Descriptive Designs And How to Appraise Them

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Descriptive DesignsAnd How to Appraise Them
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Types of Descriptive Designs

• Case Reports Series
• Case-control Cohort Studies
• Survey Research
• Reviews of the Literature

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Case Reports

• A specific type of research design that reports
  on an aspect of the management of one or two
  patients
• Case reports are the fundamental building blocks
  of scientific inquiry in health care
• Certain elements must be present in a case report
  in order for it to be publishable
• Case reports (if done properly) are not regarded
  as merely anecdotal

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Case Reports Are Gaining Respect

• Provide information about what occurs in clinical
  practice
• Interesting reading for practitioners since the
  information in case reports is practical and
  informative
• Great way to get a start in scholarly writing
• However, manuscripts are often rejected
  immediately

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Case Reports Cont.

• It may require two or three passes through the
  peer review process before case report
  manuscripts are acceptable for publication
• Dont be discouraged if you decide to submit one
• Remember that almost no manuscripts make it
  without some editing

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Submission Basics

• Study the instructions for authors before
  submission and prepare the manuscript accordingly
• Can be found in the journal
• Submit your best effort the first time
• Enlist the help of a colleague to review your
  work before submission
• Prepare yourself for the reviewers comments . . .
  dont be offended

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JMPT

• Case reports
• accounts of the diagnosis and treatment of
  unusual, difficult, or otherwise interesting
  cases that may have independent educational value
  or may contribute to better standardization of
  care for a particular health problem when
  correlated with similar reports of others.

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Why Case Report Designs

• It is important to document evidence of cases and
  their occurrence before spending large amounts of
  time and money on experimental research
• Consequently case reports are the first line of
  evidence in clinical inquiry
• Essential for communicating clinical experiences
  among clinicians

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Why Case Reports Cont.

• See Table 2 pg.44 for a complete list
• To present
• An unusual or unknown disorder
• Unusual etiology for a case
• A challenging differential diagnosis
• A new hypothesis
• A new or unique technical procedure
• Etc.

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Limitations

• Patients are managed in a non-controlled
  environment
• Consequently no generalizability to populations
• Due to possible confounding factors (i.e., the
  patient receiving unknown co-treatment)
• Observed results may be explained by the natural
  progression of disease
• Uncontrolled patient compliance

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Limitations Cont.

• Based upon the observations of a single patient,
  one can never conclude that any particular
  management strategy will be effective for other
  patients with the same condition
• A hypothesis may be offered, but it can only be
  tested using experimental clinical trials

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Limitations Cont.

• Many conditions are self-limiting or cyclical
• The patient may have improved regardless of the
  intervention used
• A cyclical condition may have presented at the
  peak of an exacerbation and merely went into
  remission during treatment
• Case presentation of groups of patients helps
  ameliorate these limitations

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Presentation Styles of Case Reports

• Several types available including
• Educational reports
• Patient management strategies and literature
  review of the condition regarding a given patient
• Diagnostic or assessment reports
• Diagnostic or analytic methods utilized
• Treatment or management reports
• The full management of a patient

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Three Varieties of Case Reports

• Based on the strictness of methods that are
  employed
• Retrospective case reports
• Written after patient care has been delivered
• Prospective case reports
• Patient care is planned out ahead of time
• Time series designs
• A clinical hypothesis is generated and tested

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Retrospective Case Reports

• Most common design reported in the literature
• The simplest variety to write
• Good design for the beginning writer
• Requires excellent practice procedures
• Specific management plan
• Valid and reliable outcome measures
• Clear chart notes

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Retrospective Cont.

• Requires the author to use the best outcome
  measures available
• If not, detracts from the credibility of the
  report
• Likely to be rejected in peer review

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Prospective Case Reports

• The difference from retrospective case reports is
  that the author plans out patient care ahead of
  time
• Begins with a review of the literature
• To determine how this planned case will
  contribute to the literature
• Published treatment protocols are found and used
  for that patient
• The best outcome measures are employed

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Prospective Cont.

• After the literature review
• The next relevant case entering the office is
  reported
• The clinician already knows exactly how to
  evaluate and manage the patient
• Measurements are taken before, during and after
  care (can be tracked over time)
• Manuscript preparation is easier because the
  literature has been reviewed ahead of time

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Time Series Case Reports

• A clinical hypothesis is generated by the doctor,
  tested over time, and documented with valid
  outcome measures
• Also considered a prospective design
• Data is recorded at specified intervals before,
  during, and after care
• A minimum of three measurements are taken during
  each phase of care to identify any trends that
  may be present

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Time Series Cont.

• Measurements taken will provide data for later
  analysis of the case
• Series of measurements taken before care
• Observation phase
• Another series of measurements taken during care
• Intervention or treatment phase
• May be appropriate for chronic conditions

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Time Series Cont.

• Time series designs are actually a type of
  experiment
• A/B design (baseline/treatment)
• A/B/A/B design (baseline/treatment/baseline/treatm
  ent)
• A/B/C design (baseline/treatment1/treatment2)
• B/A/B/A design when a baseline is not established

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A/B Design Example 1
Cervical ROM measured during baseline and
treatment phases
Baseline Treatment
Could have been daily
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A/B Design Example 2
VAS pain levels measured during baseline and
treatment phases
Baseline Treatment
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A/B/A/B Design Example
Baseline Treatment Baseline
Treatment
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A/B/C Design Example
Baseline Treatment 1 Treatment 2
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Time Series Cont.

• May be capable of showing a causal relationship
  (A/B/A/B)
• However, there are some limitations
• Limited generalizability your patient might
  react differently
• Some patients wont want to undergo multiple
  examinations without treatment
• Dramatic effects are typically required to show
  an effect

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Time Series Cont.

• Multiple published TSDs strengthen external
  validity
• So does the multiple baseline design
• Follows and compares the treatment of three or
  more patients
• Must have similar complaints and be provided a
  similar intervention
• Can help control for outside influences

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Multiple Baseline Design Three patients, each
has a different length baseline phase Dashed
lines correspond to the point of change from the
observation to intervention phases
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Multiple Baseline Design Cont.

• A cause-and-effect relationship is strengthened
  using this design because the likelihood that
  extraneous factors occurred by chance at the
  specific time treatment was started on each
  patient is small

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Case Reports

• It is not true that a report must tell of a
  unique finding
• Some case reports are published because they
  support the findings of previously published
  cases
• Also if they are useful reminders of an important
  point in diagnosis or treatment

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Most Case Reports Are on One of These Five Topics

• An unexpected association between diseases or
  symptoms
• e.g., prostate cancer presenting as LBP
• An unexpected event in the course of managing a
  patient
• e.g., a LBP patient had remarkable results using
  a certain exercise during care

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Five Topics Cont.

• Findings that shed new light on the possible
  pathogenesis of a disease or an adverse effect
• Unique or rare features of a disease
• Headache patient with double vision
• Unique therapeutic approaches
• New or modified chiropractic technique or exercise

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Checklist for Case Report Authors

• Introduction
• Is the rationale for reporting the case
  adequately explained?
• Is the rationale for reporting the case
  adequately substantiated by references?

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Checklist Cont.

• Case Description
• Is the case described adequately?
• Is the case described briefly?
• Is the case described clearly?
• Are the results of tests described adequately?
• Are the results of less common tests accompanied
  by normal values?

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Checklist Cont.

• Discussion, Comments
• Is the evidence to support the authors diagnosis
  presented adequately?
• Is the evidence to support the authors
  recommendations presented adequately?
• Are other plausible explanations considered and
  refuted?
• Do authors give directions for future study or
  management of similar cases?

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Writing the Case Report

• Use standard scientific formatting guidelines
• Uniform Requirements for Manuscripts Submitted to
  Biomedical Journals at http//www.icmje.org
• Title, Abstract, Introduction, Case Report
  (Methods), Discussion, Conclusion,
  Acknowledgements, References, Tables, and Figures.

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Title

• Title should accurately and briefly identify the
  patient
• Name the intervention involved
• Identify the outcome
• Define the population under study
• State the condition being studied
• The effect of chiropractic adjustments on
  paraspinal EMG activity in a male office worker
  with lower back pain

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Abstract and Introduction

• An abstract should simply be an organized brief
  presentation of the article
• The introduction should
• Clearly describe the purpose of the article
• Provide background information about why this
  case needs to be reported
• Provide a limited review of the literature
• Define unusual terms

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Case Report (Methods)

• A description of how the patients case was
  managed
• Assessment
• Treatment
• Frequency
• Specific methods employed
• Not merely saying chiropractic care . . .
• Patient data including outcome measures
• NDI, Oswestry, etc.

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Discussion

• Provide an overview of how the condition is
  typically managed
• Discuss differential diagnoses and how they were
  eliminated or included
• Provide a rationale for how the patient was
  managed in this case
• Provide hypotheses regarding the outcome of the
  case and why the care may or may not have been
  beneficial

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Discussion Cont.

• Discuss other possible reasons for the outcome of
  the case
• Natural history
• Other health care received
• Discuss potential faults in the case
• Offer a suggestion for future research
• Be specific about what kind of research should be
  carried out

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Conclusion

• Should be focused on what can be learned from the
  case report
• Should not provide a summary of the entire case
• Should not offer unsupported and general
  statements
• Keep in mind the limitations of case studies

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