Shireen Meher1, Lelia Duley2, Kylie Hunter3, Lisa Askie3. 1. Division of Women and Child Health, City Hospital, Birmingham, UK; University of Liverpool, Liverpool, United Kingdom. Electronic address: smeher@nhs.net. 2. Nottingham Clinical Trials Unit, University of Nottingham, Nottingham, United Kingdom. 3. National Health and Medical Research Council Clinical Trials Centre, University of Sydney, Camperdown, Australia.
Abstract
BACKGROUND: The optimum time for commencing antiplatelet therapy for the prevention of preeclampsia and its complications is unclear. Aggregate data meta-analyses suggest that aspirin is more effective if given prior to 16 weeks' gestation, but data are limited because of an inability to place women in the correct gestational age subgroup from relevant trials. OBJECTIVE: The objective of the study was to use the large existing individual participant data set from the Perinatal Antiplatelet Review of International Studies Collaboration to assess whether the treatment effects of antiplatelet agents on preeclampsia and its complications vary based on whether treatment is started before or after 16 weeks' gestation. STUDY DESIGN: A meta-analysis of individual participant data including 32,217 women and 32,819 babies recruited to 31 randomized trials comparing low-dose aspirin or other antiplatelet agents with placebo or no treatment for the prevention of preeclampsia has been published previously. Using this existing data set, we performed a prespecified subgroup analysis based on gestation at randomization to antiplatelet agents before 16 weeks, compared with at or after 16 weeks, for 4 of the main outcomes prespecified in the Perinatal Antiplatelet Review of International Studies protocol: preeclampsia, death of baby, preterm birth before 34 weeks, and small-for-gestational-age baby. Individual participant data for the subgroups were combined in a meta-analysis using RevMan software. Heterogeneity was assessed with the I2 statistic. The χ2 test for interaction was used to assess statistically significant (P < .05) differences in treatment effect between subgroups. RESULTS: There was no significant difference in the effects of antiplatelet therapy for women randomized before 16 weeks' gestation compared with those randomized at or after 16 weeks for any of the 4 prespecified outcomes: preeclampsia, relative risk, 0.90, (95% confidence interval, 0.79-1.03; 17 trials, 9241 women) for <16 weeks and relative risk, 0.90 (95% confidence interval, 0.83-0.98; 22 trials, 21,429 women) for ≥16 weeks (interaction test, P = .98); death of baby, relative risk, 0.89 (95% confidence interval, 0.73-1.09; 15 trials, 8626 women) for <16 weeks and relative risk, 0.92 (95% confidence interval, 0.79-1.07; 21 trials, 22,336 women) for ≥16 weeks (interaction test, P = .80); preterm birth prior to 34 weeks, relative risk, 0.90 (95% confidence interval, 0.77-1.04; 19 trials, 9155 women) for <16 weeks and relative risk, 0.91 (95% confidence interval, 0.82-1.00; 25 trials, 22,117 women) for ≥16 weeks (interaction test, P = .91); and small-for-gestational-age baby, relative risk, 0.76 (95% confidence interval, 0.61-0.94; 13 trials, 6393 women) for <16 weeks and relative risk, 0.95 (95% confidence interval, 0.84-1.08; 18 trials, 14,996 women) for ≥16 weeks (interaction test, P = .08). CONCLUSION: The effect of low-dose aspirin and other antiplatelet agents on preeclampsia and its complications is consistent, regardless of whether treatment is started before or after 16 weeks' gestation. Women at an increased risk of preeclampsia should be offered antiplatelet therapy, regardless of whether they are first seen before or after 16 weeks' gestation.
BACKGROUND: The optimum time for commencing antiplatelet therapy for the prevention of preeclampsia and its complications is unclear. Aggregate data meta-analyses suggest that aspirin is more effective if given prior to 16 weeks' gestation, but data are limited because of an inability to place women in the correct gestational age subgroup from relevant trials. OBJECTIVE: The objective of the study was to use the large existing individual participant data set from the Perinatal Antiplatelet Review of International Studies Collaboration to assess whether the treatment effects of antiplatelet agents on preeclampsia and its complications vary based on whether treatment is started before or after 16 weeks' gestation. STUDY DESIGN: A meta-analysis of individual participant data including 32,217 women and 32,819 babies recruited to 31 randomized trials comparing low-dose aspirin or other antiplatelet agents with placebo or no treatment for the prevention of preeclampsia has been published previously. Using this existing data set, we performed a prespecified subgroup analysis based on gestation at randomization to antiplatelet agents before 16 weeks, compared with at or after 16 weeks, for 4 of the main outcomes prespecified in the Perinatal Antiplatelet Review of International Studies protocol: preeclampsia, death of baby, preterm birth before 34 weeks, and small-for-gestational-age baby. Individual participant data for the subgroups were combined in a meta-analysis using RevMan software. Heterogeneity was assessed with the I2 statistic. The χ2 test for interaction was used to assess statistically significant (P < .05) differences in treatment effect between subgroups. RESULTS: There was no significant difference in the effects of antiplatelet therapy for women randomized before 16 weeks' gestation compared with those randomized at or after 16 weeks for any of the 4 prespecified outcomes: preeclampsia, relative risk, 0.90, (95% confidence interval, 0.79-1.03; 17 trials, 9241 women) for <16 weeks and relative risk, 0.90 (95% confidence interval, 0.83-0.98; 22 trials, 21,429 women) for ≥16 weeks (interaction test, P = .98); death of baby, relative risk, 0.89 (95% confidence interval, 0.73-1.09; 15 trials, 8626 women) for <16 weeks and relative risk, 0.92 (95% confidence interval, 0.79-1.07; 21 trials, 22,336 women) for ≥16 weeks (interaction test, P = .80); preterm birth prior to 34 weeks, relative risk, 0.90 (95% confidence interval, 0.77-1.04; 19 trials, 9155 women) for <16 weeks and relative risk, 0.91 (95% confidence interval, 0.82-1.00; 25 trials, 22,117 women) for ≥16 weeks (interaction test, P = .91); and small-for-gestational-age baby, relative risk, 0.76 (95% confidence interval, 0.61-0.94; 13 trials, 6393 women) for <16 weeks and relative risk, 0.95 (95% confidence interval, 0.84-1.08; 18 trials, 14,996 women) for ≥16 weeks (interaction test, P = .08). CONCLUSION: The effect of low-dose aspirin and other antiplatelet agents on preeclampsia and its complications is consistent, regardless of whether treatment is started before or after 16 weeks' gestation. Women at an increased risk of preeclampsia should be offered antiplatelet therapy, regardless of whether they are first seen before or after 16 weeks' gestation.
Authors: Nir Melamed; Ahmet Baschat; Yoav Yinon; Apostolos Athanasiadis; Federico Mecacci; Francesc Figueras; Vincenzo Berghella; Amala Nazareth; Muna Tahlak; H David McIntyre; Fabrício Da Silva Costa; Anne B Kihara; Eran Hadar; Fionnuala McAuliffe; Mark Hanson; Ronald C Ma; Rachel Gooden; Eyal Sheiner; Anil Kapur; Hema Divakar; Diogo Ayres-de-Campos; Liran Hiersch; Liona C Poon; John Kingdom; Roberto Romero; Moshe Hod Journal: Int J Gynaecol Obstet Date: 2021-03 Impact factor: 3.561
Authors: Mary Catherine Tolcher; Derrick M Chu; Lisa M Hollier; Joan M Mastrobattista; Diana A Racusin; Susan M Ramin; Haleh Sangi-Haghpeykar; Kjersti M Aagaard Journal: Am J Obstet Gynecol Date: 2017-04-25 Impact factor: 8.661