VALIDATION OF A CLINICAL PREDICTION RULE TO IDENTIFY PATIENTS LIKELY TO BENEFIT FROM SPINAL MANIPULATION: A RANDOMIZED CLINICAL TRIAL by John David Childs BS, Biology, U.S. Air Force Academy, 1994 MPT, Physical Therapy, U.S. Army-Baylor University, 1996 MBA, Business, University of Arizona, 2000 MS, Musculoskeletal Physical Therapy, University of Pittsburgh, 2002 Submitted to the Graduate Faculty of the School of Health and Rehabilitation Sciences in partial fulfillment of the requirements for the degree of Doctor of Philosophy University of Pittsburgh 2003 i UNIVERSITY OF PITTSBURGH SCHOOL OF HEALTH AND REHABILITATION SCIENCES This dissertation was presented by John D. Childs It was defended on June 24th, 2003 and approved by ___________________________________________ Julie M. Fritz, PhD, PT, ATC (Dissertation Chair) Assistant Professor Department of Physical Therapy, University of Pittsburgh ___________________________________________ Timothy W. Flynn, PhD, PT, OCS, FAAOMPT Program Director and Associate Professor, US Army-Baylor University Graduate Program in Physical Therapy ___________________________________________ James J. Irrgang, PhD, PT, ATC Assistant Professor and Vice Chairman for Clinical Services, Department of Physical Therapy, University of Pittsburgh and Vice President of QI and Outcomes and Director of Sports and Orthopaedic Physical Therapy, Centers for Rehab Services ___________________________________________ Anthony Delitto, PhD, PT, FAPTA Associate Professor and Chair Department of Physical Therapy, University of Pittsburgh ii Copyright by John D. Childs 2003 iii VALIDATION OF A CLINICAL PREDICTION RULE TO IDENTIFY PATIENTS LIKELY TO BENEFIT FROM SPINAL MANIPULATION: A RANDOMIZED CLINICAL TRIAL John D. Childs, PhD University of Pittsburgh, 2003 Purpose: The primary aim of this study was to validate a clinical prediction rule (CPR) to identify patients with low back pain (LBP) likely to benefit from spinal manipulation. Subjects: 131 consecutive patients referred for physical therapy. Patients with positive neurologic signs or other red flags for spinal manipulation were excluded. Method: A multicenter, randomized clinical trial. After completing a standardized history and physical examination, patients were randomly assigned to receive spinal manipulation (n=70) or a stabilization exercise intervention (n=61). Patients were seen in physical therapy twice the first week, then once a week for the next three weeks, for a total of five sessions. A single manipulative intervention was used for patients who received spinal manipulation during each of the first two sessions, who then completed the stabilization exercise intervention for the remaining three weeks. Patients who achieved at least a 50% improvement in their Oswestry Disability Questionnaire (ODQ) score were classified as a success. Patients who met at least 4/5 criteria in the CPR were classified as positive. Analyses: A 2*2*3 repeated measures multivariate analysis of variance (MANOVA) was performed, followed by a Bonferroni procedure for planned comparisons. Sensitivity, specificity, and positive and negative likelihood ratios (LR) with associated 95% confidence intervals were calculated. Results: There was a significant three-way CPR*Intervention*Time interaction for the overall repeated measures MANOVA (p<.001). Patients classified as positive on the CPR and received spinal manipulation achieved 2.5 times the minimum clinically important difference iv (MCID) on the ODQ compared to patients classified as negative on the CPR and received spinal manipulation and 3.4 times the MCID compared to patients classified as positive on the CPR but received the stabilization exercise intervention (p<.001). These results were maintained at the four-week follow-up (p<.003). With a positive LR of 13.2 (3.4, 52.1) and based on a pre-test probability of success of 44.3%, this translates into a post-test probability of success of 91.2%. Conclusions: The results of this study support the validity of the spinal manipulation CPR. Clinical Relevance: Clinicians can accurately identify patients with LBP likely to benefit from spinal manipulation. v ACKNOWLEDGMENTS Thank you to our fearless leader and department chair, Tony Delitto. Tony taught me how to stay out of people’s way and let them excel, just sticking your head in as needed to tear down the “red tape” that often stands in the way of progress. There is no better mentor or leader in our profession. It has been a privilege to be a small part of the Pittsburgh family. Many opportunities have been placed in my path simply based on being associated with many of the best in our profession. Thank you to my dissertation chair and adviser, Julie Fritz, for your being more than a mentor, but a genuine friend who works harder than almost anyone I know. Thank you for giving me the opportunity to run with a great project. I’m looking forward to years or friendship and working together. Thank you to my good friend and clinical mentor, Dick Erhard, who taught me much about how to treat patients and a little about everything else in life. There’s not much this man doesn’t know. By the way, now when is it that you are going to retire? Thank you to Jay Irrgang and Kelly Fitzgerald for introducing me to the PhD-level research process. You both have been first class mentors. Jay, you are a no-sleep machine. Kelly, you taught me how to never give up on a research question that deserves an answer. Thank you to my first clinical mentor and boss, Kevin Johnson, who gave me countless opportunities to grow professionally. Although Tim Flynn recently coined the phrase, Kevin was the first to show me to just “manip, and move on”. He is also a subject recruiting machine. Thank you to all of the physical therapists who assisted me with data collection. I could not have been successful without you: Kevin Johnson, Guy Majkowski, Maria West, Evan Kelley, David Browder, Mike Blowers, Sherri Morrow, Brian Langford, Jeff McGuire, Cory Middel, Trevor Petrou, and Kelly Rhoden. Thank you to one of my best friends and doctoral colleague, Sara Piva, who is almost as unable as I am to say “No” to a new project or adventure. This experience would not have been nearly as enjoyable if it weren’t for your friendship. I look forward to years of working together. Thank you to my friends and physical therapy colleagues from the military. To Rob Wainner, who, upon my being selected by the Air Force to pursue a PhD, let me know that Pitt was really the only program to consider. Your counsel was truly wise. To Tim Flynn, the “recovering biomechanist”, it has been a privilege having you my committee. You are one of the few who is a master clinician and researcher, all in one package. Julie Whitman, you’ve been a great friend and colleague with energy that doesn’t stop. Andrew Bennett, as a very young therapist, you’ve raised the bar for clinical excellence, showing me just how good a clinician can be. At the risk of forgetting someone, I’d like to thank a number of faculty, former doctoral colleagues, and other physical therapists that I’ve had the privilege of working with and getting vi to know at the University of Pittsburgh. You each have made a unique impact on my life: Steve George, Greg Hicks, Michelle Vignovic, Tara Ridge, Erica Baum, Joel Robb, Christian Lyons, David Browder, Pat Sparto, Jen Brach, and Kathy Kelly. Thank you to each of my parents for their unique contribution to my being able to succeed, but especially to Mom, who set an example on how to pursue excellence in everything you do. Thank you to my wonderful children, Emma and Lauren, who, although didn’t fully understand what Daddy was up to, patiently let me work from home. They had to listen to me say too many times, “I’ll be with you in just a little while.” I look forward to saying that much less often. Their rarely being impressed with anything I might do professionally helps me realize what really matters most in life. Thank you to my beautiful wife, Amy. You sacrificed countless hours of your own time letting me pursue my dreams. You made a decision early after our graduation from the Academy that becoming a fighter pilot had the potential to place an excessive burden on our family. Just as you already are as my wife and Mommy to our girls, no one doubts that you would have been among the “best of the best”. Many call it a sacrifice, but you see it simply as a blessing. Only our children and I can truly appreciate the impact of your decision in the short run. However, the passage of time through the legacy you leave will uncover you selflessness and dedication to our family for generations to come. I love you more than you will ever know. And lastly and most importantly, thank you to my Lord and Savior Jesus Christ for the provision of an opportunity to accomplish a dream. vii TABLE OF CONTENTS 1. Statement of the Problem.......................................................................................................................... 21 2. Background and Significance.................................................................................................................... 22 2.1 Prevalence and Costs Associated with LBP......................................................................................... 22 2.2 Attempts to Identify Effective Interventions for Low Back Pain............................................................ 22 2.3 Lumbopelvic Region Dysfunction a Potential Subgroup of Low Back Pain .......................................... 23