title: Positive predictive values of International Classification of Diseases, 10th revision codes for dermatologic events and hypersensitivity leading to hospitalization or emergency room visit among women with postmenopausal osteoporosis in the Danish and Swedish national patient registries.
abstract: BACKGROUND
  Clinical epidemiology research studies, including pharmacoepidemiology and pharmacovigilance studies, use routinely collected health data, such as diagnoses recorded in national health and administrative registries, to assess clinical effectiveness and safety of treatments. We estimated positive predictive values (PPVs) of International Classification of Diseases, 10th revision (ICD-10) codes for primary diagnoses of dermatologic events and hypersensitivity recorded at hospitalization or emergency room visit in the national patient registries of Denmark and Sweden among women with postmenopausal osteoporosis (PMO).
  
  
  METHODS
  This validation study included women with PMO identified from the Danish and Swedish national patient registries (2005-2014). Medical charts of the potential cases served as the gold standard for the diagnosis confirmation and were reviewed and adjudicated by physicians.
  
  
  RESULTS
  We obtained and reviewed 189 of 221 sampled medical records (86%). The overall PPV was 92.4% (95% confidence interval [CI], 85.1%-96.3%) for dermatologic events, while the PPVs for bullous events and erythematous dermatologic events were 52.5% (95% CI, 37.5%-67.1%) and 12.5% (95% CI, 2.2%-47.1%), respectively. The PPV was 59.0% (95% CI, 48.3%-69.0%) for hypersensitivity; however, the PPV of hypersensitivity increased to 100.0% (95% CI, 67.6%-100.0%) when restricting to diagnostic codes for anaphylaxis. The overall results did not vary by country.
  
  
  CONCLUSIONS
  Among women with PMO, the PPV for any dermatologic event recorded as the primary diagnosis at hospitalization or at an emergency room visit was high and acceptable for epidemiologic research in the Danish and Swedish national patient registries. The PPV was substantially lower for hypersensitivity leading to hospitalization or emergency room visit.
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus N, Denmark.
authors.forename: Kasper
authors.initials: K
authors.lastname: Adelborg
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus N, Denmark.
authors.forename: Lotte Brix
authors.initials: LB
authors.lastname: Christensen
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus N, Denmark.
authors.forename: Troels
authors.initials: T
authors.lastname: Munch
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus N, Denmark.
authors.forename: Johnny
authors.initials: J
authors.lastname: Kahlert
authors.affiliation: Department of Medicine, Clinical Epidemiology Unit, Karolinska Institutet; Department of Medicine, Clinic of Endocrinology, Metabolism and Diabetes, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Ylva
authors.initials: Y
authors.lastname: Trolle Lagerros
authors.affiliation: Department of Global Public Health and Primary Care, University of Bergen.
authors.forename: Grethe S
authors.initials: GS
authors.lastname: Tell
authors.affiliation: Department of Global Public Health and Primary Care, University of Bergen; Department of Rheumatology, Haukeland University Hospital, Bergen, Norway.
authors.forename: Ellen M
authors.initials: EM
authors.lastname: Apalset
authors.affiliation: Center for Observational Research, Amgen Inc. Thousand Oaks, CA, USA.
authors.forename: Fei
authors.initials: F
authors.lastname: Xue
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus N, Denmark.
authors.forename: Vera
authors.initials: V
authors.lastname: Ehrenstein
keywords: dermatology; pharmacoepidemiology; positive predictive value; validation