Preoperative Risk Assessment for Lumbar Fusion in Patients With Diabetes: Data-Driven Stratification of HbA1c and Same Day Glucose Levels that Predict 90-Day Complication Rates.

Study designs: Retrospective Database Analysis.

Objectives: Pre-operative glycemic control in diabetic patients undergoing lumbar fusion (LF) is essential for evaluating complication risk. However, current thresholds for preoperative HbA1c and same-day-glucose (SDG) are either non-specific or have low predictive power. This study uses HbA1c and SDG to provide data-driven risk stratification for 90-day major and wound complications in LF patients.

Methods: Using a national database, patients undergoing LF from 2013-2022 with a recorded preoperative HbA1c and SDG level were included for analysis. Multiple HbA1c and SDG strata were identified using stratum specific likelihood ratio analysis (SSLR). Each stratum was then propensity-score matched to the lowest strata and compared using risk ratios. Significance level was set at a P-value <0.05.

Results: 12,026 patients met inclusion criteria. For 90-day major complications, SSLR identified 3 predictive HbA1c (4.5-5.4, 5.5-7.9, and 8.0+) and SDG strata (60-159, 160-239, and 240+). Following propensity-matching, the 90-day major complication risk sequentially increased for HbA1c: 5.5-7.9 (1.69; P = 0.001; 95% CI 1.24-2.30), 8.0+(2.31; P < 0.001; 95% CI 1.56-3.43). Following propensity-matching, the SDG strata similarly demonstrated sequentially increasing 90-day major complication risk: 160-239 (1.34; P < 0.001; 95% CI 1.18-1.54), 240+ (1.64; P < 0.001; 95% CI 1.31-2.05). Matched analysis demonstrated a higher relative-risk of 90-day wound complications for the 8.0+ HbA1c strata (2.23; P = 0.001; 95% CI 1.37-3.63) compared to the HbA1c 4.5-5.4 strata. No other strata were identified that predicted differences in 90-day wound complications.

Conclusions: This study identified data-driven HbA1c and SDG strata that better risk-stratify 90-day major complications following LF. Instead of current single-value thresholds, these multiple strata may be utilized for better preoperative guidance.