Autonomic impairment is not explained by neurological level of injury or motor-sensory completeness

Abstract

Study design: Cross-sectional study.

Objectives: Determine how well common clinical assessments of level and completeness of injury are correlated with symptoms of autonomic blood pressure instability and secondary medical complications after spinal cord injury (SCI).

Setting: Academic medical center, United States.

Methods: Eighty-two individuals with (n = 48) and without (n = 34) SCI had symptoms of autonomic blood pressure instability quantified with the Autonomic Dysfunction Following SCI (ADFSCI) survey. Health histories quantified the secondary medical complications through number of urinary tract infections and hospitalizations in the past year, time to complete bowel program, and lifetime pressure injuries. Regression models were completed to identify strengths of associated correlations.

Results: ADFSCI scores were significantly higher in individuals with SCI than controls. Neurological level of injury and ASIA impairment scale were both minimally correlated to symptoms of autonomic blood pressure instability, accounting for only 11.5% of variability in regression models. Secondary medical complications had similar, minimal correlations to level and motor/sensory completeness of SCI (R² = 0.07 and R² = 0.03 respectively). Contrasting this, symptoms of blood pressure instability on ADFSCI far outperformed the common clinical motor/sensory bedside exam, with moderately strong correlations to the ranked number of secondary medical complications after SCI (R² = 0.31).

Conclusion: Neurological level of injury and motor/sensory completeness provided limited insights into which individuals with SCI would have blood pressure instability or secondary medical complications. Interestingly, symptoms of blood pressure instability outperform the clinical motor/sensory bedside exam, with higher correlations to secondary medical complications after SCI.

Figure 1:. Scatter plots fitted with linear regression models that tested

NLI (A), AIS (B), and total ADFSCI scores (C) as predictors of ranked total secondary medical complications in individuals with SCI. NLI, neurological level of injury. AIS, American Spinal Injury Association Impairment Scale. ADFSCI, Autonomic Dysfunction Following Spinal Cord Injury.