Age-adjusted Charlson Comorbidity Index Does Not Predict Outcomes in Patients Submitted to Noninvasive Ventilation

Comorbidities are thought to have prognostic impact on outcomes of patients submitted to noninvasive ventilation (NIV). Our goal was to determine if age-adjusted Charlson comorbidity index (ACCI) could predict outcomes in patients undergoing NIV due to acute respiratory failure.

Patients in respiratory failure submitted to NIV were prospective evaluated comparing patient's characteristics and outcomes according to ACCI≤median vs. ACCI>median. Each comorbidity composing the index was tested as predictor of NIV failure and readmission/mortality risk at 30 and 90 days, using logistic regression analysis. NIV failure was defined as need for invasive mechanical ventilation and/or death.

177 patients were enrolled. Median ACCI score was 5 points. Comparing patients with ACCI>5 with ACCI≤5, the former group was older but APACHE II was similar. Time to first NIV disconnection was inferior for ACCI>5 patients (OR 0.46, 95% CI 0.23-0.89, p=0.021), after gender and age adjustment. No differences were found in length of stay, time on NIV, NIV complications or failure, and 30 and 90-day hospital readmission or death, before and after adjustment. None of the single comorbidities was predictive of NIV failure and readmission risk, when adjusted to sex and age.

ACCI is not a good predictor for short and medium-term outcomes in patients submitted to NIV.