Multisystem inflammatory syndrome in 1.2 million children: longitudinal cohort study of risk factors.

BACKGROUND: We identified patient characteristics associated with an increased risk of developing MIS-C. METHODS: We conducted a longitudinal cohort study of 1,195,327 patients aged 0-19 years between 2006 and 2021, including the first two waves of the pandemic (February 25-August 22, 2020 and August 23, 2020-March 31, 2021). Exposures included prepandemic morbidity, birth outcomes, and family history of maternal disorders. Outcomes included MIS-C, Kawasaki disease, and other Covid-19 complications during the pandemic. We calculated risk ratios (RRs) and 95% confidence intervals (CIs) for the association between patient exposures and these outcomes using log-binomial regression models adjusted for potential confounders. RESULTS: Among 1,195,327 children, 84 developed MIS-C, 107 Kawasaki disease, and 330 other Covid-19 complications during the first year of the pandemic. Prepandemic hospitalizations for metabolic disorders (RR 11.3, 95% CI 5.61-22.6), atopic conditions (RR 3.34, 95% CI 1.60-6.97), and cancer (RR 8.11, 95% CI 1.13-58.3) were strongly associated with the risk of MIS-C, compared with no exposure. These same exposures were also associated with Kawasaki disease and other Covid-19 complications. However, birth characteristics and history of maternal morbidity were not associated with MIS-C development. CONCLUSIONS: Children with pre-existing morbidity have a considerably elevated risk of MIS-C. IMPACT: Morbidities that predispose children to multisystem inflammatory syndrome (MIS-C) are unclear. In this study, prepandemic hospitalizations for metabolic disorders, atopic conditions, and cancer were associated with an elevated risk of MIS-C. Birth characteristics and family history of maternal morbidity were not, however, associated with MIS-C. Pediatric morbidities may play a greater role in MIS-C onset than maternal or perinatal characteristics, and may help clinicians better recognize children at risk for this complication.

Impact of Covid-19 on risk of severe maternal morbidity.

BACKGROUND: We examined the risk of severe life-threatening morbidity in pregnant patients with Covid-19 infection. METHODS: We conducted a population-based study of 162,576 pregnancies between March 2020 and March 2022 in Quebec, Canada. The main exposure was Covid-19 infection, including the severity, period of infection (antepartum, peripartum), and circulating variant (wildtype, alpha, delta, omicron). The outcome was severe maternal morbidity during pregnancy up to 42 days postpartum. We estimated risk ratios (RR) and 95% confidence intervals (CI) for the association between Covid-19 infection and severe maternal morbidity using adjusted log-binomial regression models. RESULTS: Covid-19 infection was associated with twice the risk of severe maternal morbidity compared with no infection (RR 2.02, 95% CI 1.76-2.31). Risks were elevated for acute renal failure (RR 3.01, 95% CI 1.79-5.06), embolism, shock, sepsis, and disseminated intravascular coagulation (RR 1.35, 95% CI 0.95-1.93), and severe hemorrhage (RR 1.49, 95% CI 1.09-2.04). Severe antepartum (RR 13.60, 95% CI 10.72-17.26) and peripartum infections (RR 20.93, 95% CI 17.11-25.60) were strongly associated with severe maternal morbidity. Mild antepartum infections also increased the risk, but to a lesser magnitude (RR 3.43, 95% CI 2.42-4.86). Risk of severe maternal morbidity was around 3 times greater during circulation of wildtype and the alpha and delta variants, but only 1.2 times greater during omicron. CONCLUSIONS: Covid-19 infection during pregnancy increases risk of life-threatening maternal morbidity, including renal, embolic, and hemorrhagic complications. Severe Covid-19 infection with any variant in the antepartum or peripartum periods all increase the risk of severe maternal morbidity.

Effect of publicly funded assisted reproductive technology on maternal and infant outcomes: a pre- and post-comparison study.

STUDY QUESTION: Does publicly funded assisted reproductive technology result in improved maternal and infant outcomes? SUMMARY ANSWER: Publicly funded ART in Quebec was associated with reduced risks of preeclampsia, cesarean delivery, preterm birth, low birth weight and other adverse outcomes. WHAT IS KNOWN ALREADY: Publicly funded ART programs that provide free access to single embryo transfer are known to decrease the rate of multiple pregnancy, but the impact on other pregnancy outcomes is unknown. STUDY DESIGN, SIZE, DURATION: We conducted a pre- and post-comparison study of 597 416 pregnancies conceived between July 2008 and September 2015 in Quebec, Canada, a region where public funding of ART began in August 2010. PARTICIPANTS/MATERIALS, SETTING, METHODS: We included all pregnant women who conceived by ART (n = 14 309) or spontaneously (n = 583 107) and delivered a live or stillborn infant in hospitals of Quebec. The main exposure measure was conception before versus during the publicly funded ART program. Outcomes included measures of maternal and infant morbidity and mortality. We estimated risk ratios (RR) and 95% confidence intervals for the association of publicly funded ART with maternal and infant outcomes using log-binomial regression models adjusted for maternal characteristics. MAIN RESULTS AND THE ROLE OF CHANCE: In this study, 2638 pregnancies were conceived by ART before, and 11 671 were conceived by ART, during public funding. Compared with no public funding, ART funding was associated with reduced risks of severe maternal morbidity (RR 0.64, 95% CI 0.50-0.83), preeclampsia (RR 0.55, 95% CI 0.44-0.68), cesarean delivery (RR 0.83, 95% CI 0.77-0.89), preterm birth (RR 0.67, 95% CI 0.60-0.75), low birth weight (RR 0.63, 95% CI 0.55-0.72), severe neonatal morbidity (RR 0.75, 95% CI 0.57-0.99) and neonatal intensive care unit admission (RR 0.65, 95% CI 0.53-0.78). When multiple pregnancies were excluded, ART funding continued to be associated with a lower risk of preeclampsia (RR 0.61, 95% CI 0.48-0.79) and preterm birth (RR 0.85, 95% CI 0.73-0.99). However, ART funding was associated with increased risk of gestational diabetes. LIMITATIONS, REASONS FOR CAUTION: We had no information on the type of ART, number of in-vitro fertilization cycles or number of embryos transferred. We lacked data on body mass index, ethnicity and smoking and cannot rule out residual confounding. WIDER IMPLICATION OF THE FINDINGS: Our findings suggest that publicly funded ART programs that encourage single embryo transfer may have substantial benefits for a range of maternal and infant outcomes, beyond prevention of multiple births. STUDY FUNDING/COMPETING INTEREST(S): This study was supported by grant 6D02363004 from the Public Health Agency of Canada. N.A. acknowledges a career award from the Fonds de recherche du Québec-Santé (34695). The authors declare no competing interests. TRIAL REGISTRATION NUMBER: N/A.

Pregnancy outcomes in women with anorexia nervosa.

OBJECTIVE: Birth outcomes of women with anorexia nervosa are poorly understood. We hypothesized that hospitalization for anorexia nervosa before or during pregnancy is associated with an elevated risk of adverse maternal and infant birth outcomes. METHOD: We performed a retrospective cohort study of 2,134,945 pregnancies in Quebec, Canada, from 1989 to 2016. The main exposure measure was anorexia nervosa requiring hospital treatment before or during pregnancy. Outcome measures included stillbirth, preterm birth, low birth weight, small-for-gestational age birth, preeclampsia, gestational diabetes, cesarean delivery, and other pregnancy disorders. We computed risk ratios and 95% confidence intervals (CI) for the association between anorexia nervosa and birth outcomes adjusted for maternal characteristics. RESULTS: Compared with no hospitalization, anorexia nervosa hospitalization was associated with 1.99 times the risk of stillbirth (95% CI 1.20-3.30), 1.32 times the risk of preterm birth (95% CI 1.13-1.55), 1.69 times the risk of low birth weight (95% CI 1.44-1.99), and 1.52 times the risk of small-for-gestational age birth (95% CI 1.35-1.72). The associations with low birth weight and small-for-gestational age birth were more prominent in women hospitalized for anorexia nervosa during pregnancy or within 2 years of delivery. Hospitalization for anorexia nervosa was associated with certain maternal outcomes, including precipitate labor, acute liver failure, and admission to an intensive care unit. DISCUSSION: Hospitalization for anorexia nervosa before or during pregnancy is associated with adverse infant and maternal outcomes. Infants are primarily at risk of stillbirth, preterm birth, low birth weight, and small-for-gestational age birth.

Maternal Mental Disorders before Delivery and the Risk of Dental Caries in Children.

Prevention of childhood caries is an ongoing public health challenge, but the possibility of an association with maternal mental disorders has received limited attention. We estimated the extent to which maternal mental disorders are associated with an increased risk of hospitalization due to dental caries. We conducted a longitudinal cohort study of 790,758 infants born in Quebec, Canada between 2006 and 2016, with follow-up extending to 2018. We identified women with mental disorders before or during pregnancy and computed the incidence of dental caries in their children. We estimated HR and 95% CI for the association of maternal mental disorders with the risk of dental caries, adjusted for personal characteristics. Infants of women with mental disorders before or during pregnancy had a higher incidence of dental caries compared to children of women with no mental disorder (56.1 vs. 27.2 per 10,000 person-years). Maternal stress and anxiety disorders (HR = 1.73; 95% CI 1.60-1.86), depression (HR = 1.81; 95% CI 1.60-2.03), schizophrenia and delusional disorders (HR = 1.69; 95% CI 1.29-2.22), and personality disorders (HR = 1.89; 95% CI 1.70-2.11) were associated with the risk of dental caries. The associations were present throughout childhood, including after 7 years (HR = 1.65; 95% CI 1.38-1.96). Maternal mental disorders were associated with caries of the enamel, dentin, and cementum and caries that reached the dental pulp. Maternal mental disorders before or during pregnancy, especially stress and anxiety, depression, schizophrenia, and personality disorders, are associated with the risk of childhood caries. Women with a history of mental disorders may benefit from enhanced strategies for prevention of dental caries in their children.

Neonatal phototherapy and future risk of childhood cancer.

We sought to determine if neonatal phototherapy is associated with a greater risk of childhood cancer. We conducted a retrospective cohort study of 786,998 infants born in hospitals of Quebec, Canada between 2006 and 2016, with 4,660,868 person-years of follow-up over an 11-year period. The exposures were neonatal phototherapy (32,314 or 4.1% of infants) and untreated jaundice (91,855 or 11.7% of infants). The outcome was hospitalization for solid or hematopoietic childhood tumours between 2 months and 11 years of age. We used Cox proportional hazards regression models to compute hazard ratios (HR) and 95% confidence intervals (CI) for the association of phototherapy with childhood cancer, adjusted for infant characteristics. The incidence of childhood cancer was higher for infants with phototherapy (25.1 per 100,000 person-years) and untreated jaundice (23.0 per 100,000) compared to unexposed infants (21.6 per 100,000). Phototherapy appeared to be associated with late onset solid tumours, including brain/central nervous system cancers. Between age 4 and 11 years, children who received neonatal phototherapy had more than 2 times the risk of any solid tumour compared to unexposed children (HR 2.26, 95% CI 1.34-3.81). Results were similar for phototherapy compared against untreated jaundice. A similar trend was however less apparent for hematopoietic cancer. We conclude that neonatal phototherapy may be associated with a slightly increased risk of solid tumours in childhood, but cannot rule out an effect of bilirubin. Minimizing unnecessary exposure to phototherapy through adherence to recommended thresholds for treatment is encouraged.

Increased risk of hemangioma after exposure to neonatal phototherapy in infants with predisposing risk factors.

AIM: To determine the relationship between neonatal phototherapy and future risk of clinically significant hemangioma. METHODS: We analysed a cohort of 678 879 infants born after 34 weeks gestation comprising 3 975 242 person-years of follow-up over 11 years (2006-2016). The exposure was phototherapy the first 28 days of life. The outcome was hemangioma that required in-hospital treatment during follow-up. We estimated hazard ratios (HR) and 95% confidence intervals (CI) for the association of phototherapy with risk of hemangioma, accounting for preterm birth, low birthweight and congenital anomalies. RESULTS: The incidence of hemangioma was greater in neonates who received phototherapy than in untreated infants, but there was no association in adjusted models (HR 1.19, 95% CI 0.89-1.58). Risk of hemangioma was elevated in infants who received phototherapy and were born late preterm (HR 2.35, 95% CI 1.51-3.64), with low birthweight (HR 1.91, 95% CI 1.12-3.24), or with anomalies (HR 5.09, 95% CI 3.42-7.58). Without phototherapy, these three risk factors were more weakly associated with hemangioma. CONCLUSION: Neonatal phototherapy in infants with predisposing risk factors may increase the chance of hemangioma, but confirmation in further studies is needed.

Standard Period Life Table Used to Compute the Life Expectancy of Diseased Subpopulations: More Confusing Than Helpful.

Life expectancy (LE) based on a period life table (PLT) traditionally serves as a general population summary metric. It is, however, becoming more frequently reported for chronically afflicted subpopulations. In general populations, there is always an obvious real cohort sharing the hypothetical PLT cohort characteristics, and the LE estimate is intuitively understood as that real cohort mean survival time, assuming constancy of death risks. In diseased subpopulations, the correspondence between the hypothetical cohort and a real cohort is not straightforward. Furthermore, the excess mortality of chronic diseases usually changes according to age at onset and time since onset. The standard PLT method does not allow for proper control of these issues, so the LE estimate can only be deemed valid under specific assumptions. Without clear statements about the real cohort to whom the estimate is intended and the assumptions allowing disregard of the effect of age at onset and time since onset, LEs of afflicted subpopulations computed with the PLT are only abstract numbers summarizing mortality rates. If called "life expectancy," they can be seriously misleading. The same applies to health-adjusted LE.

Language and unintentional injury mortality in Quebec, Canada.

Language-based differences in unintentional injury are poorly understood, despite the importance of language as a determinant of health. This study assessed inequalities in unintentional injury mortality between Francophones and Anglophones of Quebec, Canada. We calculated age-standardised rates of death by period, region, residential deprivation and cause of injury, and estimated rate ratios for Francophones relative to Anglophones. Francophones had higher unintentional injury mortality rates than Anglophones. Inequalities decreased over time for men, but rates remained 50% higher for Francophones at the end of the study period. Rates were stable for women, but were 30% higher for Francophones compared with Anglophones. Inequalities were larger at age 15-44 years, in urban areas, and for MVCs. Better understanding of risk factors for MVCs may benefit injury prevention in Quebec. Language-based differences in injury mortality warrant attention in other multilingual populations, especially across different demographic, temporal, regional and cause-of-injury groups.

The Canadian systemic sclerosis oral health study II: the relationship between oral and global health-related quality of life in systemic sclerosis.

OBJECTIVE: Both oral and global health-related quality of life (HRQoL) are markedly impaired in SSc. In this study we aimed to determine the degree of association between oral HRQoL and global HRQoL in SSc. METHODS: Subjects were recruited from the Canadian Scleroderma Research Group registry. Global HRQoL was measured using the Medical Outcomes Trust 36-item Short Form Health Survey (SF-36) and oral HRQoL with the Oral Health Impact Profile (OHIP). The Medsger Disease Severity Score was used to determine organ involvement. Multivariate regression models determined the independent association of the OHIP with the SF-36 after adjusting for confounders. RESULTS: This study included 156 SSc subjects. The majority (90%) were women, with a mean age of 56 years, mean disease duration 13.8 years (s.d. 8.5) and 29% of the subjects had dcSSc. Mean total OHIP score was 40.8 (s.d. 32.4). Mean SF-36 mental component summary (MCS) score was 49.7 (s.d. 11.1) and physical component summary (PCS) score was 37.0 (s.d. 10.7). In adjusted analyses, the total OHIP score was significantly associated with the SF-36 MCS and PCS, accounting for 9.7% and 5.6% of their respective variances. Measures of disease severity were not related to OHIP score. CONCLUSION: Oral HRQoL in SSc is independently associated with global HRQoL. Oral HRQoL, however, is not related to physician-assessed disease severity. This suggests that physicians may be disregarding issues related to oral health. HRQoL is an additional dimension of HRQoL not captured by generic instruments such as the SF-36.

The Relationship Between Apparent Temperature and Daily Number of Live Births in Montreal.

OBJECTIVES: Temperature is a hypothesized determinant of early delivery, but seasonal and long term trends, delayed effects of temperature, and the influence of extreme cold temperatures have not yet been addressed. We aim to study the influence of apparent temperature on daily number of births, considering lag structures, seasonality and long term trends. METHODS: We used daily number of births in conjunction with apparent outdoor temperatures between 1981 and 2010 in Montreal. We used Poisson regression combined with a distributed lag nonlinear model to consider non-linear relationships between temperature and daily number of births across specific lag periods. RESULTS: We found that apparent temperature was associated with the daily number of births in Montreal, with a 1-day delay. We found an increase in births on hot days, and decrease on cold days, both offset by a harvesting effect after 4 and 5 days. CONCLUSIONS FOR PRACTICE: This study suggests that the number of births is affected by extreme temperatures. Obstetric and perinatal service providers should be prepared for spikes in the number of births caused by extreme temperatures.

Extreme heat and risk of early delivery among preterm and term pregnancies.

BACKGROUND: The relationship between ambient temperature and risk of delivery is poorly understood. We examined the association between heat and risk of delivery among preterm and term pregnancies with the use of a time-to-event design to minimize bias from seasonal variation in conception rates. METHODS: We used data on 206,929 term and 12,390 preterm singleton live births for Montreal, Canada, from June through September, 1981-2010. The exposure variables were (1) maximum daily temperatures in the week preceding birth and (2) number of consecutive days with temperatures of 32°C or above during the preceding week. We estimated hazards of delivery among preterm (<37 gestational weeks), early-term (37-38 weeks), and full-term (≥39 weeks) pregnancies for both exposures in Cox regression models, adjusting for maternal characteristics. Sensitivity analyses were carried out adjusting for markers of air pollution. RESULTS: Maximum temperatures reached at least 32°C during the preceding week for 19,829 births (9.0%). Relative to a maximum of 20°C, the hazard of delivery within term was 4% higher for maximum temperatures of 32°C or higher, but no association was found for preterm delivery. Associations were stronger with early-term than with full-term delivery. Extreme heat episodes with 4 to 7 days of maximum temperature of at least 32°C were associated with a 27% greater hazard of delivery among early-term pregnancies relative to other days. CONCLUSION: High ambient temperature and extreme heat episodes may trigger earlier delivery among term births.

The Canadian systemic sclerosis oral health study: orofacial manifestations and oral health-related quality of life in systemic sclerosis compared with the general population.

OBJECTIVE: The aim of this study was to compare oral abnormalities and oral health-related quality of life (HRQoL) of patients with SSc with the general population. METHODS: SSc patients and healthy controls were enrolled in a multisite cross-sectional study. A standardized oral examination was performed. Oral HRQoL was measured with the Oral Health Impact Profile (OHIP). Multivariate regression analyses were performed to identify associations between SSc, oral abnormalities and oral HRQoL. RESULTS: We assessed 163 SSc patients and 231 controls. SSc patients had more decayed teeth (SSc 0.88, controls 0.59, P = 0.0465) and periodontal disease [number of teeth with pocket depth (PD) >3 mm or clinical attachment level (CAL) ≥5.5 mm; SSc 5.23, controls 2.94, P < 0.0001]. SSc patients produced less saliva (SSc 147.52 mg/min, controls 163.19 mg/min, P = 0.0259) and their interincisal distance was smaller (SSc 37.68 mm, controls 44.30 mm, P < 0.0001). SSc patients had significantly reduced oral HRQoL compared with controls (mean OHIP score: SSc 41.58, controls 26.67, P < 0.0001). Multivariate regression analyses confirmed that SSc was a significant independent predictor of missing teeth, periodontal disease, interincisal distance, saliva production and OHIP scores. CONCLUSION: Subjects with SSc have impaired oral health and oral HRQoL compared with the general population. These data can be used to develop targeted interventions to improve oral health and HRQoL in SSc.

Projection scenarios of body mass index (2013-2030) for Public Health Planning in Quebec.

BACKGROUND: Projection analyses can provide estimates of the future health burden of increasing BMI and represent a relevant and useful tool for public health planning. Our study presents long-term (2013-2030) projections of the prevalence and numbers of individuals by BMI category for adult men and women in Quebec. Three applications of projections to estimate outcomes more directly pertinent to public health planning, as well as an in-depth discussion of limits, are provided with the aim of encouraging greater use of projection analyses by public health officers. METHODS: The weighted compositional regression method is applied to prevalence time series derived from sixteen cross-sectional survey cycles, for scenarios of linear change and deceleration. Estimation of the component of projected change potentially amenable to intervention, future health targets and the projected impact on type 2 diabetes, were done. RESULTS: Obesity prevalence in Quebec is projected to rise steadily from 2013 to 2030 in both men (from 18.0-19.4% to 22.2-30.4%) and women (from 15.5-16.3% to 18.2-22.4%). Corresponding projected numbers of obese individuals are (579,000-625,000 to 790,000-1,084,000) in men and (514,000-543,000 to 661,000-816,000) in women. These projected increases are found to be primarily an 'epidemiologic' rather than 'demographic' phenomenon and thus potentially amenable to public health intervention. Assessment of obesity targets for 2020 illustrates the necessity of using projected rather than current prevalence; for example a targeted 2% drop in obesity prevalence relative to 2013 translates into a 3.6-5.4% drop relative to 2020 projected levels. Type 2 diabetes is projected to increase from 6.9% to 9.2-10.1% in men and from 5.7% to 7.1-7.5% in women, from 2011-2012 to 2030. A substantial proportion of this change (25-44% for men, and 27-43% for women) is attributable to the changing BMI distribution. CONCLUSIONS: Obesity in Quebec is projected to increase and should therefore continue to be a public health priority. Application of projections to estimate the proportion of change potentially amenable to intervention, feasible health targets, and future chronic disease prevalence are demonstrated. Projection analyses have limitations, but represent a pertinent tool for public health planning.

Neighborhood-level vaccine impact on COVID-19 infection and hospital admission in Quebec, Canada, during the Delta and early Omicron periods.

OBJECTIVE: To assess the impact of COVID-19 vaccination on COVID-19 infection and hospitalisation at the population-level, and to assess the indirect effects of vaccination in the province of Quebec, Canada. METHODS: We performed a time-stratified, neighborhood-level ecologic study. The exposure was neighborhood-level vaccination (primary series) coverage; outcomes were COVID-19 infection and hospitalisation rates. We used robust Poisson regression to estimate weekly relative rates of infection and hospitalisation versus vaccination. RESULTS: Higher vaccination coverage was associated with lower COVID-19 infection rates from July 18-December 4 for the year 2021 (Delta period) (RR≈0.46 [0.39; 0.54] - 0.94 [0.83; 1.05], 85-100% vs. 60-74% coverage). From December 5-December 25, this association reversed (RR≈1.28 [1.16; 1.41] - 1.41 [1.31; 1.52]), possibly due to the Omicron variant, social behaviors and accumulation of susceptibles in more vaccinated neighborhoods. Vaccine impact against hospitalisation was maintained throughout (RR≈0.43 [0.29; 0.65] - 0.88 [0.64; 1.22]). Vaccination provided substantial indirect protection (RR≈0.43 [0.34; 0.54] - 0.81 [0.65; 1.03]). CONCLUSIONS: This study confirmed the protective impact of vaccination against severe disease regardless of variant, at the population level. Ecological analyses are a valuable strategy to evaluate vaccination programs. Population-level effects can have substantial effects and should be accounted for in public health and vaccination program planning.

Are changes in patient-reported outcomes prognostic for diffuse large B-Cell lymphoma survival? Results from the GOYA trial.

In this hypothesis-generating analysis, we examined whether longitudinal changes in patient-reported outcomes (PROs), such as symptoms, over time would be prognostic for progression-free survival (PFS) and overall survival (OS) in patients with diffuse large B-cell lymphoma (DLBCL) who were newly treated with obinutuzumab (G) in combination with CHOP (G-CHOP) or rituximab (R) with CHOP (R-CHOP), in the GOYA Phase 3 trial (NCT01287741). Our results show that from the study baseline to cycle 3 day 1, every 1-point increase (worsening) in fever symptoms was associated with a 41% higher risk of death (hazard ratio [HR], 1.41; P = 0.01). Every 1-point increase (worsening) in lumps or swelling symptoms was associated with a 27% higher risk of disease progression or death (PFS events) (HR, 1.27; P = 0.01) and a 29% higher risk of death (OS events) (HR, 1.29; P = 0.02). No significant associations were observed between survival and changes in other symptoms, such as itching. Our study suggests that changes in some PROs are related to survival in DLBCL patients.

Evolution of illness severity in hospital admissions due to COVID-19, Québec, Canada, January to April 2022.

Background: The coronavirus disease 2019 (COVID-19) severity is influenced by multiple factors, such as age, underlying medical conditions, individual immunity, infecting variant, and clinical practice. The highly transmissible Omicron variants resulted in decreased COVID-19 screening capacity, which limited disease severity surveillance. Objective: To report on the temporal evolution of disease severity among patients admitted to Québec hospitals due to COVID-19 between January 2, 2022, and April 23, 2022, which corresponded to the peak period of hospitalizations due to Omicron. Methods: Retrospective population-based cohort study of all hospital admissions due to COVID-19 in Québec, between January 2, 2022, and April 23, 2022. Study period was divided into four-week periods, corresponding roughly to January, February, March and April. Regression using Cox and Poisson generalized estimating equations (GEEs) was used to quantify temporal variations in length of stay and risk of complications (intensive care admission or in-hospital death) through time, using the Omicron peak (January 2022) as reference. Measures were adjusted for age, sex, vaccination status, presence of chronic diseases, and clustering by hospital. Results: During the study period, 9,178 of all 18,272 (50.2%) patients hospitalized with a COVID-19 diagnosis were admitted due to COVID-19. Of these, 1,026 (11.2%) were admitted to intensive care and 1,523 (16.6%) died. Compared to January, the risk of intensive care admission was 25% and 31% lower in March and April respectively, while in-hospital fatality continuously decreased by 45% lower in April. The average length of stay was temporarily lower in March (9%). Conclusion: Severity of admissions due to COVID-19 decreased in the first months of 2022, when predominant circulating variants were considered to be of similar severity. Monitoring hospital admissions due to COVID-19 can contribute to disease severity surveillance.

Moving in pain - A preliminary study evaluating the immediate effects of experimental knee pain on locomotor biomechanics.

Pain changes how we move, but it is often confounded by other factors due to disease or injury. Experimental pain offers an opportunity to isolate the independent effect of pain on movement. We used cutaneous electrical stimulation to induce experimental knee pain during locomotion to study the short-term motor adaptions to pain. While other models of experimental pain have been used in locomotion, they lack the ability to modulate pain in real-time. Twelve healthy adults completed the single data collection session where they experienced six pain intensity conditions (0.5, 1, 2, 3, 4, 5 out of 10) and two pain delivery modes (tonic and phasic). Electrodes were placed over the lateral infrapatellar fat pad and medial tibial condyle to deliver the 10 Hz pure sinusoid via a constant current electrical stimulator. Pain intensity was calibrated prior to each walking bout based on the target intensity and was recorded using an 11-point numerical rating scale. Knee joint angles and moments were recorded over the walking bouts and summarized in waveform and discrete outcomes to be compared with baseline walking. Knee joint angles changed during the swing phase of gait, with higher pain intensities resulting in greater knee flexion angles. Minimal changes in joint moments were observed but there was a consistent pattern of decreasing joint stiffness with increasing pain intensity. Habituation was limited across the 30-90 second walking bouts and the electrical current needed to deliver the target pain intensities showed a positive linear relationship. Experimental knee pain shows subtle biomechanical changes and favourable habituation patterns over short walking bouts. Further exploration of this model is needed in real-world walking conditions and over longer timeframes to quantify motor adaptations.

Intensity quantile estimation and mapping--a novel algorithm for the correction of image non-uniformity bias in HCS data.

MOTIVATION: Image non-uniformity (NU) refers to systematic, slowly varying spatial gradients in images that result in a bias that can affect all downstream image processing, quantification and statistical analysis steps. Image NU is poorly modeled in the field of high-content screening (HCS), however, such that current conventional correction algorithms may be either inappropriate for HCS or fail to take advantage of the information available in HCS image data. RESULTS: A novel image NU bias correction algorithm, termed intensity quantile estimation and mapping (IQEM), is described. The algorithm estimates the full non-linear form of the image NU bias by mapping pixel intensities to a reference intensity quantile function. IQEM accounts for the variation in NU bias over broad cell intensity ranges and data acquisition times, both of which are characteristic of HCS image datasets. Validation of the method, using simulated and HCS microtubule polymerization screen images, is presented. Two requirements of IQEM are that the dataset consists of large numbers of images acquired under identical conditions and that cells are distributed with no within-image spatial preference. AVAILABILITY AND IMPLEMENTATION: MATLAB function files are available at http://nadon-mugqic.mcgill.ca/.