L N Yelland1,2, E Schuit3, J Zamora4,5, P F Middleton1,6, A C Lim7, A H Nassar8, L Rode9,10, V Serra11, E A Thom12, C Vayssière13,14, Bwj Mol15, S Gates16. 1. South Australian Health and Medical Research Institute, Adelaide, SA, Australia. 2. School of Public Health, The University of Adelaide, Adelaide, SA, Australia. 3. Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, the Netherlands. 4. Women's Health Research Unit, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK. 5. CIBER Epidemiology and Public Health and IRYCIS, Madrid, Spain. 6. Robinson Research Institute, School of Medicine, The University of Adelaide, Adelaide, SA, Australia. 7. Department of Obstetrics & Gynecology and GROW-School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, the Netherlands. 8. Department of Obstetrics and Gynecology, American University of Beirut Medical Center, Beirut, Lebanon. 9. Department of Obstetrics, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark. 10. Department of Clinical Biochemistry, Herlev and Gentofte Hospital, Copenhagen University Hospital, Copenhagen, Denmark. 11. Maternal-Fetal Medicine Unit, Valencia Infertility Institute, University of Valencia, Valencia, Spain. 12. George Washington University Biostatistics Center, Washington, DC, USA. 13. Department of Obstetrics and Gynecology, Paule de Viguier Hospital, CHU Toulouse, Toulouse, France. 14. UMR 1027 INSERM, University of Paul Sabatier Toulouse III, Toulouse, France. 15. Department of Obstetrics and Gynaecology, Monash Medical Centre, Monash Health and Monash University, Clayton, Vic., Australia. 16. Warwick Clinical Trials Unit, University of Warwick, Coventry, UK.
Abstract
OBJECTIVE: To estimate the magnitude of the correlation between neonatal outcomes of twins and demonstrate how this information can be used in the design of randomised controlled trials (RCTs) in women with twin pregnancies. DESIGN: Secondary analysis of data from 12 RCTs. SETTING: Obstetric care in multiple countries, 2004-2012. POPULATION OR SAMPLE: 4504 twin pairs born to women who participated in RCTs to assess treatments given during pregnancy. METHODS: Intraclass correlation coefficients (ICCs) were estimated using log-binomial and linear models. MAIN OUTCOME MEASURES: Perinatal death, respiratory distress syndrome, bronchopulmonary dysplasia, intraventricular haemorrhage, necrotising enterocolitis, sepsis, neonatal intensive care unit admission, birthweight, low birthweight and two composite measures of adverse neonatal outcome. RESULTS: ICCs for the composite measures of adverse neonatal outcome were all above 0.5, indicating moderate to strong correlation between adverse outcomes of twins. For individual neonatal outcomes, median ICCs across trials ranged from 0.13 to 0.79 depending on the outcome. An example illustrates how ICCs can be used in sample size calculations for RCTs in women with twin pregnancies. CONCLUSIONS: The correlation between neonatal outcomes of twins varies considerably between outcomes and may be lower than expected. Our ICC estimates can be used for designing and analysing RCTs that recruit women with twin pregnancies and for performing meta-analyses that include such RCTs. Researchers are encouraged to report ICCs for neonatal outcomes in twins in their own RCTs. TWEETABLE ABSTRACT: Correlation between neonatal outcomes of twins depends on the outcome and may be lower than expected.
OBJECTIVE: To estimate the magnitude of the correlation between neonatal outcomes of twins and demonstrate how this information can be used in the design of randomised controlled trials (RCTs) in women with twin pregnancies. DESIGN: Secondary analysis of data from 12 RCTs. SETTING: Obstetric care in multiple countries, 2004-2012. POPULATION OR SAMPLE: 4504 twin pairs born to women who participated in RCTs to assess treatments given during pregnancy. METHODS: Intraclass correlation coefficients (ICCs) were estimated using log-binomial and linear models. MAIN OUTCOME MEASURES: Perinatal death, respiratory distress syndrome, bronchopulmonary dysplasia, intraventricular haemorrhage, necrotising enterocolitis, sepsis, neonatal intensive care unit admission, birthweight, low birthweight and two composite measures of adverse neonatal outcome. RESULTS: ICCs for the composite measures of adverse neonatal outcome were all above 0.5, indicating moderate to strong correlation between adverse outcomes of twins. For individual neonatal outcomes, median ICCs across trials ranged from 0.13 to 0.79 depending on the outcome. An example illustrates how ICCs can be used in sample size calculations for RCTs in women with twin pregnancies. CONCLUSIONS: The correlation between neonatal outcomes of twins varies considerably between outcomes and may be lower than expected. Our ICC estimates can be used for designing and analysing RCTs that recruit women with twin pregnancies and for performing meta-analyses that include such RCTs. Researchers are encouraged to report ICCs for neonatal outcomes in twins in their own RCTs. TWEETABLE ABSTRACT: Correlation between neonatal outcomes of twins depends on the outcome and may be lower than expected.
Authors: Dwight J Rouse; Steve N Caritis; Alan M Peaceman; Anthony Sciscione; Elizabeth A Thom; Catherine Y Spong; Michael Varner; Fergal Malone; Jay D Iams; Brian M Mercer; John Thorp; Yoram Sorokin; Marshall Carpenter; Julie Lo; Susan Ramin; Margaret Harper; Garland Anderson Journal: N Engl J Med Date: 2007-08-02 Impact factor: 91.245
Authors: Bing Lu; John S Preisser; Bahjat F Qaqish; Chirayath Suchindran; Shrikant I Bangdiwala; Mark Wolfson Journal: Biometrics Date: 2007-09 Impact factor: 2.571
Authors: Arianne C Lim; Ewoud Schuit; Kitty Bloemenkamp; Rob E Bernardus; Johannes J Duvekot; Jan Jaap H M Erwich; Jim van Eyck; Rolf H H Groenwold; Tom H M Hasaart; Piet Hummel; Michael M Kars; Anneke Kwee; Charlotte M van Oirschot; Mariëlle G van Pampus; Dimitri Papatsonis; Martina M Porath; Marc E Spaanderman; Christine Willekes; Janine Wilpshaar; Ben W J Mol; Hein W Bruinse Journal: Obstet Gynecol Date: 2011-09 Impact factor: 7.661
Authors: V Serra; A Perales; J Meseguer; J J Parrilla; C Lara; J Bellver; R Grifol; I Alcover; M Sala; J C Martínez-Escoriza; A Pellicer Journal: BJOG Date: 2012-08-13 Impact factor: 6.531
Authors: E Schuit; S Stock; L Rode; D J Rouse; A C Lim; J E Norman; A H Nassar; V Serra; C A Combs; C Vayssiere; M M Aboulghar; S Wood; E Çetingöz; C M Briery; E B Fonseca; K Worda; A Tabor; E A Thom; S N Caritis; J Awwad; I M Usta; A Perales; J Meseguer; K Maurel; T Garite; M A Aboulghar; Y M Amin; S Ross; C Cam; A Karateke; J C Morrison; E F Magann; K H Nicolaides; N P A Zuithoff; R H H Groenwold; K G M Moons; A Kwee; B W J Mol Journal: BJOG Date: 2014-08-22 Impact factor: 6.531
Authors: Tms van Winden; J Klumper; C E Kleinrouweler; M A Tichelaar; C A Naaktgeboren; T A Nijman; A L van Baar; A G van Wassenaer-Leemhuis; T J Roseboom; J Van't Hooft; C Roos; B W Mol; E Pajkrt; M A Oudijk Journal: BJOG Date: 2020-03-29 Impact factor: 6.531