title: Evaluation of the use of Swedish integrated electronic health records and register health care data as support clinical trials in severe asthma: the PACEHR study.
abstract: In the development of new drugs for severe asthma, it is a challenge from an ethical point of view to randomize severe asthma patients to placebo, and to obtain long-term safety data due to discontinuations. The aim of this study was to evaluate the feasibility of using electronic health record (EHR) data to create a real-world reference population of uncontrolled asthmatic patients to supplement the concurrent control/placebo group in long-term studies of asthma.
  
  
  
  EHR data from 36 primary care centres and a University hospital in Sweden were linked to Swedish mandatory health registers (2005-2013), creating a population covering 33 890 asthma patients, including data on co-morbidities, risk factors and laboratory/respiratory measurements. A severe asthma EHR reference cohort was established. We used logistic regression to estimate the propensity score (probability) of each RCT or EHR patient existing in the EHR cohort given their covariates.
  
  
  
  We created an EHR-derived reference cohort of 240 patients, matching the placebo group (N = 151) in an RCT of severe asthma. The exacerbation rate during follow-up in the EHR study population was 1.24 (weighted) compared to 0.9 in the RCT placebo group. Patients in the EHR cohort were of similar age as in the RCT placebo group, 50.6 years versus 50.1 years; had slightly higher body mass index 27.0 kg/m2versus 27.3 kg/m2; and consisted of 40% versus 34% males.
  
  
  
  The results indicate that EHRs provide an opportunity to supplement the control group in RCTs of severe diseases.
authors.affiliation: Register Centrum, Gothenburg, Sweden.
authors.forename: Stefan
authors.initials: S
authors.lastname: Franzén
authors.affiliation: Department of Medical Sciences, Respiratory, Allergy and Sleep Research, Uppsala University, Uppsala, Sweden.
authors.forename: Christer
authors.initials: C
authors.lastname: Janson
authors.affiliation: Department of Environmental Medicine, Karolinska Institute, Solna, Sweden.
authors.forename: Kjell
authors.initials: K
authors.lastname: Larsson
authors.affiliation: Centre for Applied Biostatistics, University Gothenburg, Gothenburg, Sweden.
authors.forename: Max
authors.initials: M
authors.lastname: Petzold
authors.affiliation: Statisticon AB, Uppsala, Sweden.
authors.forename: Urban
authors.initials: U
authors.lastname: Olsson
authors.affiliation: AstraZeneca, Gothenburg, Sweden.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Magnusson
authors.affiliation: AstraZeneca Nordic-Baltic, Södertälje, Sweden.
authors.forename: Gunilla
authors.initials: G
authors.lastname: Telg
authors.affiliation: AstraZeneca, Gaithersburg, USA.
authors.forename: Gene
authors.initials: G
authors.lastname: Colice
authors.affiliation: Public Health and Caring Science, Family Medicine and Preventive Medicine, Uppsala University, Uppsala, Sweden.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Johansson
authors.affiliation: AstraZeneca, Gothenburg, Sweden. mats.sundgren@astrazeneca.com.|Biometrics and Information Science, AstraZeneca, Gothenburg, SE-431 83, Mölndal, Sweden. mats.sundgren@astrazeneca.com.
authors.forename: Mats
authors.identifier: 0000-0001-5300-5217
authors.initials: M
authors.lastname: Sundgren
mesh_terms: D000328:Adult; D000368:Aged; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use*; D001249:Asthma / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D057225:Data Mining; D057286:Electronic Health Records; D005240:Feasibility Studies; D005260:Female; D006302:Health Services Research; D006785:Hospitals, University; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care; D057216:Propensity Score; D016032:Randomized Controlled Trials as Topic; D012042:Registries; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013548:Sweden; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D018927:Anti-Asthmatic Agents
keywords: Asthma; Electronic health records; Exacerbation; Placebo studies; Registries