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Read and bring to class Monday December 6

Read and bring to class Monday December 6. Hoiriis et al. A Randomized Clinical Trial Comparing Chiropractic Adjustments To Muscle Relaxants For Subacute Low Back Pain . JMPT 2004;27:388-98

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Read and bring to class Monday December 6

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  1. Read and bring to class Monday December 6 • Hoiriis et al. A Randomized Clinical Trial Comparing Chiropractic Adjustments To Muscle Relaxants For Subacute Low Back Pain. JMPT 2004;27:388-98 • Tuchin, et al.A Randomized Controlled Trial of Chiropractic Spinal Manipulative Therapy for Migraine. JMPT 2000;23:91-5) Palmer College of Chiropractic West

  2. Group Clinical Trial Designs Palmer College of Chiropractic West

  3. Randomized, Control-group Clinical Trial (RCGCT) • The most common type of clinical outcome experiment • The strongest evidence for causality • Is a prospective study that compares the effect of an intervention against a control • Commonly abbreviated RCT Palmer College of Chiropractic West

  4. RCT • Group means of patient outcomes are compared • Group receiving an intervention is compared with a control group receiving a sham treatment • The independent variable is the treatment or sham • The dependent variable is the outcome Palmer College of Chiropractic West

  5. Groups Are Equivalent • The investigator must assume that groups are equivalent regarding items like age, gender, health status, etc. • Consequently, groups will vary only in the levels of the independent variable • Treatment, sham, or an alternate form of treatment Palmer College of Chiropractic West

  6. Control • The purpose of control groups is to rule out placebo effect, spontaneous recovery, or “regression to the mean” artifact • Control conditions should be matched to active treatment on potential confounding variables (e.g., expectancy and therapeutic contact) Palmer College of Chiropractic West

  7. Wait List Control Group • One group functions as a control group while an experimental group receives an intervention • The control group later receives the intervention after a waiting period, usually when the study is completed • Suitable for studying chronic conditions Palmer College of Chiropractic West

  8. The Treatment • Need to separate treatment effects from doctor effects • Same doctors do both – matched on variables like experience, etc. • Treatment must be administered consistently across participants • “Manualized” treatment - boosts internal validity but may detract from external validity Palmer College of Chiropractic West

  9. RCT vs. Real Practice • LBP Example • Patient entering RCT must meet inclusion/exclusion criteria (i.e., age range, no pregnancies, no leg pain, etc.) • Treatment is specifically defined (i.e., side-posture, short lever manipulation, high-velocity, low-amplitude) • The number of visits is usually specified in advance Palmer College of Chiropractic West

  10. RCT vs. Real Practice Cont. • Not so selective in real practice • Some patients are pregnant, some are elderly, some are obese, have leg pain . . . • Some have severe pain or spasms • Treatment can be tailored in real practice • Instrument adjusting may be a better option with severe pain patients • No adjustment on a given day – maybe therapy or muscle work only Palmer College of Chiropractic West

  11. RCT vs. Real Practice Cont. • Obese patients need dietary advise for optimal care of LBP • Exercise • The synergistic effect of multiple modalities • Manipulation for neck pain hasn’t done very well in RCTs by itself, but has been effective when combined with exercise Palmer College of Chiropractic West

  12. Consequences of Non-equivalent Groups • If the makeup of the groups is significantly different, then differences between groups may have nothing to do with the level of treatment involved • Example – Members of the control group in a weight loss experiment having a higher prevalence of diabetes than the treatment group Palmer College of Chiropractic West

  13. Equivalent Groups • When the assumption of equivalence is met, differences between groups are more confidently attributed to the differences between treatments • Equivalent groups in clinical experiments are most frequently produced by means of random assignment Palmer College of Chiropractic West

  14. Populations • The target population must be defined before sampling • The group to which the study’s results will be generalized • May be restricted (e.g., females between 25 and 75 years of age) • Or may be broad (e.g., all adults) Palmer College of Chiropractic West

  15. Populations Cont. • The experimental population is the group from which subjects are actually chosen • Should be representative of the target population to ensure external validity (generalizability) Palmer College of Chiropractic West

  16. Participants • They need to be representative of the people who would receive the treatment in clinical settings • They need to be clearly specified • Often through use of diagnostic criteria (x-ray or MRI, etc.) • Other characteristics need to be reported to show that participants were equivalent across groups (Age, in/ex-clusion criteria) Palmer College of Chiropractic West

  17. Conclusions. Our results suggest that adverse reactions to chiropractic care for neck pain are common and that despite somewhat imprecise estimation, adverse reactions appear more likely to follow cervical spine manipulation than mobilization. Given the possible higher risk of adverse reactions and lack of demonstrated effectiveness of manipulation over mobilization, chiropractors should consider a conservative approach for applying manipulation to their patients, especially those with severe neck pain. Palmer College of Chiropractic West

  18. Participants • Of the 960 eligible patients, 624 (65%) declined participation because of a lack of interest (460), inconvenience(103), and specific treatment preferences (60). = 37.9% Palmer College of Chiropractic West

  19. Assessment • A baseline measure is needed to demonstrate group equivalence and for use as a covariate in an ANCOVA design • (a procedure in which differences in outcome are measured between groups statistically correctingforinitial status) • Follow-up – the longer the better • Measurement should be done in a number of different ways Palmer College of Chiropractic West

  20. Hierarchy for selection of a study sample Theoretic Population Experimental Population Subject selection Participants Non-participants Group assignment Experimental Control Group Group Palmer College of Chiropractic West

  21. Validity of RCT • Depends on three critical concerns • Size of the experimental population must be large enough to obtain sufficient numbers of participants • A group must be identified where sufficient numbers of subjects will have the outcome measures (Heart disease vs. VAD) • The experimental population must be available for the duration of the study Palmer College of Chiropractic West

  22. Figure 14-1 N=100 patients By coin-toss, random number generation, drawing number out of a hat, etc. Control Experimental Group Group Mean Age: 29.9 30.1 Sample Size: 51 49 Female: 43 52 Blue-collar: 33 80 Pre-treatment Pain rating: 8.2 8.5 Independent Variable: - + Random Assignment Palmer College of Chiropractic West

  23. Figure 14-1 Cont. Control Experimental Group Group Mean Age: 29.9 30.1 Sample Size: 51 49 Female: 43 52 Blue-collar: 33 80 Pre-treatment Pain rating: 8.2 8.5 Independent Variable: - + Groups are considered equivalent The only difference is the level of treatment Palmer College of Chiropractic West

  24. Equivalence is Not GuaranteedWith Random Assignment • Random assignment will be more successful • With larger samples • Fewer number of groups • We would be more confident of equivalence with 100 subjects divided into 2 groups than 30 subjects divided into 3 groups Palmer College of Chiropractic West

  25. Another Way to Attain GroupEquivalence • Direct comparison of groups prior to intervention • The second most popular method • Not nearly as powerful or accepted • Pre-treatment patient variables, such as age, gender, and diagnosis are factored in statistically • These variables are called covariates • The appropriate analysis is ANCOVA Palmer College of Chiropractic West

  26. Result of ANCOVA Palmer College of Chiropractic West

  27. Randomization • The most accepted method of attaining equivalence • The single most important design strategy for reducing the influence of bias • Strengthens the claim that group differences in the study were attributable to the intervention Palmer College of Chiropractic West

  28. Blinding • Double-blind study • A method used to prevent bias • Neither the patient nor the doctor know whether a sham, standard treatment, or new treatment is involved • As mentioned previously, blinding is nearly impossible in the chiropractic setting • Single-blind study • Patient is not aware (instrument adjusting) Palmer College of Chiropractic West

  29. Objective of RCT • Determine that mean scores of the dependent variable differ between groups after application of the independent variable • Difference must be statistically significant • The most straightforward RCT • Patients randomly assigned to two groups The classic experiment Palmer College of Chiropractic West

  30. VARIANCE Between Group Within Group Experimental Variance (Due to the treatment) + Extraneous Variance (confounders etc.) Error Variance (Not due to treatment) (Due to chance) Palmer College of Chiropractic West

  31. Variance: Important For the Statistical Analysis Between groups variance Within groups variance F = Experimental variance + Extraneous variance Error variance F = Palmer College of Chiropractic West

  32. Variance • Experiments should be designed to • Maximize experimental variance • Make sure the levels differ from each other • Measurements are valid and capable of showing a clear difference • Control extraneous variance • Minimize confounding variables • Control error variance • Accurate measurements Palmer College of Chiropractic West

  33. Group Mean vs. an Individual Patient • A RCT only considers the average patient • Your patient will NOT be average • They may be close, but each patient is unique in some way regarding • Severity • Secondary conditions • Response to care • You are a unique practitioner with a whole arsenal of treatment options Palmer College of Chiropractic West

  34. Statistical Analysis • 2 groups – t-test • Find the value for t and then see if it’s large enough to be statistically significant • 3+ groups – ANOVA • Find the value for F and then see if it’s large enough to be statistically significant Palmer College of Chiropractic West

  35. Clinical Trial • A clinical trial is a research study designed to test the safety and/or effectiveness of drugs, devices, treatments, or preventive measures in humans • They can be divided into four categories or phases • Phases 1-4 Palmer College of Chiropractic West

  36. Phases of Clinical Trials • Phase 1 determines how the treatment or drug works physiologically and any side-effects • May provide early evidence of effectiveness • Phase 2 consists of initial effectiveness studies and additional safety data • Phase 3 are expanded, longer-term studies to gather more detailed information about effectiveness and safety Palmer College of Chiropractic West

  37. Phases Cont. • Phase 4 trials are carried out after the treatment is commonly in use to determine additional risks, benefits, and best uses Palmer College of Chiropractic West

  38. Palmer College of Chiropractic West

  39. Interventional vs. Observational Trials • Interventional trials determine whether experimental treatments or new ways of using known therapies are safe and effective under controlled environments • Can’t truly judge safety until widely used • Observational trials address health issues in large groups of people or populations in natural settings • Epidemiology Palmer College of Chiropractic West

  40. Controlled vs. RandomizedClinical Trials • Controlled Group Clinical Trial • When the therapeutic effects of an intervention are unknown, a control (placebo) group must be added to the trial to compare the intervention to no therapy at all • Randomized Clinical Trial • Where a random assignment method is used to determine who is in the experimental group and who is in the control group Palmer College of Chiropractic West

  41. Types of Clinical Trials • Group Clinical Trial • Focus on research questions dealing with therapy (interventions) • Comparative Group Clinical Trial • Compares one intervention with another intervention • Compares a new intervention with a standard treatment Palmer College of Chiropractic West

  42. Subdivisions of CTs • Treatment (therapeutic) trials • Test new treatments, new techniques, new drugs, or new surgeries • Prevention trials • Look for better ways to prevent disease in people who have never had the disease or to prevent a disease from returning • May include treatments, vitamins, vaccines, or lifestyle changes Palmer College of Chiropractic West

  43. Subdivisions of CTs • Diagnostic trials • Conducted to find better diagnostic tests or procedures • Screening trials • Test the best way to detect certain diseases or health conditions • Quality of life trials (supportive care trials) • Find new ways to improve the quality of life for people with a chronic illnesses Palmer College of Chiropractic West

  44. Ethical Considerations • The well-being of the participants must be kept in mind • Risk and harm must be minimized • Patients with serious conditions may be exposed to higher risk • A study involving tension headache patients would tolerate less risk than one involving malignant brain tumor patients Palmer College of Chiropractic West

  45. Institutional Review Board (IRB) • Clinical trials must be approved and monitored by an Institutional Review Board (by federal law) • The Palmer Center for Chiropractic Research has an IRB • Includes community advocates, and others to ensure that the research is ethical and the rights of participants are protected Palmer College of Chiropractic West

  46. Informed Consent • A process where a person learns key facts about a clinical trial or research study and then agrees voluntarily to take part or decline • Subjects have a right learn about a study before deciding whether or not to participate Palmer College of Chiropractic West

  47. Informed Consent Cont. • Risks and potential benefits must be explained • It must be emphasized that it is a continuing process during the study • Subjects must have the right to withdraw at any time for any reason Palmer College of Chiropractic West

  48. Terms • Effectiveness • The ability of an intervention to produce the desired beneficial effect in actual use • A measure of the benefit of an intervention under usual conditions of clinical care • Efficacy • The ability of an intervention to produce the desired beneficial effect in expert hands and under ideal circumstances (generalizability?) Palmer College of Chiropractic West

  49. Efficacy vs. Effectiveness • Effectiveness refers to whether the treatment transfers well to real-world populations • Is needed to demonstrate external validity (a.k.a. generalizability) • Efficacy refers to whether controlled trials show a treatment effect • Is internal validity present? Palmer College of Chiropractic West

  50. Efficacy vs. Effectiveness Cont. • Efficacy shows that internal validity is present, but • Effectiveness is needed to show external validity (a.k.a. generalizability) Palmer College of Chiropractic West

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