Treatment adherence: Predictive factors and the relationship with treatment outcomes in patients with low back pain

Low back pain (LBP) is a significant health problem that is ranked as the leading cause of global disability. LBP affects approximately 80% of the population leading to an estimated $300 billion in direct and indirect costs in the United States alone. Unfortunately, this problem continues to grow with minimal change in the rate of years lost to disability over the past decade. In response to this growing problem, multiple major international guidelines have been developed to improve the provision of evidence-based medicine for patients with LBP. According to these guidelines, one of the first steps for managing this condition is physical therapy. While effective for many musculoskeletal conditions, including LBP, many patients do not experience clinically meaningful improvements in LBP following physical therapy. This has led to increased focus on identifying factors associated with outcomes in patients receiving physical therapy for LBP. One of the factors that has been demonstrated to influence patient outcomes is treatment adherence. While treatment adherence is a prerequisite for positive outcomes, there is a paucity of evidence for how treatment adherence influences outcomes in patients with LBP. In addition, there is limited understanding of what modifiable and non-modifiable factors influence treatment adherence in this population. The collective purpose of the three studies in this dissertation was to identify relevant barriers to adherence while showing how adherence relates to outcomes in patients with LBP. The first study is a retrospective analysis that demonstrates that high patient costs per visit, the presence of an opioid prescription, and symptom duration less than one month predicts non-adherence to treatment. This study led to the development of the second study, which is a prospective analysis that shows that high levels of psychological distress negatively influence treatment adherence. The final study prospectively analyzed 236 participants and demonstrates that higher levels of home exercise program compliance predict improved functional outcomes in patients with LBP. The results of this dissertation support the importance of identifying and addressing the modifiable risk factors for non-adherence to treatment, which may allow clinicians to improve the likelihood that their patients will experience significant improvement in LBP.