Introduction: Validated patient reported outcomes(PROs) for spinal disorders may be too lengthy to feasibly apply to large scale registry efforts. We set out to determine which PROs are most valid and responsive, and which domains have closest correlation(overlap). Our aim was to introduce a shorter, valid and responsive, and more feasible questionnaire for measuring effectiveness of lumbar surgery.
Methods: A total of 520 patients undergoing surgery for degenerative lumbar spine disease were enrolled into our prospective registry. Baseline and 1-yr PROs were assessed. In order to assess the validity of PROs and individual items, ROC analysis was performed. In order to assess responsiveness, standardized response means(SRM) was calculated. Correlation was assessed via Spearman rank. For PROs and their items demonstrating high validity(AUC >0.70), and for individual items with similar dimensions and high correlation, items with maximum validity were included in the final questionnaire,Vanderbilt Back Index(VBI-6).
Results: ODI(AUC: 0.77;SRM diff: 0.96) and SF-12 PCS(AUC HTI:0.76;SRM diff:0.94) were found to be most valid and responsive. For ODI, pain intensity, mobility, social life and travel had highest AUC. For SF-12 PCS, general health, climbing stairs, less accomplishment, limitation from pain, effect on work and social activities had the highest AUC. 6 of these 12 most valid and responsive items were found to have significant correlation(r=0.48,p<0.0001). Thus, 6 items out of 22(sitting, standing, social function, general health, accomplishment due to pain, effect on usual work)comprised of VBI-6. VBI-6(AUC: 0.81; SRM diff: 1.10) demonstrated better validity and responsiveness and strongly correlated with ODI(r=0.84;p<0.0001) and SF-12 PCS(r=0.81;p<0.0001).
Conclusions: The 10-item ODI and 12-item SF-12 PCS were the most valid and responsive PROs. However, a more valid and responsive instrument VBI-6 can be constructed using 6 out of 22 items. Large scale registry efforts can utilize this more feasible VBI-6, which has better validity and responsiveness than ODI and SF-12 PCS.
Patient Care: Our research shows that a shorter, feasible, and more valid and responsive outcomes instrument, VBI-6 can be utilized in large scale registry efforts to assess outcomes of degenerative spine disorders.
Learning Objectives: At the end of the session, participants should be able to: 1) identify that ODI and SF-12 are most valid and responsive patient reported outcome instruments for assessing effectiveness of lumbar surgery; 2) a novel, more feasible, valid and responsive instrument VBI-6 can be utilized in large scale registry efforts.