title: Association between secure patient-clinician email and clinical services utilisation in a US integrated health system: a retrospective cohort study.
abstract: OBJECTIVE
  To assess associations between secure patient-clinician email use and clinical services utilisation over time.
  
  
  METHODS
  Retrospective cohort study between July 2010 and December 2013. Controlling for a utilisation surge around first secure email use, we analysed difference of differences between propensity score-matched groups of secure patient-clinician email users and non-users for utilisation 1-12 months before and 7-18 months after first email (users) or a randomly assigned index date (non-users).
  
  
  METHODS
  US integrated healthcare delivery system.
  
  
  METHODS
  9345 adults with first secure email use between July 2011 and July 2012 and continuous enrolment for ≥30 months and 9345 adults without secure email use between July 2010 and July 2012 matched to users on demographics, health status, and baseline utilisation.
  
  
  METHODS
  Rates of office visits, patient-initiated phone calls, scheduled telephone visits, after-hours clinic visits, emergency department visits, and hospitalisations.
  
  
  RESULTS
  After controlling for multiple factors, no statistically significant differences in utilisation between secure email users and non-users occurred. Utilisation transiently increased by 88-237% around first email use. Annual rates of patient-initiated phone calls decreased among secure email users, 0.2 fewer calls per person (95% CI -0.3 to -0.1), from a mean of 4.1 calls per person 1-12 months before first use to a mean of 3.8 calls per person 7-18 months after first use. Rates of patient-initiated phone calls also decreased among non-users, 0.1 fewer calls per person (95% CI -0.2 to 0.0), from a mean of 4.2 calls per person 1-12 months before the index date to mean of 4.1 calls per person 7-18 months after the index date.
  
  
  CONCLUSIONS
  Compared with non-users, patient use of secure email with clinicians was not associated with statistically significant differences in clinical services utilisation 7-18 months after first use.
authors.affiliation: Health Information Technology Transformation and Analytics, Kaiser Permanente, Oakland, California, USA.
authors.forename: Di
authors.initials: D
authors.lastname: Meng
authors.affiliation: Institute for Health Research, Kaiser Permanente Colorado, Denver, Colorado, USA.
authors.forename: Ted E
authors.initials: TE
authors.lastname: Palen
authors.affiliation: Health Information Technology Transformation and Analytics, Kaiser Permanente, Oakland, California, USA.
authors.forename: Joanne
authors.initials: J
authors.lastname: Tsai
authors.affiliation: Health Information Technology Transformation and Analytics, Kaiser Permanente, Oakland, California, USA.
authors.forename: Melanie
authors.initials: M
authors.lastname: McLeod
authors.affiliation: Health Information Technology Transformation and Analytics, Kaiser Permanente, Oakland, California, USA.
authors.forename: Terhilda
authors.initials: T
authors.lastname: Garrido
authors.affiliation: Health Information Technology Transformation and Analytics, Kaiser Permanente, Oakland, California, USA.
authors.forename: Heather
authors.initials: H
authors.lastname: Qian
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000553:Ambulatory Care / Q000706:statistics & numerical data*; D003120:Colorado; D019033:Delivery of Health Care, Integrated / Q000706:statistics & numerical data*; D034742:Electronic Mail / Q000706:statistics & numerical data*; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D012189:Retrospective Studies; D055815:Young Adult