Nonlinear Association of Preoperative HbA1c With 30‑Day Complications After Inguinal Hernia Mesh Repair and Effect Modification by Day‑of‑Surgery Hyperglycemia.

BACKGROUND

Whether chronic glycemic control relates nonlinearly to outcomes after inguinal hernia mesh repair and whether day-of-surgery hyperglycemia modifies risk remains uncertain. We assessed the continuous hemoglobin A1c (HbA1c)-risk curve for 30-day complications and 1-year recurrence.

METHODS

We performed a single-center prospective cohort of adults undergoing elective inguinal hernia mesh repair from January 2017 to December 2023. Exposures were preoperative HbA1c within 30 days (continuous; <5.7%, 5.7% to 6.4%, 6.5% to 7.9%, ≥8.0%) and day-of-surgery glucose (DOS-BG) ≥180 versus <180 mg/dL. Analyses used multivariable logistic regression with restricted cubic splines, HbA1c×DOS-BG interaction testing, prespecified confounder adjustment, and multiple imputation, and Cox models for recurrence.

RESULTS

We analyzed 3420 procedures; DOS-BG ≥180 mg/dL occurred in 22.0%. The 30-day composite occurred in 315 (9.2%). HbA1c was nonlinearly associated with risk ( p _nonlin=0.008): relative to <5.7%, aORs were 1.11 (95% CI: 0.89-1.38), 1.38 (1.04-1.83), and 1.92 (1.31-2.81) for 5.7% to 6.4%, 6.5% to 7.9%, and ≥8.0%, respectively. DOS-BG ≥180 mg/dL was associated with higher modeled risk (aOR: 1.41, 1.14-1.74) and modified the HbA1c effect ( p _interaction=0.03). Adjusted risks were 6.8% at HbA1c 5.5% and 11.6% at 8.5% with DOS-BG <180 mg/dL, versus 10.2% and 17.5% with DOS-BG ≥180 mg/dL. At 1 year, 55 recurrences/reoperation events (1.6%) occurred (KM: 1.7%, 95% CI: 1.3-2.2); adjusted hazards increased modestly with HbA1c (ordered trend P =0.08).

CONCLUSIONS

Preoperative HbA1c relates nonlinearly to 30-day complications, and day-of-surgery hyperglycemia was associated with higher modeled risk across the HbA1c range. Findings support continuous HbA1c-based risk stratification. However, specific optimization thresholds require external validation.