Week 4: Case Designs Flashcards
What are the two types of case designs?
- Case report:
-an article that describes a n in-depth description if the clinical course of ONE patient
-typically consists of complaints, examination findings, diagnosis, treatment, or adverse effects
-no hypothesis, data analysis, of generalizable conclusions - Case series:
Two or more case reports in a single paper
What is the 4 purposes of a case study (case report)?
- Understand unusual conditions:
- describe rare clinical presentations that aren’t often encountered
- uniques situations may offer perspectives to change car guidelines or clinical decision making - Provide example of innovative or creative therapies
- changes in technology and additional knowledge can lead to new therapeutic approaches.
- case studies provide a good forum to communicate thus - Generating and testing theories
- in the absence of evidence, clinical decisions must rely on theory
- case studies can help to develop new theories or offer insight into existing theories - Providing future research direction
- case studies can highlight issues that require further study
What are the advantages and disadvantages of case studies?
Advantages:
-clear description of treatment and outcomes
-highlight the clinical-decision making process
-useful for describing rare occurrences or conditions
Disadvantages:
-no alternatives are presented
-may be ‘best case’ scenario
Why do practitioners like case studies?
- they are easier to read and shorter than other types of journal articles
- quick to prepare, so new info is rapidly available to practitioners
- highly relevant to clinical practice
- has the full management of a patient
- while experimental studies typically involve only a specific intervention
What are the limitations of a case report?
Natural progression of the condition:
-the issue can never be fully addressed without comparing treatment and control groups in a RTC
-the outcome might have been the same without the treatment
Improvement may have been the result of a placebo effect
The patient may of had an atypical response to the treatment
-other patients who receive the same treatment for the same condition may respond differently
Care is delivered in an uncontrolled environment
-extraneous factors may effect the outcome
Describe the structure of a case report
Structure is slightly difference from other research articles
-abstract, introduction, case description, discussion and references.
The case description replaces methods and results and is most important part.
Introduction:
Typically quite brief and provides background info about condition, what motivated the case report, ie what’s uniques about the case. A short review of the literature that will be expanded on in the discussion section.
Case description:
-presents case with regard to the diagnosis, intervention and outcome
-case description should include: chief complaint, complete medical history, diagnostic tests, diagnosis, treatment, outcome, follow-up actions if any.
Discussion: why the case is important and educational, explains unanswered questions, offers an interpretation of the study’s findings.
-limitations to either the methods that were employed of the evidence that was presented should be mentioned.
-the need for further research and the types of studies that should be conducted
Preparation of case reports
Does not typically require approval from an institutional review board (ethics)
However patient confidentiality should be respected
Case reports/ series should address the following:
- clearly defined study question
- well-described study population
- well-described intervention
- valid-outcome measures
- appropriate (if any) statistical analysis
- well described results
What are some reasons case reports are returned to authors for revision?
- claims of cause-effect relationship between interventions and outcomes
- lack of detail about the examination and the intervention
- lack of detail about decision making
Case reports/ series are highly susceptible to bias: what are the 3 types of bias found commonly in case reports?
- Selection bias: author may selectively chose patients
- Observational bias: the doctors believes or expectations may effect outcomes
- there is no blinding to prevent this bias - Natural progression of the condition:
- may make the results look much better than what they really are
- less of a problem with case series as groups of cases are involved - Regression to the mean:
- patients with initial extreme scores will likely have more normal scores on re-evaluation
Appraising case reports
Is the case really unique or uncommon?
-sometimes the same topic is replicated, but eventually new studies should involve more sophisticated designs
Was the literature review adequate?
-an explanation if how the literature relates to the current case
-references should be derived from valid sources; principally peer-reviewed journals
Was the case adequately described in the case description section?
-described clearly and comprehensively, includes the patient health history, examination, diagnosis, treatment and final outcome
Was the study population described well enough?
-selection criteria (based on diagnosis, examination, laboratory, or radio graphic findings, or condition severity
We’re the outcome measures suitable for the given clinical circumstances?
Dud the author point out the studies limitations and suggest alternate explanations?
We’re suggestions for future research offered?
Interpretation of case report
Due to the inherent nature of case reports, conclusions of causation cannot be made!
