Stable blood sugar associated with better outcomes after TJA

Patients with type 2 diabetes who had preoperative hypoglycemia (low blood sugar) and hyperglycemia (high blood sugar) fared worse after total joint replacement surgery than those who were able to keep their blood sugar (HbA1c) at normal levels, according to the results of a study presented in poster P102.

Many individual factors (including timing of last meal) are examined to determine a “normal blood glucose level,” but most physicians recommend keeping blood glucose levels between 70 mg/dL and 120 mg/dL. Patients with diabetes or hypoglycemia are urged to narrow that range even further and have their physician identify what is “normal” for them.

Previous studies have found that patients with diabetes have a higher risk of complications after cardiac surgery, as well as a higher level of microvascular and macrovascular complications.

The study involved 121 consecutive patients with type 2 diabetes who underwent primary total joint replacements (88 total knee arthroplasties and 33 total hip arthroplasties) at a single medical center. Patients were evaluated based on preoperative HbA1c levels and divided into three groups—25 percent of patients were hypoglycemic (mean 6 percent), 50 percent were within normal ranges (mean 6.9 percent) and 25 percent were hyperglycemic (mean 8.7 percent). Patient-oriented outcomes, complications, length of stay, and hospital costs were compared among the three groups.

Researchers found a significant trend toward worse scores in all categories among patients whose blood sugar fell within the lowest and highest ranges. At 2.7 years (range: 2 to 5 years), they found no significant differences between quartiles. A trend for worse scores in the lowest and highest quartiles was identified for several different outcome measures, including physical and social functioning. Length of stay and hospital costs were higher in both the lowest and the highest quartiles.

“When set in a graph, the results looked like an inverted bell, with complications spiking on both ends of the spectrum and dipping in the middle,” said coauthor Carlos J. Lavernia, MD, chief of orthopaedics at Mercy Hospital in Miami. “Even after controlling for all external factors that could have affected the outcomes, the inverted-bell shape remained intact, indicating that diabetic patients who control their blood sugar prior to surgery will inevitably have better outcomes.”

Coauthors with Dr. Lavernia for “The Effect of Diabetic Control in Total Joint Arthroplasty Outcomes” are Juan S. Contreras; Jose Carlos Alcerro, MD; and Mark Rossi, PhD.

Disclosure information: Dr. Lavernia—MAKO Surgical Corp., Johnson & Johnson, Zimmer, Journal of Arthroplasty, American Association of Hip and Knee Surgeons; Dr. Alcerro—no conflicts; Dr. Rossi—no conflicts.