Pre-eclampsia is a pregnancy disorder that occurs after 20 weeks gestation defined by high blood pressure and protein in the urine. Pre-eclampsia and other blood pressure related disorders of pregnancy occur in 10% of pregnancies worldwide and may lead to severe complications for both mother and baby (e.g., stroke, stillbirth). As pre-eclampsia currently has no cure, prevention is the most effective way to reduce its associated complications. Some trials have demonstrated that low-dose aspirin (75-150 mg) is effective at preventing severe forms of pre-eclampsia among women at high risk of developing pre-eclampsia. Although the definition of “high-risk” women and the dosage and timing of aspirin during pregnancy have varied in these trials, national (e.g., in the United Kingdom (UK) and Canada) and international guidelines (World Health Organization) recommend aspirin use for the prevention of pre-eclampsia among women at high risk. However, it is not known how well the UK guideline is followed in everyday clinical practice. This study will address this question by describing the use of low-dose aspirin among pregnant women in the UK over a 20-year period. We will describe how use has changed over time, both overall and in groups defined by maternal characteristics such as age and pre-eclampsia risk factors. In addition, we will examine how the publication of the UK National Institute for Health and Care Excellence (NICE) guidelines in this area impacted the prescription of low-dose aspirin among pregnant women.
Pre-eclampsia is a major contributor to severe maternal and neonatal complications. In addition to the short-term complications, pre-eclampsia is associated with an increased long-term risk of maternal cardiovascular disease. Randomized controlled trials have suggested that low-dose aspirin is efficacious for the prevention or delay of the onset of pre-eclampsia among high-risk women. National treatment guidelines including the 2010 United Kingdom (UK) National Institute for Health and Care Excellence (NICE) recommend the use of aspirin for the prevention of pre-eclampsia among high-risk women. However, it is unknown how frequently aspirin is prescribed to women at high risk of pre-eclampsia in everyday clinical practice. In addition, the impact of NICE guidelines recommending the use of aspirin in this patient population on prescription patterns is unclear. We propose to examine the real-world use of aspirin among pregnant women at high risk for pre-eclampsia using the CPRD, its pregnancy register, and Hospital Episode Statistics data from April, 1998 to March, 2021. Women between 18 to 45 years with a delivery during the study period recorded in the CPRD pregnancy register will be included. The endpoints will be prescription rates for aspirin among high-risk and among all pregnancies. We will estimate annual prescription rates and corresponding 95% confidence interval (CIs) using negative binomial regression. Calendar time trends will be described overall, by aspirin dosage, and by maternal characteristics. In addition, we will describe the timing and duration of use, overall and over time. Finally, we will examine the impact of the publication of the 2010 and 2019 NICE guidelines on prescribing patterns and dosage via interrupted time-series analysis. The results from this study will help to refine our understanding of the real-world use of aspirin in pregnancy and trends in prescription patterns due to changes in treatment guidelines in this area.
• Prescription rates of low-dose aspirin (<150 mg/day), overall and over calendar time
• Prescription rates of low-dose aspirin by dosage (75 mg/day, 76-150 mg/day) and by maternal characteristics (age, parity, body mass index (BMI), multi-fetal pregnancy, pre-existing comorbidity [e.g. chronic hypertension, type 1 or 2 diabetes, autoimmune disease], family history of hypertension and race)
• Gestational age at first low-dose aspirin prescription (also grouped by trimesters: first (<13 weeks), second (13-26 weeks), and third (≥ 27 weeks) and cumulative duration of use during pregnancy
• Prescription rates of low-dose aspirin by gestational age at delivery, bleeding complications and preeclampsia diagnosis, severity
Samy Suissa - Chief Investigator - Sir Mortimer B Davis Jewish General Hospital
Robert Platt - Corresponding Applicant - McGill University
Kristian Filion - Collaborator - McGill University
Laura Magee - Collaborator - King's College London (KCL)
Natalie Dayan - Collaborator - Research Institute of the McGill University Health Centre
pauline reynier - Collaborator - Sir Mortimer B Davis Jewish General Hospital
Ugochinyere Vivian Ukah - Collaborator - McGill University
Ying Cui - Collaborator - Sir Mortimer B Davis Jewish General Hospital
Qi Zhang - Collaborator - Sir Mortimer B Davis Jewish General Hospital
HES Admitted Patient Care;ONS Death Registration Data;Pregnancy Register