Background <p>Patients who undergo tracheostomy and remain ventilator-dependent for over 21 days (defined as prolonged mechanical ventilation, PMV) represent a critically ill subgroup with high long-term mortality. Existing prognostic models such as the ProVent score may not fully capture the specific risk profile of these patients. This study aimed to develop and validate a novel prognostic model, the Tracheostomy-ProVent score, to predict 3-, 6-, and 12-month mortality using clinical variables measured on day 21 of mechanical ventilation.</p> Methods <p>This retrospective cohort study included 213 tracheostomized adult patients who received invasive mechanical ventilation for more than 21 consecutive days in a tertiary care hospital between February 2011 and February 2023. Multivariate logistic regression was used to identify predictors of mortality and construct a scoring model. Model performance was assessed using area under the receiver operating characteristic curve and calibration analyses.</p> Results <p>The cumulative mortality rates in our patient cohort were 55.9%, 62.5%, and 66.7% at the 3-month, 6-month, and 1-year time points, respectively. The Tracheostomy-ProVent score showed strong predictive accuracy, with areas under the receiver operating characteristic curves of 0.871, 0.886, and 0.875 for 3-, 6-, and 12-month mortality, respectively. Notably, the new score significantly outperformed the original ProVent score in predicting 1-year mortality (AUC 0.875 vs. 0.768). The key clinical variables that were consistently associated with mortality included the requirement for vasopressors, platelet count of &lt; 150 × 10³/µL, PaO₂/FiO₂ ratio of &lt; 200 mmHg, and serum albumin level of ≤ 2.8&#xa0;g/dL on day 21 of MV.</p> Conclusion <p>The Tracheostomy-ProVent score demonstrates potential as a valuable tool for advanced risk stratification in tracheostomized patients. However, external validation is required to confirm its generalizability prior to widespread clinical application.</p>