Inadequate Glycemic Control is Associated with Surgical Site Infection in Total Joint Arthroplasty. A Systematic Review and Meta-analysis

Background: The association between inadequate glycemic control and surgical site infection (SSI) following total hip (THA) and total knee arthroplasty (TKA) has been widely discussed, however remains unclear.

Methods: We searched OVID-Medline, Embase, Web of Science and reference lists of relevant studies from inception up to December 1, 2016. Data were extracted by two independent investigators. Authors were contacted if important information on the paper’s content was absent. The main independent variable was glycemic control; controlled or uncontrolled as defined by (i) Glycated hemoglobin (HbA1C) levels;(ii) perioperative glucose values or (iii) International Classification of Diseases codes for diabetes with or without complication. We included in the meta-analysis studies in which inadequate glycemic control was defined by a certain HbA1C cut-off (range,6.5%-8%). Studies looking at HbA1C levels as a continuous variable were excluded.

Results: Overall 22 observational studies were identified examining the association between glycemic control and SSI (superficial, deep, or both). Fourteen studies reported on the association between HbA1C levels and SSI. The meta-analysis from 10 of these studies showed a significant higher risk for SSI in patients with inadequate glycemic control (pooled odds ratio[OR]:1.17, 95% confidence interval[CI]:1.008-1.365;p=0.03;I²=81.34%). However, when examining only those studies who considered HbA1C with a cutoff of 7% as uncontrolled (6 studies), this association was no longer noticed (pooled OR:0.92, 95% CI:0.76-1.10;p=0.37;I²=54.25%). Nine studies assessed the association between perioperative hyperglycemia and infection; diversity between these studies precluded us from examining them in a meta-analysis. However, there is evidence to support an independent association with SSI.

Discussion: The results of this systematic review support the association between inadequate glycemic control and postoperative infection. Patients with uncontrolled glycemic control should be optimized preoperatively. From an institutional stand point, preoperative Hba1C levels 7.5%-8%, and not the commonly used cutoff of 7% should be considered the goal for adequate control.