Epidural Steroids May Increase Fracture Risk

Norra MacReady

June 17, 2013

Lumbar epidural steroid injections (LESIs) are associated with an increased risk for spinal fracture, according to the results of a large retrospective analysis.

Just a single additional LESI increased the risk for fracture by 21%, Shlomo Mandel, MD, MPH, an orthopedic surgeon from the Henry Ford Health System, Detroit, Michigan, and colleagues report in an article published in the June 5 issue of the Journal of Bone and Joint Surgery. Moreover, "an increasing number of LESIs was associated with an increasing likelihood of fracture," they write.

Therapeutic steroids may reduce the pain of lumbar radiculopathy when less-aggressive treatments fail, the authors explain. However, use of LESIs could promote deterioration of skeletal quality, "particularly after frequent and prolonged treatment. Indeed, exogenous use of steroids is the leading cause of secondary osteoporosis."

Dr. Mandel and coauthors identified 50,345 patients who had been treated in the Henry Ford Health System and whose records contained at least 1 of the spine-related diagnosis codes included in the International Classification of Diseases, Ninth Edition (ICD-9). Of those, 3415 patients had received at least 1 LESI. The researchers randomly selected 3000 patients from the LESI group for the analysis and matched them with a control group of 3000 patients who were similar with respect to demographic features, recent exogenous steroid exposure, and metabolic conditions that influence bone integrity, but who had not undergone LESI. In the LESI group, the researchers examined patient records for the 5 years after the date of their first injection or the time when their documented history ended. For the control group, the researchers examined their records for the 5 years after diagnosis with a relevant disorder.

The median ages for the LESI and control groups were 66.41 ± 10.53 years and 66.49 ± 10.61 years, respectively (P = .930). Of the 10 ICD-9 diagnoses studied, only lumbago was significantly more prevalent in the control group (91.9% of patients vs 90% in the LESI group; P = .011), whereas the patients receiving LESI had significantly more sciatica (44.9% vs 40.7%; P = .021). There were no other significant differences between the 2 populations with respect to ICD-9 codes, and the authors point out that even the statistically significant differences were small in absolute terms.

The authors found that "[i]ncreasing the number of injections by one increased the risk for fracture by a factor of 1.21 (95% confidence interval [CI], 1.08 to 1.30...p=.003)." Among patients who sustained multiple fractures, LESI was associated with a hazard ratio of 1.29 (95% CI, 1.22 - 1.37; P = .001).

"[W]e demonstrated a significant increase in the risk of vertebral fractures among patients treated with LESIs," they conclude.

This "is the first scientifically rigorous effort to quantify the fracture risk associated with epidural steroid administration," Andrew J. Schoenfeld, MD, from the William Beaumont Army Medical Center, El Paso, Texas, notes in a accompanying commentary .

Other authors have worried that LESIs might exacerbate skeletal fragility, but supporting evidence has been scarce, Dr. Schoenfeld points out. "Of greater concern, the definable fracture risk as documented by Mandel et al. should be set against the best available evidence regarding the long-term efficacy of these interventions, which is admittedly less than robust."

Still, he advises readers to make note of the study's limitations, including the retrospective nature of the analysis, the heterogeneity of the indications used for performing LESIs, and the fact that some patients who received LESIs may have sought treatment elsewhere for any fractures. "This fact in and of itself could potentially confound some of the findings, and the rate of vertebral fracture following epidural steroid injections may be underestimated as a result." He recommends that clinicians consider these findings before prescribing LESIs for elderly patients.

The authors have various financial disclosures. Full conflict-of-interest information is available on the journal's Web site. Dr. Schoenfeld has disclosed no relevant financial relationships.

J Bone Joint Surg Am. 2013;95:961-964; e78(1-2). Article abstract, Commentary extract


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