ELectronic Archimedes spiral Neural Network (ELANN)

The Archimedes spiral is a clinical tool that aids in the diagnosis and monitoring of essential tremor. However, spiral ratings may vary based on experience and training of the rating physician. This study sought to generate an objective standard model for tremor evaluation using convolutional neural networks. One senior movement disorders neurologist (Neurologist 1) with over 30 years of clinical experience used the Bain and Findley Spirography Rating Scale to rate 1653 Archimedes spiral images from 46 essential tremor patients (mild to severe tremor) and 75 control subjects (no to mild tremor). Neurologist 1's labels were used as the reference standard to train the model. After training the model, a randomly selected subset of spiral testing data was re-evaluated by Neurologist 1, by a second senior movement disorders neurologist (Neurologist 2) with over 27 years of clinical experience, and by our model. Cohen's Weighted Kappa 95% confidence intervals were calculated from all rater comparisons to determine if our model performs with the same proficiency as two senior movement disorders neurologists. The Cohen's Weighted Kappa 95% confidence intervals for the agreement between the reference standard scores and Neurologist 1's rerated scores, for the agreement between the reference standard scores and Neurologist 2's scores, and for the agreement between the reference standard scores and our model's scores were 0.93-0.98, 0.86-0.94, and 0.89-0.96, respectively. With overlapping Cohen's Weighted Kappa 95% confidence intervals for all agreement comparisons, we demonstrate that our model evaluates spirals with the same proficiency as two senior movement disorders neurologists.

Improving tremor response to focused ultrasound thalamotomy

MRI-guided high-intensity focused ultrasound thalamotomy is an incisionless therapy for essential tremor. To reduce adverse effects, the field has migrated to treating at 2 mm above the anterior commissure-posterior commissure plane. We perform MRI-guided high-intensity focused ultrasound with an advanced imaging targeting technique, four-tract tractography. Four-tract tractography uses diffusion tensor imaging to identify the critical white matter targets for tremor control, the decussating and non-decussating dentatorubrothalamic tracts, while the corticospinal tract and medial lemniscus are identified to be avoided. In some patients, four-tract tractography identified a risk of damaging the medial lemniscus or corticospinal tract if treated at 2 mm superior to the anterior commissure-posterior commissure plane. In these patients, we chose to target 1.2-1.5 mm superior to the anterior commissure-posterior commissure plane. In these patients, post-operative imaging revealed that the focused ultrasound lesion extended into the posterior subthalamic area. This study sought to determine if patients with focused ultrasound lesions that extend into the posterior subthalamic area have a differnce in tremor improvement than those without. Twenty essential tremor patients underwent MRI-guided high-intensity focused ultrasound and were retrospectively classified into two groups. Group 1 included patients with an extension of the thalamic-focused ultrasound lesion into the posterior subthalamic area. Group 2 included patients without extension of the thalamic-focused ultrasound lesion into the posterior subthalamic area. For each patient, the percent change in postural tremor, kinetic tremor and Archimedes spiral scores were calculated between baseline and a 3-month follow-up. Two-tailed Wilcoxon rank-sum tests were used to compare the improvement in tremor scores, the total number of sonications, thermal dose to achieve initial tremor response, and skull density ratio between groups. Group 1 had significantly greater postural, kinetic, and Archimedes spiral score percent improvement than Group 2 (P values: 5.41 × 10-5, 4.87 × 10-4, and 5.41 × 10-5, respectively). Group 1 also required significantly fewer total sonications to control the tremor and a significantly lower thermal dose to achieve tremor response (P values: 6.60 × 10-4 and 1.08 × 10-5, respectively). No significant group differences in skull density ratio were observed (P = 1.0). We do not advocate directly targeting the posterior subthalamic area with MRI-guided high-intensity focused ultrasound because the shape of the focused ultrasound lesion can result in a high risk of adverse effects. However, when focused ultrasound lesions naturally extend from the thalamus into the posterior subthalamic area, they provide greater tremor control than those that only involve the thalamus.

Corrigendum to: A novel fully automated MRI-based deep-learning method for classification of 1p/19q co-deletion status in brain gliomas

[This corrects the article DOI: 10.1093/noajnl/vdaa066.].

Errata: Brain tumor IDH, 1p/19q, and MGMT molecular classification using MRI-based deep learning: an initial study on the effect of motion and motion correction

[This corrects the article DOI: 10.1117/1.JMI.9.1.016001.].

Focused ultrasound using a novel targeting method four-tract tractography for magnetic resonance-guided high-intensity focused ultrasound targeting

Magnetic resonance-guided high-intensity focused ultrasound thalamotomy is a Food and Drug Administration-approved treatment for essential tremor. The target, the ventral intermediate nucleus of the thalamus, is not visualized on standard, anatomic MRI sequences. Several recent reports have used diffusion tensor imaging to target the dentato-rubro-thalamic-tract. There is considerable variability in fibre tracking algorithms and what fibres are tracked. Targeting discrete white matter tracts with magnetic resonance-guided high-intensity focused ultrasound is an emerging precision medicine technique that has the promise to improve patient outcomes and reduce treatment times. We provide a technical overview and clinical benefits of our novel, easily implemented advanced tractography method: four-tract tractography. Our method is novel because it targets both the decussating and non-decussating dentato-rubro-thalamic-tracts while avoiding the medial lemniscus and corticospinal tracts. Our method utilizes Food and Drug Administration-approved software and is easily implementable into existing workflows. Initial experience using this approach suggests that it improves patient outcomes by reducing the incidence of adverse effects.

Brain tumor IDH, 1p/19q, and MGMT molecular classification using MRI-based deep learning: an initial study on the effect of motion and motion correction

Purpose: Deep learning has shown promise for predicting the molecular profiles of gliomas using MR images. Prior to clinical implementation, ensuring robustness to real-world problems, such as patient motion, is crucial. The purpose of this study is to perform a preliminary evaluation on the effects of simulated motion artifact on glioma marker classifier performance and determine if motion correction can restore classification accuracies. Approach: T2w images and molecular information were retrieved from the TCIA and TCGA databases. Simulated motion was added in the k-space domain along the phase encoding direction. Classifier performance for IDH mutation, 1p/19q co-deletion, and MGMT methylation was assessed over the range of 0% to 100% corrupted k-space lines. Rudimentary motion correction networks were trained on the motion-corrupted images. The performance of the three glioma marker classifiers was then evaluated on the motion-corrected images. Results: Glioma marker classifier performance decreased markedly with increasing motion corruption. Applying motion correction effectively restored classification accuracy for even the most motion-corrupted images. For isocitrate dehydrogenase (IDH) classification, 99% accuracy was achieved, exceeding the original performance of the network and representing a new benchmark in non-invasive MRI-based IDH classification. Conclusions: Robust motion correction can facilitate highly accurate deep learning MRI-based molecular marker classification, rivaling invasive tissue-based characterization methods. Motion correction may be able to increase classification accuracy even in the absence of a visible artifact, representing a new strategy for boosting classifier performance.

Fundamentals of Radiation Oncology for Treatment of Vertebral Metastases

The fields of both radiology and radiation oncology have evolved considerably in the past few decades, resulting in an increased ability to delineate between tumor and normal tissue to precisely target and treat vertebral metastases with radiation therapy. These scientific advances have also led to improvements in assessing treatment response and diagnosing toxic effects related to radiation treatment. However, despite technological innovations yielding greatly improved rates of palliative relief and local control of osseous spinal metastases, radiation therapy can still lead to a number of acute and delayed posttreatment complications. Treatment-related adverse effects may include pain flare, esophageal toxic effects, dermatitis, vertebral compression fracture, radiation myelopathy, and myositis, among others. The authors provide an overview of the multidisciplinary approach to the treatment of spinal metastases, indications for surgical management versus radiation therapy, various radiation technologies and techniques (along with their applications for spinal metastases), and current principles of treatment planning for conventional and stereotactic radiation treatment. Different radiologic criteria for assessment of treatment response, recent advances in radiologic imaging, and both common and rare complications related to spinal irradiation are also discussed, along with the imaging characteristics of various adverse effects. Familiarity with these topics will not only assist the diagnostic radiologist in assessing treatment response and diagnosing treatment-related complications but will also allow more effective collaboration between diagnostic radiologists and radiation oncologists to guide management decisions and ensure high-quality patient care. ^©RSNA, 2021.

Formulation and characterization of zein/chitosan complex particles stabilized Pickering emulsion with the encapsulation and delivery of vitamin D3

BACKGROUND

Pickering emulsions (PEs) which are stabilized by solid particles instead of surfactants have recently attracted tremendous attentions due to their non-toxic and long-term stable nature. In the current study, we fabricated and characterized zein (ZN)/chitosan (CS) complex particles (ZNCSPs) stabilized PE for the encapsulation and delivery of vitamin D₃ .

RESULTS

The ZNCSPs were synthesized with different ratios, i.e. 1:1, 1:1.5 and 1:2 to investigate the optimum ratio. Transmission electron microscopy observations showed the spherical nature with smooth surface of the obtained particles in the case of ZNCS ratio 1:1.5 and 1:2. Furthermore, ζ-potential values for the these particles were 32.53 ± 1.3 and 52.86 ± 0.68 mV respectively, indicating particles with (1:2) being more stable than 1:1.5. Thereafter, using these particles, the PEs were successfully formulated with different oil (medium chain triglyceride) fractions (330, 500 and 660 g kg^-1 ). The emulsions were evaluated for stability during storage and against different environmental factors including pH, temperature and ionic strength on the creaming indices (CIs) of these emulsions. The results demonstrated that the PEs with oil fractions 330 and 500 g kg^-1 exhibited significant stability during storage, particularly the ones with 500 g kg^-1 oil fractions which were stable against all the tested parameters. Finally, the prepared PEs were evaluated as efficient delivery system by encapsulating and delivering vitamin D₃ . In vitro drug release profile confirmed sustained and controlled release of the encapsulated vitamin D₃ .

CONCLUSION

Overall, our findings suggest that ZNCSPs can be promising stabilizers for stable PEs that can be used as potential delivery systems in food, cosmetic and pharmaceutical industries. © 2021 Society of Chemical Industry.

Probing Cerebral Metabolism with Hyperpolarized 13C Imaging after Opening the Blood-Brain Barrier with Focused Ultrasound

Transient disruption of the blood-brain barrier (BBB) with focused ultrasound (FUS) is an emerging clinical method to facilitate targeted drug delivery to the brain. The focal noninvasive disruption of the BBB can be applied to promote the local delivery of hyperpolarized substrates. In this study, we investigated the effects of FUS on imaging brain metabolism using two hyperpolarized ¹³C-labeled substrates in rodents: [1-¹³C]pyruvate and [1-¹³C]glycerate. The BBB is a rate-limiting factor for pyruvate delivery to the brain, and glycerate minimally passes through the BBB. First, cerebral imaging with hyperpolarized [1-¹³C]pyruvate resulted in an increase in total ¹³C signals (p = 0.05) after disrupting the BBB with FUS. Significantly higher levels of both [1-¹³C]lactate (lactate/total ¹³C signals, p = 0.01) and [¹³C]bicarbonate (p = 0.008) were detected in the FUS-applied brain region as compared to the contralateral FUS-unaffected normal-appearing brain region. The application of FUS without opening the BBB in a separate group of rodents resulted in comparable lactate and bicarbonate productions between the FUS-applied and the contralateral brain regions. Second, ¹³C imaging with hyperpolarized [1-¹³C]glycerate after opening the BBB showed increased [1-¹³C]glycerate delivery to the FUS-applied region (p = 0.04) relative to the contralateral side, and [1-¹³C]lactate production was consistently detected from the FUS-applied region. Our findings suggest that FUS accelerates the delivery of hyperpolarized molecules across the BBB and provides enhanced sensitivity to detect metabolic products in the brain; therefore, hyperpolarized ¹³C imaging with FUS may provide new opportunities to study cerebral metabolic pathways as well as various neurological pathologies.

MRI and tractography techniques to localize the ventral intermediate nucleus and dentatorubrothalamic tract for deep brain stimulation and MR-guided focused ultrasound: a narrative review and update

The thalamic ventral intermediate nucleus (VIM) can be targeted for treatment of tremor by several procedures, including deep brain stimulation (DBS) and, more recently, MR-guided focused ultrasound (MRgFUS). To date, such targeting has relied predominantly on coordinate-based or atlas-based techniques rather than directly targeting the VIM based on imaging features. While general regional differences of features within the thalamus and some related white matter tracts can be distinguished with conventional imaging techniques, internal nuclei such as the VIM are not discretely visualized. Advanced imaging methods such as quantitative susceptibility mapping (QSM) and fast gray matter acquisition T1 inversion recovery (FGATIR) MRI and high-field MRI pulse sequences that improve the ability to image the VIM region are emerging but have not yet been shown to have reliability and accuracy to serve as the primary method of VIM targeting. Currently, the most promising imaging approach to directly identify the VIM region for clinical purposes is MR diffusion tractography.In this review and update, the capabilities and limitations of conventional and emerging advanced methods for evaluation of internal thalamic anatomy are briefly reviewed. The basic principles of tractography most relevant to VIM targeting are provided for familiarization. Next, the key literature to date addressing applications of DTI and tractography for DBS and MRgFUS is summarized, emphasizing use of direct targeting. This literature includes 1-tract (dentatorubrothalamic tract [DRT]), 2-tract (pyramidal and somatosensory), and 3-tract (DRT, pyramidal, and somatosensory) approaches to VIM region localization through tractography.The authors introduce a 3-tract technique used at their institution, illustrating the oblique curved course of the DRT within the inferior thalamus as well as the orientation and relationship of the white matter tracts in the axial plane. The utility of this 3-tract tractography approach to facilitate VIM localization is illustrated with case examples of variable VIM location, targeting superior to the anterior commissure-posterior commissure plane, and treatment in the setting of pathologic derangement of thalamic anatomy. Finally, concepts demonstrated with these case examples and from the prior literature are synthesized to highlight several potential advantages of tractography for VIM region targeting.

A Fully Automated Deep Learning Network for Brain Tumor Segmentation

We developed a fully automated method for brain tumor segmentation using deep learning; 285 brain tumor cases with multiparametric magnetic resonance images from the BraTS2018 data set were used. We designed 3 separate 3D-Dense-UNets to simplify the complex multiclass segmentation problem into individual binary-segmentation problems for each subcomponent. We implemented a 3-fold cross-validation to generalize the network's performance. The mean cross-validation Dice-scores for whole tumor (WT), tumor core (TC), and enhancing tumor (ET) segmentations were 0.92, 0.84, and 0.80, respectively. We then retrained the individual binary-segmentation networks using 265 of the 285 cases, with 20 cases held-out for testing. We also tested the network on 46 cases from the BraTS2017 validation data set, 66 cases from the BraTS2018 validation data set, and 52 cases from an independent clinical data set. The average Dice-scores for WT, TC, and ET were 0.90, 0.84, and 0.80, respectively, on the 20 held-out testing cases. The average Dice-scores for WT, TC, and ET on the BraTS2017 validation data set, the BraTS2018 validation data set, and the clinical data set were as follows: 0.90, 0.80, and 0.78; 0.90, 0.82, and 0.80; and 0.85, 0.80, and 0.77, respectively. A fully automated deep learning method was developed to segment brain tumors into their subcomponents, which achieved high prediction accuracy on the BraTS data set and on the independent clinical data set. This method is promising for implementation into a clinical workflow.

DEVELOPING twin-specific 75-g oral glucose tolerance test diagnostic thresholds for gestational diabetes based on the risk of future maternal diabetes: a population-based cohort study

OBJECTIVE

To develop twin-specific outcome-based oral glucose tolerance test (OGTT) diagnostic thresholds for GDM based on the risk of future maternal type-2 diabetes.

DESIGN

A population-based retrospective cohort study (2007-2017).

SETTING

Ontario, Canada.

METHODS

Nulliparous women with a live singleton (n = 55 361) or twin (n = 1308) birth who underwent testing for gestational diabetes mellitus (GDM) using a 75-g OGTT in Ontario, Canada (2007-2017). We identified the 75-g OGTT thresholds in twin pregnancies that were associated with similar incidence rates of future type-2 diabetes to those associated with the standard OGTT thresholds in singleton pregnancies.

RESULTS

For any given 75-g OGTT value, the incidence rate of future maternal type-2 diabetes was lower for women with a twin than women with a singleton pregnancy. Using women with a negative OGTT as reference, the risk of future maternal type-2 diabetes in twin pregnancies with a positive OGTT based on the standard OGTT thresholds (9.86 per 1000 person years, adjusted hazard ratio (aHR) 4.79, 95% CI 2.69-8.51) was lower than for singleton pregnancies with a positive OGTT (18.74 per 1000 person years, aHR 8.22, 95% CI 7.38-9.16). The twin-specific OGTT fasting, 1-hour and 2-hour thresholds identified in the current study based on correlation with future maternal type-2 diabetes were 5.8 mmol/l (104 mg/dl), 11.8 mmol/l (213 mg/dl) and 10.4 mmol/l (187 mg/dl), respectively.

CONCLUSIONS

We identified potential twin-specific OGTT thresholds for GDM that are associated with a similar risk of future type-2 diabetes to that observed in women diagnosed with GDM in singleton pregnancies based on standard OGTT thresholds.

TWEETABLE ABSTRACT

Potential twin-specific OGTT thresholds for GDM were identified.

MRI-Based Deep-Learning Method for Determining Glioma MGMT Promoter Methylation Status

BACKGROUND AND PURPOSE

O6-Methylguanine-DNA methyltransferase (MGMT) promoter methylation confers an improved prognosis and treatment response in gliomas. We developed a deep learning network for determining MGMT promoter methylation status using T2 weighted Images (T2WI) only.

MATERIALS AND METHODS

Brain MR imaging and corresponding genomic information were obtained for 247 subjects from The Cancer Imaging Archive and The Cancer Genome Atlas. One hundred sixty-three subjects had a methylated MGMT promoter. A T2WI-only network (MGMT-net) was developed to determine MGMT promoter methylation status and simultaneous single-label tumor segmentation. The network was trained using 3D-dense-UNets. Three-fold cross-validation was performed to generalize the performance of the networks. Dice scores were computed to determine tumor-segmentation accuracy.

RESULTS

The MGMT-net demonstrated a mean cross-validation accuracy of 94.73% across the 3 folds (95.12%, 93.98%, and 95.12%, [SD, 0.66%]) in predicting MGMT methylation status with a sensitivity and specificity of 96.31% [SD, 0.04%] and 91.66% [SD, 2.06%], respectively, and a mean area under the curve of 0.93 [SD, 0.01]. The whole tumor-segmentation mean Dice score was 0.82 [SD, 0.008].

CONCLUSIONS

We demonstrate high classification accuracy in predicting MGMT promoter methylation status using only T2WI. Our network surpasses the sensitivity, specificity, and accuracy of histologic and molecular methods. This result represents an important milestone toward using MR imaging to predict prognosis and treatment response.

A novel fully automated MRI-based deep-learning method for classification of 1p/19q co-deletion status in brain gliomas

BACKGROUND

One of the most important recent discoveries in brain glioma biology has been the identification of the isocitrate dehydrogenase (IDH) mutation and 1p/19q co-deletion status as markers for therapy and prognosis. 1p/19q co-deletion is the defining genomic marker for oligodendrogliomas and confers a better prognosis and treatment response than gliomas without it. Our group has previously developed a highly accurate deep-learning network for determining IDH mutation status using T2-weighted (T2w) MRI only. The purpose of this study was to develop a similar 1p/19q deep-learning classification network.

METHODS

Multiparametric brain MRI and corresponding genomic information were obtained for 368 subjects from The Cancer Imaging Archive and The Cancer Genome Atlas. 1p/19 co-deletions were present in 130 subjects. Two-hundred and thirty-eight subjects were non-co-deleted. A T2w image-only network (1p/19q-net) was developed to perform 1p/19q co-deletion status classification and simultaneous single-label tumor segmentation using 3D-Dense-UNets. Three-fold cross-validation was performed to generalize the network performance. Receiver operating characteristic analysis was also performed. Dice scores were computed to determine tumor segmentation accuracy.

RESULTS

1p/19q-net demonstrated a mean cross-validation accuracy of 93.46% across the 3 folds (93.4%, 94.35%, and 92.62%, SD = 0.8) in predicting 1p/19q co-deletion status with a sensitivity and specificity of 0.90 ± 0.003 and 0.95 ± 0.01, respectively and a mean area under the curve of 0.95 ± 0.01. The whole tumor segmentation mean Dice score was 0.80 ± 0.007.

CONCLUSION

We demonstrate high 1p/19q co-deletion classification accuracy using only T2w MR images. This represents an important milestone toward using MRI to predict glioma histology, prognosis, and response to treatment.

Prevalence and Incidence of Microhemorrhages in Adolescent Football Players

BACKGROUND AND PURPOSE

SWI is an advanced imaging modality that is especially useful in cerebral microhemorrhage detection. Such microhemorrhages have been identified in adult contact sport athletes, and the sequelae of these focal bleeds are thought to contribute to neurodegeneration. The purpose of this study was to utilize SWI to determine whether the prevalence and incidence of microhemorrhages in adolescent football players are significantly greater than those of adolescent noncontact athletes.

MATERIALS AND METHODS

Preseason and postseason SWI was performed and evaluated on 78 adolescent football players. SWI was also performed on 27 adolescent athletes who reported no contact sport history. Two separate one-tailed Fisher exact tests were performed to determine whether the prevalence and incidence of microhemorrhages in adolescent football players are greater than those of noncontact athlete controls.

RESULTS

Microhemorrhages were observed in 12 football players. No microhemorrhages were observed in any controls. Adolescent football players demonstrated a significantly greater prevalence of microhemorrhages than adolescent noncontact controls (P = .02). Although 2 football players developed new microhemorrhages during the season, microhemorrhage incidence during 1 football season was not statistically greater in the football population than in noncontact control athletes (P = .55).

CONCLUSIONS

Adolescent football players have a greater prevalence of microhemorrhages compared with adolescent athletes who have never engaged in contact sports. While microhemorrhage incidence during 1 season is not significantly greater in adolescent football players compared to adolescent controls, there is a temporal association between playing football and the appearance of new microhemorrhages.

Consistent opening of the blood brain barrier using focused ultrasound with constant intravenous infusion of microbubble agent

The blood brain barrier (BBB) is a major obstacle to the delivery of therapeutics to the brain. Focused ultrasound (FUS) in combination with microbubbles can non-invasively open the BBB in a targeted manner. Bolus intravenous injections of microbubbles are standard practice, but dynamic influx and clearance mechanisms prevent delivery of a uniform dose with time. When multiple targets are selected for sonication in a single treatment, uniform serum concentrations of microbubbles are important for consistent BBB opening. Herein, we show that bubble infusions were able to achieve consistent BBB opening at multiple target sites. FUS exposures were conducted with different Definity microbubble concentrations at various acoustic pressures. To quantify the effects of infusion on BBB opening, we calculated the MRI contrast enhancement rate. When infusions were performed at rates of 7.2 µl microbubbles/kg/min or below, we were able to obtain consistent BBB opening without injury at all pressures. However, when infusion rates exceeded 20 µl/kg/min, signs of injury occurred at pressures from 0.39 to 0.56 MPa. When compared to bolus injections, a bubble infusion offers a more controlled and consistent approach to multi-target BBB disruption.

Advanced MRI techniques for transcranial high intensity focused ultrasound targeting

Magnetic resonance guided high intensity focused ultrasound is a novel, non-invasive, image-guided procedure that is able to ablate intracranial tissue with submillimetre precision. It is currently FDA approved for essential tremor and tremor dominant Parkinson’s disease. The aim of this update is to review the limitations of current landmark-based targeting techniques of the ventral intermediate nucleus and demonstrate the role of emerging imaging techniques that are relevant for both magnetic resonance guided high intensity focused ultrasound and deep brain stimulation. A significant limitation of standard MRI sequences is that the ventral intermediate nucleus, dentatorubrothalamic tract, and other deep brain nuclei cannot be clearly identified. This paper provides original, annotated images demarcating the ventral intermediate nucleus, dentatorubrothalamic tract, and other deep brain nuclei on advanced MRI sequences such as fast grey matter acquisition T1 inversion recovery, quantitative susceptibility mapping, susceptibility weighted imaging, and diffusion tensor imaging tractography. Additionally, the paper reviews clinical efficacy of targeting with these novel MRI techniques when compared to current established landmark-based targeting techniques. The paper has widespread applicability to both deep brain stimulation and magnetic resonance guided high intensity focused ultrasound.

Universal drug coverage and income-related disparities in glycaemic control

AIMS

To examine whether income-related disparities in glycaemic control decline after the age of 65 years, when publicly funded universal drug insurance is acquired in Ontario, Canada.

METHODS

We conducted a population-based cross-sectional study using linked administrative healthcare databases. Adults with diabetes, aged 40-89 years, with available HbA_1c data were included (N = 716 297). Income was based on median neighbourhood household income. Multiple linear regression was used to test for effect modification of age ≥65 years on the relationship between income and HbA_1c .

RESULTS

There was a significant inverse association between income and HbA_1c level. After adjusting for baseline factors, the effect of income on HbA_1c level was significantly greater for individuals aged <65 years (mean difference HbA_1c for lowest vs highest income group +2.5 mmol/mol, 95% CI +2.3 to +2.7 [+0.23%, 95% CI 0.21 to 0.24]) than for those aged ≥65 years (+1.2 mmol/mol, 95% CI +1.0 to +1.3 [+0.11%, 95% CI 0.10 to 0.12]; P < 0.0001 for interaction).

CONCLUSIONS

Despite universal access to healthcare, people with diabetes with lower incomes had significantly worse glycaemic control compared with their counterparts on higher incomes. However, income gradients in glycaemic control were markedly reduced after the age of 65 years, possibly as a result of access to prescription drug coverage.

Fundamentals of Radiation Oncology for Neurologic Imaging

Although the physical and biologic principles of radiation therapy have remained relatively unchanged, a technologic renaissance has led to continuous and ever-changing growth in the field of radiation oncology. As a result, medical devices, techniques, and indications have changed considerably during the past 20-30 years. For example, advances in CT and MRI have revolutionized the treatment planning process for a variety of central nervous system diseases, including primary and metastatic tumors, vascular malformations, and inflammatory diseases. The resultant improved ability to delineate normal from abnormal tissue has enabled radiation oncologists to achieve more precise targeting and helped to mitigate treatment-related complications. Nevertheless, posttreatment complications still occur and can pose a diagnostic challenge for radiologists. These complications can be divided into acute, early-delayed, and late-delayed complications on the basis of the time that they manifest after radiation therapy and include leukoencephalopathy, vascular complications, and secondary neoplasms. The different irradiation technologies and applications of these technologies in the brain, current concepts used in treatment planning, and essential roles of the radiation oncologist in the setting of brain disease are reviewed. In addition, relevant imaging findings that can be used to delineate the extent of disease before treatment, and the expected posttreatment imaging changes are described. Common and uncommon complications related to radiation therapy and the associated imaging manifestations also are discussed. Familiarity with these entities may aid the radiologist in making the diagnosis and help guide appropriate management. ^©RSNA, 2020.

A novel fully automated MRI-based deep-learning method for classification of IDH mutation status in brain gliomas

BACKGROUND

Isocitrate dehydrogenase (IDH) mutation status has emerged as an important prognostic marker in gliomas. Currently, reliable IDH mutation determination requires invasive surgical procedures. The purpose of this study was to develop a highly accurate, MRI-based, voxelwise deep-learning IDH classification network using T2-weighted (T2w) MR images and compare its performance to a multicontrast network.

METHODS

Multiparametric brain MRI data and corresponding genomic information were obtained for 214 subjects (94 IDH-mutated, 120 IDH wild-type) from The Cancer Imaging Archive and The Cancer Genome Atlas. Two separate networks were developed, including a T2w image-only network (T2-net) and a multicontrast (T2w, fluid attenuated inversion recovery, and T1 postcontrast) network (TS-net) to perform IDH classification and simultaneous single label tumor segmentation. The networks were trained using 3D Dense-UNets. Three-fold cross-validation was performed to generalize the networks' performance. Receiver operating characteristic analysis was also performed. Dice scores were computed to determine tumor segmentation accuracy.

RESULTS

T2-net demonstrated a mean cross-validation accuracy of 97.14% ± 0.04 in predicting IDH mutation status, with a sensitivity of 0.97 ± 0.03, specificity of 0.98 ± 0.01, and an area under the curve (AUC) of 0.98 ± 0.01. TS-net achieved a mean cross-validation accuracy of 97.12% ± 0.09, with a sensitivity of 0.98 ± 0.02, specificity of 0.97 ± 0.001, and an AUC of 0.99 ± 0.01. The mean whole tumor segmentation Dice scores were 0.85 ± 0.009 for T2-net and 0.89 ± 0.006 for TS-net.

CONCLUSION

We demonstrate high IDH classification accuracy using only T2-weighted MR images. This represents an important milestone toward clinical translation.

Smoking, Pain Intensity, and Opioid Consumption 1-3 Months After Major Surgery: A Retrospective Study in a Hospital-Based Transitional Pain Service

Introduction

The present study investigated the associations between smoking, pain, and opioid consumption in the 3 months after major surgery in patients seen by the Transitional Pain Service. Current smoking status and lifetime pack-years were expected to be related to higher pain intensity, more opioid use, and poorer opioid weaning after surgery.

Methods

A total of 239 patients reported smoking status in their presurgical assessment (62 smokers, 92 past smokers, and 85 never smokers). Pain and daily opioid use were assessed in hospital before postsurgical discharge, at first outpatient visit (median of 1 month postsurgery), and at last outpatient visit (median of 3 months postsurgery). Pain was measured using numeric rating scale. Morphine equivalent daily opioid doses were calculated for each patient.

Results

Current smokers reported significantly higher pain intensity (p < .05) at 1 month postsurgery than never smokers and past smokers. Decline in opioid consumption differed significantly by smoking status, with both current and past smokers reporting a less than expected decline in daily opioid consumption (p < .05) at 3 months. Decline in opioid consumption was also related to pack-years, with those reporting higher pack-years having a less than expected decline in daily opioid consumption at 3 months (p < .05).

Conclusions

Smoking status may be an important modifiable risk factor for pain intensity and opioid use after surgery.

Implications

In a population with complex postsurgical pain, smoking was associated with greater pain intensity at 1 month after major surgery and less opioid weaning 3 months after surgery. Smoking may be an important modifiable risk factor for pain intensity and opioid use after surgery.

Diabetes transition care and adverse events: a population-based cohort study in Ontario, Canada

AIMS

To describe patterns of primary and diabetes care during transition age (17 to < 19 years) into early adulthood (age 19 to 26 years), and to evaluate the association of primary and diabetes care patterns during transition age with the risk of adverse events in early adulthood.

METHODS

We conducted a population-based cohort study of individuals in Ontario, Canada who were diagnosed with diabetes aged < 15 years and who turned 17 between November 2006 and March 2011, followed until March 2015 (n = 2525). Using linked administrative databases, we examined healthcare use during: 'pre-transition-age' (15 to < 17 years), 'transition-age' (17 to < 19 years), and 'early adulthood' (19 to 26 years). The main outcomes were time to death or ketoacidosis and rate of diabetes-related admissions. The main exposures were the gap in diabetes care and primary care visits during transition age.

RESULTS

There were < 6 deaths and 446 individuals (17.7%) had at least one admission for ketoacidosis during early adulthood. In all, 1188 individuals (47.0%) had a > 12-month gap in diabetes care and 241 (9.5%) had no primary care visits during transition age. A gap in diabetes care of > 12 months and no primary care visits during transition age were associated with an increased risk of ketoacidosis or death (adjusted hazard ratio 1.31, 95% CI 1.04-1.66 and adjusted hazard ratio 1.42, 95% CI 1.02-1.97, respectively).

CONCLUSIONS

In Ontario, Canada, where physician and hospital-based services are universally covered, a high proportion of young adults with diabetes have insufficient care during transition age and this is associated with a higher risk of important adverse outcomes in early adulthood. Ensuring primary care involvement during transition may be a strategy to reduce morbidity.

Differences in prevalence of diabetes among immigrants to Canada from South Asian countries

AIMS

The prevalence of diabetes is high in South Asians migrants. However, most previous research has studied South Asians as a collective whole. The aim of this study was to examine diabetes prevalence among immigrants from five South Asian countries living in Ontario, Canada.

METHODS

Population-based health care and immigration databases were used to compare crude and adjusted diabetes prevalence on 1 January 2012 between immigrants to Ontario from different South Asians countries and the non-immigrant population. The prevalence of diabetes was also stratified by various sociodemographic factors.

RESULTS

There were 431 765 first-generation South Asian immigrants; 68 440 (crude prevalence of 15.9%) of whom had a diagnosis of diabetes. After standardization for age, sex and income, diabetes prevalence was highest among South Asians from Sri Lanka (26.8%) followed by Bangladesh (22.2%), Pakistan (19.6%), India (18.3%) and Nepal (16.5%) in comparison with the non-immigrant population (11.6%). Increased prevalence was evident among men compared with women in each country of South Asia. Sociodemographic indicators including income, education, English proficiency and refugee status were associated with increased prevalence of diabetes in specific populations from South Asia.

CONCLUSION

Striking differences in the prevalence of diabetes are evident among immigrants from different countries of South Asia. Awareness of the heterogeneity will help in recognizing priorities for the delivery of primary care for specific South Asian migrant populations with a range of settlement needs that also encompass social determinants of health.

Mental health visits and low socio-economic status in adolescence are associated with complications of Type 1 diabetes in early adulthood: a population-based cohort study

AIM

To determine the association of mental health visits and socio-economic status in late adolescence with the risk of mortality and acute and chronic diabetes complications in early adulthood.

METHODS

We conducted a population-based cohort study of individuals in Ontario, Canada, who had their 20th birthday between January 1999 and March 2015 and a diagnosis of diabetes prior to their 15^th birthday, using linked administrative databases (n=8491). The main outcome was death; other outcomes were hypoglycaemia or hyperglycaemia-related hospitalizations and emergency department visits and chronic diabetes complications (dialysis, ophthalmological and macrovascular complications).

RESULTS

Over the course of 59 361 person-years there were 127 deaths.. Low socio-economic status and mental health visits were both associated with a higher risk of death [hazard ratio 2.03, (95% CI 1.13 to 3.64) and 2.45 (95% CI 1.71 to 3.51), respectively]. Those with the lowest socio-economic status and a mental health visit had a higher rate of diabetes-related hospitalizations (rate ratio 4.84, 95% CI 3.64 to 6.44) and emergency department visits (rate ratio 3.15, 95% CI 1.79 to 5.54). Low socio-economic status and mental health visits were both associated with an increased risk of any chronic complication [hazard ratio 1.54 (95% CI 1.21 to 1.96) and 1.57 (95% CI 1.35 to 1.81), respectively].

CONCLUSION

We identified significant socio-economic and mental health disparities in the risk of death and acute and chronic complications in early adulthood for people with childhood-onset diabetes. Targeted interventions to prevent adverse events for these adolescents at highest risk should be evaluated.

Gestational diabetes care and outcomes for refugee women: a population-based cohort study

AIM

To determine the prevalence of adverse clinical outcomes, the rates of healthcare utilization, and the incidence of post-partum Type 2 diabetes in refugees with gestational diabetes (GDM), compared with other immigrants and non-immigrants.

METHODS

A population-based cohort study was conducted using healthcare databases in Ontario, Canada. Over 40 000 women with GDM having singleton live births between 2002 and 2014 were identified. We identified GDM adverse outcomes such as macrosomia, pre-eclampsia and respiratory distress syndrome. Antenatal and newborn healthcare utilization were ascertained. Women were then followed for diagnosis of diabetes post-partum.

RESULTS

Both refugees and other immigrants had a lower rate than non-immigrants of many adverse GDM outcomes, including pre-eclampsia [relative risk (RR) 0.65, 95% confidence interval (95% CI) 0.44-0.95 and 0.61, 95% CI 0.52-0.72, respectively], preterm birth (RR 0.87, 95% CI 0.75-0.995 and 0.85, 95% CI 0.80-0.91, respectively), and respiratory distress syndrome (RR 0.83, 95% CI 0.70-0.97 and 0.78, 95% CI 0.72-0.84, respectively). However, refugees were less likely to attend well-baby care in time for the first routine vaccination (RR 0.92, 95% CI 0.88-0.95). Incidence of post-partum diabetes was high in all groups, but refugee women were at increased risk (hazard ratio 1.23, 95% CI 1.11-1.37).

CONCLUSIONS

Despite different circumstances leading to migration, refugees have a similar 'healthy immigrant effect' to other immigrants, with respect to adverse GDM outcomes. However, newborns of refugees were less likely to have well-baby care, and refugee women were also at especially high risk of developing diabetes post-partum. These are both important public health issues.

Effect of multiparity and ethnicity on the risk of development of diabetes: a large population-based cohort study

AIMS

To investigate the relationship between increasing parity and diabetes in a large, population-based cohort, and to examine if this relationship is different among high-risk ethnic groups.

METHODS

A population-based, retrospective cohort study was performed in 738 440 women aged 18-50 years, who delivered babies in Ontario between 1 April 2002 and 31 March 2011. Diabetes incidence postpartum was calculated for each parity and ethnic group. A multivariable analysis of the effect of parity and ethnicity on the incidence of diabetes was performed using a Cox proportional hazards model, adjusting for confounders.

RESULTS

The diabetes incidence rate per 1000 person-years was 3.69 in women with 1 delivery, 4.12 in women with 3 deliveries and 7.62 in women with ≥5 deliveries. Women with ≥3 deliveries had a higher risk of developing diabetes compared with women with 1 delivery [adjusted hazard ratios 1.06 (95% CI 1.01-1.11) for 3 deliveries, 1.33 (95% CI 1.25-1.43) for 4 deliveries and 1.53 (95% CI 1.41-1.66) for ≥5 deliveries). A similar rise in risk could be seen in Chinese and South-Asian women, with the most influence in Chinese women [hazard ratio 4.59 (95% CI 2.36-8.92) for ≥5 deliveries].

CONCLUSIONS

There was a positive and graded relationship between increasing parity and risk of development of diabetes. The influence of parity was seen in all ethnicities. This association may be partly related to increasing weight gain and retention with increasing parity, or deterioration in β-cell function. This merits further exploration.

Sex of the baby and future maternal risk of Type 2 diabetes in women who had gestational diabetes

AIMS

Women who develop gestational diabetes mellitus have a chronic defect in the secretion of insulin by the pancreatic β cells that underlies both their diagnostic hyperglycaemia in pregnancy and their elevated lifetime risk of developing Type 2 diabetes in the future. It has recently emerged that carrying a male fetus is associated with poorer maternal β-cell function and an increased risk of gestational diabetes, whereas the development of gestational diabetes when carrying a girl (as compared with a boy) predicts a comparatively higher risk of early progression to Type 2 diabetes before any subsequent pregnancy. In this context, we sought to determine the impact of fetal sex on the long-term risk of Type 2 diabetes in women with gestational diabetes.

METHODS

Using population-based administrative databases, we identified all women in Ontario, Canada, with a singleton live-birth first pregnancy complicated by gestational diabetes between April 2000 and March 2010 (n = 23 363). We compared the risk of subsequent Type 2 diabetes after pregnancy in those who carried a girl (n = 11 229) vs. those who carried a boy (n = 12 134).

RESULTS

Over median 5.5 years follow-up, 5483 women (23.5%) were diagnosed with diabetes. Compared with those who carried a boy, women who had a girl had an elevated risk of subsequently developing diabetes (adjusted hazard ratio = 1.06, 95% CI 1.01-1.12).

CONCLUSIONS

Among women with gestational diabetes, those who are carrying a girl have a slightly higher overall future risk of Type 2 diabetes.

Depressive symptoms predict non-completion of a structured exercise intervention for people with Type 2 diabetes

AIM

To quantify the impact of depressive symptoms on completion of exercise-based rehabilitation for Type 2 diabetes management.

METHODS

Depressive symptoms were assessed using the Center for Epidemiological Studies Depression scale in a prospective cohort of consecutive patients with Type 2 diabetes entering a 6-month hybrid (home- and clinic-based) exercise rehabilitation programme. Attendance at exercise sessions was monitored and programme completion/non-completion was ascertained.

RESULTS

Of the programme participants (n=624, mean age 55.6±10.5 years, 47% male), 26.8% endorsed significant depressive symptoms (depression score ≥16) and 68.1% completed the intervention, attending 54.6±30.0% of supervised exercise sessions. Baseline depressive symptoms (depression scale score ≥16) increased the risk of non-completion [hazard ratio 1.49 (95% CI 1.10-2.03); P = 0.010], and predicted fewer sessions attended (β=-2.1, P= 0.002) in adjusted models. A depression score threshold of ≥10 (48.4% of participants) predicted non-completion [hazard ratio 1.60 (95% CI 1.19-2.17); P= 0.002) with optimum accuracy. Non-completions resulting from lack of interest (18.9 vs. 11.0%; P= 0.026) and medical complications (14.6 vs. 6.6%; P= 0.006) were more common among participants with depression scores ≥10. Greater hazard ratios for depression scores ≥10 were observed in subgroups not currently using insulin [hazard ratio 1.70 (95% CI 1.24-2.33); P= 0.001), or an antidepressant [hazard ratio 1.83 (95% CI 1.32-2.54); P<0.001].

CONCLUSIONS

Depressive symptoms were highly prevalent among participants with Type 2 diabetes entering exercise-based rehabilitation, and even mild depressive symptoms posed a significant barrier to completion. Depression screening may help target additional supports to facilitate completion of exercise interventions for people with Type 2 diabetes.

Short-term risk of cancer among women with previous gestational diabetes: a population-based study

AIMS

To evaluate the relationship between gestational diabetes (GDM) and incidence of cancer in women within the first decade postpartum.

METHODS

This population-based retrospective cohort study compared the risk of cancer in women with GDM with that of a matched control group comprising pregnant women without diabetes. We included women from Ontario, Canada aged 20-50 years with no history of cancer who had given birth between 1995 and 2008 (N = 149 049). Women with GDM (N = 49 684) were matched on age and year of giving birth, in a ratio of 1:2, to pregnant women without diabetes (N = 99 365).

RESULTS

Over a median 8-year follow-up, there were a total of 2927 (1.5%) cancers. After adjustment for covariates, we found no significant difference in overall risk of cancer between women with GDM and matched control subjects; however, GDM was associated with a significantly greater risk of thyroid cancer (adjusted hazard ratio 1.24, 95% CI 1.05, 1.46) and a significantly lower risk of premenopausal breast cancer (hazard ratio 0.86, 95% CI 0.75, 0.98) compared with matched control subjects.

CONCLUSIONS

This large population-based study did not find a greater risk of cancers among women with GDM during the first decade postpartum; however, GDM was associated with a higher risk of thyroid cancer and a lower risk of premenopausal breast cancer. Further studies are needed to confirm these findings.

Early specialist care for diabetes: who benefits most? A propensity score-matched cohort study

AIMS

To examine whether early endocrinologist care reduces the risk of cardiovascular complications among newly diagnosed patients with diabetes of differing complexity.

METHODS

We conducted a population-based propensity score-matched cohort study using provincial health data from Ontario, Canada. Adults (≥ 30 years) diagnosed with diabetes between 1 April 1998 and 31 March 2006 who received endocrinologist care in the first year of diagnosis were matched to a comparison group receiving primary care alone (N = 79 020) based on propensity scores and medical complexity (assigned using information on chronic conditions). Individuals were followed for 3- and 5-year outcomes, including non-fatal acute myocardial infarction or coronary heart disease death (primary endpoint), major cardiovascular events (acute myocardial infarction, stroke) or all-cause death, amputation and end-stage renal disease.

RESULTS

Among medically complex patients, early endocrinologist care was associated with a lower 3-year incidence of the primary endpoint (hazard ratio 0.89, 95% CI 0.78-1.01) and major cardiovascular events or all-cause death (hazard ratio 0.91, 95% CI 0.85-0.97). These effects persisted after accounting for a higher incidence of end-stage renal disease on follow-up and were greatest in those with ≥ 3 visits to an endocrinologist (primary endpoint: hazard ratio 0.69, 95% CI 0.56-0.86 and 0.61, 95% CI 0.45-0.82, for unadjusted and end-stage renal disease adjusted analyses, respectively). In contrast, no benefit was observed in the non-medically complex subgroup. Overall effects were similar at 5 years.

CONCLUSIONS

Early endocrinologist care is associated with a lower incidence of cardiovascular events and death among newly diagnosed patients with diabetes who have comorbid medical conditions.

A population-based study of ethnicity and breast cancer stage at diagnosis in Ontario

BACKGROUND

Breast cancer stage at diagnosis is an important predictor of survival. Our goal was to compare breast cancer stage at diagnosis (by American Joint Committee on Cancer criteria) in Chinese and South Asian women with stage at diagnosis in the remaining general population in Ontario.

METHODS

We used the Ontario population-based cancer registry to identify all women diagnosed with breast cancer during 2005-2010, and we applied a validated surname algorithm to identify South Asian and Chinese women. We used logistic regression to compare, for Chinese or South Asian women and for the remaining general population, the frequency of diagnoses at stage ii compared with stage i and stages ii-iv compared with stage i.

RESULTS

The registry search identified 1304 Chinese women, 705 South Asian women, and 39,287 women in the remaining general population. The Chinese and South Asian populations were younger than the remaining population (mean: 54, 57, and 61 years respectively). Adjusted for age, South Asian women were more often diagnosed with breast cancer at stage ii than at stage i [odds ratio (or): 1.28; 95% confidence interval (ci): 1.08 to 1.51] or at stages ii-iv than at stage i (or: 1.27; 95% ci: 1.08 to 1.48); Chinese women were less likely to be diagnosed at stage ii than at stage i (or: 0.82; 95% ci: 0.72 to 0.92) or at stages ii-iv than at stage i (or: 0.73; 95% ci: 0.65 to 0.82).

CONCLUSIONS

Breast cancers were diagnosed at a later stage in South Asian women and at an earlier stage in Chinese women than in the remaining population. A more detailed analysis of ethnocultural factors influencing breast screening uptake, retention, and care-seeking behavior might be needed to help inform and evaluate tailored health promotion activities.

Gender differences in the impact of poverty on health: disparities in risk of diabetes-related amputation

AIMS

To assess the combined impact of socio-economic status and gender on the risk of diabetes-related lower extremity amputation within a universal healthcare system.

METHODS

We conducted a population-based cohort study using administrative health databases from Ontario, Canada. Adults with pre-existing or newly diagnosed diabetes (N = 606 494) were included and the incidence of lower extremity amputation was assessed for the period 1 April 2002 to 31 March 2009. Socio-economic status was based on neighbourhood-level income groups, assigned to individuals using the Canadian Census and their postal code of residence.

RESULTS

Low socio-economic status was associated with a significantly higher incidence of lower extremity amputation (27.0 vs 19.3 per 10,000 person-years in the lowest (Q1) vs the highest (Q5) socio-economic status quintile. This relationship persisted after adjusting for primary care use, region of residence and comorbidity, and was greater among men (adjusted Q1:Q5 hazard ratio 1.41, 95% CI 1.30-1.54; P < 0.0001 for all male gender-socio-economic status interactions) than women (hazard ratio 1.20, 95% CI 1.06-1.36). Overall, the incidence of lower extremity amputation was higher among men than women (hazard ratio for men vs women: 1.87, 95% CI 1.79-1.96), with the greatest disparity between men in the lowest socio-economic status category and women in the highest (hazard ratio 2.39, 95% CI 2.06-2.77 and hazard ratio 2.30, 95% CI 1.97-2.68, for major and minor amputation, respectively).

CONCLUSIONS

Despite universal access to hospital and physician care, we found marked socio-economic status and gender disparities in the risk of lower extremity amputation among patients with diabetes. Men living in low-income neighbourhoods were at greatest risk.

Value of short-interval computed tomography when sonography fails to visualize the appendix and shows otherwise normal findings

OBJECTIVES

The purpose of this study was to evaluate the type and incidence of disorders revealed by short-interval computed tomography (CT) in patients with suspected appendicitis after graded compression sonography fails to reveal the appendix and shows otherwise normal findings.

METHODS

Computed tomographic findings and clinical courses were assessed retrospectively for 318 patients identified consecutively in a searchable database who met inclusion criteria specifying that sonography was the initial imaging examination for suspected appendicitis; sonography revealed nonvisualization of the appendix and otherwise normal results; and abdominopelvic CT was performed within 48 hours after sonography.

RESULTS

Of the 318 patients, short-interval CT revealed normal findings in 250 (78.6%). Appendicitis was revealed in 52 (16.4%) others, of whom 7 had perforation and all of whom had pathologic results confirming these CT findings. Important alternative diagnoses other than appendicitis were revealed in 16 (5.0%) others, including 2 (0.6%) who required urgent surgery and 14 (4.4%) who did not. No significant differences were observed between adult patients (>18 years) and pediatric patients.

CONCLUSIONS

Most short-interval CT scans in this clinical setting reveal normal findings, and relatively few disclose appendicitis or disorders that require urgent surgery. In view of concerns regarding radiation exposure associated with CT, these observations argue for the development of clinical triage methods that differentiate patients who are likely to benefit from short-interval postsonography CT from those who are not.

A quantitative measure of diabetes risk in community practice impacts clinical decisions: the PREVAIL initiative

BACKGROUND AND AIMS

While predictive tools are being developed to identify those at highest risk for developing diabetes, little is known whether these assays affect clinical care.

METHODS AND RESULTS

Thirty sites who used the PreDx(®) (Tethys BioScience, Emeryville, CA) abstracted clinical information from baseline clinic visits prior to a PreDx test and from the most recent visit at time of abstraction. All visits occurred between May 2008-April 2011 (median follow-up 198 days, IQR 124-334). The primary analysis was the influence of the PreDx test (5-year diabetes prediction) on subsequent care; descriptive statistics were used to summarize baseline and follow-up variables. Overall 913 patients with 2 abstracted visits were included. Relative to baseline, median SBP decreased 1.5 mmHg (p = 0.039), DBP decreased 2 mmHg (p < 0.001), LDL-C decreased 4 mg/dL (p = 0.009), and HDL-C increased 2 mg/dL (p < 0.001) at follow-up. Behavioral or lifestyle counseling was not significantly different from baseline to follow-up (71.2% vs. 68.1% (p = 0.077), but BMI was lower by 0.2 kg/m(2) at follow up (p = 0.013). At follow-up, more patients were prescribed metformin (13.7% vs. 9.7%, p < 0.001). A higher PreDx score was significantly associated with metformin prescription (p = 0.0003), lifestyle counseling (p = 0.0099), and a lower BMI at follow-up (p = 0.007).

CONCLUSION

The use of a prognostic test in patients perceived to be high risk for diabetes was associated with a modest but significant increase in the prescription of metformin and lifestyle interventions and a reduction in BMI.

Mortality trends in patients with and without diabetes in Ontario, Canada and the UK from 1996 to 2009: a population-based study

AIMS/HYPOTHESIS

The aim of this study was to determine the contemporary rate ratio of mortality and changes over time in individuals with vs without diabetes.

METHODS

Annual age- and sex-adjusted mortality rates were compared for adults (>20 years) with and without diabetes in Ontario, Canada, and the UK from January 1996 to December 2009 using The Health Improvement Network (THIN) and Ontario databases. The total number of individuals evaluated increased from 8,757,772 in 1996 to 12,696,305 in 2009.

RESULTS

The excess risk of mortality for individuals with diabetes in both cohorts was significantly lower during later vs earlier years of the follow-up period (1996-2009). In Ontario the diabetes mortality rate ratio decreased from 1.90 (95% CI 1.86, 1.94) in 1996 to 1.51 (1.48, 1.54) in 2009, and in THIN from 2.14 (1.97, 2.32) to 1.65 (1.57, 1.72), respectively. In Ontario and THIN, the mortality rate ratios among diabetic patients in 2009 were 1.67 (1.61, 1.72) and 1.81 (1.68, 1.94) for those aged 65-74 years and 1.11 (1.10, 1.13) and 1.19 (1.14, 1.24) for those aged over 74 years, respectively. Corresponding rate ratios in Ontario and THIN were 2.45 (2.36, 2.54) and 2.64 (2.39, 2.89) for individuals aged 45-64 years, and 4.89 (4.35, 5.45) and 5.18 (3.73, 6.69) for those aged 20-44 years.

CONCLUSIONS/INTERPRETATION

The excess risk of mortality in individuals with vs without diabetes has decreased over time in both Canada and the UK. This may be in part due to earlier detection and higher prevalence of early diabetes, as well as to improvements in diabetes care.

Trends in selection and timing of first-line pharmacotherapy in older patients with type 2 diabetes diagnosed between 1994 and 2006

AIMS

To characterize temporal trends in the selection and timing of first-line pharmacotherapy among older patients with Type 2 diabetes.

DESIGN AND METHODS

We studied five population-based cohorts every 3 years, from 1994 to 2006. In each of those years, we identified all subjects aged 66 years or older newly diagnosed with diabetes and determined the initial glucose-lowering drug and the time between diagnosis and drug initiation. We calculated the proportion of patients prescribed each agent and estimated time from diagnosis to initiation using Kaplan-Meier survival analysis.

RESULTS

We identified a total of 64 368 eligible people who initiated drug therapy during the study period. From 1994 to 2006, first-line metformin use increased from 20.1 to 79.0%. Glyburide (glibenclamide) decreased from 71.1% of all first-line therapies in 1994 to 9.8% in 2006, while first-line use of insulin or combination therapy have changed little at approximately 5% each. No other medication exceeded 2% of first-line therapies. The median time from diagnosis to initiation of pharmacotherapy increased dramatically during the study period, from 1.8 years in 1994 to 4.6 years in 2006.

CONCLUSIONS

Metformin has become the most commonly used initial medication for the treatment of diabetes. Although guidelines have evolved to recommend more aggressive initiation and intensification of pharmacotherapy, our results suggest that the time from diagnosis to initiation has increased substantially.

Progression through diabetes therapies among new elderly users of metformin: a population-based study

AIMS

To examine temporal changes in progression to second-line therapies among older patients with diabetes newly treated with metformin.

METHODS

We conducted a population-based study among residents of Ontario, Canada aged 66 years and older with diabetes newly treated with metformin monotherapy in 1997, 2000, 2003 or 2006. Each annual cohort was followed until progression to a second oral hypoglycaemic agent, insulin or until 31 December 2010. Time to progression to a second oral hypoglycaemic agent or insulin was compared across the cohorts.

RESULTS

In the four annual cohorts, we identified a total of 46 104 people newly treated with metformin monotherapy. The median time to progression to any second diabetes therapy lengthened significantly over time, from 5.0 years in 1997 to 6.1 years in 2003 (P < 0.0001). Similarly, the time to progression to insulin lengthened over the study period (P = 0.03). Furthermore, the choice of second-line therapy changed over time. While 80.7% of new metformin users in 1997 progressed to glyburide therapy as second-line treatment, the corresponding figure by 2006 was only 45.1% as newer treatment options emerged.

CONCLUSIONS

Although recent guidelines recommend aggressive intensification of oral therapy for patients with Type 2 diabetes, older Ontarians with diabetes who started metformin in 2006 remained on monotherapy for longer than those who started in 1997. Furthermore, although there is no consensus regarding a preferred second-line therapy, the introduction of new alternatives has led to greater variation in the selection of second-line therapies in this population.

Adverse cardiovascular events during treatment with glyburide (glibenclamide) or gliclazide in a high-risk population

AIMS

Sulphonylureas promote insulin release by inhibiting pancreatic potassium channels. Older sulphonylureas such as glyburide (glibenclamide), but not newer ones such as gliclazide, antagonize similar channels in myocardium, interfering with the protective effects of ischaemic preconditioning. Whether this imparts a higher risk of adverse cardiac events is unknown.

METHODS

We conducted a population-based cohort study of patients aged 66 years and older who were hospitalized for acute myocardial infarction or who underwent percutaneous coronary intervention between 1 April 2007 and 31 March 2010 while receiving either glyburide or gliclazide. We used a high-dimensional propensity score matching process to ensure similarity of glyburide- and gliclazide-treated patients. The primary outcome was a composite of death or hospitalization for myocardial infarction or heart failure.

RESULTS

During the 2-year study period, we matched 1690 patients treated with glyburide to 984 patients treated with gliclazide at the time of hospitalization for acute myocardial infarction or percutaneous coronary intervention. We found no difference in the risk of the composite outcome among patients receiving glyburide (adjusted hazard ratio 1.01; 95% CI 0.86-1.18). We found similar results in secondary analyses of each outcome individually, and in two supplementary analyses (haemorrhage and pneumonia) in which we anticipated no difference between the two patient groups.

CONCLUSIONS

Among older patients hospitalized for acute myocardial infarction or percutaneous coronary intervention, treatment with glyburide is not associated with an increased risk of future adverse cardiovascular events relative to gliclazide, suggesting that the effect of glyburide on ischaemic preconditioning is of little clinical relevance.

Increased rates of adverse outcomes for gestational diabetes and pre-pregnancy diabetes in on-reserve First Nations Women in Ontario, Canada

AIMS

To compare the prevalence of diabetes in pregnancy, pregnancy care and adverse pregnancy outcomes in on-reserve First Nations women vs. non-First Nations women in Ontario, Canada.

METHODS

A retrospective population-based cohort study was performed. All 487368 live singleton hospital deliveries between 1 April 2002 and 31 March 2010 were identified. Outcomes were defined by linking mothers and infants to provincial healthcare administrative databases.

RESULTS

Diabetes in pregnancy was more prevalent in First Nations women (10.3 vs. 6.0%). They received less pregnancy care and had higher rates of adverse outcomes than non-First Nations women with diabetes.

CONCLUSIONS

First Nations women are at a higher risk of diabetes in pregnancy and adverse outcomes. This highlights the need for increased care for pregnant First Nations women.

Using the Johns Hopkins' Aggregated Diagnosis Groups (ADGs) to predict 1-year mortality in population-based cohorts of patients with diabetes in Ontario, Canada

AIMS

There are limited validated methods to ascertain comorbidities for risk adjustment in ambulatory populations of patients with diabetes using administrative health-care databases. The objective was to examine the ability of the Johns Hopkins' Aggregated Diagnosis Groups to predict mortality in population-based ambulatory samples of both incident and prevalent subjects with diabetes.

METHODS

Retrospective cohorts constructed using population-based administrative data. The incident cohort consisted of all 346,297 subjects diagnosed with diabetes between 1 April 2004 and 31 March 2008. The prevalent cohort consisted of all 879,849 subjects with pre-existing diabetes on 1 January, 2007. The outcome was death within 1 year of the subject's index date.

RESULTS

A logistic regression model consisting of age, sex and indicator variables for 22 of the 32 Johns Hopkins' Aggregated Diagnosis Group categories had excellent discrimination for predicting mortality in incident diabetes patients: the c-statistic was 0.87 in an independent validation sample. A similar model had excellent discrimination for predicting mortality in prevalent diabetes patients: the c-statistic was 0.84 in an independent validation sample. Both models demonstrated very good calibration, denoting good agreement between observed and predicted mortality across the range of predicted mortality in which the large majority of subjects lay. For comparative purposes, regression models incorporating the Charlson comorbidity index, age and sex, age and sex, and age alone had poorer discrimination than the model that incorporated the Johns Hopkins' Aggregated Diagnosis Groups.

CONCLUSIONS

Logistical regression models using age, sex and the John Hopkins' Aggregated Diagnosis Groups were able to accurately predict 1-year mortality in population-based samples of patients with diabetes.

Impact of gestational diabetes on the risk of diabetes following pregnancy among Chinese and South Asian women

AIMS/HYPOTHESIS

Ethnicity and gestational diabetes mellitus (GDM) are both risk factors for the development of type 2 diabetes. However, it is uncertain whether ethnicity modifies the effect of GDM on diabetes risk. We aimed to determine the risk of diabetes following pregnancy with and without GDM for Chinese and South Asian women compared with white women.

METHODS

Using healthcare databases, all 1,050,108 women aged 20-49 with live births between January 1995 and June 2008 in Ontario were identified. They were followed for up to 15 years for the diagnosis of diabetes.

RESULTS

The age-standardised prevalences of GDM were 4.1%, 7.1% and 2.9% for Chinese, South Asian and white women, respectively. The cumulative incidence of diagnosed diabetes at the median follow-up time of 7.6 years was 16.5% and 1.8% for Chinese women with and without GDM, 31.8% and 3.6% for South Asian women with and without GDM, and 25.7% and 1.8% for white women with and without GDM. The presence of GDM conferred an increase in the risk for diabetes after pregnancy of more than 13-fold in white women, but only a nine- to tenfold increase among Chinese and South Asian women.

CONCLUSIONS/INTERPRETATION

Although one-third of South Asian women with GDM were diagnosed with diabetes within 8 years postpartum, the incremental impact of GDM on diabetes risk was not as strong among Chinese and South Asian women as it was among white women.

Increased rates of adverse outcomes for gestational diabetes and pre-pregnancy diabetes in on-reserve First Nations Women in Ontario, Canada

AIMS

To compare the prevalence of diabetes in pregnancy, pregnancy care and adverse pregnancy outcomes in on-reserve First Nations women vs. non-First Nations women in Ontario, Canada.

METHODS

A retrospective population-based cohort study was performed. All 487368 live singleton hospital deliveries between 1 April 2002 and 31 March 2010 were identified. Outcomes were defined by linking mothers and infants to provincial healthcare administrative databases.

RESULTS

Diabetes in pregnancy was more prevalent in First Nations women (10.3 vs. 6.0%). They received less pregnancy care and had higher rates of adverse outcomes than non-First Nations women with diabetes.

CONCLUSIONS

First Nations women are at a higher risk of diabetes in pregnancy and adverse outcomes. This highlights the need for increased care for pregnant First Nations women.

The effectiveness of implementing a reminder system into routine clinical practice: does it increase postpartum screening in women with gestational diabetes?

Introduction

During regular care, women with previous gestational diabetes mellitus (GDM) rarely receive the recommended screening test for type 2 diabetes, a 2-hour oral glucose tolerance test ( OGTT), in the postpartum period. The current study examined whether the implementation of a reminder system improved screening rates.

Methods

Based on our previous randomized control trial, we implemented a postpartum reminder (letter or phone call) protocol into routine care at two of three clinical sites. We verified postpartum testing by searching hospital laboratory databases and by linking to the provincial physician service claims database. The primary outcome was the proportion of patients who underwent an OGTT within 6 months of delivery.

Results

Women who received care in a setting using a reminder system were more likely to receive an OGTT within 6 months postpartum (28%) compared with usual care (14%). The OGTT rates for both reminder groups were lower than that found in our randomized control trial (28% vs. 60%).

Conclusion

Although the screening rates remain low, postpartum reminders doubled screening rates using the recommended test, the OGTT.

Effect of subsequent pregnancies on the risk of developing diabetes following a first pregnancy complicated by gestational diabetes: a population-based study

AIMS

Women with gestational diabetes mellitus have a high risk of developing Type 2 diabetes, secondary to post-partum progression of the chronic pancreatic ß-cell defect that underlies their presenting with dysglycaemia in pregnancy. Insulin-sensitizing therapy can decrease this risk of Type 2 diabetes, partly by offloading the secretory demand placed on the ß-cells. Conversely, however, it is not known whether the considerable secretory demands posed by the physiologic insulin resistance of a subsequent pregnancy could accelerate the progression to Type 2 diabetes. Thus, we sought to determine whether subsequent pregnancies are associated with the risk of developing diabetes following gestational diabetes.

METHODS

Using a population-based administrative database, we identified all women in Ontario, Canada, whose first pregnancy was between April 2000 and March 2007 and was complicated by gestational diabetes (n = 16,817). This cohort was followed for a median 4.5 years for subsequent pregnancies and the development of diabetes.

RESULTS

During follow-up, 2731 women (16.2%) developed diabetes. Gestational diabetes recurred in 41.5% of subsequent pregnancies. Interestingly, after covariate adjustment, a subsequent pregnancy was associated with a reduced risk of diabetes (adjusted hazard ratio (HR) = 0.68, 95%CI 0.60-0.76; P < 0.0001). Specifically, whereas each subsequent gestational diabetes pregnancy was associated with a modestly increased risk of diabetes (adjusted HR = 1.16, 95%CI 1.01-1.34; P = 0.03), each non-gestational diabetes pregnancy was associated with a significantly reduced risk of diabetes (adjusted HR=0.34, 95%CI 0.27-0.41; P < 0.0001).

CONCLUSIONS

A subsequent pregnancy is not necessarily associated with an increased risk of Type 2 diabetes following gestational diabetes. Instead, the absence of recurrent gestational diabetes in a subsequent pregnancy may identify a lessened risk of developing Type 2 diabetes in this high-risk patient population.

The effectiveness of implementing a reminder system into routine clinical practice: does it increase postpartum screening in women with gestational diabetes?

INTRODUCTION

During regular care, women with previous gestational diabetes mellitus (GDM) rarely receive the recommended screening test for type 2 diabetes, a 2-hour oral glucose tolerance test (OGTT), in the postpartum period. The current study examined whether the implementation of a reminder system improved screening rates.

METHODS

Based on our previous randomized control trial, we implemented a postpartum reminder (letter or phone call) protocol into routine care at two of three clinical sites. We verified postpartum testing by searching hospital laboratory databases and by linking to the provincial physician service claims database. The primary outcome was the proportion of patients who underwent an OGTT within 6 months of delivery.

RESULTS

Women who received care in a setting using a reminder system were more likely to receive an OGTT within 6 months postpartum (28%) compared with usual care (14%). The OGTT rates for both reminder groups were lower than that found in our randomized control trial (28% vs. 60%).

CONCLUSION

Although the screening rates remain low, postpartum reminders doubled screening rates using the recommended test, the OGTT.

Abnormal screening glucose challenge test in pregnancy and future risk of diabetes in young women

AIMS

Pregnant women commonly undergo screening for gestational diabetes mellitus (GDM) using a 50-g glucose challenge test (GCT), followed by a diagnostic oral glucose tolerance test (OGTT) in those women in whom the GCT is abnormal. Although it has long been recognized that GDM is associated with subsequent Type 2 diabetes, it has recently emerged that any degree of abnormal antepartum glucose homeostasis predicts an increased risk of postpartum glucose intolerance. Thus, in this context, we sought to determine whether women who have a pregnancy complicated by an abnormal GCT, but who do not have GDM, are at increased risk of subsequent diabetes, compared with their peers with an abnormal GCT.

METHODS

A population-based, retrospective cohort study was conducted. Women referred for an antepartum OGTT indicative of an abnormal GCT (n = 15 381), but without GDM, were matched (for age, region, socioeconomic status, and year of delivery) with up to four other women without such referral (n = 61 237). The two cohorts were followed over a median 6.4 years for the development of diabetes.

RESULTS

The rate of incident diabetes was 5.04 cases per 1000 person-years in the cohort of women who underwent an antepartum OGTT, compared with 1.74 cases per 1000 person-years in women without an OGTT. The hazard ratio for subsequent diabetes in women with an antepartum OGTT was 2.56 (95% confidence interval 2.28, 2.87) (P < 0.0001).

CONCLUSIONS

Even in the absence of GDM, abnormal screening GCT in pregnancy is associated with an increased future risk of diabetes in young women.

New use of rosiglitazone decreased following publication of a meta-analysis suggesting harm

AIMS

It is uncertain whether meta-analyses lead to changes in prescribing practices. We studied trends in the prescribing of glucose-lowering therapy before and after the publication of a meta-analysis suggesting harm from rosiglitazone.

METHODS

We examined the prescription records of all residents of Ontario, Canada, aged > or = 66 years. For each week between January and December 2007, we identified new users of five categories of glucose-lowering medications: rosiglitazone, pioglitazone, metformin, glibenclamide (glyburide) and insulin. The effect of the meta-analysis was assessed using interventional autoregressive integrated moving-average models.

RESULTS

Following the release of the meta-analysis, there was a sudden decline in new users of rosiglitazone (P = 0.01), mirrored by a nearly identical but transient increase in new users of pioglitazone (P < 0.001). There was also a net decline in new users of thiazolidinediones as a class (P < 0.001). The number of new users of other glucose-lowering medications did not change.

CONCLUSIONS

A highly-publicized meta-analysis regarding rosiglitazone's potential harms led to an abrupt decline in new users of the drug, as well as a transient surge in new use of pioglitazone.