645 Getting What You Pay For: Impact of Copayments on Physical Therapy Initiation, Timing, and Continuation for Acute-Onset Low Back Pain

Abstract

INTRODUCTION: Physical therapy (PT) is an important component of acute low back pain (LBP) management. Despite established guidelines, heterogeneity in medical management remains common. METHODS: The IBM Watson Health MarketScan claims database was queried for adult patients with new-onset idiopathic LBP. The primary outcomes-of-interest were timing and overall utilization of PT services. Additional outcomes-of-interest included timing of opioid prescribing. Actual and inferred copayments based on specialist visit claims were used to evaluate the relationship between PT copayment and incidence of PT initiation. Multivariable regression models were used to evaluate factors influencing PT usage. RESULTS: Overall, 2,467,389 patients were included. PT initiation, among those with at ≥1 PT service during the year after LBP diagnosis (30.6%), occurred at a median of 8 days post-diagnosis (IQR 1-55). Among those with at least one PT encounter, incidence of subsequent PT visits was significantly lower for those with high initial PT copayments. High initial PT copayments, while inversely correlated with PT utilization, were directly correlated with subsequent opioid use. High PT copayments affected relative timing of PT and opioid initiation, with every $10 increase associated with a delay in PT initiation of 3.06 days (95%CI 2.76-3.36) and an advancement of opioid prescription by 2.58 days (95%CI 2.24-2.92). For multivariable whole-cohort analyses, incidence of PT initiation among patients with inferred copayments in the 50-75th and 75th-100th percentiles was significantly lower than those below the 50th percentile (HR = 0.893 [95% CI 0.887-0.899] and HR=0.905 [95% CI 0.899-0.912], respectively). CONCLUSIONS: Higher PT copayments correlated with reduced PT utilization; higher PT copayments and lower opioid copayments were independent contributors to delayed PT initiation and higher opioid use. In patients covered by plans charging high PT copayments, opioid use was significantly higher. Co-pays impact long-term adherence to PT.