Marian J Vermeulen

Institute for Clinical Evaluative Sciences | ICES

IntroductionHealth care systems have faced unprecedented challenges due to the COVID-19 pandemic. Access to timely population-based data has been vital to informing public health policy and practice. Methods We describe how ICES, an independent not-for-profit research and analytic institute in Ontario, Canada, pivoted existing research infrastructu...

It is not known whether non-ABO antibodies confers any protective effect against SARS-CoV-2 infection or COVID-19 severe illness, alone, or in conjunction with O blood group. This cohort study included 413,576 persons in Ontario, Canada with known ABO blood group and non-ABO antibody screen status, and who subsequently underwent SARS-CoV-2 viral RN...

Background: The ABO and rhesus (Rh) blood groups may influence risk for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Objective: To determine whether ABO and Rh blood groups are associated with risk for SARS-CoV-2 infection and severe coronavirus disease 2019 (COVID-19) illness. Design: Population-based cohort study....

Objectives To determine the long-term trajectories of health system use by persons with dementia as they remain in the community over time. Design Population-based cohort study using health administrative data. Setting Ontario, Canada from 1 April 2007 to 31 March 2014. Participants 62 622 community-dwelling adults aged 65+ years with prevalent...

ICES was founded in 1992 to study the health care system and promote effective, efficient and equitable health care. Over 27 years later, the goal remains largely unchanged, though the institute has grown in size and impact. Created as an independent not-for-profit research institute and given what was, at the time, unprecedented access to administ...

Health systems strive to enable persons with Alzheimer’s and related dementias to remain at home to maximize their quality of life. There is limited evidence describing long-term trajectories of health system use by persons with dementia as they remain in the community over time. A cohort of 62,622 community-dwelling older adults was followed for s...

Objectives: Evidence is mixed regarding the impact of false-positive (FP) newborn bloodspot screening (NBS) results on health care use. Using cystic fibrosis (CF) as an example, we determined the association of FP NBS results with health care use in infants and their mothers in Ontario, Canada. Methods: We conducted a population-based cohort stu...

Objective Efforts to enable persons with dementia to remain at home longer, and to reduce use of costly acute care resources, are at the forefront of policy agendas internationally. Foundational to planning appropriate health system supports is the ongoing, comparable and accurate estimation of the prevalence and incidence of dementia across region...

Objectives There is a growing need to broaden access to administrative health data in order to support decision making and planning by health system stakeholders. An initiative funded by the Ontario Ministry of Health and Long-Term Care, the Applied Health Research Question (AHRQ) portfolio leverages the linked administrative health data holdings a...

Background: Antibiotic stewardship is a required organizational practice for Canadian acute care hospitals, yet data are scarce regarding the quantity and composition of antibiotic use across facilities. We sought to examine the variability, and risk-adjusted variability, in antibiotic use across acute care hospitals in Ontario, Canada's most popu...

Importance: Fetal safety of magnetic resonance imaging (MRI) during the first trimester of pregnancy or with gadolinium enhancement at any time of pregnancy is unknown. Objective: To evaluate the long-term safety after exposure to MRI in the first trimester of pregnancy or to gadolinium at any time during pregnancy. Design, setting, and partici...

The Institute for Clinical Evaluative Sciences (ICES) is one of only a few organizations in Ontario permitted to access, link and analyze health administrative data for the purpose of generating evidence to inform decisions in policy and practice. Although ICES is a leading research institute, its access to the data has historically been restricted...

Objectives: To evaluate maternal world region of birth, as well as maternal country of origin, and the associated risk of admission of 1) a mother to a maternal ICU, 2) her infant to a neonatal ICU, or 3) both concurrently to an ICU. Design: Retrospective population-based cohort study. Setting: Entire province of Ontario, Canada, from 2003 to...

Background Emergency department (ED) crowding has been associated with adverse events, including short-term death and hospitalization among discharged patients. The mechanisms are poorly understood, but may include altered physician decision-making about ED discharge of higher-risk patients. One example is patients with transient ischemic attack (T...

We sought to determine whether patients seen in hospitals who had reduced overall emergency department (ED) length of stay (LOS) in the 2 years following the introduction of the Ontario Emergency Room Wait Time Strategy were more likely to experience improvements in other measures of ED quality of care for three important conditions. Retrospective...

In 2008, a pay-for-performance program was implemented in sequential waves in Ontario emergency departments (EDs), with the aim of reducing length of stay. We seek to evaluate its effects on ED length of stay and quality of care. This was a retrospective observational study of ED visits in Ontario from April 1, 2007, to March 31, 2011, using multiv...

Introduction Emergency department (ED) crowding is associated with adverse outcomes. Several jurisdictions have established benchmarks and targets for length-of-stay (LOS) to reduce crowding. An evaluation has been conducted on whether performance on Ontario's ED LOS benchmarks is associated with reduced risk of death or hospitalization. A retrospe...

Objectives: In recent years, Lean manufacturing principles have been applied to health care quality improvement efforts to improve wait times. In Ontario, an emergency department (ED) process improvement program based on Lean principles was introduced by the Ministry of Health and Long-Term Care as part of a strategy to reduce ED length of stay (L...

White BA, Chang Y, Grabowski B G. Using Lean-Based Systems Engineering to Increase Capacity in the Emergency Department. West J Emerg Med. 2014;15(7):770–776. To the editor: We read with interest the article by White et al., “Using Lean-Based Systems Engineering to Increase Capacity in the Emergency Department,” in which the authors conclude that...

Early diagnosis of children with meningitis or septicemia remains a significant challenge in emergency medicine. We seek to describe the frequency of repeated emergency department (ED) visits among children admitted with meningitis or septicemia in Ontario, Canada. In this retrospective cohort study, using health administrative data, we included al...

Study objective In recent years, lean principles have been applied to improve wait times in the emergency department (ED). In 2009, an ED process improvement program based on lean methods was introduced in Ontario as part of a broad strategy to reduce ED length of stay and improve patient flow. This study seeks to determine the effect of this progr...

Background Cerebral palsy (CP) has a multifactorial etiology, and placental vascular disease may be one major risk factor. The risk of placental vascular disease may be lower among some immigrant groups. We studied the association between immigrant status and the risk of CP. Methods We conducted a population-based retrospective cohort study of all...

Background Low socioeconomic status (SES) is associated with adverse health outcomes. Possible explanations include differences in health status, access to health care, and care provided by clinicians. We sought to determine whether SES is associated with computed tomography (CT) use in the emergency department (ED). Methods A retrospective cohort...

Study objective: We compare secular trends in computed tomography (CT) utilization in emergency departments (EDs) in the United States and Ontario, Canada. Methods: Using a systematic survey in the US (The National Hospital Ambulatory Medical Care Survey) and administrative databases in Ontario, we performed a retrospective study of ED visits fr...

Background: Low socioeconomic status (SES) is associated with adverse health outcomes. Possible explanations include differences in health status, access to health care, and care provided by clinicians. We sought to determine whether SES is associated with computed tomography (CT) use in the emergency department (ED). Methods: A retrospective co...

Background: Concurrent admission of a mother and her newborn to separate intensive care units (herein referred to as co-ICU admission), possibly in different centres, can magnify family discord and stress. We examined the prevalence and predictors of mother-infant separation and mortality associated with co-ICU admissions. Methods: We completed...

To evaluate the effect of emergency department (ED) clinical decision units (CDUs) on overall ED patient flow in a pilot project funded in 2008 by the Ontario Ministry of Health and Long-Term Care (MOHLTC). A retrospective analysis of unscheduled ED visits at seven CDU pilot and nine control sites was conducted using administrative data. The author...

Background: The role of public reporting in improving hospital quality of care is controversial. Reporting of hospital-acquired infection rates has been introduced in multiple health care systems, but its relationship to infection rates has been understudied. Our objective was to determine whether mandatory public reporting by hospitals is associa...

Maternal placental syndromes (MPS)-gestational hypertension, pre-eclampsia and placental abruption/infarction-are more prevalent in women with features of the metabolic syndrome (MetSyn). Both MPS and the MetSyn predispose to left ventricular impairment and sympathetic dominance after delivery. Whether this translates into a higher risk of heart fa...

In Ontario, clinical decision units (CDUs) were implemented as a pilot project in 2008 by the Ministry of Health and Long-Term Care as part of its strategy to reduce emergency department (ED) waiting times. Our objective was to describe general characteristics of the program at each of the participating sites and to examine barriers and facilitator...

The evaluation of emergency department (ED) quality of care is hampered by the absence of consensus on appropriate measures. We sought to develop a consensus on a prioritized and parsimonious set of evidence-based quality of care indicators for EDs. The process was led by a nationally representative steering committee and expert panel (representati...

Practice pattern variations are often attributed to physician decision-making with no accounting for patient preferences. To test whether a mass media television broadcast unrelated to health was associated with changes in the rate and characteristics of visits for acute emergency care. Time-series analysis of emergency department visits for any re...

Appendix: Supplementary tables of full model results

To determine whether patients who are not admitted to hospital after attending an emergency department during shifts with long waiting times are at risk for adverse events. Population based retrospective cohort study using health administrative databases. Setting High volume emergency departments in Ontario, Canada, fiscal years 2003-7. All emergen...

Diagnostic and procedural codes used to identify the cohort, comorbidity, and outcome features. (0.03 MB DOC)

Codes used to identify inpatient or outpatient major radiodiagnostic imaging (for the study exposure) as well as outpatient prenatal ultrasonography. (0.04 MB DOC)

Characteristics of mothers and their infants who were exposed to a major radiodiagnostic testing in pregnancy and who were included or excluded from the study. (0.04 MB DOC)

The association between fetal exposure to major radiodiagnostic testing in pregnancy-computed tomography (CT) and radionuclide imaging-and the risk of childhood cancer is not established. We completed a population-based study of 1.8 million maternal-child pairs in the province of Ontario, from 1991 to 2008. We used Ontario's universal health care-l...

Timely reperfusion therapy for ST-elevation myocardial infarction (STEMI) is an important determinant of outcome, yet targets for time to treatment are frequently unmet in North America. Prehospital strategies can reduce time to reperfusion. We sought to determine the extent to which emergency medical services (EMS) use these strategies in Canada....

Most patients are admitted to the hospital through the emergency department (ED), and ED waiting times partly reflect the availability of inpatient beds. We test whether the balance between daily hospital admissions and discharges affects next-day ED length of stay. We conducted a cross-sectional study of hospitals in metropolitan Toronto, served b...

While elevated maternal weight in early pregnancy is associated with a higher rate of preeclampsia, the risk of placental abruption and placental infarction is unknown. We evaluated the risk of placental abruption, placental infarction, and preeclampsia in association with maternal weight quintile at approximately 17 weeks' gestation in 386 323 wom...

Restrictions on non-urgent hospital care imposed to control the 2003 Toronto severe acute respiratory syndrome outbreak led to substantial disruptions in hospital clinical practice, admission, and transfer patterns. We assessed whether there were unintended health consequences to seriously ill hospitalized patients. STUDY DESIGN, SETTING, AND POPUL...

Acanthosis nigricans (AN) is a cutaneous manifestation of insulin resistance (1). Among women with gestational diabetes mellitus (GDM), it is not known whether AN is associated with greater need for insulin therapy in pregnancy or adverse perinatal outcomes. We performed a prospective cohort study of consecutive women with GDM or impaired glucose...

To evaluate the feasibility of a prehospital randomized controlled trial comparing transcutaneous pacing (TCP) with dopamine for unstable bradycardia. Unstable bradycardic patients who failed to respond to a fluid bolus and up to 3mg atropine were enrolled. The intervention was dopamine or TCP with crossover to dopamine if TCP failed. The primary o...

Maternal diabetes before pregnancy is associated with adverse maternal and perinatal outcomes, including acquired hypertension during pregnancy (1,2,3). The maternal placental syndromes preeclampsia and abruption or infarction of the placenta (4) are also more prevalent in women with insulin resistance, diabetes, and the metabolic syndrome (3,5–8)....

Question: I knew that angiotensin-converting enzyme (ACE) inhibitors were risky to use during late pregnancy because they can cause renal shutdown in the fetus. Recently I heard of a study that claimed first-trimester exposure (when many patients still are unaware of their pregnancies) can also cause major malformations. Is this proven? Answer:...

To derive and validate an International Classification of Diseases-10 (ICD-10) version of the Ontario Acute Myocardial Infarction (AMI) mortality prediction rules, used to adjust for case-mix differences in studies of AMI patients using administrative data. We linked the records of all Ontario patients admitted with AMI (2002-2004) with mortality d...

Maternal obesity and pre-pregnancy diabetes mellitus, features of the metabolic syndrome (MetSyn), are individual risk factors for neural tube defects (NTD). Whether they, in combination with additional features of MetSyn, alter this risk is not known. We evaluated the risk of NTD in association with maternal features of the MetSyn. We used a popul...

Objectives: The primary aim was to derive a new termination of resuscitation (TOR) clinical prediction rule for advanced life support paramedics (ALS) and to measure both its pronouncement rate and diagnostic test characteristics. Secondary aims included measuring the test characteristics of a previously derived and published basic life support te...

Substance use in pregnancy is associated with placental abruption, but the risk of fetal death independent of abruption remains undetermined. Our objective was to examine the effect of maternal drug dependence on placental abruption and on fetal death in association with abruption and independent of it. To examine placental abruption and fetal deat...

This study evaluates inter-rater reliability and comfort of BLS providers with the application of an out-of-hospital Basic Life Support Termination of Resuscitation (BLS TOR) clinical prediction rule. This rule suggests that continued BLS cardiac resuscitation is futile and can be terminated in the field if the following three conditions are met: (...

Restrictions on the nonurgent use of hospital services were imposed in March 2003 to control an outbreak of severe acute respiratory syndrome (SARS) in Toronto, Ont. We describe the impact of these restrictions on health care utilization and suggest lessons for future epidemics. We performed a retrospective population-based study of the Greater Tor...

The current crisis in the emergency care system is characterized by worsening emergency department (ED) overcrowding. Lack of health insurance is widely perceived to be a major contributing factor to ED overcrowding in the United States. This study aimed to compare ED visit rates in the United States and Ontario, Canada, according to demographic an...

People who immigrate to Western nations may experience fewer chronic health problems than original residents of those countries, which raises concerns about long-term environmental or lifestyle factors in those countries. We tested whether the "healthy immigrant effect" extends to the risk of placental dysfunction during the short interval of pregn...

Low maternal vitamin B(12) status may be a risk factor for neural tube defects (NTDs). Prior studies used relatively insensitive measures of B(12), did not adjust for folate levels, and were conducted in countries without folic acid food fortification. In Canada, flour has been fortified with folic acid since mid-1997. We completed a population-bas...

Subarachnoid hemorrhage (SAH) can be devastating, yet its initial presentation may be limited to common symptoms and subtle signs, potentially leading to misdiagnosis. Little is known about population rates of misdiagnosis of SAH, or hospital factors that may contribute to it. We estimated the population-based rate of missed SAH among emergency dep...

Comparisons of outcomes between patients treated and untreated in observational studies may be biased due to differences in patient prognosis between groups, often because of unobserved treatment selection biases. To compare 4 analytic methods for removing the effects of selection bias in observational studies: multivariable model risk adjustment,...

Missed diagnosis of acute myocardial infarction is associated with adverse clinical outcomes and more dollars recovered in malpractice suits than any other condition. The rate of missed diagnosis varies between emergency departments (EDs); we hypothesized that it is associated with the volume of acute myocardial infarction patients treated in an ED...

Background: Current influenza pandemic models predict a surge in influenza-related hospitalizations in affected jurisdictions. One proposed strategy to increase hospital surge capacity is to restrict elective hospitalizations, yet the degree to which this measure would meet the anticipated is unknown. Objectives: To compare the reduction in hosp...

We prospectively evaluated a clinical prediction rule to be used by emergency medical technicians (EMTs) trained in the use of an automated external defibrillator for the termination of basic life support resuscitative efforts during out-of-hospital cardiac arrest. The rule recommends termination when there is no return of spontaneous circulation,...

Efforts to control an outbreak of severe acute respiratory syndrome (SARS) in Toronto, Canada, led to the imposition of major restrictions on nonurgent use of hospital-based services. To describe a methodology to determine the impact of the restrictions on healthcare utilization. DESIGN, SETTING, POPULATION: Population-based study of the Greater To...

Placental dysfunction (PD), which may manifest partly as the hypertensive disorders of pregnancy and abruption or infarction of the placenta, occurs more commonly in women with obesity, chronic hypertension, diabetes mellitus, and dyslipidemia-each a major feature of the metabolic syndrome. However, the relationship between the metabolic syndrome a...

Maternal placental syndromes, including the hypertensive disorders of pregnancy and abruption or infarction of the placenta, probably originate from diseased placental vessels. The syndromes arise most often in women who have metabolic risk factors for cardiovascular disease, including obesity, pre-pregnancy hypertension, diabetes mellitus, and dys...

Women who are homeless during pregnancy may be exposed to poor nutrition, violence and substance use, yet the health status of their newborn infants has not been systematically evaluated. We undertook a study to provide preliminary estimates of the risk of adverse perinatal outcomes among Canadian women who are homeless or marginally housed during...

Current acute myocardial infarction (AMI) guidelines call for reperfusion to be given to all eligible patients within a set time interval after hospital arrival, yet current hospital performance benchmarks are based on the median door-to-intervention time among treated patients. Our objective is to compare hospital performance rankings when door-to...

Background: Although biphasic defibrillation waveforms appear to be superior to monophasic waveforms in terminating VF, their relative benefits in out-of-hospital resuscitation are incompletely understood. Prior comparisons of defibrillation waveform efficacy in out-of-hospital cardiac arrest (OHCA) are confined to patients presenting in a shockab...

Difficulty maintaining physician staffing in emergency departments (EDs) prompted the government of Ontario to offer alternate funding arrangements (AFAs) to replace fee-for-service remuneration for physicians working in EDs. To analyze the effect of AFAs on physician staffing and practice patterns. We obtained Ontario Health Insurance Program fee-...

Maternal obesity is likely a risk factor for neural tube defects (NTDs). By late 1997, it became mandatory in Canada that all refined wheat flour be fortified with folic acid. Because overweight women may consume greater quantities of refined wheat flour, we questioned whether their risk of NTD changed after flour fortification. A retrospective pop...

To measure the patient access time interval and characterize its contribution to the total emergency medical services (EMS) response time interval; to compare the patient access time intervals for patients located three or more floors above ground with those less than three floors above or below ground, and specifically in the apartment subgroup; a...

We estimate the effect of emergency department (ED) crowding on door-to-needle time for patients given intravenous thrombolysis for suspected acute myocardial infarction. This was a retrospective observational study of patients thrombolyzed in the ED for suspected acute myocardial infarction in 1998 to 2000 in 25 community and teaching hospital EDs...

Most studies comparing women with and without pregestational diabetes mellitus have not systematically screened for fetal anomalies in early pregnancy, potentially leading to selection bias. To evaluate the risk for certain congenital anomalies in women participating in an antenatal maternal screening program. Retrospective cohort study. We studied...

Maternal body mass and the presence of diabetes mellitus are probable risk factors for neural tube defects (NTDs). The association between maternal ethnicity and the risk of NTDs remains poorly understood, however. We performed a retrospective population-based study and included all women in Ontario who underwent antenatal maternal screening (MSS)...

Objectives: To estimate mortality rates and identify clinical variables associated with mortality among patients with hemodynamically unstable bradycardia in an urban emergency medical services (EMS) system. Methods:This was a retrospective study conducted in a large, urban EMS system. Adult non–cardiac arrest patients transported by advanced life...

To estimate mortality rates and identify clinical variables associated with mortality among patients with hemodynamically unstable bradycardia in an urban emergency medical services (EMS) system. This was a retrospective study conducted in a large, urban EMS system. Adult non-cardiac arrest patients transported by advanced life support paramedics f...

By January 1998, most of Canada's cereal grain products were being fortified with folic acid. Among 336963 women who underwent antenatal maternal serum screening, the prevalence of orofacial clefts did not change from before (1.15 per 1000) to after (1.21 per 1000) food fortification (prevalence ratio, 1.06; 95% confidence interval, 0.86-1.30).

This study examines the extent to which position in the occupational hierarchy is predictive of declines in perceived health status over a 48 month period in a representative sample of the Canadian labor force. We hypothesized that the proportion of workers reporting a decline in health status would be greater among persons in lower position in the...

Neuroblastoma, an embryonic tumor, is the second most common pediatric tumor and is the most prevalent extracranial solid tumor in children. Results of previous studies have suggested that maternal vitamin intake may decrease the risk of several childhood cancers. In January 1997, Canada began fortifying flour with folic acid for the prevention of...

The optimal management of symptomatic hypoglycemia in the prehospital setting remains uncertain, particularly in the absence of intravenous access (1,2). We performed an audit in Toronto, ON, Canada, and compared prehospital patient care outcomes following administration of oral glucose gel versus subcutaneous glucagon. For the city’s population of...

To estimate the associated risk of folate and vitamin B12 (B12) insufficiency, as well as vitamin repletion, following folic acid food fortification. Retrospective cross-sectional study over a 5-year period. Two large laboratory databases in the provinces of Ontario and British Columbia, Canada. Canadian women aged 65 years and over who underwent c...

To determine the effect of simultaneous ambulance diversion at multiple emergency departments (EDs) (gridlock) on transport delays for patients with chest pain. Retrospective data on consecutive ambulance patients with chest pain and the diversion status of EDs in Toronto were obtained from January 1998 to December 1999. Gridlock was calculated sep...

Polymorphisms of maternal genes responsible for normal folate metabolism may be associated with an increased risk of fetal trisomy 21. By January 1998, most of Canada's flour was being fortified with folic acid. We investigated whether the prevalence of antenatally and postnatally detected trisomy 21 changed before and after folic acid food fortifi...

Objectives: To determine the effect of simultaneous ambulance diversion at multiple emergency departments (EDs) (gridlock) on transport delays for patients with chest pain. Methods: Retrospective data on consecutive ambulance patients with chest pain and the diversion status of EDs in Toronto were obtained from January 1998 to December 1999. Gridlo...

The administration of antiplatelet drugs before coronary artery bypass graft surgery (CABG) is associated with an increased risk of major hemorrhage and related surgical reexploration. Little is known about the relative effect of combined clopidogrel and aspirin on blood product use around the time of CABG. We evaluated the associated risk between...

We determine the relationship between physician, nursing, and patient factors on emergency department use of ambulance diversion. Data were collected at 1 ED in Toronto, Ontario, Canada, on the duration of ambulance diversion during consecutive 8-hour intervals from January to December 1999 (intervals=1,095). By using time series methods, the assoc...

Emergency department overcrowding sometimes results in diversion of ambulances to other locations. We sought to determine the resulting prehospital delays for cardiac patients. Data on consecutive patients with chest pain who were transported to Toronto hospitals by ambulance were obtained for a 4-month period in 1997 and a 4-month period in 1999,...