Diabetes Mellitus Does Not Impact Achievement of a Minimum Clinically Important Difference Following Anterior Cervical Discectomy and Fusion

Background: Diabetes mellitus (DM) has been identified as a risk factor for poorer outcomes following anterior cervical discectomy and fusion (ACDF). This study aims to evaluate the impact DM has on achievement of MCID (minimum clinically important difference) following ACDF.

Methods: A surgical database was reviewed for patients who underwent primary, single-level ACDF procedures with posterior instrumentation. Visual analog scales (VAS) Arm and Neck, Neck Disability Index (NDI), and Patient-Reported Outcomes Measurement Information System (PROMIS) and 12-item Short Form (SF-12) scores for physical function (PF) were recorded. MCID achievement was calculated using pre-established values from the literature. Intergroup differences in demographic, perioperative characteristics, mean outcome scores and rates of MCID achievement were calculated.

Results: There were 43 patients with diabetes and 320 patients without diabetes. DM status was significantly associated with age, ethnicity, hypertension, American Society of Anesthesiologists physical classification score, Charlson Comorbidity Index, and insurance type (all P ≤ 0.041). Postoperative length of stay was significantly greater for the DM group (P = 0.011). Mean VAS Arm and NDI differed at 6 months (P ≤ 0.049, both) and PROMIS-PF differed from 6 weeks through 6 months (P ≤ 0.039, all). Patients without diabetes significantly improved in all PROMs by 1 year postoperatively (P < 0.01, all). Patients with diabetes significantly improved in VAS Neck and Arm, SF-12 physical component score, and PROMIS-PF by 1 year (all P ≤ 0.013) but NDI significantly improved only at 12 weeks (P = 0.038). Intergroup differences for MCID achievement were demonstrated at 6 months for NDI and SF-12 physical component score (P ≤ 0.008).

Conclusions: Although moderate intergroup differences in MCID achievement were demonstrated, the results of this study suggest that patients may realize similar benefits of ACDF surgery regardless of DM status.