Abstract
Background
Prospective registries have emerged as a feasible way to capture real-world care across large patient populations. However, the proven validity of more robust and cumbersome patient reported outcomes instruments (PROi) must be balanced with what is feasible to apply in large-scale registry efforts.
Purpose
To determine the relative validity and responsiveness of common PROi in accurately determining effectiveness of lumbar fusion for degenerative lumbar spondylolisthesis in registry efforts.
Study Design
Prospective cohort study
Patient Sample
Fifty-eight patients undergoing TLIF for degenerative lumbar spondylolisthesis
Outcome Measures
Patient reported outcome measures for pain (Numeric Rating Scale NRS-BP, NRS-LP), disability (ODI), general health (SF-12), quality of life (EQ-5D) and depression (Zung Depression Scale) were assessed.
Methods
Fifty-eight patients undergoing primary TLIF for lumbar spondylolisthesis were entered into an institutional registry and prospectively followed for two years. There was no funding source for this study and the authors do not have any conflict of interest. Baseline and two-year patient-reported outcomes were assessed. In order to assess the validity of PROi to discriminate between effective and non-effective improvements, receiver operating characteristic (ROC) curves were generated for each outcomes instrument. An area under the curve(AUC) of ≥0.80 was considered an accurate discriminator. The difference between standardized response means (SRM) in patients reporting meaningful improvement versus not was calculated to determine the relative responsiveness of each instrument.
Results
For pain and disability, ODI had AUC=0.94, suggesting it as an accurate discriminator of meaningful improvement. ODI was most responsive to postoperative improvement (SRM difference:2.18), followed by NRS-BP and NRS-LP. For general health and quality of life, SF-12 PCS (AUC:0.90), Zung (AUC:0.89) and SF-12 MCS (AUC:0.85) were all accurate discriminators of meaningful improvement, however, EQ-5D was most accurate (AUC:0.97). EQ-5D was also most responsive (SRM difference:2.83).
Conclusions
For pain and disability, ODI was the most valid and responsive measure of effectiveness of lumbar fusion. NRS-BP and NRS-LP should not be used as substitutes for ODI in measuring effectiveness of care in registry efforts. For health-related quality of life, EQ-5D was the most valid and responsive measure of improvement, however, SF-12 and Zung are valid alternatives with less responsiveness.
