title: Methodological Challenges in Studies Comparing Prehospital Advanced Life Support with Basic Life Support.
abstract: Determining the most appropriate level of care for patients in the prehospital setting during medical emergencies is essential. A large body of literature suggests that, compared with Basic Life Support (BLS) care, Advanced Life Support (ALS) care is not associated with increased patient survival or decreased mortality. The purpose of this special report is to synthesize the literature to identify common study design and analytic challenges in research studies that examine the effect of ALS, compared to BLS, on patient outcomes. The challenges discussed in this report include: (1) choice of outcome measure; (2) logistic regression modeling of common outcomes; (3) baseline differences between study groups (confounding); (4) inappropriate statistical adjustment; and (5) inclusion of patients who are no longer at risk for the outcome. These challenges may affect the results of studies, and thus, conclusions of studies regarding the effect of level of prehospital care on patient outcomes should require cautious interpretation. Specific alternatives for avoiding these challenges are presented. Li T , Jones CMC , Shah MN , Cushman JT , Jusko TA . Methodological challenges in studies comparing prehospital Advanced Life Support with Basic Life Support. Prehosp Disaster Med. 2017;32(4):444-450.
authors.affiliation: 1Department of Emergency Medicine,University of Rochester School of Medicine & Dentistry,Rochester,New YorkUSA.
authors.forename: Timmy
authors.initials: T
authors.lastname: Li
authors.affiliation: 1Department of Emergency Medicine,University of Rochester School of Medicine & Dentistry,Rochester,New YorkUSA.
authors.forename: Courtney M C
authors.initials: CMC
authors.lastname: Jones
authors.affiliation: 1Department of Emergency Medicine,University of Rochester School of Medicine & Dentistry,Rochester,New YorkUSA.
authors.forename: Manish N
authors.initials: MN
authors.lastname: Shah
authors.affiliation: 1Department of Emergency Medicine,University of Rochester School of Medicine & Dentistry,Rochester,New YorkUSA.
authors.forename: Jeremy T
authors.initials: JT
authors.lastname: Cushman
authors.affiliation: 2Department of Public Health Sciences,University of Rochester School of Medicine & Dentistry,Rochester,New YorkUSA.
authors.forename: Todd A
authors.initials: TA
authors.lastname: Jusko
mesh_terms: D006801:Humans; D008020:Life Support Care / Q000379:methods*; D016015:Logistic Models; D017063:Outcome Assessment, Health Care
keywords:  ALS Advanced Life Support;  BLS Basic Life Support;  ED emergency department;  EMS Emergency Medical Services;  GCS Glasgow Coma Scale;  ISS Injury Severity Score; bias; confounding; epidemiology; study design