervention, were the groups treated equally?

List: May not have considered environmental factors such as pollution, UV and other

radiation exposure.

6. (b) Have the authors taken account of the potential confounding factors in the design and/or in their analysis?

Yes Can’t Tell No

HINT: Look for • restriction in design, and techniques e.g. modelling, stratified-, regression-, or sensitivity analysis to correct, control or adjust for confounding factors

Comments: The author did consider the bias in dietary intake of beef and pork due to a

rich religion in the Indian setting most participant either did not consume beef or pork. The author resorted to using mutton as a true indicator of the effects of red meat

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Section B: What are the results?

7. How large was the treatment effect?

Comments:

8. How precise was the estimate of the treatment effect?

HINT: Consider • what are the bottom line results • is the analysis appropriate to the design • how strong is the association between exposure and outcome (look at the odds ratio) • are the results adjusted for confounding, and might confounding still explain the association • has adjustment made a big difference to the OR

HINT: Consider • size of the p-value • size of the confidence intervals • have the authors considered all the

important variables • how was the effect of subjects

refusing to participate evaluated

Comments:

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9. Do you believe the results?

Yes No

HINT: Consider • big effect is hard to ignore! • Can it be due to chance, bias, or confounding • are the design and methods of this study sufficiently flawed to make the results unreliable • consider Bradford Hills criteria (e.g. time sequence, does-response gradient, strength, biological plausibility)

Comments: The study was carried out in an appropriate manner. Biases were considered and cases and controls were taken in an appropriate manner. Study findings also aligned with other studies of the same nature. The study was carried out over a considerable amount of time to provide an accurate reflection of the factors under study and can be generalized to the population.

Section C: Will the results help locally? 10. Can the results be applied to the local population?

Yes Can’t Tell No

HINT: Consider whether • the subjects covered in the study could be sufficiently different from your population to cause concern • your local setting is likely to differ much from that of the study • can you quantify the local benefits and harms

Comments: It can be applied to the local population as most of the risk factors study apply to the population. The food criteria used is generally similar to the food consumed in the local population as well as a good proportion of the local population does consist of the Indo-Fijian population. The socio-economic factor s considered also align much closely to the local population.

11. Do the results of this study fit with other available evidence?

Yes Can’t Tell No

HINT: Consider • all the available evidence from RCT’s Systematic Reviews, Cohort Studies, and Case Control Studies as well, for consistency

Comments: The author has referenced a number of studies which produce similar results in terms of smoking, alcohol, eggs and red meat consumption. It was also noted that different results in terms of the consumption of Fish was monitored however this may have been due to different types and amounts of fish consumed. Rem Remember ember One observational study rarely provides sufficiently robust evidence to recommend changes to clinical practice or within health policy decision making. However, for certain questions observational studies provide the only evidence. Recommendations from observational studies are always stronger when supported by other evidence.

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