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Limitations of Administrative Databases in Spine Research: A Study in Obesity
Proceedings of the NASS 29th Annual Meeting / The Spine Journal 14 (2014) 1S–183S previously reported for other disease conditions but not for spinal cord tumors. RESULTS: The GIF analysis for patients with spinal cord tumors showed excess relatedness for disease among close and distant relationships (case GIF5 3.82; control mean GIF 5 2.68, p50.07), and a significant excess relatedness for spinal cord cancer when only distant relationships were considered (p50.02). RRs for spinal cord cancer were elevated, but not significantly, in 2nd and 3rd degree relatives (RR52.9; p50.15 and RR52.0;p50.14) further suggesting a familial predisposition to spinal cord tumors. CONCLUSIONS: The significant excess relatedness of cases over controls for distant relationships and the elevated RRs to distant relatives suggest a heritable predisposition to spinal cord tumors. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2014.08.133
103. Limitations of Administrative Databases in Spine Research: A Study in Obesity Nicholas Golinvaux1, Daniel D. Bohl, MPH1, Bryce Basques2, Michael Fu2, Elizabeth C. Gardner, MD1, Jonathan N. Grauer, MD1; 1 Yale University School of Medicine, New Haven, CT, US; 2New Haven, CT, US BACKGROUND CONTEXT: Recently, national inpatient database use in orthopedic research has risen sharply. Specifically, spine surgery research has seen a substantial increase in these studies, as database sample sizes allow for large-scale analyses of perioperative risk factors and surgical outcomes. The results of these studies now play a significant role in the diagnosis and treatment decisions of orthopedic surgeons. Unfortunately, without firsthand knowledge of each major database, it can be difficult to judge whether a study presents valid results to the specific questions being asked. Many limitations to using databases exist, including a rising concern over the ability of administrative claims data, such as ICD-9 codes, to accurately determine comorbidity rates. PURPOSE: The present study examines these limitations using the easily quantifiable and objective variable of obesity to definitively clarify the relationship between ICD-9 codes and clinical reality. STUDY DESIGN/SETTING: A cross-sectional study comparing ICD-9 codes for obesity to chart-documented body mass index (BMI) at a large tertiary academic medical center. PATIENT SAMPLE: All patients spending at least one night in the hospital as an inpatient between April 1, 2013 and April 16, 2013. Obstetrics and gynecology, psychiatry, and pediatric patients were excluded. OUTCOME MEASURES: Proportion of patients for whom ICD-9 obesity diagnosis codes assigned at hospital discharge match chart-documented BMI. METHODS: For each patient, ICD-9 diagnosis codes and chart-documented body mass index (BMI) were directly compared. RESULTS: 2,075 patients were included in the study. Of 573 patients deemed ‘‘obese’’ with a calculated BMI between 30.0-39.9, only 109 patients received the correct ICD-9 code (278.00), giving this code a sensitivity of 0.19. Of 174 patients deemed ‘‘morbidly obese’’ with a calculated BMI above 40, 84 patients received the correct ICD-9 code (278.01), giving this code a sensitivity of 0.48. CONCLUSIONS: This study highlights obesity as an example of the potential errors inherent to using ICD-9-coded databases for research. ICD-9 codes correctly identified just 19% of obese patients, an inclusion rate that would be unacceptable in any other study design. This selection bias has the potential to significantly sway the outcomes of
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studies using ICD-9-coded databases. We further postulate that obesity is likely not the only comorbidity for which these results hold true. As database research constitutes an increasing proportion of newly published studies, the orthopedic and spine surgery communities must realize that results can be significantly skewed by database source data, and thus should not be blindly accepted simply by virtue of large sample sizes. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2014.08.134
104. Patient-Reported and Performance-Based Outcome Measures Following Spine Surgery: A Longitudinal Analysis Kristin Archer, PhD, DPT1, Stephen Wegener, PhD2, Susan Vanston3, Mackenzie L. Bird3, Matthew J. McGirt, MD4, Joseph S. Cheng, MD, MS5, Oran S. Aaronson, MD1, Clinton J. Devin, MD3; 1Vanderbilt University Medical Center, Nashville, TN, US; 2Johns Hopkins, Baltimore, MD, US; 3Nashville, TN, US; 4Carolina Neurosurgery and Spine Associates, Charlotte, NC, US; 5Vanderbilt University Medical Center Department of Neurosurgery, Nashville, TN, US BACKGROUND CONTEXT: Studies recommend using both patient-reported and performance measures when evaluating postoperative recovery. However, performance-based tests for patients undergoing spine surgery have received little attention in the literature. PURPOSE: The primary purpose of this study was to determine the trajectory of both patient-reported and performance-based outcomes and the strength of the relationship between these measures in patients undergoing spine surgery. STUDY DESIGN/SETTING: Secondary analysis of data from 91 patients who were recruited from an academic medical center as part of a prospective clinical trial (NCT01131611). PATIENT SAMPLE: Ninety-one patients, 21 to 81 years of age, undergoing surgical treatment of a lumbar degenerative condition (spinal stenosis, spondylosis with or without myelopathy, and degenerative spondylolisthesis) using laminectomy with or without arthrodesis procedures. OUTCOME MEASURES: The patient-reported outcomes were pain (Brief Pain Inventory (BPI)), disability (Oswestry Disability Index (ODI)), and general physical health measured by the SF-12 physical component scale (PCS). Performance-based tests included the 5 Chair Stand to assess lower extremity strength, Timed Up and Go (TUG) to assess functional mobility, and 10-Meter Walk to assess gait speed in meters/second. METHODS: Patients completed questionnaires and performance-based tests preoperatively and at 6 weeks, 3 months and 6 months after surgery. Differences over time were analyzed using repeated-measures analysis of variance and pairwise comparisons with a Bonferroni correction. Effect sizes were calculated to determine responsiveness of measures. Pearson product correlation coefficients with a Bonferroni correction tested associations between patient-reported and performance-based tests. The level of significance was set at a50.05. RESULTS: Follow-up rates at 6 months for the patient-reported and performance-based measures were 92% and 86%, respectively. All of the patient-reported and performance-based outcomes demonstrated a statistically significant improvement from preoperative to each postoperative time point (corrected p ! .05). The order of responsiveness from largest to smallest effect size of improvement from preoperative to 6 months was BPI, SF-12 PCS, ODI, 10-Meter Walk, 5 Chair Stand, and TUG. Little to no correlation was found between patient-reported and performance-based measures preoperatively. Low-to-moderate
Refer to onsite Annual Meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosures and FDA device/drug status at time of abstract submission.
103. Limitations of Administrative Databases in Spine Research: A Study in Obesity Nicholas Golinvaux1, Daniel D. Bohl, MPH1, Bryce Basques2, Michael Fu2, Elizabeth C. Gardner, MD1, Jonathan N. Grauer, MD1; 1 Yale University School of Medicine, New Haven, CT, US; 2New Haven, CT, US BACKGROUND CONTEXT: Recently, national inpatient database use in orthopedic research has risen sharply. Specifically, spine surgery research has seen a substantial increase in these studies, as database sample sizes allow for large-scale analyses of perioperative risk factors and surgical outcomes. The results of these studies now play a significant role in the diagnosis and treatment decisions of orthopedic surgeons. Unfortunately, without firsthand knowledge of each major database, it can be difficult to judge whether a study presents valid results to the specific questions being asked. Many limitations to using databases exist, including a rising concern over the ability of administrative claims data, such as ICD-9 codes, to accurately determine comorbidity rates. PURPOSE: The present study examines these limitations using the easily quantifiable and objective variable of obesity to definitively clarify the relationship between ICD-9 codes and clinical reality. STUDY DESIGN/SETTING: A cross-sectional study comparing ICD-9 codes for obesity to chart-documented body mass index (BMI) at a large tertiary academic medical center. PATIENT SAMPLE: All patients spending at least one night in the hospital as an inpatient between April 1, 2013 and April 16, 2013. Obstetrics and gynecology, psychiatry, and pediatric patients were excluded. OUTCOME MEASURES: Proportion of patients for whom ICD-9 obesity diagnosis codes assigned at hospital discharge match chart-documented BMI. METHODS: For each patient, ICD-9 diagnosis codes and chart-documented body mass index (BMI) were directly compared. RESULTS: 2,075 patients were included in the study. Of 573 patients deemed ‘‘obese’’ with a calculated BMI between 30.0-39.9, only 109 patients received the correct ICD-9 code (278.00), giving this code a sensitivity of 0.19. Of 174 patients deemed ‘‘morbidly obese’’ with a calculated BMI above 40, 84 patients received the correct ICD-9 code (278.01), giving this code a sensitivity of 0.48. CONCLUSIONS: This study highlights obesity as an example of the potential errors inherent to using ICD-9-coded databases for research. ICD-9 codes correctly identified just 19% of obese patients, an inclusion rate that would be unacceptable in any other study design. This selection bias has the potential to significantly sway the outcomes of
51S
studies using ICD-9-coded databases. We further postulate that obesity is likely not the only comorbidity for which these results hold true. As database research constitutes an increasing proportion of newly published studies, the orthopedic and spine surgery communities must realize that results can be significantly skewed by database source data, and thus should not be blindly accepted simply by virtue of large sample sizes. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2014.08.134
104. Patient-Reported and Performance-Based Outcome Measures Following Spine Surgery: A Longitudinal Analysis Kristin Archer, PhD, DPT1, Stephen Wegener, PhD2, Susan Vanston3, Mackenzie L. Bird3, Matthew J. McGirt, MD4, Joseph S. Cheng, MD, MS5, Oran S. Aaronson, MD1, Clinton J. Devin, MD3; 1Vanderbilt University Medical Center, Nashville, TN, US; 2Johns Hopkins, Baltimore, MD, US; 3Nashville, TN, US; 4Carolina Neurosurgery and Spine Associates, Charlotte, NC, US; 5Vanderbilt University Medical Center Department of Neurosurgery, Nashville, TN, US BACKGROUND CONTEXT: Studies recommend using both patient-reported and performance measures when evaluating postoperative recovery. However, performance-based tests for patients undergoing spine surgery have received little attention in the literature. PURPOSE: The primary purpose of this study was to determine the trajectory of both patient-reported and performance-based outcomes and the strength of the relationship between these measures in patients undergoing spine surgery. STUDY DESIGN/SETTING: Secondary analysis of data from 91 patients who were recruited from an academic medical center as part of a prospective clinical trial (NCT01131611). PATIENT SAMPLE: Ninety-one patients, 21 to 81 years of age, undergoing surgical treatment of a lumbar degenerative condition (spinal stenosis, spondylosis with or without myelopathy, and degenerative spondylolisthesis) using laminectomy with or without arthrodesis procedures. OUTCOME MEASURES: The patient-reported outcomes were pain (Brief Pain Inventory (BPI)), disability (Oswestry Disability Index (ODI)), and general physical health measured by the SF-12 physical component scale (PCS). Performance-based tests included the 5 Chair Stand to assess lower extremity strength, Timed Up and Go (TUG) to assess functional mobility, and 10-Meter Walk to assess gait speed in meters/second. METHODS: Patients completed questionnaires and performance-based tests preoperatively and at 6 weeks, 3 months and 6 months after surgery. Differences over time were analyzed using repeated-measures analysis of variance and pairwise comparisons with a Bonferroni correction. Effect sizes were calculated to determine responsiveness of measures. Pearson product correlation coefficients with a Bonferroni correction tested associations between patient-reported and performance-based tests. The level of significance was set at a50.05. RESULTS: Follow-up rates at 6 months for the patient-reported and performance-based measures were 92% and 86%, respectively. All of the patient-reported and performance-based outcomes demonstrated a statistically significant improvement from preoperative to each postoperative time point (corrected p ! .05). The order of responsiveness from largest to smallest effect size of improvement from preoperative to 6 months was BPI, SF-12 PCS, ODI, 10-Meter Walk, 5 Chair Stand, and TUG. Little to no correlation was found between patient-reported and performance-based measures preoperatively. Low-to-moderate
Refer to onsite Annual Meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosures and FDA device/drug status at time of abstract submission.