Fitting multilevel models in complex survey data with design weights: Recommendations

Abstract Background Multilevel models (MLM) offer complex survey data analysts a unique approach to understanding individual and contextual determinants of public health. However, little summarized guidance exists with regard to fitting MLM in complex survey data with design weights. Simulation work suggests that analysts should scale design weights using two methods and fit the MLM using unweighted and scaled-weighted data. This article examines the performance of scaled-weighted and unweighted analyses across a variety of MLM and software programs. Methods Using data from the 2005–2006 National Survey of Children with Special Health Care Needs (NS-CSHCN: n = 40,723) that collected data from children clustered within states, I examine the performance of scaling methods across outcome type (categorical vs. continuous), model type (level-1, level-2, or combined), and software (Mplus, MLwiN, and GLLAMM). Results Scaled weighted estimates and standard errors differed slightly from unweighted analyses, agreeing more with each other than with unweighted analyses. However, observed differences were minimal and did not lead to different inferential conclusions. Likewise, results demonstrated minimal differences across software programs, increasing confidence in results and inferential conclusions independent of software choice. Conclusion If including design weights in MLM, analysts should scale the weights and use software that properly includes the scaled weights in the estimation.</p

The Cool Little Kids randomised controlled trial: Population-level early prevention for anxiety disorders

Background: The World Health Organization predicts that by 2030 internalising problems (e.g. depression and anxiety) will be second only to HIV/AIDS in international burden of disease. Internalising problems affect 1 in 7 school aged children, impacting on peer relations, school engagement, and later mental health, relationships and employment. The development of early childhood prevention for internalising problems is in its infancy. The current study follows two successful &lsquo;efficacy&rsquo; trials of a parenting group intervention to reduce internalising disorders in temperamentally inhibited preschool children. Cool Little Kids is a population-level randomised trial to determine the impacts of systematically screening preschoolers for inhibition then offering a parenting group intervention, on child internalising problems and economic costs at school entry.Methods/Design: This randomised trial will be conducted within the preschool service system, attended by more than 95% of Australian children in the year before starting school. In early 2011, preschool services in four local government areas in Melbourne, Australia, will distribute the screening tool. The &asymp;16% (n&asymp;500) with temperamental inhibition will enter the trial. Intervention parents will be offered Cool Little Kids, a 6-session group program in the local community, focusing on ways to develop their child&rsquo;s bravery skills by reducing overprotective parenting interactions. Outcomes one and two years post-baseline will comprise child internalising diagnoses and symptoms, parenting interactions, and parent wellbeing. An economic evaluation (costconsequences framework) will compare incremental differences in costs of the intervention versus control children to incremental differences in outcomes, from a societal perspective. Analyses will use the intention-to-treat principle, using logistic and linear regression models (binary and continuous outcomes respectively) to compare outcomes between the trial arms.Discussion: This trial addresses gaps for internalising problems identified in the 2004 World Health Organization Prevention of Mental Disorders report. If effective and cost-effective, the intervention could readily be applied at a population level. Governments consider mental health to be a priority, enhancing the likelihood that an effective early prevention program would be adopted in Australia and internationally.<br /

Modified En Bloc Spondylectomy for Tumors of the Thoracic and Lumbar Spine Surgical Technique and Outcomes

Background: Total en bloc spondylectomy (TES) for the treatment of spinal tumors decreases local recurrence and improves survival compared with intralesional resection. TES approaches vary in both the number of stages to complete the procedure and instruments with which osteotomies are performed. Methods: We describe a 2-stage technique that employs the use of threadwire saws. We performed a retrospective review of cases of primary tumors and solitary metastases involving the thoracic or lumbar spine treated with use of our modified technique at our institution between 2010 and 2016, identifying eligible patients by searching for specific phrases in operative reports found in our oncologic database. Clinical notes, operative notes, imaging reports, and pathology reports were reviewed for all patients. Results: Thirty-three patients underwent our modified technique, in which we pass a threadwire saw between the vertebral body and the thecal sac. The most common tumor type was chordoma (64%), and tumors were most commonly located in the lumbar spine (61%). There were no intraoperative injuries to the spinal cord or great vessels. One patient experienced a dural tear secondary to the passage of a saw. Seventeen (52%) of the patients had perioperative complications, with 1 death. Seven (22%) of the patients had complications occurring within 90 days after discharge, and 8 (25%) had complications occurring > 90 days after discharge. Instrumentation failure was observed in 8 cases (25%). Negative margins were obtained in 94% of the cases. Local recurrence was observed in 2 cases (6%). The majority of patients had normal motor function at the time of the most recent follow-up. Conclusions: Our modified en bloc spondylectomy represents an effective technique for the resection of spinal tumors in selected patients, allowing for visualization of vessels anterior to the spine and the avoidance of spinal cord injury. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence

Quality of life after en bloc resection of tumors in the mobile spine

BACKGROUND CONTEXT: Little has been reported regarding the patient-centered quality-of-life (QOL) outcomes after en bloc spondylectomy (ES). Despite lower local recurrence rates, it is unknown whether outcomes justify the surgical morbidity. PURPOSE: The purpose of this study was to report on patient QOL after ES as measured by validated instruments and to identify factors that may predict better postoperative QOL. STUDY DESIGN: This is a retrospective case-control study (Level III). PATIENT SAMPLE: Thirty-five consecutive patients with mobile spine tumors were included. Twenty-seven patients underwent en bloc resection, whereas 8 patients received definitive radiation and no surgery. Minimum follow-up was 6 months (median, 32 months). OUTCOME MEASURES: The outcome measures were European Quality Group 5-Dimensional Questionnaire (EQ5D), four Patient-Reported Outcome Measurement Information System (PROMIS) short-form metrics, Neck Disability Index, and Oswestry Disability Index (ODI). METHODS: We performed statistical comparisons between the surgery and radiation groups, of the general US population, and within the study group itself to identify predictors of higher QOL scores. RESULTS: We identified a significant difference in QOL between the surgery and radiation groups in only one instrument, PROMIS pain interference, with surgery having more pain interference (15.7 vs. 10.1, p=.04). For most metrics, including EQ5D, pain interference, pain behavior, and ODI, scores were around one standard deviation worse than the US population mean. Multivariable linear regression for each instrument demonstrated that preoperative factors such as better performance status, tumor location in the cervical spine, lack of mechanical back or neck pain, and shorter fusion span were independently predictive of better QOL scores. Postoperative factors such as poor performance status, chronic narcotic use, and local recurrence were more dominant than preoperative factors in predicting worse QOL. CONCLUSIONS: Patients may experience more pain interference after surgery as opposed to definitive radiotherapy, but we did not identify a difference for most metrics. Quality of life in our study group was significantly worse than the general population for most metrics. Cervical tumors, lack of mechanical pain, better baseline performance status, and less extensive surgery predict better QOL after surgery. (C) 2015 Elsevier Inc. All rights reserved