Background: Given reports about variation in opioid prescribing, concerns about increasing opioid use and its associated negative consequences make understanding the sources of variability important. The aims of the study were to assess the extent of and factors associated with geographic variation in early opioid prescribing for acute, work-related, low back pain (LBP).
Methods: Cases were selected from workers compensation administrative data filed between January 1, 2002 and December 31, 2003 and included claims from states with more than 40 cases. Early opioid prescribing (one or more prescriptions within first 15 days) was the outcome. Weighted coefficient of variation (wCOV) estimated geographic variation, and multilevel models measured variability controlling for individual and contextual factors.
Results: Of the 8,262 claimants, 21.3% received at least one early opioid prescription. Significant between-state variation was found (wCOV = 53%), from 5.7% (Massachusetts) to 52.9% (South Carolina). Seventy-nine percent of the between-state variation was explained by three contextual factors: state household income inequality (prevalence ratio [PR] 1.06, 95% confidence interval [CI] = 1.01, 1.12), number of physicians per capita (PR 0.99, 95% CI = 0.98, 0.99), and workers compensation cost containment effort score (PR 1.12, 95% CI = 1.02, 1.24). Individual-level factors, including severity, explained only a small portion of the geographic variability.
Conclusion: Geographic variation of early opioid prescribing for acute LBP is important and almost fully explained by state-level contextual factors. The study suggests that clinician and patient interaction and the subsequent decision to use opioids are substantially framed by social conditions and control systems. Am. J. Ind. Med. 52:162-171, 2009. (c) 2008 Wiley-Liss, Inc.