title: Validation of self-reported comorbidity status of breast cancer patients with medical records: the California Breast Cancer Survivorship Consortium (CBCSC).
abstract: OBJECTIVE
  To compare information from self-report and electronic medical records for four common comorbidities (diabetes, hypertension, myocardial infarction, and other heart diseases).
  
  
  METHODS
  We pooled data from two multiethnic studies (one case-control and one survivor cohort) enrolling 1,936 women diagnosed with breast cancer, who were members of Kaiser Permanente Northern California.
  
  
  RESULTS
  Concordance varied by comorbidity; kappa values ranged from 0.50 for other heart diseases to 0.87 for diabetes. Sensitivities for comorbidities from self-report versus medical record were similar for racial/ethnic minorities and non-Hispanic Whites, and did not vary by age, neighborhood socioeconomic status, or education. Women with a longer history of comorbidity or who took medications for the comorbidity were more likely to report the condition. Hazard ratios for all-cause mortality were not consistently affected by source of comorbidity information; the hazard ratio was lower for diabetes, but higher for the other comorbidities when medical record versus self-report was used. Model fit was better when the medical record versus self-reported data were used.
  
  
  CONCLUSIONS
  Comorbidities are increasingly recognized to influence the survival of patients with breast or other cancers. Potential effects of misclassification of comorbidity status should be considered in the interpretation of research results.
authors.affiliation: University of Southern California, 1540 Alcazar St. CHP-133, Los Angeles, CA, 90089-9003, USA. vigen@usc.edu.
authors.forename: Cheryl
authors.initials: C
authors.lastname: Vigen
authors.affiliation: Division of Research, Kaiser Permanente Northern California, 2000 Broadway, Oakland, CA, 94612, USA.
authors.forename: Marilyn L
authors.initials: ML
authors.lastname: Kwan
authors.affiliation: Cancer Prevention Institute of California, 2201 Walnut Ave #300, Fremont, CA, 94538, USA.
authors.forename: Esther M
authors.initials: EM
authors.lastname: John
authors.affiliation: Cancer Prevention Institute of California, 2201 Walnut Ave #300, Fremont, CA, 94538, USA.
authors.forename: Scarlett Lin
authors.initials: SL
authors.lastname: Gomez
authors.affiliation: Cancer Prevention Institute of California, 2201 Walnut Ave #300, Fremont, CA, 94538, USA.
authors.forename: Theresa H M
authors.initials: TH
authors.lastname: Keegan
authors.affiliation: Beckman Research Institute of the City of Hope, 1500 East Duarte Road, Duarte, CA, 91010, USA.
authors.forename: Yani
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Cancer Prevention Institute of California, 2201 Walnut Ave #300, Fremont, CA, 94538, USA.
authors.forename: Salma
authors.initials: S
authors.lastname: Shariff-Marco
authors.affiliation: University of Southern California, 1540 Alcazar St. CHP-133, Los Angeles, CA, 90089-9003, USA.
authors.forename: Kristine R
authors.initials: KR
authors.lastname: Monroe
authors.affiliation: Stanford University School of Medicine, 291 Campus Drive, Stanford, CA, 94305, USA.
authors.forename: Allison W
authors.initials: AW
authors.lastname: Kurian
authors.affiliation: Cancer Prevention Institute of California, 2201 Walnut Ave #300, Fremont, CA, 94538, USA.
authors.forename: Iona
authors.initials: I
authors.lastname: Cheng
authors.affiliation: Division of Research, Kaiser Permanente Northern California, 2000 Broadway, Oakland, CA, 94612, USA.
authors.forename: Bette J
authors.initials: BJ
authors.lastname: Caan
authors.affiliation: Division of Research, Kaiser Permanente Northern California, 2000 Broadway, Oakland, CA, 94612, USA.
authors.forename: Valerie S
authors.initials: VS
authors.lastname: Lee
authors.affiliation: Division of Research, Kaiser Permanente Northern California, 2000 Broadway, Oakland, CA, 94612, USA.
authors.forename: Janise M
authors.initials: JM
authors.lastname: Roh
authors.affiliation: Beckman Research Institute of the City of Hope, 1500 East Duarte Road, Duarte, CA, 91010, USA.
authors.forename: Leslie
authors.initials: L
authors.lastname: Bernstein
authors.affiliation: University of Southern California, Health Sciences Campus, 4650 Sunset Blvd, SRT 600A, MS#54, Los Angeles, CA, 90027-6016, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Sposto
authors.affiliation: University of Southern California, Health Sciences Campus, NOR 4443, Mail Code:9175, Los Angeles, CA, 90089-9175, USA.
authors.forename: Anna H
authors.initials: AH
authors.lastname: Wu
mesh_terms: D001943:Breast Neoplasms / Q000453:epidemiology*; D002140:California / Q000453:epidemiology; D015897:Comorbidity; D057286:Electronic Health Records; D005006:Ethnicity; D005260:Female; D006801:Humans; D008875:Middle Aged; D016016:Proportional Hazards Models; D044469:Racial Groups; D012111:Residence Characteristics; D057566:Self Report; D015996:Survival Rate; D017741:Survivors; D044465:White People
keywords: Breast cancer; Comorbidity; Concordance; Misclassification; Sensitivity and specificity; Survival