One-year mortality in patients requiring prolonged mechanical ventilation: multicenter evaluation of the ProVent score

INTRODUCTION: Current severity-of-illness indexes are unable to assess the long-term prognosis of patients requiring prolonged mechanical ventilation. A prognostic scoring system (Prognosis for Prolonged Ventilation score - ProVent - score) seems able to evaluate one-year mortality of such patients. However, testing of the model outside the developers' centers has not been reported. So, it is unclear how the ProVent score performs in non-US and non-tertiary ICUs. The goal of our study was to evaluate its performances in a French multicenter, community hospital-based setting. METHODS: In three primary ICUs, 201 patients requiring mechanical ventilation for at least 21 days were enrolled in a retrospective cohort study. ICU mortality was abstracted from medical records and, for patients discharged alive from the ICU, one-year mortality was determined by telephone calls to patients’ general practitioners. RESULTS: One-year mortality was 60% (n = 120). On day 21 of ventilation, ProVent score value was 0 in 19 patients (9%), 1 in 63 patients (31%), 2 in 64 patients (32%), 3 in 37 patients (18%), and ≥4 in 18 patients (9%), respectively. For ProVent score values ranging from 0 to ≥4, one-year mortality rates were 21%, 43%, 67%, 78%, and 94%, respectively. The area under the curve (AUC) of the receiver operator characteristic (ROC) curve for the ProVent score was 0.74 (95% confidence interval 0.671 to 0.809). Stepwise logistic regression analysis showed that only three variables (age ≥65 years, vasopressors, and hemodialysis) were independently associated with one-year mortality in our population. In assigning one point to each variable, we created a French ProVent score. The Hosmer-Lemeshow goodness-of-fit statistic was 1.36 (DF = 6, P = 0.857) and the AUC of the ROC curve was 0.742 (95% confidence interval 0.673 to 0.810). One-year mortality rates for French ProVent score ranging from 0 to 3 were 34.6%, 70.9%, 83.3% and 100%, respectively (P <0.0001). CONCLUSIONS: The ProVent score is able, even in non-US ICUs and in community hospitals, to accurately identify among patients requiring prolonged mechanical ventilation those who are at high risk of one-year mortality. Its simplification appears possible. However, further validation of this French ProVent score in a larger external sample is indicated.