Effects of Preoperative HbA1c on Postoperative Outcomes Following Transforaminal and Posterior Lumbar Interbody Fusion

= 0.624), or number of levels fused (non-DM: 1.3, DM: 1.1, p = 0.399, t = 0.845). The DM cohort reported poorer preoperative PROMIS overall (non-DM: 28.6, DM: 23.7, p = 0.003, t = 3.071), PROMIS physical (non-DM: 37.5, DM: 33.1, p = 0.004, t = 2.904), and PROMIS mental (non-DM: 43.7, DM: 38.9, p = 0.023, t = 2.304) scores but were found to have similar preoperative ODI scores (non-DM: 45.2, DM: 53.1, p = 0.058, t = 1.912). Clinical improvement was comparable between the two groups, exceeding MCID at one-year follow-up. Both cohorts achieved MMI at similar rates. Multivariate analysis showed that preoperative HbA1c was not correlated with the rate of MCID achievement, MMI, or outcome scores when controlling for age, BMI, sex, care partner presence, number of levels fused, procedure type, approach type, and complications. There was no difference in outcomes between MIS and open surgery patients. Conclusion Elevated preoperative HbA1c was correlated with worse preoperative outcome measures. Despite this, both diabetic and non-diabetic patients achieved similar postoperative recoveries following elective PLIF and TLIF, with no difference in long-term outcomes, complications, and rate of improvement. Our results highlight the importance of continued research on preoperative optimization, risk management, patient counseling, and the development of individualized treatment plans.