Incidence and Risk Factors of Pneumonia in Individuals With Acute Spinal Cord Injury: A Multi-national, Multi-center, Prospective Cohort Study

Abstract

Objective: To describe the occurrence of pneumonia in individuals with acute spinal cord injury (SCI) and identify its key predictors.

Design: Multi-centric, longitudinal cohort study.

Setting: 10 specialized SCI rehabilitation units in Europe and Australia.

Participants: Eligible were 902 men and women with acute SCI, aged 18 years or older, with cervical or thoracic lesions and not dependent on 24-hour mechanical ventilation; 503 participated in the study (N=503).

Interventions: Not applicable.

Main outcome measures: We assessed demographics and lesion related parameters at study entry, and any pneumonia events throughout inpatient rehabilitation. Respiratory function, decubitus, and urinary tract infections were assessed at 1, 3, and 6 months post injury as well as at discharge from inpatient rehabilitation. Time to event (pneumonia) analyses were done using the Kaplan-Meier method, and potential predictors for pneumonia were analyzed with multivariable survival models.

Results: Five hundred three patients with SCI were included, with 70 experiencing at least 1 pneumonia event. 11 participants experienced 2 or more events during inpatient rehabilitation. Most events occurred very early after injury, with a median of 6 days. Pneumonia risk was associated with tetraplegia (hazard ratio [HR]=1.78; 95% confidence interval [CI] 1.00-3.17) and traumatic etiology (HR=3.75; 95% CI 1.30-10.8) American Spinal Injury Impairment Scale (AIS) A (HR=5.30; 95% CI 2.28-12.31), B (HR=4.38; 95% CI 1.77-10.83), or C (HR=4.09; 95% CI 1.71-9.81) lesions. For every 10 cmH₂O increase in inspiratory muscle strength, pneumonia risk was reduced by 13% (HR=0.87; 95% CI 0.78-0.97).

Conclusion: Pneumonia is a major complication after SCI with the highest incidence very early after injury. Individuals with traumatic or AIS A, B, or C tetraplegia are at highest risk for pneumonia.

Keywords: Maximal respiratory pressures; Predictor; Pulmonary infection; Rehabilitation; Tetraplegia.