Do Case Reports and Case Series Generate Clinical Discoveries About Preeclampsia? A Systematic Review

Ghayath Janoudi,1,2 Mara Uzun (Rada),3 Stephanie T Boyd,1 Deshayne B Fell,2,4 Joel G Ray,5 Angel M Foster,6 Randy Giffen,7 Tammy J Clifford,2,8 Mark C Walker1,2,9– 12 1Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada; 2School of Epidemiology and Public Health, University of Ottawa, Ottawa, ON, Canada; 3Independent Researcher, Ottawa, ON, Canada; 4Children’s Hospital of Eastern Ontario (CHEO) Research Institute, Children’s Hospital of Eastern Ontario, Ottawa, ON, Canada; 5Departments of Medicine, Health Policy Management and Evaluation, and Obstetrics and Gynecology, St Michael’s Hospital, University of Toronto, Toronto, ON, Canada; 6Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada; 7IBM Canada, IBM, Toronto, ON, Canada; 8Canadian Institute of Health Research, Government of Canada, Ottawa, ON, Canada; 9International and Global Health Office, University of Ottawa, Ottawa, ON, Canada; 10Department of Obstetrics and Gynecology, University of Ottawa, Ottawa, ON, Canada; 11Department of Obstetrics, Gynecology & Newborn Care, The Ottawa Hospital, Ottawa, ON, Canada; 12BORN Ontario, Children’s Hospital of Eastern Ontario, Ottawa, ON, CanadaCorrespondence: Mark C Walker, Clinical Epidemiology Program, Ottawa Hospital Research Institute, Centre for Practice Changing Research, Box 241, 501 Smyth Road, Ottawa, ON, K1H 8L6, Canada, Tel +1 613-798-5555 x76655, Email mwalker@toh.caBackground: Preeclampsia is a leading cause of maternal and perinatal mortality and morbidity. The management of preeclampsia has not changed much in more than two decades, and its aetiology is still not fully understood. Case reports and case series have traditionally been used to communicate new knowledge about existing conditions. Whether this is true for preeclampsia is not known.Objective: To determine whether recent case reports or case series have generated new knowledge and clinical discoveries about preeclampsia.Methods: A de