Physical Therapy Intervention Study Designs Spring 2025 PDF

PRESEARCHTICE Physical Therapy Intervention Research Designs Part 1 - Study Designs PT 8271 Session 1 Patient case: Two weeks after tearing her anterior cruciate ligament while playing summer league basketball, an 18-year-old female high school senior underwent anterior cruciate...

PRESEARCHTICE Physical Therapy Intervention Research Designs Part 1 - Study Designs PT 8271 Session 1 Patient case: Two weeks after tearing her anterior cruciate ligament while playing summer league basketball, an 18-year-old female high school senior underwent anterior cruciate ligament reconstruction and medial meniscal repair. Ten days after surgery, she presents with pain at rest that she rates as 4/10 on a numeric rating scale. She has 0° passive knee extension with a 5° quadriceps muscle lag. Active and passive knee flexion is limited to 65°. Her ambulation is limited with crutches. She is unable to bear full weight on the involved limb at this time. Moderate swelling and effusion is apparent, resulting in difficulty performing an isometric quadriceps contraction compared with the noninjured side.  Problem list Weightbearing Gait abnormalities Quad strength Single leg stability  Intervention PICO Adolescents who recently underwent anterior cruciate ligament reconstruction and a medial meniscus repair… …is ______________ … …compared with ____________________ … …more effective to ____________________? What study design to best answer this clinical question?  6 S Model / Evidence Hierarchy Clinical Practice Guidelines Systematic Reviews Studies: – Randomized Clinical Trials – Cohort Studies – Case-control studies – Case reports Basic Study Design Notation R = Randomization (Random assignment) O = Observation (Measurement) X = Intervention  Some Basic Research Definitions Independent variable – A variable that is manipulated by the investigator which is thought to influence another variable The cause Practice example – treatment Dependent variable – A variable that is assumed to be caused by another variable The effect Practice example – outcome Cross-sectional design O  Longitudinal design O X O Prospective versus retrospective Single-group pretest-posttest design O X O  Two-group non-randomized design O X O O X O Observational studies: Cohort versus case- control  Two-group randomized pretest-posttest design R O X O O X O  Pretest-posttest randomized control group design R O X O O O  Posttest-ONLY randomized control group design R X O O Pretest-posttest randomized control group design with follow-up R O X O O O O O Multiple group pretest-posttest randomized design R O X O O X O O X O  Summary Random assignment to treatment groups helps to improve internal validity Prospective better than retrospective Cohort better than case-control Bottom Line for Patient Case Evidence from Clinical Practice Guidelines Evidence from Systematic Reviews Evidence from Experimental Studies Evidence from Observational Studies  Activity READ: Winemiller MH, Billow RG, Laskowski ER, Harmsen WS. Effect of magnetic versus sham-magnetic insoles on plantar heel pain: a randomized controlled trial. JAMA 2003; 290(11):1474-1477. PMID: 13129987 PHYSICAL THERAPY INTERVENTION RESEARCH DESIGNS Part 2 – Internal Validity PT 8271 Week 1 STEPS OF EVIDENCE-BASED PRACTICE  Formulate a clear clinical question from a patient’s problem  Search the literature for relevant clinical articles  Critically appraise the evidence for its validity and its usefulness  Implement useful findings in clinical practice  Evaluate our performance VALIDITY IN RESEARCH DESIGN  Internal Validity: the potential for confounding factors to interfere with the relationship between the independent and dependent variables  Can the results be trusted?  e.g., in step 3 of EBP appraise the validity of the evidence  External Validity: can the results be generalized to other persons, settings, or times?  Do the results apply to my patient?  e.g., in step 3 of EBP appraise the usefulness of the evidence POTENTIAL BIASES/THREATS TO INTERNAL VALIDITY OF INTERVENTION STUDIES  Groups different at the start of the study  May differ in prognosis  Groups may become different as the study proceeds  Placebo effects, co-intervention, assessment of outcome  Groups may differ at the end of treatment (other than experimental effect)  Loss to follow-up  Omitting patients who did not receive assigned treatment  Investigator bias PRETEST-POSTTEST RANDOMIZED CONTROL GROUP DESIGN R O X O O O APPRAISING VALIDITY OF INTERVENTION STUDIES  CONSORT statement  Checklists  Cards from Evidence Based Medicine book  Key question tables in Evidence Based Physical Therapy text  PEDro scale CONSORT  Consolidated Standards of Reporting Trials  25 item checklist  Flow diagram  http://www.consort-statement.org/ For more information: Moher D, Hopewell S, Schulz KF, et al. CONSORT 2010 explanation and elaboration: updated guidelines for reporting parallel group randomised trials. BMJ. 2010; 340:c869. Available at: http://www.bmj.com/content/340/bmj.c869.long CONSORT EVIDENCE-BASED MEDICINE BOOK  Recommend text  Straus SE, Glaziou P, Richardson WS, Haynes RB. Evidence-Based Medicine: How to Practice and Teach It, Fifth Edition. Edinburgh: Elsevier Churchill Livingstone; 2018. ISBN: 978-0702062964.  https://ebm-tools.knowledgetranslation.net/ EVIDENCE-BASED MEDICINE APPRAISING STUDIES OF THERAPY  Was the assignment of patients to treatment groups randomized?  Was the randomization concealed?  Were the groups similar at the start of the trial?  Was follow-up of patients sufficiently long and complete?  Were all patients analyzed in the groups to which they were randomized?  Who was blinded? Patients, clinicians and study personnel?  Were groups treated equally, apart from the experimental therapy?  PEDRO SCORE PEDro is the Physiotherapy Evidence Database. The "PEDro score" is determined simply by counting the number of items (excluding item 1) that are satisfied in the report of a randomized clinical trial. The PEDro score can therefore range from 0 to 10 out of 10 and a higher score represents greater internal validity of the study. To ensure the quality of ratings, all trials are rated twice, and a third rater resolves any disagreements. http://www.pedro.org.au/scale_item.html PEDRO SCALE 1. Eligibility criteria and source (not scored) 2. Random allocation 3. Concealed allocation 4. Baseline comparability 5. Blinding of subjects 6. Blinding of therapists 7. Blinding of assessors 8. Adequate follow-up 9. Intention-to-treat analysis 10. Between-group comparisons 11. Point estimates and variability INTENTION TO TREAT (ITT)  In randomized trials, a method to analyze data according to how the participants were randomly assigned to groups, regardless of whether or not they completed or received that treatment. A good thing to include in research design however may be poorly understood and sometimes poorly implemented  Due to confusion in interpretation was removed from CONSORT  ITT analysis versus per-protocol analysis APPLY THE PEDRO SCALE TO: Kulig K, et al. An intensive, progressive exercise program reduces disability and improves functional performance in patients after single-level lumbar microdiskectomy. Phys Ther. 2009 Nov;89(11):1145-1157.  Random allocation  Concealed allocation  Baseline comparability  Blinding of subjects  Blinding of therapists  Blinding of assessors  Adequate follow-up  Intention-to-treat analysis  Between-group comparisons  Point estimates and variability  Physical Therapy Intervention Research Designs Part 3 – External Validity PT 8271 Week 1  KEY POINTS  Contrast external and internal validity of a study and why both are important.  Random assignment versus random sampling  Discuss the generalizability of a study’s results.  Identify populations and samples.  Differentiate probability and non-probability sampling.  Identify different sampling techniques.  Identify potential threats to external validity  Steps Of Evidence-Based Practice  Formulate a clear clinical question from a patient’s problem  Search the literature for relevant clinical articles  Critically appraise the evidence for its validity and its usefulness  Implement useful findings in clinical practice  Evaluate our performance  Population  Target population  The aggregate of individuals to whom the investigators wish to apply the results  Accessible population  The pool of potential research subjects that are available  Sample  A collection of individuals taken from the population for the purposes of a research study.  Terminology: subjects or participants  Parameters relate to populations  Statistics relate to samples  Inclusion Criteria  Attributes that make an individual eligible for a study.  Exclusion Criteria  Use to eliminate individuals from participation in a study.  May confound results  May be contraindications to treatment  Sampling Techniques  Non-probability sampling  A sample that was selected by non- random methods  Examples: volunteers, using available patients  Probability sampling  A sample chosen from the population using random methods  Note  Difference between random sampling and random assignment  Random sampling refers to how the persons were selected from the population and relates to external validity  Random assignment refers to how the sample was divided into treatment groups and relates to internal validity  Non-Probability Sampling  Convenience: uses available patients  Very common in healthcare literature  Consecutive > nonconsecutive  Quota: uses stratification to obtain representative proportions of specific subgroups  Purposive: uses a predefined criteria to select a specific group  Snowball: uses recommendations from participants to locate other participants with similar characteristics  Probability Sampling  Random: every person in the population has an equal chance of being selected for a study  Systematic: a defined interval is used to select persons from a list of the population members  Stratified: separates the population into separate groups before selecting a random sample from each group  Disproportional: a stratified sample that uses weighting to account for characteristics which are not evenly distributed in the population  Example: gender of physical therapists  Cluster (multistage): large subgroups selected at random from the population and then smaller groups from the subgroups are selected  Potential biases/threats to external validity  Interaction of treatment and selection  Do results from one sample apply to other samples or to the population?  Interaction of treatment and setting  Do results in a rehabilitation setting apply to outpatient or home health settings?  Interaction of treatment and history  Do results from the past apply to the current healthcare environment? Patient case: Two weeks after tearing her anterior cruciate ligament while playing summer league basketball, an 18-year-old female high school senior underwent anterior cruciate ligament reconstruction and medial meniscal repair. Ten days after surgery, she presents with pain at rest that she rates as 4/10 on a numeric rating scale. She has 0° passive knee extension with a 5° quadriceps muscle lag. Active and passive knee flexion is limited to 65°. Her ambulation is limited with crutches. She is unable to bear full weight on the involved limb at this time. Moderate swelling and effusion is apparent, resulting in difficulty performing an isometric quadriceps contraction compared with the noninjured side.  Summary  External Validity of a study  Believability of the study  Applicability of the study to your patient  Importance of both internal and external validity to clinicians and investigators Tying it All Together  Efficacy The benefit of an intervention as compared to a control or standard program. – Examines behavior of variables under controlled, randomized (experimental) conditions. Internal validity: high External validity: low or high  Effectiveness Benefits and use of the procedure under “real world” conditions. Internal validity: generally lower than efficacy studies External validity: may be higher than efficacy studies  Week 1 Main Points Study design Internal validity = Quality External validity = Applicability Patient case: Two weeks after tearing her anterior cruciate ligament while playing summer league basketball, an 18-year-old female high school senior underwent anterior cruciate ligament reconstruction and medial meniscal repair. Ten days after surgery, she presents with pain at rest that she rates as 4/10 on a numeric rating scale. She has 0° passive knee extension with a 5° quadriceps muscle lag. Active and passive knee flexion is limited to 65°. Her ambulation is limited with crutches. She is unable to bear full weight on the involved limb at this time. Moderate swelling and effusion is apparent, resulting in difficulty performing an isometric quadriceps contraction compared with the noninjured side.  What’s next Complete activity for session 1 – appraising an intervention article Session 2: Descriptive and inferential statistics Priming activity Intervention article assignment due in February  Patient Case for Session 1 Activity Charles Martin is a 32-year-old man who installs security systems. His work is physically demanding requiring a significant amount of lifting, bending, twisting, and maintenance of awkward positions. He also has two sons: a 2-year-old and a newborn. Seven months ago he began to experience significant pain of his back, right buttock, and right leg, which became progressively worse to the point that he experienced pain throughout his work day and when playing with his 2-year-\old son (wrestling, chasing, and spinning him). He underwent a two-level L4-L5, L5-S1 microdiskectomy 2 months ago. Mr. Martin states he has experienced a significant decrease in back and leg pain after the surgery. He currently works a full day but is restricted to a desk job at the main office. At home, he can lift and care for the newborn, but he has not yet tried to lift his 2-year-old. Mr. Martin’s goal is to go back to work installing security systems without restrictions and play with his 2- year-old as he did before the pain began.  THANK YOU!!! ANY QUESTIONS?