Study data presented at the annual meeting of the American Society for Surgery of the Hand indicate that patients with diabetes who have hemoglobin A1c (HbA1c) levels of 7 percent or greater experience higher and longer-lasting elevations of blood glucose after corticosteroid injections in the hand than those whose HbA1c levels are better controlled. The authors believe that HbA1c levels, therefore, may be useful for predicting the impact of these injections on blood glucose elevations and for counseling these patients prior to the injection.

Hand disorders, such as carpal tunnel syndrome and de Quervain tenosynovitis, are common among diabetic patients and are frequently managed with corticosteroid injections. However, corticosteroid injections can temporarily elevate blood glucose levels in patients with diabetes, according to Jake Schroeder, BA, a medical student at Thomas Jefferson University doing research at the Rothman Institute in Philadelphia. 

“We sought to assess the relationship between HbA1c levels—the standard measure of assessing long-term glycemic control in diabetic patients—and the intensity of the increased blood glucose levels after corticosteroid injections,” he said. “We hypothesized that patients with higher HbA1c levels—reflecting poorer glycemic control—would experience a greater magnitude of postinjection elevation in blood glucose.”

Study methods, results
The researchers prospectively evaluated 25 diabetic patients treated with local corticosteroid injections in a hand surgeon’s office. Patients self-reported their most recent HbA1c values and their normal average baseline glucose levels at the time of injection (Table 1). Each patient received a 1 mL injection containing 10mg of triamcinolone acetonide. Daily follow-up phone interviews were conducted to record postinjection glucose levels until levels returned to baseline.

Twenty patients (80 percent) experienced postinjection blood glucose elevations relative to baseline. The elevations were transient, lasting no longer than 5 days. Patients with HbA1c values of 7 percent or greater had higher blood glucose elevations (P = 0.003) and maintained the elevations for a longer period of time (P = 0.0004) than patients with lower HbA1c levels.

“When stratified based on HbA1c, patients with values greater than 7 percent experienced greater and more prolonged increases in blood glucose elevations, in spite of having essentially the same average baseline blood glucose values as patients with values less than 7 percent,” Mr. Schroeder said.

Patients with higher HbA1c levels also experienced a higher number of hyperglycemic events (P < 0.0001), compared to patients with lower HbA1c levels. “It’s also important to note that the average HbA1c value of patients who had hyperglycemic events—defined as blood glucose levels greater than 180—was 8.1 percent, versus 6.4 percent in patients who had no hyperglycemia events,” said Mr. Schroeder.

The researchers concluded that patients with poorly controlled diabetes are more susceptible to injection-related blood glucose elevations. “Specifically, it appears that an HbA1c value greater than 7 percent corresponds to an increased incidence of hyperglycemic events as well as more prolonged elevations of greater magnitude,” Mr. Schroeder said. “It is possible that HbA1c levels can be used to roughly predict the degree of blood glucose elevation after corticosteroid injections into the hands of diabetic patients.”

Study limitations
According to Mr. Schroeder, the study was meant to replicate a clinical scenario in which patients typically present without prospective measurements while following their usual testing routine. However, he did admit that it had several limitations, including the usage of only one type and dosage of corticosteroid. “We also did not prospectively measure baseline glucose or HbA1c, instead relying on patients to self-report. Furthermore, we did not attempt to differentiate between pre- and postprandial measurements, which could affect the magnitude of elevation.”

Despite these limitations, the authors believe that their results show that HbA1c may be a useful tool when counseling patients about how corticosteroid injections may affect their blood glucose levels.

Mr. Schroeder’s coauthors of “Elevated Hemoglobin A1c Levels Correlate With Blood Glucose Elevation in Diabetic Patients Following Local Corticosteroid Injection in the Hand: A Prospective Study” are Pedro K. Beredjiklian, MD; Jonas L. Matzon, MD; Kevin Lutsky, MD; C. Edward Hoffler II, PhD, MD; and Nayoung Kim, BS.

Disclosures: Dr. Beredjiklian—Tornier; Dr. Lutsky—Synthes, American Society for Surgery of the Hand; Drs. Matzon and Hoffler and Mr. Schroeder and Mr. Kim—no conflicts.

Maureen Leahy is assistant managing editor of AAOS Now. She can be reached at leahy@aaos.org

Bottom Line

• HbA1c levels of 7 percent or greater are a marker of poor glucose control in patients with diabetes.
• The results of this small study indicate that diabetic patients with HbA1c levels of 7 percent or greater have postinjection elevations in blood glucose that are higher and last longer than those with lower HbA1c levels.
• HbA1c levels may be used to roughly predict the degree of blood glucose elevation in patients with diabetes following corticosteroid injections.

Additional Information:
Best Papers (Papers 1-8) (see Paper 8)