Reproducibility of the international spinal cord injury quality of life basic data set: an international psychometric study

Psychometric study. To examine the reproducibility of the international spinal cord injury quality of life basic data set (QoL-BDS) in an international sample of community-dwelling adults with spinal cord injury or disease (SCI/SCD) and in subgroups with respect to age (< 50 vs. ≥ 50 years) and etiology. Outpatient rehabilitation clinics and community. Participants were people living with SCI/D in four countries, at least 1 year post onset and at least 18 years of age. The QoL-BDS consists of three items on satisfaction with life as a whole, physical health and psychological health rated on a 0–10 numerical rating scale. A fourth item on satisfaction with social life was included based on feedback from participants. A total of 79 people were included. Median age was 52 years. Most participants (69.6%) had SCI, paraplegia (53%), and 40.5% reported a motor complete injury. Median time between tests was 14 days (range 4–27). Intra-class correlation (ICC) values of the items ranged from 0.66 to 0.80. ICC values of the three-item and four-item total scores were identical and good (0.83; 95% CI 0.75–0.89). Subgroup analyses showed ICC values ranging from 0.76 to 0.83. Bland–Altman plots suggested no bias for the three-item total score, but some bias for the four-item total score. The limits of agreement of both scores were similar, wide at individual level and small at group level. This study provides evidence of reproducibility of the current version of the QoL-BDS. When adding a fourth item, reproducibility was maintained.