Michael C. Fu

Variations in Data Collection Methods Between National Databases Affect Study Results: A Comparison of the Nationwide Inpatient Sample and National Surgical Quality Improvement Program Databases for Lumbar Spine Fusion Procedures

BACKGROUND There has been an increasing use of national databases to conduct orthopaedic research. Questions regarding the validity and consistency of these studies have not been fully addressed. The purpose of this study was to test for similarity in reported measures between two national databases commonly used for orthopaedic research. METHODS A retrospective cohort study of patients undergoing lumbar spinal fusion procedures during 2009 to 2011 was performed in two national databases: the Nationwide Inpatient Sample and the National Surgical Quality Improvement Program. Demographic characteristics, comorbidities, and inpatient adverse events were directly compared between databases. RESULTS The total numbers of patients included were 144,098 from the Nationwide Inpatient Sample and 8434 from the National Surgical Quality Improvement Program. There were only small differences in demographic characteristics between the two databases. There were large differences between databases in the rates at which specific comorbidities were documented. Non-morbid obesity was documented at rates of 9.33% in the Nationwide Inpatient Sample and 36.93% in the National Surgical Quality Improvement Program (relative risk, 0.25; p < 0.05). Peripheral vascular disease was documented at rates of 2.35% in the Nationwide Inpatient Sample and 0.60% in the National Surgical Quality Improvement Program (relative risk, 3.89; p < 0.05). Similarly, there were large differences between databases in the rates at which specific inpatient adverse events were documented. Sepsis was documented at rates of 0.38% in the Nationwide Inpatient Sample and 0.81% in the National Surgical Quality Improvement Program (relative risk, 0.47; p < 0.05). Acute kidney injury was documented at rates of 1.79% in the Nationwide Inpatient Sample and 0.21% in the National Surgical Quality Improvement Program (relative risk, 8.54; p < 0.05). CONCLUSIONS As database studies become more prevalent in orthopaedic surgery, authors, reviewers, and readers should view these studies with caution. This study shows that two commonly used databases can identify demographically similar patients undergoing a common orthopaedic procedure; however, the databases document markedly different rates of comorbidities and inpatient adverse events. The differences are likely the result of the very different mechanisms through which the databases collect their comorbidity and adverse event data. Findings highlight concerns regarding the validity of orthopaedic database research.

Using the ACS-NSQIP to identify factors affecting hospital length of stay after elective posterior lumbar fusion.

Study Design. Retrospective cohort study of the American College of Surgeons National Surgical Quality Improvement Program database from 2005 to 2010 that included 1861 patients who had undergone elective posterior lumbar fusion. Objective. To characterize factors that were independently associated with increased hospital length of stay (LOS) in patients who had undergone elective posterior lumbar fusion. Summary of Background Data. Posterior lumbar spine fusion is a common surgical procedure used to treat lumbar spine pathology. LOS is an important clinical variable and a major determinant of inpatient hospital costs. There is lack of studies in the literature using multivariate analysis to examine specifically the predictors of LOS after elective posterior lumbar fusion. Methods. Patients who underwent elective posterior lumbar fusion from 2005 to 2010 were identified in the American College of Surgeons National Surgical Quality Improvement Program database. Preoperative and intraoperative variables were extracted for each case and a multivariate linear regression was performed to assess the contribution of each variable to LOS. Results. A total of 1861 patients who had undergone elective posterior lumbar fusion were identified. The average age for patients in this cohort was 60.6 ± 13.9 years (mean ± standard deviation) with a body mass index of 30.3 ± 6.2 kg/m2. Of the total patients, 44.7% of patients were male. LOS was in the range from 0 days to 51 days. Multivariate linear regression identified age (P < 0.001), morbid obesity (body mass index ≥ 40 kg/m2, P < 0.001), American Society of Anesthesiologists class (P = 0.001), operative time (P < 0.001), multilevel procedure (P = 0.001), and intraoperative transfusion (P < 0.001) as significant predictors of extended LOS. Conclusion. The identified preoperative and intraoperative variables associated with extended LOS after elective posterior lumbar fusion may be helpful to clinicians for patient counseling and postoperative planning. Level of Evidence: 3

Increased risk of complications after anterior cervical discectomy and fusion in the elderly: an analysis of 6253 patients in the American College of Surgeons National Surgical Quality Improvement Program database.

Study Design. Retrospective cohort analysis of anterior cervical discectomy and fusion (ACDF) surgical procedures using a prospectively collected database. Objective. To characterize the 30-day postoperative outcomes in elderly patients undergoing ACDF after adjustment for comorbidities using a multi-institutional database. Summary of Background Data. Prior studies on the effect of age after ACDF have mostly focused on in-hospital complications, have come from single institutions, or have included ACDF in pooled analyses and have not distinctly analyzed the specific complications associated with age after ACDF. Methods. Patients undergoing ACDF were selected in the American College of Surgeons National Surgical Quality Improvement Program database from 2005 to 2012. Patients were stratified into 4 age-groups: 18 to 39 years, 40 to 64 years, 65 to 74 years, and 75 years or more (based on standard deviation cohorts). Patients in the different age categories were compared using the &khgr;2 statistic, the Fisher exact test, and analysis of variance. Multivariate linear/logistic regression models were used to adjust for preoperative comorbidities. Significance was defined as P < 0.05. Results. Data were available for 6253 patients who underwent ACDF. On multivariate logistic regression, both groups of elderly patients (65–74 and ≥75 yr) were more likely to have blood transfusions, reoperations, urinary complications, extended length of stays, and 1 or more complication, overall. Only patients 65 to 74 years were more likely to have a pulmonary embolism/deep vein thrombosis, whereas only patients aged 75 years or older were more likely to experience respiratory complications, central nervous system complications, or death. There were no differences in complication rates between the 18- to 39-year age-group and 40- to 64-year age-group. The 18- to 39-year age-group and 75-year age-group had shorter operating room times. Conclusion. Older age is an independent risk factor for greater morbidity and longer hospitalizations after ACDF, even after adjustment for comorbidities when compared with younger patients. Surgeons should be aware of the increased risk of multiple complications for patients of advanced age in their surgical decision making. Level of Evidence: 3

Anterior and posterior cervical fusion in patients with high body mass index are not associated with greater complications

BACKGROUND CONTEXT Obesity has been associated with adverse surgical outcomes; however, limited information is available regarding the effect of obesity on cervical spinal fusion outcomes. PURPOSE To determine the effect of obesity on complication rates after cervical fusions. STUDY DESIGN/SETTING Retrospective cohort analysis of prospectively collected data on cervical fusion surgeries. PATIENT SAMPLE Patients in the ACS-NSQIP database from 2005 to 2010 undergoing cervical anterior or posterior fusion. OUTCOME MEASURES Primary outcome measures were 30-day postsurgical complications, including mortality, deep-vein thrombosis, pulmonary embolism, septic complications, system-specific complications, and having ≥1 complication overall. Secondary outcomes were time spent in the operating room, blood transfusions, length of stay, and reoperation within 30 days. METHODS Patients undergoing anterior or posterior cervical fusions in the 2005-2010 American College of Surgeons National Surgical Quality Improvement Program were selected using Current Procedural Terminology codes. Anterior cervical fusion patients were categorized into four groups on the basis of body mass index (BMI): nonobese (18.5-29.9 kg/m(2)), obese I (30-34.9 kg/m(2)), obese II (35-39.9 kg/m(2)), and obese III (≥40 kg/m(2)). Posterior cervical patients were categorized into two groups based on the basis of BMI: nonobese (18.5-29.9 kg/m(2)) and obese (≥30 kg/m(2)) due to the smaller sample size. Patients in the obese categories were compared with patients in the nonobese categories by the use of χ(2), Fishers exact test, Student t test, and analysis of variance. Multivariate linear/logistic regression models were used to adjust for preoperative comorbidities. The authors report no sources of funding or conflicts of interest related to this study. RESULTS Data were available for 3,671 and 400 patients who underwent anterior or posterior cervical fusion, respectively. Obese class III patients only showed a greater incidence of deep-vein thrombosis after anterior fusions on univariate analysis. Obese patients only showed longer mean surgical times and total operating room times after posterior fusions on univariate analysis. On multivariate analyses, these differences did not remain significant. There were also no differences in multivariate analyses for overall and system-specific complication rates, lengths of hospital stay, reoperation rates, and mortality among the obesity groups when compared with the nonobese groups with anterior or posterior cervical fusions. CONCLUSIONS High BMI, regardless of obesity class, does not appear to be associated with increased complications after cervical fusion in the 30-day postoperative period.

Factors Affecting Length of Stay and Complications After Elective Anterior Cervical Discectomy and Fusion: A Study of 2164 Patients From The American College of Surgeons National Surgical Quality Improvement Project Database (ACS NSQIP).

Study Design: Retrospective review of the prospective American College of Surgeons National Surgical Quality Improvement Project (ACS NSQIP) database with 30-day follow-up of 2164 patients undergoing elective anterior cervical discectomy and fusion (ACDF). Objective: To determine factors independently associated with increased length of stay (LOS) and complications after ACDF to facilitate preoperative planning and setting of realistic expectations for patients and providers. Summary of Background Data: The effect of individual preoperative factors on LOS and complications has been evaluated in small-scale studies. Large database analysis with multivariate analysis of these variables has not been reported. Methods: The ACS NSQIP database from 2005 to 2010 was queried for patients undergoing ACDF procedures. Preoperative and perioperative variables were collected. Multivariate regression determined significant predictors (P<0.05) of extended LOS and complications. Results: Average LOS was 2.0±4.0 days (mean±SD) with a range of 0–103 days. By multivariate analysis, age 65 years and above, functional status, transfer from facility, preoperative anemia, and diabetes were the preoperative factors predictive of extended LOS. Major complications, minor complications, and extended surgery time were the perioperative factors associated with increased LOS. The elongating effect of these variables was determined, and ranged from 0.5 to 5.0 days. Seventy-one patients (3.3%) had a total of 92 major complications, including return to operating room (40), venous thrombotic events (13), respiratory (21), cardiac (6), mortality (5), sepsis (4), and organ space infection (3). Multivariate analysis determined ASA score ≥3, preoperative anemia, age 65 years and above, extended surgery time, and male sex to be predictive of major complications (odds ratios ranging between 1.756 and 2.609). No association was found between levels fused and LOS or complications. Conclusion: Extended LOS after ACDF is associated with factors including age, anemia, and diabetes, as well as the development of postoperative complications. One in 33 patients develops a major complication postoperatively, which are associated with an increased LOS of 5 days.

July effect in elective spine surgery: analysis of the American College of Surgeons National Surgical Quality Improvement Program database.

Study Design. Retrospective cohort. Objective. To evaluate for the presence and magnitude of the “July effect” within elective spine surgery. Summary of Background Data. The July effect is the hypothetical increase in morbidity and mortality thought to be associated with the influx of new (or newly promoted) trainees during the first portion of the academic year. Studies evaluating for the presence and magnitude of the July effect have demonstrated conflicting results. Methods. We accessed the American College of Surgeons National Surgical Quality Improvement Program database from 2005–2010. Statistical analyses were conducted using bivariate and multivariate logistic regression. Results. A total of 14,986 cases met inclusion criteria and constitute the study population. Of these, 26.5% occurred in the first academic quarter and 25.3% had resident involvement. The rate of serious adverse events was 1.9 times higher and the rate of any adverse events was 1.6 times higher among cases with resident involvement than among those without (P < 0.001 for both). Among cases without resident involvement, the rates of serious adverse events and any adverse events did not differ by academic quarter. Similarly, among cases with resident involvement, the rates of serious adverse events and any adverse events did not differ by academic quarter. Conclusion. We could not demonstrate that the training of new (or newly promoted) residents is associated with an increase in the adverse events of spine surgery. Safeguards that have been put in place to ensure patient safety during this training period seem to be effective. Although adverse events were more common among cases with resident involvement than among cases without resident involvement, our data suggest that this association is more likely a product of the riskier population of cases in which residents participate than of the resident involvement itself. Level of Evidence: 3

Risk Factors for Short-term Adverse Events and Readmission After Arthroscopic Meniscectomy Does Age Matter?

Background: Recent studies have questioned the efficacy of meniscectomy in older patients with and without evidence of osteoarthritis; however, it continues to be frequently performed. There is limited information about age and other risk factors for adverse events and readmission after the procedure. This knowledge is vital to understand the true risk profile of this common surgery. Purpose: To investigate if age and medical comorbidities were risk factors for postoperative adverse events and readmission after meniscectomy. Study Design: Case-control study; Level of evidence, 3. Methods: Patients who underwent arthroscopic meniscectomy between 2005 and 2012 were identified from the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database. Age ≥65 years and medical comorbidities were evaluated as risk factors for any adverse event (AAE), severe adverse events (SAEs), and readmission after meniscectomy using univariate and multivariate analyses. Results: A total of 17,774 patients who underwent meniscectomy were identified. The mean age was 53.0 ± 13.6 years. A total of 3420 patients (19.2%) were ≥65 years. Overall, 208 patients (1.17%) had AAE, 203 patients (1.14%) had an SAE, and 102 patients were readmitted (0.97%). Multivariate logistic regression analyses demonstrated no significant differences between age groups for the occurrence of AAE, SAEs, and readmission. Patients with American Society of Anesthesiologists classification ≥3 had increased odds of AAE (odds ratio [OR], 1.58), SAEs (OR, 1.59), and readmission (OR, 1.99). Patients with diabetes had increased odds of AAE (OR, 1.57) and SAEs (OR, 1.51). Smokers had increased odds of readmission (OR, 1.67). Patients with pulmonary disease had increased odds of AAE (OR, 1.76) and SAEs (OR, 1.70). Conclusion: Meniscectomy is a safe procedure in older patients, as age over 65 years did not increase the odds of any of the adverse events studied. However, regardless of age, patients with an increased comorbidity burden and those with a history of smoking are at increased risk of adverse events and/or readmission after the procedure. Clinical Relevance: Knowledge of these risk factors for adverse events and readmission provides essential information for patient selection and preoperative counseling.

Preoperative Nutritional Status as an Adjunct Predictor of Major Postoperative Complications Following Anterior Cervical Discectomy and Fusion.

Study Design:Retrospective analysis of the National Surgical Quality Improvement Program (NSQIP), a prospectively collected multicenter surgical outcomes database. Objective:To determine the effect of preoperative nutritional status, as measured by serum albumin concentration, on outcomes following anterior cervical discectomy and fusion (ACDF). Summary of Background Data:Nutritional status has been shown to be an important predictor of postoperative recovery and outcomes. Serum albumin concentration is an established marker of overall nutrition and systemic disease, however, its correlation to outcomes following ACDF is unknown. Methods:ACDF cases from 2005 to 2010 were identified in the NSQIP and categorized by preoperative serum albumin: normal (≥3.5 g/dL), hypoalbuminemic (<3.5 g/dL), or not measured. Independent demographic and comorbidity variables were assessed, including American Society of Anesthesiologists (ASA) classification. Risk factors for major postoperative complications were identified, including preoperative hypoalbuminemia, and incorporated into a multivariable logistic regression model to determine the strength of preoperative hypoalbuminemia as an adjusted predictor of major postoperative complications. Results:There were 3671 ACDF cases, of which 1382 (37.6%) had preoperative albumin measurements. Patients with albumin measurements were older and more likely to have higher ASA class, hypertension, and diabetes. Hypoalbuminemic patients had higher rates of having any major postoperative complication(s), specifically pulmonary complications, cardiac complications, and reoperation, relative to those with normal albumin (all P<0.01). These patients also had longer lengths of stay (5.0 vs. 1.9 d). With multivariable regression, preoperative hypoalbuminemia was a strong independent predictor of major postoperative complications, with an adjusted odds ratio of 3.37 (P=0.003). Conclusions:In this analysis of a prospective surgical outcomes database, preoperative serum hypoalbuminemia was an important adjunct predictor of major complications following ACDF. In high-risk patients with multiple medical comorbidities, we recommend that clinicians consider nutritional screening and optimization as part of preoperative risk assessment.

Discharge to Inpatient Facilities After Total Hip Arthroplasty Is Associated With Increased Postdischarge Morbidity

BACKGROUND Discharge disposition accounts for significant variability in costs after elective total hip arthroplasty (THA). Therefore, institutions must evaluate the short-term clinical outcomes associated with postdischarge care options. The present study intends to characterize the associations between short-term morbidity after primary THA and discharge destination. METHODS Primary elective unilateral THA cases performed for osteoarthritis were identified in the American College of Surgeons National Surgical Quality Improvement Program registry from 2011 to 2014. Propensity scores were used to adjust for selection bias in discharge destination, based on demographics, obesity class, preoperative functional status, modified Charlson comorbidity index, American Society of Anesthesiologists (ASA) class, and the presence of predischarge complications. Propensity-adjusted multivariate logistic regressions were used to examine associations between discharge destination and postdischarge complications, controlling for selection bias based on observable patient characteristics. RESULTS Among 54,837 THA cases included in the study, 40,576 (74%) were discharged home, and 14,261 (26%) were discharged to inpatient facilities. In multivariate propensity-adjusted analyses, patients discharged to continued inpatient care after THA were more likely to have septic complications (odds ratio, 2.34; 95% confidence interval, 1.58-3.45), urinary complications (1.51; 1.21-1.90), readmission (1.44; 1.29-1.59), wound complications (1.31; 1.09-1.57), and respiratory complications (1.93; 1.21-3.07). CONCLUSION Discharge to continued inpatient care following THA is associated with increased odds of postdischarge morbidity and unplanned readmission, after propensity score adjustment for predischarge characteristics. Additional research is needed on the impact of devoting resources toward facilitating discharge to home after THA.

Discrepancies in spine surgeon conflict of interest disclosures between a national meeting and physician payment listings on device manufacturer web sites

BACKGROUND CONTEXT Previous studies have identified inconsistencies in physician conflict-of-interest disclosures at academic meetings. The Physician Payment Sunshine Act (PPSA) will require industry to disclose anything of value given to physicians by 2014. In preparation, some spine device companies have begun reporting payments online. PURPOSE To evaluate potential inconsistencies between physician disclosures and payments reported by industry before the PPSA implementation. STUDY DESIGN Comparison of publically available disclosure/payment data. PATIENT SAMPLE Physicians participating in the 2011 North American Spine Society (NASS) annual meeting and physicians listed on the 2010 physician payment web sites of Medtronic and Depuy Spine. METHODS Disclosures of participants at NASS were compared with the published Medtronic and Depuy Spine physician payments. The periods reflected by the disclosures compared should have coincided (except the Depuy site, which was only listed for one quarter of the NASS disclosure period). Discrepancies were noted whenever participant disclosures and company listings did not match as well as whenever payment ranges did not overlap. Fishers exact test was used to compare disclosure discrepancy rates based on Medtronic payment size. No funding was received for this work. The authors report no conflicts of interest directly related to this study; however, one of the authors does do consulting unrelated to this study. RESULTS Medtronic and Depuy Spine were disclosed by 12.1% and 8.75% of NASS participants, respectively. Based on NASS disclosures, 52.4% of NASS participants affiliated with Medtronic had their disclosures inaccurately reflected on the Medtronic web site. Based on Medtronic payment postings, 45.7% of NASS participants listed on Medtronics webpage had discrepancies in their NASS disclosures. Those who received payments <