Joint and interactive associations of nutritional risk and pulmonary infection with tracheostomy decannulation in neurorehabilitation inpatients: a retrospective cohort study

Background Nutritional risk and pulmonary infection are common in tracheostomized patients entering neurorehabilitation. Their coexistence may combine limited physiological reserve with respiratory instability, but evidence on their joint association and interaction with decannulation is limited. Methods This retrospective cohort included 884 tracheostomized adults with neurological disorders admitted to a tertiary rehabilitation department between January 2020 and May 2025. Nutritional risk was defined as a Nutritional Risk Screening 2002 score ≥3, and active pulmonary infection was assessed at rehabilitation admission. Successful decannulation within 30 days was the event. Cox models were used to explore individual and joint associations and multiplicative interaction. The primary adjusted model was adjusted for demographic characteristics, comorbidity, neurological severity, and acute-care trajectory. An extended model additionally included concurrent respiratory-support, airway-protection, secretion-management, and care-related characteristics. Fifteen-day, pre-rehabilitation timing, and censoring sensitivity analyses were performed. Adjusted 15-and 30-day decannulation probabilities and 30-day restricted mean time remaining tracheostomized were also estimated. Results Overall, 574 patients (64.9%) were successfully decannulated within 30 days. Kaplan–Meier probabilities of decannulation were 95.4% with neither condition, 82.2% with pulmonary infection alone, 85.6% with nutritional risk alone, and 49.5% with both conditions. In the primary adjusted model, the hazard ratios (HRs) were 0.619 [95% confidence interval (CI), 0.475–0.806] for pulmonary infection alone, 0.642 (95% CI, 0.483–0.853) for nutritional risk alone, and 0.203 (95% CI, 0.157–0.262) for both conditions. The multiplicative interaction was significant (interaction HR, 0.510; 95% CI, 0.356–0.731; P < 0.001). Adjusted 30-day decannulation probabilities were 94.9%, 85.0%, 86.0%, and 47.6%, respectively. The dual-positive phenotype had a 30-day restricted mean time remaining tracheostomized of 22.8 days versus 10.5 days with neither condition, and the adjusted 30-day additive interaction contrast was −28.5 percentage points (95% CI, −35.2 to −15.8). Findings were similar in the extended, 15-day, timing-adjusted, and censoring sensitivity analyses. Conclusions Nutritional risk and active pulmonary infection at rehabilitation admission were each associated with a lower rate of successful decannulation. Their coexistence showed a stronger joint association on the multiplicative hazard scale and an adverse departure from additivity on the 30-day absolute probability scale. These findings support combined nutritional and respiratory assessment.