• BACKGROUND
    • Although diabetes mellitus (DM) has been established as a risk factor for infection after lower extremity arthroplasty, no association has been reported with shoulder arthroplasty.
  • METHODS
    • We queried a national database for patients with DM who underwent primary shoulder arthroplasty. We identified perioperative hemoglobin A1c (HbA1c) levels and assessed the incidence of wound complications within 6 months and deep infection that required surgical intervention within 1 year for each HbA1c level. We performed a receiver operating characteristic analysis to determine a threshold value of HbA1c.
  • RESULTS
    • Patients with DM had markedly higher rates of wound complications (1.4% versus 0.9%; odds ratio, 1.22; P = 0.028) and deep infection (0.7% versus 0.4%; odds ratio, 1.47; P = 0.001). The rates of wound complications (P = 0.0008) and deep postoperative infection (P = 0.002) increased markedly as the perioperative HbA1c level increased. Receiver operating characteristic analysis demonstrated an inflection point at an HbA1c level of 8.0 mg/dL (P = 0.017; sensitivity, 50%; specificity, 75%).
  • CONCLUSIONS
    • The risk of wound complications and deep postoperative infection in patients with DM increases as the perioperative HbA1c level increases. An HbA1c level >8.0 mg/dL could serve as a threshold for a markedly increased risk of infection.
  • LEVEL OF EVIDENCE
    • Therapeutic level III, case-control study, treatment study.