Agreement between primary care and hospital diagnosis of schizophrenia and bipolar disorder : a cross-sectional, observational study using record linkage

Funding: Support for this project was provided by North York General Hospital.People with serious mental illness die 10–25 years sooner than people without these conditions. Multiple challenges to accessing and benefitting from healthcare have been identified amongst this population, including a lack of coordination between mental health services and general health services. It has been identified in other conditions such as diabetes that accurate documentation of diagnosis in the primary care chart is associated with better quality of care. It is suspected that if a patient admitted to the hospital with serious mental illness is then discharged without adequate identification of their diagnosis in the primary care setting, follow up (such as medication management and care coordination) may be more difficult. We identified cohorts of patients with schizophrenia and bipolar disorder who accessed care through the North York Family Health Team (a group of 77 family physicians in Toronto, Canada) and North York General Hospital (a large community hospital) between January 1, 2012 and December 31, 2014. We identified whether labeling for these conditions was concordant between the two settings and explored predictors of concordant labeling. This was a retrospective cross-sectional study using de-identified data from the Health Databank Collaborative, a linked primary care-hospital database. We identified 168 patients with schizophrenia and 370 patients with bipolar disorder. Overall diagnostic concordance between primary care and hospital records was 23.2% for schizophrenia and 15.7% for bipolar disorder. Concordance was higher for those with multiple (2+) inpatient visits (for schizophrenia: OR 2.42; 95% CI 0.64–9.20 and for bipolar disorder: OR 8.38; 95% CI 3.16–22.22). Capture-recapture modeling estimated that 37.4% of patients with schizophrenia (95% CI 20.7–54.1) and 39.6% with bipolar disorder (95% CI 25.7–53.6) had missing labels in both settings when adjusting for patients’ age, sex, income quintiles and co-morbidities. In this sample of patients accessing care at a large family health team and community hospital, concordance of diagnostic information about serious mental illness was low. Interventions should be developed to improve diagnosis and continuity of care across multiple settings.Publisher PDFPeer reviewe

Biomechanical Characterization of Complex Thin Bone structures in The Human Craniofacial Skeleton

In spite of burgeoning of new technologies in the field of maxillofacial surgery, such as novel methods for osteosynthesis, bone substitution and bone regeneration, the reconstruction of the craniofacial skeleton (CFS) remains a challenge. Complications and failure in existing technologies and treatments for the CFS may be attributed in part to an incomplete understanding of the biomechanical environment in which these technologies are expected to perform. Characterizing the morphology and biomechanical behaviour of this complex and unique structure is important to understanding its global response to mechanical demands. This thesis aims to characterize the biomechanical behaviour of thin bone regions and sutures in the CFS. We investigated the impact of image degradation in CT scans on the ability to develop accurate specimen-specific FE models. Image degradation resulted in large increases in cortical thickness and decreases in scan intensity, which corresponded to significant changes in maximum principal strains in the FE models. A new semi-automated connectivity technique was developed to quantify the degree of fusion in sutures and revealed varying degrees of connectivity and interdigitation depending on the suture location. Morphological features characterized using this technique were incorporated into idealized suture FE models and analysed under multiple loading directions. The idealized FE models revealed that the impact of the number of interdigitations on the strain energy absorption in the suture/bone complex is dependent on the loading direction (inversely related under pressure and directly related under perpendicular and pressure loading); similar behaviour was seen in a μCT based specimen-specific FE model. Three-point bending tests on bone samples containing sutures revealed a positive correlation between the number of interdigitations and bending strength. Finally, experimental testing of full cadaveric heads demonstrated inter-specimen consistency in strain magnitude and direction under muscle loading in spite of morphological differences. Overall, these findings provide new insight into the complex morphology of the CFS, limitations of current clinical imaging and the biomechanical behaviour of thin bone structures and their articulations. This work forms a solid foundation for future development of image analysis, modeling and experimental investigations focused on characterizing the global behaviour of the CFS.Ph

Analysis of pelvic strain in different gait configurations in a validated cohort of computed tomography based finite element models

The pelvis functions to transmit upper body loads to the lower limbs and is critical in human locomotion. Semi-automated, landmark-based finite element (FE) morphing and mapping techniques eliminate the need for segmentation and have shown to accelerate the generation of multiple specimen-specific pelvic FE models to enable the study of pelvic mechanical behaviour. The purpose of this research was to produce an experimentally validated cohort of specimen-specific FE models of the human pelvis and to use this cohort to analyze pelvic strain patterns during gait. Using an initially segmented specimen-specific pelvic FE model asa source model, four more specimen-specific pelvic FE models were generated from target clinical CT scans using landmark-based morphing and mapping techniques. FE strains from the five models were compared to the experimental strains obtained from cadaveric testing via linear regression analysis, (R2 values ranging from 0.70 to 0.93). Inter-specimen variability in FE strain distributions was seen among the five specimen-specific pelvic FE models. The validated cohort of specimen-specific pelvic FE models was utilized to examine pelvic strains at different phases of the gait cycle. Each validated specimen-specific FE model was reconfigured into gait cycle phases representing heel-strike/heel-off and midstance/midswing. No significant difference was found in the double-leg stance and heel-strike/heel-off models (p=0.40). A trend was observed between double-leg stance and midstance/midswing models (p=0.07), and a significant difference was found between heel-strike/heel-off models and midstance/midswing models (p=0.02). Significant differences were also found in comparing right vs. left models (heel-strike/heel-off p=0.14, midstance/midswing p=0.04).This study was supported by the Natural Sciences and Engineering Research Council, the Ontario Graduate Scholarship program, the High Performance Facility at the Centre for Computational Biology at the Hospital for Sick Children, Toronto, Ontario, Canada and SciNet, University of Toronto, Toronto, Ontario, Canada