Development and validation of a deep vein thrombosis risk nomogram for post-operative complications in prostate...

Post-operative deep vein thrombosis (DVT) significantly compromises outcomes in prostate cancer (PCa) surgery patients. This study aimed to develop and validate a clinically applicable nomogram for individualized DVT risk stratification.

In this retrospective matched case-control study, 500 PCa patients (150 DVT, 350 non-DVT) undergoing surgery (2018-2023) were analyzed after rigorous DVT confirmation via duplex ultrasonography (92.2% adherence) and radiologist adjudication (κ = 0.86). To address the inflated DVT incidence due to case-control sampling, inverse probability weighting corrected sampling bias (weighted DVT incidence 12.3% versus true 12.1%), with post-weighting covariate balance confirmed by a standardized mean difference <0.08. Independent predictors were identified through multivariate logistic regression, with nomogram construction and validation (bootstrap optimism correction; temporal validation cohort n = 103). Decision curve analysis (DCA) evaluated clinical utility by quantifying net benefit across threshold probabilities (5%-80%).

Age (OR 1.045 [95% CI 1.022-1.072] per year), surgery duration (OR 1.018/10 [95% CI 1.011-1.025 per min), preoperative D-dimer (OR 1.315 [95% CI 1.192-1.451] for every 0.1 mg/L), prostate-specific antigen density (PSAD; OR 4.805 [95% CI 2.761-8.365] per unit), and advanced tumour stage (T3-T4, OR 3.512 [95% CI 2.012-6.115]) were significant predictors. The nomogram demonstrated excellent discrimination (optimism-corrected area under the curve [AUC] = 0.942; temporal validation AUC=0.918) and calibration (slope = 0.94). Clinical thresholds: age ≥68.3 years, surgery ≥159.7 min, D-dimer ≥0.92 mg/L, PSAD ≥2.95 ng/mL/cm³. DCA revealed optimal clinical utility at 10%-60% risk thresholds, with a maximum net benefit (0.111) at 10% threshold probability, consistently outperforming default treatment strategies.

This validated nomogram integrates five readily available clinical variables to precisely quantify DVT risk in PCa surgical patients. It enables personalized preoperative risk assessment, facilitating targeted prophylaxis to mitigate thromboembolic complications beyond guideline-compliant prevention.