Background: The rates of epidural steroid injections have increased dramatically over time, with conflicting evidence regarding the efficacy of epidural steroid injections for the treatment of various low-back pain disorders. Given the uncertainty about their role, we sought to evaluate the geographic variation in the use of epidural steroid injections for low back pain within the United States. We also sought to determine whether greater rates of epidural steroid injections are associated with lower rates of lumbar surgery.
Methods: We used the 2001 Medicare Physician Part-B claims to examine the geographic variation in the use of epidural steroid injections. Current Procedural Technology codes were used to identify the number of procedures performed as well as the percentage of injections that were fluoroscopically guided. Procedure rates were analyzed with use of several geographic indicators, including state, United States Census Bureau regions (Northeast, South, Midwest, and West), and health referral regions as defined by the Dartmouth Atlas of Health Care.
Results: In 2001, there was a 7.7-fold difference between the state with the lowest rate (Hawaii at 5.2 per 1000) and the state with the highest rate (Alabama at 39.9 per 1000). The variation among health referral regions, which are smaller in size, was even greater, with an 18.4-fold difference from 5.6 per 1000 in Honolulu, Hawaii, to 103.6 per 1000 in Palm Springs, California. Higher statewide rates of epidural steroid injections were associated with significantly higher rates of lumbar surgery (p = 0.001). In areas with high injection rates, a significantly higher percentage of patients who sought care for low back pain received injections (p < 0.001). In addition, in areas with high injection rates, a significantly higher percentage of patients who presented with low back pain received both injections and lumbar surgery within the same year (p < 0.001).
Conclusions: There is substantial geographic variation in the rates of epidural steroid injections within the United States. Southern states tend to have the highest procedure rates, whereas northeastern states have the lowest. Injection rates are positively correlated with lumbar surgery rates; therefore, epidural steroid injections do not appear to be substituting for lumbar surgeries or reducing overall rates of lumbar surgery.