Advanced imaging use and delays among inpatients with psychiatric comorbidity.

OBJECTIVE: To determine whether presence of a psychiatric comorbidity impacts use of inpatient imaging tests and subsequent wait times. METHODS: This was a retrospective cohort study of all patients admitted to General Internal Medicine (GIM) at five academic hospitals in Toronto, Ontario from 2010 to 2019. Exposure was presence of a coded psychiatric comorbidity on admission. Primary outcome was time to test, as calculated from the time of test ordering to time of test completion, for computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, or peripherally inserted central catheter (PICC) insertion. Multilevel mixed-effects models were used to identify predictors of time to test, and marginal effects were used to calculate differences in absolute units (h). Secondary outcome was the rate of each type of test included. Subgroup analyses were performed according to type of psychiatric comorbidity: psychotic, mood/anxiety, or substance use disorder. RESULTS: There were 196,819 GIM admissions from 2010to 2019. In 77,562 admissions, ≥1 advanced imaging test was performed. After adjusting for all covariates, presence of any psychiatric comorbidity was associated with increased time to test for MRI (adjusted difference: 5.3 h, 95% confidence interval [CI]: 3.9-6.8), PICC (adjusted difference: 3.7 h, 95% CI: 1.6-5.8), and ultrasound (adjusted difference: 3.0 h, 95% CI: 2.3-3.8), but not for CT (adjusted difference: 0.1 h, 95% CI: -0.3 to 0.5). Presence of any psychiatric comorbidity was associated with lower rate of ordering for all test types (adjusted difference: -17.2 tests per 100 days hospitalization, interquartile range: -18.0 to -16.3). CONCLUSIONS: There was a lower rate of ordering of advanced imaging among patients with psychiatric comorbidity. Once ordered, time to test completion was longer for MRI, ultrasound, and PICC. Further exploration, such as quantifying rates of cancelled tests and qualitative studies evaluating hospital, provider, and patient barriers to timely advanced imaging, will be helpful in elucidating causes for these disparities.

Imaging delays among medical inpatients in Toronto, Ontario: A cohort study.

BACKGROUND: Imaging procedures are commonly performed on hospitalized patients and waiting for these could increase length-of-stay. The study objective was to quantify delays for imaging procedures in General Internal Medicine and identify contributing patient, physician, and system factors. METHODS: This was a retrospective cohort study of medical inpatients admitted to 5 hospitals in Toronto, Ontario (2010-2019), with at least one imaging procedure (CT, MRI, ultrasound, or peripherally-inserted central catheter [PICC] insertion). The primary outcome was time-to-test, and the secondary outcome was acute length-of-stay after test ordering. RESULTS: The study cohort included 73,107 hospitalizations. Time-to-test was longest for MRI (median 22 hours) and shortest for CT (median 7 hours). The greatest contributors to time-to-test were system factors such as hospital site (up to 22 additional hours), location of test ordering (up to 10 additional hours), the timing of test ordering relative to admission (up to 13 additional hours), and ordering during weekends (up to 21 additional hours). Older patient age, having more comorbidities, and residence in a low-income neighborhood were also associated with testing delays. Each additional hour spent waiting for a test was associated with increased acute length-of-stay after test ordering, ranging from 0.4 additional hours for CT to 1.2 hours for MRI. CONCLUSIONS: The greatest contributors to testing delays relate to when and where a test was ordered. Wait times affect length-of-stay and the quality of patient care. Hospitals can apply our novel approach to explore opportunities to decrease testing delays locally.

Variation in the risk of death due to COVID-19: An international multicenter cohort study of hospitalized adults.

BACKGROUND: There is wide variation in mortality among patients hospitalized with COVID-19. Whether this is related to patient or hospital factors is unknown. OBJECTIVE: To compare the risk of mortality for patients hospitalized with COVID-19 and to determine whether the majority of that variation was explained by differences in patient characteristics across sites. DESIGN, SETTING, AND PARTICIPANTS: An international multicenter cohort study of hospitalized adults with laboratory-confirmed COVID-19 enrolled from 10 hospitals in Ontario, Canada and 8 hospitals in Copenhagen, Denmark between January 1, 2020 and November 11, 2020. MAIN OUTCOMES AND MEASURES: Inpatient mortality. We used a multivariable multilevel regression model to compare the in-hospital mortality risk across hospitals and quantify the variation attributable to patient-level factors. RESULTS: There were 1364 adults hospitalized with COVID-19 in Ontario (n = 1149) and in Denmark (n = 215). In Ontario, the absolute risk of in-hospital mortality ranged from 12.0% to 39.8% across hospitals. Ninety-eight percent of the variation in mortality in Ontario was explained by differences in the characteristics of the patients. In Denmark, the absolute risk of inpatients ranged from 13.8% to 20.6%. One hundred percent of the variation in mortality in Denmark was explained by differences in the characteristics of the inpatients. CONCLUSION: There was wide variation in inpatient COVID-19 mortality across hospitals, which was largely explained by patient-level factors, such as age and severity of presenting illness. However, hospital-level factors that could have affected care, including resource availability and capacity, were not taken into account. These findings highlight potential limitations in comparing crude mortality rates across hospitals for the purposes of reporting on the quality of care.

Estimating the Use of Potentially Inappropriate Medications Among Older Adults in the United States.

OBJECTIVES: Inappropriate prescribing of medications is common in health care, and is an important safety concern, especially for older adults, who have a high burden of comorbidity and are at greater risk for medication-related adverse events. This study aims to estimate the extent and cost of potentially inappropriate prescribing of medications to older adults in the United States. DESIGN: A cross-sectional study. SETTING: Medicare Part D Prescription Drug Program data set (2014-2018). PARTICIPANTS: Older adults who were enrolled in Medicare Part D Prescription Drug Program between 2014 and 2018. MEASUREMENTS: Potentially inappropriate medications were identified using the 2019 American Geriatrics Society Beers Criteria®. RESULTS: In 2018, 7.3 billion doses of potentially inappropriate medications were dispensed. The most common medications by number of doses dispensed were proton pump inhibitors, benzodiazepines, and tricyclic antidepressants, and the top five unique medications by reported spending were dexlansoprazole, esomeprazole, omeprazole, dronedarone, and conjugated estrogens. From 2014 to 2018, 43 billion doses of potentially inappropriate medications were dispensed, with a reported spending of $25.2 billion. CONCLUSION: Potentially inappropriate medication use among older adults is both common and costly. Careful attention to potentially inappropriate medication use and deprescribing when clinically appropriate could reduce costs and potentially improve outcomes among older adults.

Understanding when real world data can be used to replicate a clinical trial: A cross-sectional study of medications approved in 2011.

PURPOSE: To determine how commonly pre-approval clinical trials could potentially be replicated using real-world data from insurance claims databases. METHODS: We conducted a cross-sectional study of medications approved by the FDA in 2011. For each medication, we reviewed the drug's label and the details of the pivotal clinical trials supporting its approval. We assessed whether each clinical trial could be replicated using an insurance claims databases by determining whether the following pivotal trial features could be reliably captured in claims data: study outcome, inclusion criteria, exclusion criteria, and the presence of an appropriate active comparator. RESULTS: In 2011, 28 new medications were approved. The most common disease areas were oncology (N = 8, 29%), infectious disease (N = 5, 18%), and neurology (N = 4, 14%). The primary outcome of pre-approval clinical trials was identifiable in claims databases for six (21%) of the medications. Two (ticagrelor and linagliptin) had at least 80% of inclusion and exclusion criteria that could be identified in claims databases and had an available active comparator. The non-identifiable primary outcomes were related to patient-reported symptoms (N = 9, 32%), imaging findings (N = 5, 18%), laboratory values (N = 5, 18%), or other measurements (eg, blood pressure) not typically available in insurance claims databases (N = 4, 14%). CONCLUSIONS: Among drugs FDA-approved in 2011, two (7%) had a pre-approval trial that could be replicated using insurance claims databases. In such qualifying trials, replication using claims databases could be useful in assessing whether they provide concordant results.

Maternal schizophrenia and adverse birth outcomes: what mediates the risk?

PURPOSE: Maternal schizophrenia is associated with adverse birth outcomes, but the reasons for this remain unclear. In a population-based cohort of infants born to women with schizophrenia, we determined the occurrence of key perinatal outcomes and explored whether factors identifiable in our datasets explained any elevated risk. METHODS: Using population-level health administrative data linked to clinical birth-registry data in Ontario, Canada (2006-2011), we examined the relative risk (RR) of preterm birth (< 37 weeks), small for gestational age (SGA), and Apgar scores < 8 in infants of women with schizophrenia (n = 4279) versus infants of unaffected women (n = 286,147). Generalized estimating equations determined whether reproductive history, maternal health conditions, pregnancy exposures, and complications explained elevated RRs. RESULTS: Among infants of women with schizophrenia, risk was higher for prematurity (11.4% vs. 6.9%, aRR 1.64, 95% CI 1.51-1.79), SGA (3.5% vs. 2.5%, aRR 1.40, 95% CI 1.20-1.64), and Apgar score < 8 at 1 (19.0% vs. 12.8%, aRR 1.49, 95% CI 1.40-1.59) and 5 min (5.6% vs. 3.0%, aRR 1.90, 95% CI 1.68-2.16). Smoking, fourfold more common among women with schizophrenia, was the variable that explained the greatest proportion of the elevated aRR for prematurity (9.9%), SGA (28.7%), and Apgar < 8 at 1 and 5 min (9.8%, 5.6%). Illicit substance use, certain reproductive history variables, and pregnancy complications also contributed to the elevated aRR for preterm birth. CONCLUSIONS: Elevated risks of preterm birth, SGA, and low Apgar scores in infants of women with schizophrenia are partly explained by potentially modifiable factors such as smoking and illicit drug use, suggesting opportunities for targeted intervention.

Gastric Emptying of Low- and High-Caloric Liquid Meals Measured Using Ultrasonography in Healthy Volunteers.

PURPOSE: Delayed gastric emptying is present in patients with functional dyspepsia (FD), diabetes mellitus, and neurological diseases. Diet may affect gastric emptying symptoms in patients with FD. We sought to determine the extent to which gastric emptying and symptoms of dyspepsia are influenced by caloric content in healthy subjects using ultrasonography. MATERIALS AND METHODS: 32 healthy volunteers were given 2 meals with different caloric content in random order. Gastric emptying was determined using ultrasonography to measure antral area when fasting, and postprandially at intervals of 0, 10, 20, and 30 min. Dyspeptic symptoms including discomfort, nausea, and fullness were graded. RESULTS: The antral area following a high-caloric meal compared to a low-caloric meal was significantly increased at 0, 10, 20, and 30 min (P=0.0203,<0.0001<0.0001,<0.0001, respectively), as was the median fullness (P<0.0048, 0.0001, 0.0009, 0.0001, respectively) measured at the same time points. There was a weak correlation (r2=0.1, P<0.0001) between the antral area and subjective fullness. No differences between gastric emptying in males and females were found. CONCLUSION: The caloric content of a meal influences gastric emptying. Using ultrasonography to measure the antral area helps us to assess gastric emptying and therefore to assess patients with functional dyspepsia.

Infant feeding practices within a large electronic medical record database.

BACKGROUND: The emerging adoption of the electronic medical record (EMR) in primary care enables clinicians and researchers to efficiently examine epidemiological trends in child health, including infant feeding practices. METHODS: We completed a population-based retrospective cohort study of 8815 singleton infants born at term in Ontario, Canada, April 2002 to March 2013. Newborn records were linked to the Electronic Medical Record Administrative data Linked Database (EMRALD™), which uses patient-level information from participating family practice EMRs across Ontario. We assessed exclusive breastfeeding patterns using an automated electronic search algorithm, with manual review of EMRs when the latter was not possible. We examined the rate of breastfeeding at visits corresponding to 2, 4 and 6 months of age, as well as sociodemographic factors associated with exclusive breastfeeding. RESULTS: Of the 8815 newborns, 1044 (11.8%) lacked breastfeeding information in their EMR. Rates of exclusive breastfeeding were 39.5% at 2 months, 32.4% at 4 months and 25.1% at 6 months. At age 6 months, exclusive breastfeeding rates were highest among mothers aged ≥40 vs. < 20 years (rate ratio [RR] 2.45, 95% confidence interval [CI] 1.62-3.68), urban vs. rural residence (RR 1.35, 95% CI 1.22-1.50), and highest vs. lowest income quintile (RR 1.18, 95% CI 1.02-1.36). Overall, immigrants had similar rates of exclusive breastfeeding as non-immigrants; yet, by age 6 months, among those residing in the lowest income quintile, immigrants were more likely to exclusively breastfeed than their non-immigrant counterparts (RR 1.43, 95% CI 1.12-1.83). CONCLUSIONS: We efficiently determined rates and factors associated with exclusive breastfeeding using data from a large EMR database.

Concomitant preterm birth and severe small-for-gestational age birth weight among infants of immigrant mothers in Ontario originating from the Philippines and East Asia: a population-based study.

OBJECTIVES: Women from the Philippines form one of the largest immigrant groups to North America. Their newborns experience higher rates of preterm birth (PTB), and separately, small-for-gestational age (SGA) birth weight, compared with other East Asians. It is not known if Filipino women are at elevated risk of concomitant PTB and severe SGA (PTB-SGA), a pathological state likely reflective of placental dysfunction and neonatal morbidity. METHODS: We conducted a population-based study of all singleton or twin live births in Ontario, from 2002 to 2011, among immigrant mothers from the Philippines (n=27 946), Vietnam (n=15 297), Hong Kong (n=5618), South Korea (n=5148) and China (n=42 517). We used modified Poisson regression to generate relative risks (RR) of PTB-SGA, defined as a birth <37 weeks' gestation and a birth weight <5th percentile. RRs were adjusted for maternal age, parity, marital status, income quintile, infant sex and twin births. RESULTS: Relative to mothers from China (2.3 per 1000), the rate of PTB-SGA was significantly higher among infants of mothers from the Philippines (6.5 per 1000; RR 2.91, 95% CI 2.27 to 3.73), and those from Vietnam (3.7 per 1000; RR 1.68, 95% CI 1.21 to 2.34). The RR of PTB-SGA was not higher for infants of mothers from Hong Kong or South Korea. INTERPRETATION: Among infants born to immigrant women from five East Asian birthplaces, the risk of PTB-SGA was highest among those from the Philippines. These women and their fetuses may require additional monitoring and interventions.

Estimated reductions in provider-initiated preterm births and hospital length of stay under a universal acetylsalicylic acid prophylaxis strategy: a retrospective cohort study.

BACKGROUND: Hypertensive disorders, especially preeclampsia, are the leading reason for provider-initiated preterm birth. We estimated how universal acetylsalicylic acid (ASA) prophylaxis might reduce rates of provider-initiated preterm birth associated with preeclampsia and intrauterine growth restriction, which are related conditions. METHODS: We performed a cohort study of singleton hospital births in 2013 in Canada, excluding Quebec. We estimated the proportion of term births and provider-initiated preterm births affected by preeclampsia and/or intrauterine growth restriction, and the corresponding mean maternal and newborn hospital length of stay. We projected the potential number of cases reduced and corresponding hospital length of stay if ASA prophylaxis lowered cases of preeclampsia and intrauterine growth restriction by a relative risk reduction (RRR) of 10% (lowest) or 53% (highest), as suggested by randomized clinical trials. RESULTS: Of the 269 303 singleton live births and stillbirths in our cohort, 4495 (1.7%) were provider-initiated preterm births. Of the 4495, 1512 (33.6%) had a diagnosis of preeclampsia and/or intrauterine growth restriction. The mean maternal length of stay was 2.0 (95% confidence interval [CI] 2.0-2.0) days among term births unaffected by either condition and 7.3 (95% CI 6.1-8.6) days among provider-initiated preterm births with both conditions. The corresponding values for mean newborn length of stay were 1.9 (95% CI 1.8-1.9) days and 21.8 (95% CI 17.4-26.2) days. If ASA conferred a 53% RRR against preeclampsia and/or intrauterine growth restriction, 3365 maternal and 11 591 newborn days in hospital would be averted. If ASA conferred a 10% RRR, 635 maternal and 2187 newborn days in hospital would be averted. INTERPRETATION: A universal ASA prophylaxis strategy could substantially reduce the burden of long maternal and newborn hospital stays associated with provider-initiated preterm birth. However, until there is compelling evidence that administration of ASA to all, or most, pregnant women reduces the risk of preeclampsia and/or intrauterine growth restriction, clinicians should continue to follow current clinical practice guidelines.

On-Premise Alcohol Establishments and Ambulance Calls for Trauma, Assault, and Intoxication.

Alcohol contributes to intentional and unintentional injury. We explored on-premise licensed alcohol establishments (LAEs) and emergency medical service (EMS) ambulance calls.We completed a retrospective population-based study in the Region of Peel, Ontario, 2005 to 2014, where alcohol sales are tightly regulated and healthcare is universally available. We included participants age ≥ 19 years. Longitude-latitude coordinates of all 696 LAEs and all 267,477 EMS ambulance calls were ascertained, and then assigned to 1 of 1568 dissemination areas (DA) in Peel. Relative risks (RRs) described the association between density of on-premise LAEs (by DA deciles) and the rate of EMS calls, adjusted for material deprivation, and density of beer/liquor stores in each DA.There was a curvilinear relation between LAE density and EMS calls for trauma, rising from 45.3 per 1000 in DAs with no LAEs to 381.0 per 1000 in decile-10 (adjusted RR 7.83, 95% confidence interval [CI] 6.15-9.97). This relation was more pronounced for alcohol-focused LAEs, and highest among younger males. Calls for assault (RR 2.67, 95% CI 1.26-5.65) and intoxication (RR 4.00, 95% CI 1.41-11.38) were more likely on the last day of the month and the day thereafter, compared to 1 week prior. At 02:00 hours, when LAEs must stop selling alcohol, there was a considerable rise in assault-related calls in DAs with LAE but not in DAs without LAEs.On-premise LAEs contribute to EMS calls for trauma and assault, especially among young males, around last call, and when monthly pay cheques are cashed.

Clinical risk factors for pre-eclampsia determined in early pregnancy: systematic review and meta-analysis of large cohort studies.

OBJECTIVE: To develop a practical evidence based list of clinical risk factors that can be assessed by a clinician at ≤ 16 weeks' gestation to estimate a woman's risk of pre-eclampsia. DESIGN: Systematic review and meta-analysis of cohort studies. DATA SOURCES: PubMed and Embase databases, 2000-15. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Cohort studies with ≥ 1000 participants that evaluated the risk of pre-eclampsia in relation to a common and generally accepted clinical risk factor assessed at ≤ 16 weeks' gestation. DATA EXTRACTION: Two independent reviewers extracted data from included studies. A pooled event rate and pooled relative risk for pre-eclampsia were calculated for each of 14 risk factors. RESULTS: There were 25,356,688 pregnancies among 92 studies. The pooled relative risk for each risk factor significantly exceeded 1.0, except for prior intrauterine growth restriction. Women with antiphospholipid antibody syndrome had the highest pooled rate of pre-eclampsia (17.3%, 95% confidence interval 6.8% to 31.4%). Those with prior pre-eclampsia had the greatest pooled relative risk (8.4, 7.1 to 9.9). Chronic hypertension ranked second, both in terms of its pooled rate (16.0%, 12.6% to 19.7%) and pooled relative risk (5.1, 4.0 to 6.5) of pre-eclampsia. Pregestational diabetes (pooled rate 11.0%, 8.4% to 13.8%; pooled relative risk 3.7, 3.1 to 4.3), prepregnancy body mass index (BMI) >30 (7.1%, 6.1% to 8.2%; 2.8, 2.6 to 3.1), and use of assisted reproductive technology (6.2%, 4.7% to 7.9%; 1.8, 1.6 to 2.1) were other prominent risk factors. CONCLUSIONS: There are several practical clinical risk factors that, either alone or in combination, might identify women in early pregnancy who are at "high risk" of pre-eclampsia. These data can inform the generation of a clinical prediction model for pre-eclampsia and the use of aspirin prophylaxis in pregnancy.

Preterm Delivery in Relation to Neighbourhood-Level Adult Premature Mortality.

OBJECTIVE: To assess the influence of neighbourhood-level adult premature mortality on a woman's risk of preterm delivery (PTD). METHODS: We included 286 872 singleton live birth deliveries in Toronto, Ontario, between 2002 and 2011. The study exposure was neighbourhood premature mortality rate, expressed in quintiles (Q), among adults aged 20 to 49 years living within each of Toronto's 140 neighbourhoods. The primary study outcome was PTD at 24 to 36 weeks' gestation. Logistic regression analysis generated unadjusted ORs, adjusted ORs, and 95% CIs, controlling for maternal age, parity, marital status, material deprivation index Q, maternal and paternal birthplace, and infant sex. RESULTS: For all 140 neighbourhoods, the mean rate of premature deaths was 0.66 per 100 females and 1.17 per 100 males aged 20 to 49 years. The rate of PTD increased linearly in relation to the neighbourhood rate of premature mortality among adult females, from 5.3 per 100 in Q1 with the lowest rate of premature mortality to 6.3 per 100 in Q5 (OR 1.22; 95% CI 1.13 to 1.31). The adjusted ORs were attenuated but remained significant (1.13; 95% CI 1.05 to 1.22). A similar pattern was demonstrated for the relation between neighbourhood premature mortality among adult males and PTD. CONCLUSION: Women residing in neighbourhoods with high rates of premature adult mortality are at elevated risk of PTD, even after adjusting for measured socioeconomic factors that include marital status and material deprivation.

Maternal and paternal birthplace and risk of stillbirth.

OBJECTIVES: To evaluate the influence of maternal and paternal country of origin on stillbirth risk. METHODS: We conducted a retrospective case-control study of all deliveries in Ontario between 2002 and 2011. We included 1373 stillbirths and 1 166 097 live births that had a documented country of origin for both parents. All newborns were singleton, born at between 20 and 42 weeks' gestation, and weighed 250 g to 7000 g. We computed adjusted odds ratios (aOR) and 95% confidence intervals for the risk of stillbirth associated with parental country of origin. Models were adjusted for infant sex, maternal age, parity, marital status, and residential income quintile. RESULTS: Compared with parent pairs in which both parents were Canadian-born, the aOR of stillbirth was higher whether immigrant parents came from the same country (aOR 1.32, 95% CI 1.16 to 1.51) or from different countries (aOR 1.34, 95% CI 1.08 to 1.65). The risk of stillbirth was highest for immigrant parents coming from the same country if that country had a high domestic stillbirth rate (aOR 1.60, 95% CI 1.30 to 1.97). CONCLUSION: Maternal and paternal country of origin influences stillbirth risk. Foreign-born couples, especially those originating from a country with a high stillbirth rate, are at greater risk. Attention should focus on identifying genetic and environmental risk factors for stillbirth among specific immigrant groups, including developing prevention strategies for high-risk couples.

Objectif : Évaluer l'influence du pays d'origine de la mère et du père sur le risque de mortinaissance. Méthodes : Nous avons mené une étude cas-témoins rétrospective portant sur tous les accouchements ayant eu lieu en Ontario entre 2002 et 2011. Nous avons inclus 1 373 mortinaissances et 1 166 097 naissances vivantes pour lesquelles le pays d'origine des deux parents avait été documenté. Tous les enfants visés étaient issus d'une grossesse monofœtale, étaient nés entre 20 et 42 semaines de gestation, et présentaient un poids se situant entre 250 g et 7 000 g. Nous avons calculé des rapports de cotes corrigés (RCc) et des intervalles de confiance à 95 % pour ce qui est du risque de mortinaissance associé au pays d'origine parental. Les effets exercés sur les modèles par le sexe du nouveau-né, l'âge maternel, la parité, l'état matrimonial et le quintile de revenu résidentiel ont été neutralisés. Résultats : Par comparaison avec des paires de parents comptant deux personnes nées au Canada, le RCc de la mortinaissance était plus élevé lorsque les parents immigrants provenaient du même pays (RCc, 1,32; IC à 95 %, 1,16 - 1,51) ou de pays différents (RCc, 1,34; IC à 95 %, 1,08 - 1,65). Le risque de mortinaissance atteignait son apogée lorsque les parents immigrants provenaient d'un même pays au sein duquel le taux domestique de mortinaissance était élevé (RCc, 1,60; IC à 95 %, 1,30 - 1,97). Conclusion : Le pays d'origine de la mère et du père exerce une influence sur le risque de mortinaissance. Les couples nés à l'étranger, particulièrement ceux qui proviennent d'un pays comptant un taux élevé de mortinaissance, sont exposés à un risque accru. Nous devrions nous centrer sur l'identification des facteurs de risque génétiques et environnementaux de mortinaissance au sein de groupes particuliers d'immigrants, ainsi que sur l'élaboration de stratégies de prévention à l'intention des couples exposés à des risques élevés.

Risk threshold for starting low dose aspirin in pregnancy to prevent preeclampsia: an opportunity at a low cost.

BACKGROUND: Preeclampsia (PE) increases maternal and perinatal morbidity and mortality. Based on a multitude of data from randomized clinical trials, clinical practice guidelines endorse using ASA to prevent PE in women who are "at risk." However, data are lacking about the level of absolute risk to warrant starting ASA prophylaxis. METHODS AND FINDINGS: We present two approaches for objectively determining the minimum absolute risk for PE at which ASA prophylaxis is justified. The first is a new approach-the minimum control event rate (CERmin). The second approach uses a pre-existing concept-the minimum event rate for treatment (MERT). Here we show how the CERmin is derived, and then use the CERmin and the MERT to guide us to a reasonable risk threshold for starting a woman on ASA prophylaxis against PE based on clinical risk assessment. We suggest that eligible women need not be at "high risk" for preeclampsia to warrant ASA, but rather at some modestly elevated absolute risk of 6-10%. CONCLUSIONS: Given its very low cost, its widespread availability, ease of administration and its safety profile, ASA is a highly attractive agent for the prevention of maternal and perinatal morbidity worldwide.