Ascertainment and description of pedestrian and bicycling injuries and fatalities in Ontario from administrative health records 2003-2017: contributions of non-collision falls and crashes.

INTRODUCTION: Pedestrian and bicycling injuries may be less likely to be captured by traffic injury surveillance relying on police reports. Non-collision injuries, including pedestrian falls and single bicycle crashes, may be more likely than motor vehicle collisions to be missed. This study uses healthcare records to expand the ascertainment of active transportation injuries and evaluate their demographic and clinical features. METHODS: We identified pedestrian and bicyclist injuries in records of deaths, hospitalisations and emergency department visits in Ontario, Canada, between 2002 and 2017. We described the most common types of clinical injury codes among these records and assessed overall counts and proportions of injury types captured by each ascertainment definition. We also ascertained relevant fall injuries where the location was indicated as 'street or highway'. RESULTS: Pedestrian falls represented over 50% of all pedestrian injuries and affected all age groups, particularly non-fatal falls. Emergency department records indicating in-traffic bicycle injuries not involving a collision with motor vehicles increased from 14% of all bicycling injury records in 2003 to 34% in 2017. The overall number of injuries indicated by these ascertainment methods was substantially higher than official counts derived from police reports. CONCLUSION: The use of healthcare system records to ascertain bicyclist and pedestrian injuries, particularly to include non-collision falls, can more fully capture the burden of injury associated with these transportation modes.

Identification of combined resistance to Meloidogyne enterolobii and M. incognita in sweetpotato genotypes.

Root-knot nematodes, genus Meloidogyne, are the most damaging nematodes of sweetpotato causing yield reduction and aesthetic damage of the marketable product. Several sweetpotato cultivars currently grown in the United States have intermediate to high resistance to Meloidogyne incognita, however, many of these cultivars are susceptible to M. enterolobii. Therefore, the response of 69 sweetpotato genotypes to M. enterolobii and M. incognita was evaluated under greenhouse conditions to identify potential sources of resistance. The cultivars 'Beauregard' and 'Jewel' were used as controls. Results showed that sweetpotato genotypes were either highly resistant or highly susceptible to M. enterolobii, while they showed a wide spectrum response to M. incognita ranging from highly susceptible to highly resistant. Twenty-six genotypes were resistant to M. enterolobii and eleven genotypes were resistant to M. incognita. Combined resistance to M. enterolobii and M. incognita was observed in three sweetpotato genotypes. Selected genotypes from this study will be used to incorporate the observed resistance into a commercially viable sweetpotato cultivar.

Cotton host resistance as a tool for managing Rotylenchulus reniformis in Louisiana.

The reniform nematode, Rotylenchulus reniformis, is a major yield-limiting pest of upland cotton (Gossypium hirsutum) in the United States that has been steadily increasing in incidence in many states. Reniform nematode-resistant cotton cultivars have recently become commercially available for cotton producers; however, few field trials have evaluated their efficacy as a nematode management tool. The aim of this study was to evaluate reniform nematode population development, plant growth, and seed cotton yield of reniform nematode-resistant cotton cultivars in two nematode-infested fields in Louisiana. Replicated small-plot field trials were conducted in St. Joseph, LA (NERS field) and Winnsboro, LA (MRRS field) during the 2022 and 2023 growing seasons. In 2022, cultivars evaluated included: (1) DP 1646 B2XF (susceptible/tolerant), (2) DP 2141NR B3XF (resistant), (3) PHY 332 W3FE (resistant), (4) PHY 411 W3FE (resistant), and (5) PHY 443 W3FE (resistant). In 2023, an additional susceptible cotton cultivar, PHY 340 W3FE, was also included. All nematode-resistant cotton cultivars evaluated provided suppression of reniform nematode population development relative to that of the susceptible cotton cultivars, with suppression of nematode soil population densities at harvest ranging from 49 - 81% relative to DP 1646 B2XF. The resistant cultivar PHY 411 W3FE provided the most consistent suppression of reniform nematode population development, reducing reniform nematode soil population densities at harvest in both field locations and both trial years. In contrast, DP 2141NR B3XF only reduced soil population densities at harvest in the NERS field in 2023. Despite relatively consistent nematode suppression and improvements in plant vigor ratings and canopy coverage associated with the resistant cotton cultivars, a yield increase was only observed with PHY 332 W3FE and PHY 411 W3FE planted at the NERS field in 2023. Despite strong resistance to reniform nematode in the evaluated cotton cultivars, nematode soil population densities still increased during the growing season in plots planted with resistant cotton cultivars, emphasizing the need for additional management tactics to use alongside host resistance. This study indicates that new reniform nematode-resistant cotton cultivars show promising potential to reduce nematode population development during the growing season in Louisiana.

Characterizing high-cost healthcare users among adults with back pain in Ontario, Canada: a population-based cohort study.

ABSTRACT: Some patients with back pain contribute disproportionately to high healthcare costs; however, characteristics of high-cost users with back pain are not well defined. We described high-cost healthcare users based on total costs among a population-based cohort of adults with back pain within the Ontario government's single-payer health system across sociodemographic, health, and behavioural characteristics. We conducted a population-based cohort study of Ontario adult (aged 18 years or older) respondents of the Canadian Community Health Survey (CCHS) with back pain (2003-2012), linked to administrative data (n = 36,605; weighted n = 2,076,937, representative of Ontario). Respondents were ranked based on gradients of total healthcare costs (top 1%, top 2%-5%, top 6%-50%, and bottom 50%) for 1 year following the CCHS survey, with high-cost users as top 5%. We used multinomial logistic regression to investigate characteristics associated with the 4 cost groups. Top 5% of cost users accounted for 49% ($4 billion CAD) of total healthcare spending, with inpatient hospital care as the largest contributing service type (approximately 40% of costs). Top 5% high-cost users were more likely aged 65 years or older (ORtop1% = 16.6; ORtop2-5% = 44.2), with lower income (ORtop1% = 3.6; ORtop 2-5% = 1.8), chronic disease(s) (ORtop1% = 3.8; ORtop2-5% = 1.6), Aggregated Diagnosis Groups measuring comorbidities (ORtop1% = 25.4; ORtop2-5% = 13.9), and fair/poor self-rated general health (ORtop1% = 6.7; ORtop2-5% = 4.6) compared with bottom 50% users. High-cost users tended to be current/former smokers, obese, and report fair/poor mental health. High-cost users (based on total costs) among adults with back pain account for nearly half of all healthcare spending over a 1-year period and are associated with older age, lower income, comorbidities, and fair/poor general health. Findings identify characteristics associated with a high-risk group for back pain to inform healthcare and public health strategies that target upstream determinants.

Effects of chiropractic use on medical healthcare utilization and costs in adults with back pain in Ontario, Canada from 2003 to 2018: a population-based cohort study.

BACKGROUND: Adults with back pain commonly consult chiropractors, but the impact of chiropractic use on medical utilization and costs within the Canadian health system is unclear. We assessed the association between chiropractic utilization and subsequent medical healthcare utilization and costs in a population-based cohort of Ontario adults with back pain. METHODS: We conducted a population-based cohort study that included Ontario adult respondents of the Canadian Community Health Survey (CCHS) with back pain from 2003 to 2010 (n = 29,475), followed up to 2018. The CCHS data were individually-linked to individual-level health administrative data up to 2018. Chiropractic utilization was self-reported consultation with a chiropractor in the past 12 months. We propensity score-matched adults with and without chiropractic utilization, accounting for confounders. We evaluated back pain-specific and all-cause medical utilization and costs at 1- and 5-year follow-up using negative binomial and linear (log-transformed) regression, respectively. We assessed whether sex and prior specialist consultation in the past 12 months were effect modifiers of the association. RESULTS: There were 6972 matched pairs of CCHS respondents with and without chiropractic utilization. Women with chiropractic utilization had 0.8 times lower rate of cause-specific medical visits at follow-up than those without chiropractic utilization (RR5years = 0.82, 95% CI 0.68-1.00); this association was not found in men (RR5years = 0.96, 95% CI 0.73-1.24). There were no associations between chiropractic utilization and all-cause physician visits, all-cause emergency department visits, all-cause hospitalizations, or costs. Effect modification of the association between chiropractic utilization and cause-specific utilization by prior specialist consultation was found at 1-year but not 5-year follow-up; cause-specific utilization at 1 year was lower in adults without prior specialist consultation only (RR1year = 0.74, 95% CI 0.57-0.97). CONCLUSIONS: Among adults with back pain, chiropractic use is associated with lower rates of back pain-specific utilization in women but not men over a 5-year follow-up period. Findings have implications for guiding allied healthcare delivery in the Ontario health system.

Association between physiotherapy utilization and medical healthcare utilization and costs in adults with back pain from Ontario, Canada: a population-based cohort study.

ABSTRACT: This study examined the association between physiotherapy utilization and subsequent medical healthcare utilization and costs in a population-based sample of adults with back pain in Ontario. We conducted a population-based cohort study of Ontario respondents with back pain (≥18 years) of the Canadian Community Health Survey 2003 to 2010 cycles, linked to health administrative data up to 2018. Physiotherapy utilization was defined as self-reported consultation with a physiotherapist in the past 12 months. A propensity score-matched cohort was conducted to match adults with and without physiotherapy utilization, accounting for potential confounders. We assessed associations using negative-binomial and linear (log-transformed) regression to evaluate outcomes of healthcare utilization (back pain-specific and all-cause) and costs, respectively, at 1- and 5-year follow-up. There were 4343 pairs of matched respondents. Compared with those who did not receive physiotherapy, adults who received physiotherapy were more likely to have back pain-specific physician visits (RR women (5years) = 1.48, 95% CI 1.24-1.75; RR men (5years) = 1.42, 95% CI 1.10-1.84). Women who received physiotherapy had 1.11 times the rate of all-cause physician visits (RR 1year = 1.11, 95% CI 1.02-1.20), and men who received physiotherapy had 0.84 times the rate of all-cause hospitalizations (RR 5years = 0.84, 95% CI 0.71-0.99) than those who did not. There was no association between physiotherapy utilization and healthcare costs. Adults with back pain who received physiotherapy are more likely to have back pain-specific physician visits up to 5-year follow-up than those who did not. Physiotherapy utilization is linked to some sex-based differences in all-cause healthcare utilization but not differences in costs. Findings inform interprofessional collaboration and allied healthcare delivery for back pain in Ontario.

Recovery of Aconitic Acid from Sweet Sorghum Plant Extract Using a Solvent Mixture, and Its Potential Use as a Nematicide.

Trans-aconitic acid (TAA) is naturally present in sweet sorghum juice and syrup, and it has been promoted as a potential biocontrol agent for nematodes. Therefore, we developed a process for the extraction of aconitic acid from sweet sorghum syrup. The process economics were evaluated, and the extract was tested for its capability to suppress the motility of the nematodes Caenorhabditis elegans and Meloidogyne incognita. Aconitic acid could be efficiently extracted from sweet sorghum syrup using acetone:butanol:ethanol mixtures, and it could be recovered from this solvent with a sodium carbonate solution, with an overall extraction and recovery efficiency of 86%. The estimated production cost was USD 16.64/kg of extract and this was highly dependent on the solvent cost, as the solvent was not recycled but was resold for recovery at a fraction of the cost. The extract was effective in reducing the motility of the parasitic M. incognita and causing over 78% mortality of the nematode when 2 mg/mL of TAA extract was added. However, this positive result could not conclusively be linked solely to TAA. An unidentified component (or components) in the acetone:butanol:ethanol sweet sorghum extract appears to be an effective nematode inhibitor, and it may merit further investigation. The impact of aconitic acid on C. elegans appeared to be entirely controlled by pH.

In utero Exposure to Maternal Diabetes and the Risk of Cerebral Palsy: A Population-based Cohort Study.

BACKGROUND: Evidence on the effects of in utero exposure to maternal diabetes on cerebral palsy (CP) in offspring is limited. We aimed to examine the effects of pregestational (PGDM) and gestational diabetes (GDM) separately on CP risk and the mediating role of increased fetal size. METHODS: In a population-based study, we included all live births in Ontario, Canada, between 2002 and 2017 followed up through 2018 (n = 2,110,177). Using administrative health data, we estimated crude and adjusted associations between PGDM or GDM and CP using Cox proportional hazards models to account for unequal follow-up in children. For the mediation analysis, we used marginal structural models to estimate the controlled direct effect of PGDM (and GDM) on the risk of CP not mediated by large-for-gestational age (LGA). RESULTS: During the study period, 5,317 children were diagnosed with CP (187 exposed to PGDM and 171 exposed to GDM). Children of mothers with PGDM showed an increased risk (hazard ratio [HR]: 1.84 [95% confidence interval (CI): 1.59, 2.14]) after adjusting for maternal sociodemographic and clinical factors. We found no associations between GDM and CP (adjusted HR: 0.91 [0.77, 1.06]). Our mediation analysis estimated that LGA explained 14% of the PDGM-CP association. CONCLUSIONS: In this population-based birth cohort study, maternal pregestational diabetes was associated with increased risk of CP, and the increased risk was not substantially mediated by the increased fetal size.

Prevalence and temporal trends of cerebral palsy in children born from 2002 to 2017 in Ontario, Canada: Population-based cohort study.

AIM: To examine the prevalence and temporal trends of cerebral palsy (CP) overall and by population characteristics. METHOD: We identified 2 110 177 live births born in the province of Ontario, Canada, between 2002 and 2017 using administrative health data and estimated CP prevalence in children aged 0 to 16 years overall and by specific population characteristics. We also examined temporal trends in CP rates - overall and by characteristics - in young children (0-4 years) by their year of birth between 2002 and 2013 (n=1 587 087 live births) to allow for an equal follow-up time (4 years and 364 days) for all children. RESULTS: Overall CP prevalence among children aged 0 to 16 years was 2.52 (95% confidence interval 2.45-2.59) per 1000 live births. CP rates in ages 0 to 4 years peaked at 2.86 in 2007 births, but steadily declined afterwards to 1.94 per 1000 live births in 2013. CP rates were higher in children born preterm, small for gestational age, males, multiples, children with congenital malformations, and in children of young (<20 years), old (≥40 years), primiparous, or grand multiparous (≥4) mothers; differences by these characteristics decreased over time. We observed socioeconomic disparities in CP rates that persisted over time. INTERPRETATION: Despite the decreasing trend of CP rates overall, CP rates varied by the child and maternal characteristics over time. WHAT THIS PAPER ADDS: Overall cerebral palsy (CP) prevalence was 2.5 per 1000 live births among children born from 2002 to 2017. CP prevalence peaked in children born in 2007 then steadily decreased between 2007 and 2013. Changes in CP rates varied over time by child and maternal characteristics. Socioeconomic inequalities in CP persisted and remained stable over the study period.

In Utero Exposure to Maternal Injury and the Associated Risk of Cerebral Palsy.

Importance: Although maternal unintentional injury during pregnancy has shown negative impacts on the mother and fetus, the evidence on its long-term associations with children's neurodevelopment is limited. Objective: To examine the association between maternal unintentional injury and cerebral palsy (CP) in offspring. Design, Setting, and Participants: This was a population-based, longitudinal, cohort study of all in-hospital live births born between April 1, 2002, and March 31, 2017, in a publicly funded health care system setting of Ontario, Canada. Infants born more than 20 weeks' gestation were included and followed up until March 31, 2018. Excluded from the analysis were stillbirths, infants with missing or invalid records, and births with missing or invalid birth characteristics. Data were analyzed from March 1 to June 30, 2021. Exposures: Maternal unintentional injury during pregnancy ascertained based on inpatient or emergency department diagnoses. Main Outcomes and Measures: CP diagnosis between birth and the end of follow-up in 2018 with the CP case definition of a single inpatient or 2 or more outpatient diagnoses at least 2 weeks apart between birth and age 16 years. Results: Of 2 110 177 children included in this study (mean [SD] gestational age, 38.8 [1.9] weeks; 1 082 520 male [51.3%]), 81 281 (3.9%) were exposed in utero to maternal unintentional injury. During a median (IQR) follow-up time of 8 (4-12) years, 5317 children (0.3%) were diagnosed with CP (292 CP cases [5.5%] were exposed to maternal unintentional injury). The mean incidence rates of CP were 4.36 and 2.93 per 10 000 child-years in the exposed and the unexposed group, respectively. Children exposed to maternal unintentional injury had a modest increase in the risk of CP, compared with those unexposed (hazard ratio [HR], 1.33; 95% CI, 1.18-1.50) after adjusting for maternal sociodemographic and clinical characteristics. Severe injuries that resulted in hospitalization and delivery within 1 week from the injury conferred higher risks of CP (adjusted HR, 2.18; 95% CI, 1.29-3.68 and adjusted HR, 3.40; 95% CI, 1.93-6.00, respectively). Results were robust in multiple bias analyses. Conclusions and Relevance: In this Canadian population-based birth cohort study, in utero exposure to maternal unintentional injury was associated with an increased risk of CP, with a higher risk with more severe injuries. These findings fill an important gap in knowledge on the potential role of maternal injury on children's neurodevelopment outcomes. Public health professionals and stakeholders should be aware of these potential long-term consequences on offspring when designing programs and providing recommendations about safety during pregnancy. Early monitoring and developmental assessment of children exposed to maternal injury might be warranted.

Evaluation of fumigant and non-fumigant nematicides for management of Rotylenchulus reniformis on sweetpotato.

Reniform nematode (Rotylenchulus reniformis) is a major pest of sweetpotato in many production regions in Southern United States. Applying soil fumigants and non-fumigant nematicides are the primary management strategies available to growers. This study compared the relative efficacy of nematicides (1,3-dichloropropene, fluopyram, oxamyl, fluazaindolizine, aldicarb, Majestene, and fluensulfone) for management of reniform nematode on sweetpotato. Fumigating soil with 1,3-dichloropropene consistently reduced soil population densities of reniform nematode at the time of planting in both trial years (31 - 36% reduction relative to the untreated control); however, the duration of suppression varied greatly by growing season. A similar trend was observed with fluopyram (56 - 67% reduction) and aldicarb (63 - 65% reduction), which provided season-long suppression of reniform nematode population development in 2021 but had no impact in 2022. In 2021, nematicide application had no impact on yield; however, in 2022, oxamyl and aldicarb increased the yield of U.S.#1 grade sweetpotato. Overall, soil fumigation with 1,3-dichloropropene and in-furrow application of fluopyram and aldicarb provided the most consistent suppression of reniform nematode on sweetpotato.

Predicting hospitalisations related to ambulatory care sensitive conditions with machine learning for population health planning: derivation and validation cohort study.

OBJECTIVE: To predict older adults' risk of avoidable hospitalisation related to ambulatory care sensitive conditions (ACSC) using machine learning applied to administrative health data of Ontario, Canada. DESIGN, SETTING AND PARTICIPANTS: A retrospective cohort study was conducted on a large cohort of all residents covered under a single-payer system in Ontario, Canada over the period of 10 years (2008-2017). The study included 1.85 million Ontario residents between 65 and 74 years old at any time throughout the study period. DATA SOURCES: Administrative health data from Ontario, Canada obtained from the (ICES formely known as the Institute for Clinical Evaluative Sciences Data Repository. MAIN OUTCOME MEASURES: Risk of hospitalisations due to ACSCs 1 year after the observation period. RESULTS: The study used a total of 1 854 116 patients, split into train, validation and test sets. The ACSC incidence rates among the data points were 1.1% for all sets. The final XGBoost model achieved an area under the receiver operating curve of 80.5% and an area under precision-recall curve of 0.093 on the test set, and the predictions were well calibrated, including in key subgroups. When ranking the model predictions, those at the top 5% of risk as predicted by the model captured 37.4% of those presented with an ACSC-related hospitalisation. A variety of features such as the previous number of ambulatory care visits, presence of ACSC-related hospitalisations during the observation window, age, rural residence and prescription of certain medications were contributors to the prediction. Our model was also able to capture the geospatial heterogeneity of ACSC risk in Ontario, and especially the elevated risk in rural and marginalised regions. CONCLUSIONS: This study aimed to predict the 1-year risk of hospitalisation from ambulatory-care sensitive conditions in seniors aged 65-74 years old with a single, large-scale machine learning model. The model shows the potential to inform population health planning and interventions to reduce the burden of ACSC-related hospitalisations.

Joint effects of back pain and mental health conditions on healthcare utilization and costs in Ontario, Canada: a population-based cohort study.

ABSTRACT: We assessed the joint effects of back pain and mental health conditions on healthcare utilization and costs in a population-based sample of adults in Ontario. We included Ontario adult respondents of the Canadian Community Health Survey between 2003 and 2012, followed up to 2018 by linking survey data to administrative databases. Joint exposures were self-reported back pain and mental health conditions (fair/poor mental health, mood, and anxiety disorder). We built negative binomial, modified Poisson and linear (log-transformed) models to assess joint effects (effects of 2 exposures in combination) of comorbid back pain and mental health condition on healthcare utilization, opioid prescription, and costs. The models were adjusted for sociodemographic, health-related, and behavioural factors. We evaluated positive additive and multiplicative interaction (synergism) between back pain and mental health conditions with relative excess risk due to interaction (RERI) and ratio of rate ratios (RRs). The cohort (n = 147,486) had a mean age of 46 years (SD = 17), and 51% were female. We found positive additive and multiplicative interaction between back pain and fair/poor mental health (RERI = 0.40; ratio of RR = 1.12) and mood disorder (RERI = 0.41; ratio of RR = 1.04) but not anxiety for back pain-specific utilization. For opioid prescription, we found positive additive and multiplicative interaction between back pain and fair/poor mental health (RERI = 2.71; ratio of risk ratio = 3.20) and anxiety (RERI = 1.60; ratio of risk ratio = 1.80) and positive additive interaction with mood disorder (RERI = 0.74). There was no evidence of synergism for all-cause utilization or costs. Combined effects of back pain and mental health conditions on back pain-specific utilization or opioid prescription were greater than expected, with evidence of synergism. Health services targeting back pain and mental health conditions together may provide greater improvements in outcomes.

Sensitivity of Meloidogyne enterolobii and M. incognita to fluorinated nematicides.

BACKGROUND: Meloidogyne enterolobii (Yang and Eisenback) was recently introduced into Louisiana on contaminated sweetpotato planting material. Given the known variation in sensitivity to nematicides within the genus Meloidogyne, there is question as to whether fluorinated nematicides will be as efficacious toward M. enterolobii as they are with M. incognita (Chitwood). Using a series of in vitro and growth cabinet experiments, this study compared the sensitivity of M. enterolobii and M. incognita to four synthetic non-fumigant nematicides (fluopyram, fluensulfone, fluazaindolizine, and oxamyl). RESULTS: Meloidogyne enterolobii had lower sensitivity to nematicides than M. incognita in the majority of the in vitro exposure assays. Similar levels of reduction in root infectivity were observed after nematicide exposure among both nematode species. Fluopyram showed high hatching inhibition for both Meloidogyne species at low concentrations [median effective concentration (EC50 ) values of 0.273 to 0.018 mg L-1 ], whereas fluensulfone showed high root penetration inhibition at low concentrations (EC50 values of 0.151 to 0.065 mg L-1 ) relative to that of other evaluated nematicides. For both Meloidogyne species, each of the four non-fumigant nematicides reduced root galling (58-96% reduction for M. enterolobii, 71-100% reduction for M. incognita) and egg production (63-99% reduction for M. enterolobii, 58-96% reduction for M. incognita) on sweetpotato when applied at the label recommended rate. CONCLUSION: Fluorinated nematicides and oxamyl show capacity to suppress M. enterolobii on sweetpotato. © 2021 Society of Chemical Industry.

Risk stratification for COVID-19 hospitalization: a multivariable model based on gradient-boosting decision trees.

BACKGROUND: The COVID-19 pandemic has led to an increased demand for health care resources and, in some cases, shortage of medical equipment and staff. Our objective was to develop and validate a multivariable model to predict risk of hospitalization for patients infected with SARS-CoV-2. METHODS: We used routinely collected health records in a patient cohort to develop and validate our prediction model. This cohort included adult patients (age ≥ 18 yr) from Ontario, Canada, who tested positive for SARS-CoV-2 ribonucleic acid by polymerase chain reaction between Feb. 2 and Oct. 5, 2020, and were followed up through Nov. 5, 2020. Patients living in long-term care facilities were excluded, as they were all assumed to be at high risk of hospitalization for COVID-19. Risk of hospitalization within 30 days of diagnosis of SARS-CoV-2 infection was estimated via gradient-boosting decision trees, and variable importance examined via Shapley values. We built a gradient-boosting model using the Extreme Gradient Boosting (XGBoost) algorithm and compared its performance against 4 empirical rules commonly used for risk stratifications based on age and number of comorbidities. RESULTS: The cohort included 36 323 patients with 2583 hospitalizations (7.1%). Hospitalized patients had a higher median age (64 yr v. 43 yr), were more likely to be male (56.3% v. 47.3%) and had a higher median number of comorbidities (3, interquartile range [IQR] 2-6 v. 1, IQR 0-3) than nonhospitalized patients. Patients were split into development (n = 29 058, 80.0%) and held-out validation (n = 7265, 20.0%) cohorts. The gradient-boosting model achieved high discrimination (development cohort: area under the receiver operating characteristic curve across the 5 folds of 0.852; validation cohort: 0.8475) and strong calibration (slope = 1.01, intercept = -0.01). The patients who scored at the top 10% captured 47.4% of hospitalizations, and those who scored at the top 30% captured 80.6%. INTERPRETATION: We developed and validated an accurate risk stratification model using routinely collected health administrative data. We envision that modelling such risk stratification based on routinely collected health data could support management of COVID-19 on a population health level.

Neighbourhood material deprivation and severe maternal morbidity: a population-based cohort study in Ontario, Canada.

OBJECTIVES: Rates of age-associated severe maternal morbidity (SMM) have increased in Canada, and an association with neighbourhood income is well established. Our aim was to examine SMM trends according to neighbourhood material deprivation quintile, and to assess whether neighbourhood deprivation effects are moderated by maternal age. DESIGN, SETTING AND PARTICIPANTS: A population-based retrospective cohort study using linked administrative databases in Ontario, Canada. We included primiparous women with a live birth or stillbirth at ≥20 weeks' gestational age. PRIMARY OUTCOME: SMM from pregnancy onset to 42 days postpartum. We calculated SMM rate differences (RD) and rate ratios (RR) by neighbourhood material deprivation quintile for each of four 4-year cohorts from 1 April 2002 to 31 March 2018. Log-binomial multivariable regression adjusted for maternal age, demographic and pregnancy-related variables. RESULTS: There were 1 048 845 primiparous births during the study period. The overall rate of SMM was 18.0 per 1000 births. SMM rates were elevated for women living in areas with high material deprivation. In the final 4-year cohort, the RD between women living in high vs low deprivation neighbourhoods was 3.91 SMM cases per 1000 births (95% CI: 2.12 to 5.70). This was higher than the difference observed during the first 4-year cohort (RD 2.09, 95% CI: 0.62 to 3.56). SMM remained associated with neighbourhood material deprivation following multivariable adjustment in the pooled sample (RR 1.16, 95% CI: 1.11 to 1.21). There was no evidence of interaction with maternal age. CONCLUSION: SMM rate increases were more pronounced for primiparous women living in neighbourhoods with high material deprivation compared with those living in low deprivation areas. This raises concerns of a widening social gap in maternal health disparities and highlights an opportunity to focus risk reduction efforts toward disadvantaged women during pregnancy and postpartum.

Effect of back problems on healthcare utilization and costs in Ontario, Canada: a population-based matched cohort study.

ABSTRACT: We assessed the effect of back problems on healthcare utilization and costs in a population-based sample of adults from a single-payer health system in Ontario. We conducted a population-based cohort study of Ontario respondents aged ≥18 years of the Canadian Community Health Survey (CCHS) from 2003 to 2012. The CCHS data were individually linked to health administrative data to measure healthcare utilization and costs up to 2018. We propensity score-matched (hard matched on sex) adults with self-reported back problems to those without back problems, accounting for sociodemographic, health-related, and behavioural factors. We evaluated cause-specific and all-cause healthcare utilization and costs adjusted to 2018 Canadian dollars using negative binomial and linear (log transformed) regression models. After propensity score matching, we identified 36,806 pairs (women: 21,054 pairs; men: 15,752 pairs) of CCHS respondents with and without back problems (mean age 51 years, standard deviation = 18). Compared with propensity score matched adults without back problems, adults with back problems had 2 times the rate of cause-specific visits (rate ratio [RR]women 2.06, 95% confidence interval [CI] 1.88-2.25; RRmen 2.32, 95% CI 2.04-2.64), slightly more all-cause physician visits (RRwomen 1.12, 95% CI 1.09-1.16; RRmen 1.10, 95% CI 1.05-1.14), and 1.2 times the costs (women: 1.21, 95% CI 1.16-1.27; men: 1.16, 95% CI 1.09-1.23). Incremental annual per-person costs were higher in adults with back problems than those without back problems (women: $395, 95% CI $281-$509; men: $196, 95% CI $94-$300). This corresponded to $532 million for women and $227 million for men (adjusted to 2018 Canadian dollars) annually in Ontario given the high prevalence of back problems. Given the high health system burden, new strategies to effectively prevent and treat back problems and thus potentially reduce the long-term costs are warranted.

Déterminants individuels et sociaux du test de dépistage du SRAS-CoV-2 et de l'obtention d'un résultat positif en Ontario, au Canada: une étude populationnelle.

CONTEXTE: Optimiser la réponse de la santé publique pour diminuer le fardeau de la COVID-19 nécessite la caractérisation de l'hétérogénéité du risque posé par la maladie à l'échelle de la population. Cependant, l'hétérogénéité du dépistage du SRAS-CoV-2 peut fausser les estimations selon le modèle d'étude analytique utilisé. Notre objectif était d'explorer les biais collisionneurs dans le cadre d'une vaste étude portant sur les déterminants de la maladie et d'évaluer les déterminants individuels, environnementaux et sociaux du dépistage et du diagnostic du SRAS-CoV-2 parmi les résidents de l'Ontario, au Canada. MÉTHODES: Nous avons exploré la présence potentielle de biais collisionneurs et caractérisé les déterminants individuels, environnementaux et sociaux de l'obtention d'un test de dépistage et d'un résultat positif à la présence de l'infection au SRAS-CoV-2 à l'aide d'analyses transversales parmi les 14,7 millions de personnes vivant dans la collectivité en Ontario, au Canada. Parmi les personnes ayant obtenu un diagnostic, nous avons utilisé des études analytiques distinctes afin de comparer les prédicteurs pour les personnes d'obtenir un résultat de test de dépistage positif plutôt que négatif, pour les personnes symptomatiques d'obtenir un résultat de test de dépistage positif plutôt que négatif et pour les personnes d'obtenir un résultat de test de dépistage positif plutôt que de ne pas obtenir un résultat positif (c.-à-d., obtenir un résultat de test de dépistage négatif ou ne pas obtenir de test de dépistage). Nos analyses comprennent des tests de dépistage réalisés entre le 1er mars et le 20 juin 2020. RÉSULTATS: Sur 14 695 579 personnes, nous avons constaté que 758 691 d'entre elles ont passé un test de dépistage du SRAS-CoV-2, parmi lesquelles 25 030 (3,3 %) ont obtenu un résultat positif. Plus la probabilité d'obtenir un test de dépistage s'éloignait de zéro, plus la variabilité généralement observée dans la probabilité d'un diagnostic était grande parmi les modèles d'études analytiques, particulièrement en ce qui a trait aux facteurs individuels. Nous avons constaté que la variabilité dans l'obtention d'un test de dépistage était moins importante en fonction des déterminants sociaux dans l'ensemble des études analytiques. Les facteurs tels que le fait d'habiter dans une région ayant une plus haute densité des ménages (rapport de cotes corrigé 1,86; intervalle de confiance [IC] à 95 % 1,75­1,98), une plus grande proportion de travailleurs essentiels (rapport de cotes corrigé 1,58; IC à 95 % 1,48­1,69), une population atteignant un plus faible niveau de scolarité (rapport de cotes corrigé 1,33; IC à 95 % 1,26­1,41) et une plus grande proportion d'immigrants récents (rapport de cotes corrigé 1,10; IC à 95 % 1,05­1,15), étaient systématiquement corrélés à une probabilité plus importante d'obtenir un diagnostic de SRAS-CoV-2, peu importe le modèle d'étude analytique employé. INTERPRÉTATION: Lorsque la capacité de dépister est limitée, nos résultats suggèrent que les facteurs de risque peuvent être estimés plus adéquatement en utilisant des comparateurs populationnels plutôt que des comparateurs de résultat négatif au test de dépistage. Optimiser la lutte contre la COVID-19 nécessite des investissements dans des interventions structurelles déployées de façon suffisante et adaptées à l'hétérogénéité des déterminants sociaux du risque, dont le surpeuplement des ménages, l'occupation professionnelle et le racisme structurel.

Depression-related weight change and incident diabetes in a community sample.

This cohort study aimed to compare the incidence of type 2 diabetes in adults with depression-related weight gain, depression-related weight loss, depression with no weight change, and no depression. The study sample included 59,315 community-dwelling adults in Ontario, Canada. Depression-related weight change in the past 12 months was measured using the Composite International Diagnostic Interview-Short Form. Participants were followed for up to 20 years using administrative health data. Cox proportional hazards models compared the incidence of type 2 diabetes in adults with depression-related weight change and in adults with no depression. Adults with depression-related weight gain had an increased risk of type 2 diabetes compared to adults no depression (HR 1.70, 95% CI 1.32-2.20), adults with depression-related weight loss (HR 1.62, 95% CI 1.09-2.42), and adults with depression with no weight change (HR 1.39, 95% CI 1.03-1.86). Adults with depression with no weight change also had an increased risk of type 2 diabetes compared to those with no depression (HR 1.23, 95% CI 1.04-1.45). Associations were stronger among women and persisted after adjusting for attained overweight and obesity. Identifying symptoms of weight change in depression may aid in identifying adults at higher risk of type 2 diabetes and in developing tailored prevention strategies.

Development and Validation of a Machine Learning Model Using Administrative Health Data to Predict Onset of Type 2 Diabetes.

Importance: Systems-level barriers to diabetes care could be improved with population health planning tools that accurately discriminate between high- and low-risk groups to guide investments and targeted interventions. Objective: To develop and validate a population-level machine learning model for predicting type 2 diabetes 5 years before diabetes onset using administrative health data. Design, Setting, and Participants: This decision analytical model study used linked administrative health data from the diverse, single-payer health system in Ontario, Canada, between January 1, 2006, and December 31, 2016. A gradient boosting decision tree model was trained on data from 1 657 395 patients, validated on 243 442 patients, and tested on 236 506 patients. Costs associated with each patient were estimated using a validated costing algorithm. Data were analyzed from January 1, 2006, to December 31, 2016. Exposures: A random sample of 2 137 343 residents of Ontario without type 2 diabetes was obtained at study start time. More than 300 features from data sets capturing demographic information, laboratory measurements, drug benefits, health care system interactions, social determinants of health, and ambulatory care and hospitalization records were compiled over 2-year patient medical histories to generate quarterly predictions. Main Outcomes and Measures: Discrimination was assessed using the area under the receiver operating characteristic curve statistic, and calibration was assessed visually using calibration plots. Feature contribution was assessed with Shapley values. Costs were estimated in 2020 US dollars. Results: This study trained a gradient boosting decision tree model on data from 1 657 395 patients (12 900 257 instances; 6 666 662 women [51.7%]). The developed model achieved a test area under the curve of 80.26 (range, 80.21-80.29), demonstrated good calibration, and was robust to sex, immigration status, area-level marginalization with regard to material deprivation and race/ethnicity, and low contact with the health care system. The top 5% of patients predicted as high risk by the model represented 26% of the total annual diabetes cost in Ontario. Conclusions and Relevance: In this decision analytical model study, a machine learning model approach accurately predicted the incidence of diabetes in the population using routinely collected health administrative data. These results suggest that the model could be used to inform decision-making for population health planning and diabetes prevention.