Health related functional status in men with spinal cord injury: relationship with lesion level and endurance capacity

Study design: Cross-sectional study. Objectives: To determine the relationship of health related functional status with lesion level and endurance capacity in persons with spinal cord injury (SCI). Methods: Thirty-seven men with SCI were divided in four lesion groups: high tetraplegia (motor complete; C5 - C6, n = 10), low tetraplegia (motor complete, C6/7 - C8, n = 9). motor incomplete tetraplegia (n = 7), and paraplegia (n = 11). Health related functional status was measured with the short version of the Sickness Impact Profile (SIP68), including a physical (SOM), psychological (PSY) and social subscore (SOC). Endurance capacity, defined as maximal power output (POmax) and peak oxygen uptake (VO2peak), was measured in a maximal exercise test on a wheelchair ergometer. Results: Total SIP68-score and SOM were significantly different between lesion groups, showing higher values in the high- and low-tetraplegia group. There were no differences between lesion groups for PSY and SOC subscores. VO2peak and POmax were significantly higher in the paraplegia group, compared to the high and low tetraplegia groups. VO2peak was also higher in the motor incomplete versus other tetraplegia groups. Significant Spearman correlation coefficients were found for VO2peak and POmax with SIP68 and SOM (ranging from -0.68 to -0.79) and SOC (ranging from -0.39 to -0.51). No significant relationship was found with PSY. Hierarchical regression analysis showed that after correction for lesion level, 22% of the variance of SIP68, 8% of the variance of SOM, and 30% of the variance of SOC was explained by POmax or VO2peak. Conclusions: Results indicate that there is an evident relationship between the physical dimensions of health related functional status and lesion level, but not for the psychological and social dimensions. After controlling for lesion level a significant amount of the variance of health related functional status can be explained by endurance capacity parameters. Although no causal relationships can be established in this cross-sectional study, these results suggest that functional status may be improved by increasing the endurance capacity.