AANS Neurosurgeon : Features

Volume 24, Number 2, 2015

Registry Science Has Identified Opportunities for Improvement in Spine Care

Scott L. Parker, MD; and Anthony L. Asher, MD, FAANS

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Health care, as a proportion of the U.S. gross domestic product, has increased faster than any other industry. (1) As a result, “value-based” reforms are being adopted by most stakeholders to help achieve sustainability of the U.S. health-care system. Value-based health care seeks to bend the cost curve and optimize population health by providing effective care, while eliminating unnecessary services and avoidable expenses. (2)

Reliable data related to the safety and effectiveness of care is fundamental to understanding and promoting health-care value. Current benchmarks of acceptable morbidity and treatment effectiveness are generally based on retrospective reviews or a limited number of tightly controlled studies. These traditional analyses often fail to account for important variations across patient populations, disease states or health-care settings, and have been inappropriately applied in clinical settings not represented by the research environments. Additional drawbacks related to randomized prospective trials include significant costs, complexity and practical/ethical considerations related to randomization.

Given the limitations of traditional forms of evidence to inform value-based decision-making, clinical registries have been increasingly employed to generate evidence and ascertain the effectiveness of clinical interventions in routine practice. Compared with other forms of clinical data acquisition, patient care registries can be cost-effective and easily scaled to accommodate numerous users. Well-designed registries can yield data that is both reliable and valid. Importantly, and unlike tightly controlled prospective clinical trials, registry data can more readily be generalized to broad patient populations. As such, health-care policy makers, purchasers and payers are progressively encouraging the use of registries to develop high-quality clinical data.

Neurosurgery’s Entry into Registry Science
The National Neurosurgery Quality and Outcomes Database (N2QOD) is a national collaborative registry of quality and outcomes reporting after low-back surgery. This program is designed to establish, for the first time, a robust national mechanism of quality reporting, risk-adjusted benchmarking, comparative effectiveness analysis, and evidence-based practice improvement for spine surgery. Detailed methods of the N2QOD are described elsewhere. (3,4) Briefly, the N2QOD is a prospective observational registry recording 30-day morbidity and 3- and 12-month quality data for five common surgical lumbar spine diagnoses: first-time surgery for disc herniation, stenosis and spondylolisthesis, as well as revision surgery for either recurrent disc herniation or adjacent segment disease. The N2QOD lumbar module was launched in March 2012 and has now enrolled more than 15,000 patients in total, making this the largest society-based North American cooperative spine surgery registry. Furthermore, more than 6,000 patients have now crossed the 12-month follow-up threshold. This volume of data has allowed identification of opportunities for improvement that will help patients and practitioners avoid adverse outcomes and improve surgical spine care quality. Some of these opportunities are briefly outlined below.

Unplanned Hospital Readmission Within 90 Days of Surgery
Prior research into post-operative spine readmissions has relied heavily on administrative databases; as such, these analyses have been restricted by the inherent limitations of such information sources. Nevertheless, the results of these prior investigations have found rates of 30-day readmission after spine surgery ranging from 2.5 percent to 8.4 percent. (5-11) In the first prospective, multicenter analysis of hospital readmissions following spine surgery, we assessed data from the N2QOD registry to understand the factors associated with unplanned hospital readmission following elective spine surgery.

Some 10,204 consecutive patients undergoing elective lumbar surgery were identified and analyzed, and 701 (6.9%) patients were readmitted to the hospital (for any cause) within 90-days postoperatively. Factors significantly associated with increased risk of readmission in multivariate analysis were (odds ratio [confidence interval]) greater preoperative disability (higher ODI score): 1.2 [1.02-1.39]; prior lumbar spine surgery: 1.3 [1.1-1.6] Medicare insurance: 1.4 [1.02-1.6]; higher ASA score: 1.8 [1.5-3.0]. This data promises to assist identification of high-risk patients for hospital readmission following spine surgery. Moving forward, appropriate allocation of resources may help to reduce the incidence of postoperative unplanned readmissions and its associated effects on surgical outcomes, health-care costs, and overall quality of care delivered.

Predicting Patient Improvement Following Lumbar Spine Surgery
Understanding pre-operative patient factors that significantly impact post-operative outcomes following lumbar spine surgery will facilitate improved surgical effectiveness. As such, we set out to develop a predictive model for 12-month pain, disability and quality of life in patients undergoing elective lumbar spine surgery.

A total of 3,770 patients had completed 12-month follow-up and were included in this analysis. From a population perspective, all patient-reported outcomes (PROs) were significantly improved (p<0.0001) by 3 months post-operatively and remained so at 12 months post-operatively. Factors significantly associated with worse post-operative outcomes included worse baseline PRO scores, disabled or retired occupation status, previous surgeries, smoking history, higher pre-operative anxiety score (modified somatic perception questionnaire, MSPQ), higher ASA grade, longer symptom duration, diagnosis of adjacent segment disease, and workers’ compensation.

Factors significantly associated with better post-operative outcomes included greater level of education and diagnosis of disc herniation. Five separate novel predictive models generated from this data were able to accurately predict a patient’s 12-month back pain-visual analog scale (BP-VAS) score, leg pain (LP-VAS) score, Oswestry Disability Index (ODI) score and EuroQol-5D (EQ-5D) score with 94, 90, 95 and 95 percent accuracy, respectively. Moving forward, these novel predictive models can be used during pre-operative patient counseling to facilitate shared decision-making (and thus promote patient-focused care) and help set appropriate expectations prior to surgery (appropriate expectations have been linked to improved patient satisfaction following surgical interventions). (12-15)

Importance of Longitudinal Surveillance
Despite the realized and theoretical benefits of large-scale registry efforts, these programs can be exceedingly costly and, if not managed efficiently, can add to existing economic burdens of health-care services. Therefore, a “registry science” is needed to help make registries a practical and economically defensible way to empower value-based, health-care reform.

Long-term follow-up is of vital importance in understanding the sustainability of treatment effects of lumbar spine surgery and is fundamental to powering evidence-based economic health-care reform. This activity is also the most costly and challenging aspect of patient-reported outcome registries. If short-term patient benefit can serve as an adequate predictor of treatment outcomes after prolonged intervals, then significant economic savings may be realized in the application of registries to spine care-directed, value-based measurement and reform.

We analyzed whether 3-month outcome measurements suffice to identify effective versus non-effective care for degenerative lumbar surgery. In an analysis of 3,073 patients, 65 percent (n=1,982) of patients achieved clinically significant improvement for ODI at 3 months; 85 percent maintained, and 15 percent did not. The remaining 35 percent (n=1,091) of patients did not achieve clinically significant improvement at 3 months; 63 percent remained below threshold, 37 percent went on to achieve clinically significant improvement at 12 months. In aggregate analysis, 77 percent of patients were concordant at 3 and 12 months, 23 percent were discordant. The 3-month ODI differed from 12-month by an absolute difference of 11.9 ± 10.8, and predictive modeling estimations of 12-month ODI differed from actual 12-month by 10.7 ± 9.0 points (p=0.001). Based on this data, 3-month ODI does not accurately predict 12-month ODI, as predicted 12-month scores were only able to be reliably estimated within a 20-point absolute ODI range. Many patients failing to benefit from surgery by 3 months do so by 12 months, and many report loss of benefit. We conclude that longitudinal surveillance cannot be overlooked, and prospective longitudinal registries need to span at least 12 months to determine true effectiveness of spine care.

The N2QOD registry is now positioned to determine the combined contribution of patient variables to specific clinical and patient-reported outcomes. These analyses will ultimately facilitate shared decision-making and encourage efficient allocation of health-care resources, thus significantly advancing the value paradigm in spine care.

Scott L. Parker, MD, received his medical degree from The Johns Hopkins University School of Medicine and is currently a fourth-year neurosurgery resident at Vanderbilt University Medical Center. Anthony L. Asher, MD, FAANS, is co-medical director of the Carolinas Healthcare System Neuroscience Institute and is neurological surgery residency program director at Carolinas Medical Center. He is also clinical professor in neurosurgery at the University of North Carolina, Carolinas Medical Center and Vanderbilt University. Currently a director of the American Board of Neurological Surgery and a Director at Large of the American Association of Neurological Surgeons, Dr. Asher is currently vice president of NeuroPoint Alliance. The authors reported no conflicts for disclosure.


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One Comment

  1. Hooshang saberi says:

    I would like to thank the authors for their novel approach to modern management strategies for management of spinal disorders

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