A retrospective single-center study in 232 adult patients evaluated the effect of diabetes mellitus (DM) and glycemic control on perianal abscess recurrence within 6 months after primary incision and drainage. Patients with relapse had a higher prevalence of DM (45.6% vs. 15.2%, p < 0.001) and a higher median HbA1c (9.49% vs. 8.23%, p < 0.001). Multivariable analysis identified five independent predictors of recurrence: DM (OR 3.99, 95% CI 1.61–9.88, p = 0.003), HbA1c (OR 1.50 per 1% increase, 95% CI 1.18–1.92, p < 0.001), BMI (OR 1.95 per 1 kg/m², 95% CI 1.43–2.06), age (OR 1.11 per year, 95% CI 1.06–1.16, p < 0.001) and low vs. high abscess location (OR 0.36, 95% CI 0.14–0.97, p = 0.044). The prediction model achieved an AUC of 0.897 (95% CI 0.814–0.957) with an optimism-adjusted Harrell C-index of 0.892 after bootstrap validation (1,000 replicates). The model showed good calibration and clinical utility over a wide range of threshold probabilities. DM and poor glycemic control are independent risk factors with a dose-response relationship between HbA1c and recurrence. The model requires external validation before clinical use.