Anthony L. Asher, Silky Chotai, Clinton J. Devin, Theodore Speroff, Frank E. Harrell Jr., Hui Nian, Robert S. Dittus, Praveen V. Mummaneni, John J. Knightly, Steven D. Glassman, Mohamad Bydon, Kristin R. Archer, Kevin T. Foley and Matthew J. McGirt
Prospective longitudinal outcomes registries are at the center of evidence-driven health care reform. Obtaining real-world outcomes data at 12 months can be costly and challenging. In the present study, the authors analyzed whether 3-month outcome measurements sufficiently represent 12-month outcomes for patients with degenerative lumbar disease undergoing surgery.
Data from 3073 patients undergoing elective spine surgery for degenerative lumbar disease were entered into a prospective multicenter registry (N2QOD). Baseline, 3-month, and 12-month follow-up Oswestry Disability Index (ODI) scores were recorded. The absolute differences between actual 12- and 3-month ODI scores was evaluated. Additionally, the authors analyzed the absolute difference between actual 12-month ODI scores and a model-predicted 12-month ODI score (the model used patients' baseline characteristics and actual 3-month scores). The minimal clinically important difference (MCID) for ODI of 12.8 points and the substantial clinical benefit (SCB) for ODI of 18.8 points were used based on the previously published values. The concordance rate of achieving MCID and SCB for ODI at 3-and 12-months was computed.
The 3-month ODI scores differed from 12-month scores by an absolute difference of 11.9 ± 10.8, and predictive modeling estimations of 12-month ODI scores differed from actual 12-month scores by a mean (± SD) of 10.7 ± 9.0 points (p = 0.001). Sixty-four percent of patients (n = 1982) achieved an MCID for ODI at 3 months in comparison with 67% of patients (n = 2088) by 12 months; 51% (n = 1731) and 61% (n = 1860) of patients achieved SCB for ODI at 3 months and 12 months, respectively. Almost 20% of patients had ODI scores that varied at least 20 points (the point span of an ODI functional category) between actual 3- and 12-month values. In the aggregate analysis of achieving MCID, 77% of patients were concordant and 23% were discordant in achieving or not achieving MCID at 3 and 12 months. The discordance rates of achieving or not achieving MCID for ODI were in the range of 19% to 27% for all diagnoses and treatments (decompression with and without fusion). The positive and negative predictive value of 3-months ODI to predict 12-month ODI was 86% and 60% for MCID and 82% and 67% for SCB.
Based on their findings, the authors conclude the following: 1) Predictive methods for functional outcome based on early patient experience (i.e., baseline and/or 3-month data) should be used to help evaluate the effectiveness of procedures in patient populations, rather than serving as a proxy for long-term individual patient experience. 2) Prospective longitudinal registries need to span at least 12 months to determine the effectiveness of spine care at the individual patient and practitioner level.
Leah Y. Carreon, Steven D. Glassman, Zoher Ghogawala, Praveen V. Mummaneni, Matthew J. McGirt and Anthony L. Asher
Transforaminal lumbar interbody fusion (TLIF) has become the most commonly used fusion technique for lumbar degenerative disorders. This suggests an expectation of better clinical outcomes with this technique, but this has not been validated consistently. How surgical variables and choice of health utility measures drive the cost-effectiveness of TLIF relative to posterolateral fusion (PSF) has not been established. The authors used health utility values derived from Short Form-6D (SF-6D) and EQ-5D and different cost-effectiveness thresholds to evaluate the relative cost-effectiveness of TLIF compared with PSF.
From the National Neurosurgery Quality and Outcomes Database (N2QOD), 101 patients with spondylolisthesis who underwent PSF were propensity matched to patients who underwent TLIF. Health-related quality of life measures and perioperative parameters were compared. Because health utility values derived from the SF-6D and EQ-5D questionnaires have been shown to vary in patients with low-back pain, quality-adjusted life years (QALYs) were derived from both measures. On the basis of these matched cases, a sensitivity analysis for the relative cost per QALY of TLIF versus PSF was performed in a series of cost-assumption models.
Operative time, blood loss, hospital stay, and 30-day and 90-day readmission rates were similar for the TLIF and PSF groups. Both TLIF and PSF significantly improved back and leg pain, Oswestry Disability Index (ODI) scores, and EQ-5D and SF-6D scores at 3 and 12 months postoperatively. At 12 months postoperatively, patients who had undergone TLIF had greater improvements in mean ODI scores (30.4 vs 21.1, p = 0.001) and mean SF-6D scores (0.16 vs 0.11, p = 0.001) but similar improvements in mean EQ-5D scores (0.25 vs 0.22, p = 0.415) as patients treated with PSF. At a cost per QALY threshold of $100,000 and using SF-6D–based QALYs, the authors found that TLIF would be cost-prohibitive compared with PSF at a surgical cost of $4830 above that of PSF. However, with EQ-5D–based QALYs, TLIF would become cost-prohibitive at an increased surgical cost of $2960 relative to that of PSF. With the 2014 US per capita gross domestic product of $53,042 as a more stringent cost-effectiveness threshold, TLIF would become cost-prohibitive at surgical costs $2562 above that of PSF with SF-6D–based QALYs or at a surgical cost exceeding that of PSF by $1570 with EQ-5D–derived QALYs.
As with all cost-effectiveness studies, cost per QALY depended on the measure of health utility selected, durability of the intervention, readmission rates, and the accuracy of the cost assumptions.
Anthony L. Asher, Matthew J. McGirt, Steven D. Glassman, Rachel Groman, Dan K. Resnick, Melissa Mehrlich, Elizabeth Spivey and Paul McCormick
Clinical registries have emerged in the current resource-restricted environment of modern medicine as useful and logical mechanisms for providing health care stakeholders with high-quality data related to the safety, effectiveness, and value of specific interventions. Temporal and qualitative requirements for data acquisition in the context of clinical registries have rapidly expanded as clinicians and other stakeholders increasingly recognize the central importance of this information to the intelligent transformation of health care processes. Despite the potential of more robust clinical data collection efforts to advance the science of care, certain aspects of these newer systems, particularly the prospective, longitudinal acquisition of clinical data and direct patient contact, represent areas of structural overlap between emerging quality improvement efforts and traditional models of human subjects research. This overlap has profound implications for the design and implementation of modern clinical registries. In this paper, the authors describe the evolution of clinical registries as important tools for advancing the science of practice, and review the existing federal regulations that apply to these systems.