Changes in pulmonary function during the early years after inpatient rehabilitation in persons with spinal cord injury: a prospective cohort study

Abstract

Objective: To describe changes in pulmonary function (PF) during the 5 years after inpatient rehabilitation in persons with spinal cord injury (SCI) and to study potential determinants of change.

Design: Prospective cohort study.

Setting: Eight rehabilitation centers with specialized SCI units.

Participants: Persons with SCI (N=180).

Interventions: Not applicable.

Main outcome measures: PF was determined by forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) as a percentage of the predicted value, at the start of rehabilitation, at discharge, and 1 and 5 years after discharge from inpatient rehabilitation. The population was divided into 3 subgroups on the basis of whether their PF declined, stabilized, or improved.

Results: FVC improved on average 5.1% over the whole period between discharge of inpatient rehabilitation and 5 years thereafter, but changes differed largely between persons. FVC declined in 14.9% of the population during the first year after discharge. During this year, body mass index, inspiratory muscle strength, change in peak power output, and change in peak oxygen uptake differed significantly between subgroups. FVC declined in 28.3% of the population during the following 4 years, but no differences were found between the subgroups for this period. Subgroups based on changes in FEV1 differed only with respect to change in peak oxygen uptake the first year after discharge.

Conclusions: In our study, many persons with SCI showed a decline in PF, larger than the normal age-related decline, during the 5 years after inpatient rehabilitation. Results suggest that a decline in PF during the first year after inpatient rehabilitation is associated with higher body mass index, lower inspiratory muscle strength, and declined physical fitness.

Keywords: AIS; American Spinal Injury Association Impairment Scale; BMI; CI; FEV(1); FVC; Longitudinal studies; MET; MIP; PF; POpeak; Pulmonary function test; Rehabilitation; SCI; Spinal cord injuries; Vital capacity; Vo(2)peak; body mass index; confidence interval; forced expiratory volume in 1 second; forced vital capacity; maximal inspiratory pressure; metabolic equivalent value; peak oxygen consumption; peak power output; pulmonary function; spinal cord injury.