Metabolic and Endocrine Effects of Repeated Epidural and Sacroiliac Joint Corticosteroid Injections

Repeated Epidural and Sacroiliac Joint Glucocorticoid Injections and Their Effect on Hypothalamic-Pituitary-Adrenal Axis Suppression and Metabolic Status

Corticosteroid injections into the epidural space or sacroiliac joint are increasingly used for the treatment of chronic neck, low back, and leg pain. These injections may have several side effects, including suppression of the body's adrenal glands to produce steroids (adrenal suppression) and negative effects on metabolism (weight gain, increased blood pressure, and high blood sugar levels).

The purpose of this study is to determine the time course and predictors of adrenal suppression and the metabolic effects of corticosteroid injections for chronic pain.

The investigators hypothesize normalization of adrenal function to occur within three weeks of injection in most individuals. An increased frequency of injections is predicted to lead to prolonged adrenal suppression. Corticosteroid injections are also hypothesized to lead to increases in body weight, blood pressure, and blood sugar levels, particularly in diabetic individuals.

Interventional pain procedures using corticosteroid injections (CIs), such as epidural steroid injections (ESIs) and sacroiliac joint injections (SIJIs), may have adverse metabolic and endocrine effects, including suppression of the hypothalamic-pituitary-adrenal axis (HPAA), hypertension, weight gain, and hyperglycemia. Based on sparse data on these adverse effects following repeated, long-term CIs, current guidelines suggest a maximum frequency of four to six injections annually, even though patients may benefit from more frequent treatments.

This prospective cohort study will follow first-time or repeat ESI or SIJI patients receiving injections with 0.5 mL bupivacaine 0.25% and 15 mg dexamethasone sodium phosphate at a maximum frequency of once every six weeks in order to:

• determine the frequency and duration of HPAA suppression;
• determine the incidence and predictors of prolonged (≥ 3 weeks) HPAA suppression;
• determine the baseline incidence and predictors of HPAA suppression in chronic pain patients presenting for their first CI; and
• determine the effect of CIs on body weight, resting blood pressure, and glycemic control over a six-month period.

Inclusion Criteria:

• Patients receiving SI joint or epidural corticosteroid injections
• At least 18 years of age

Exclusion Criteria:

• Contraindication to corticosteroid injection (infection; pregnancy; uncontrolled diabetes mellitus [per patient's report]; active congestive heart failure; coagulopathy; medical conditions that prohibit holding anticoagulant or antiplatelet therapy, with the exception of aspirin, for at least two weeks prior to injection; and allergy to iodinated contrast dye, corticosteroids, or amide local anesthetics)
• Known disorder of the hypothalamic-pituitary-adrenal axis
• Corticosteroid injection within 6 weeks of study enrollment