Associations Between Diurnal Timing of Spinal Cord Injury and Its Etiology and Co-Morbidities.

Circadian rhythms play a role in time-of-day differences in risk, presenting severity and outcomes of stroke. Injury time-of-day effects, however, on occurrence, presenting severity and acute hospital outcomes have not been yet reported in patients with neurotrauma. Therefore, acute post-spinal cord injury hospitalization records of 759 patients from the prospective NACTN registry that contained information about the time of injury were analyzed. No major demographic differences were observed between groups with time of injury between 6:00-12:00, 12:00-18:00, 18:00-24:00, or 0:00-6:00. Two etiological factors including falls or sports/recreation-related accidents showed significant effects of time of injury with peaks in the 6:00-12:00 or 18:00-24:00 groups, respectively. History of diabetes or drug abuse was also significantly related to injury timing peaking in 6:00-12:00 or 18:00-24:00 groups, respectively. ASIA score-determined presenting severity during the first week post-injury was not significantly affected by timing of injury. Pairwise comparisons, however, revealed worse motor but not sensory ASIA scores after injuries at 24:00-6:00 than any other group. These data suggest diurnal modulation of spinal cord injury risk because of specific mechanisms such as falls or sports-related accidents. Moreover, some co-morbidities may interact with those injury mechanisms as exemplified by the established risk elevation of falls in those with diabetes mellitus. Finally, while diurnal timing of the injury may modulate presenting severity, more patient records are needed to verify those effects.