title: Effect of continuity of care on hospital utilization for seniors with multiple medical conditions in an integrated health care system.
abstract: OBJECTIVE
  Lower continuity of care has been associated with higher rates of adverse outcomes for persons with multiple chronic medical conditions. It is unclear, however, whether this relationship also exists within integrated systems that offer high levels of informational continuity through shared electronic health records.
  
  
  METHODS
  We conducted a retrospective cohort study of 12,200 seniors with 3 or more chronic conditions within an integrated delivery system. Continuity of care was calculated using the Continuity of Care Index, which reflects visit concentration with individual clinicians. Using Cox proportional hazards regression permitting continuity to vary monthly until the outcome or censoring event, we separately assessed inpatient admissions and emergency department visits as a function of primary care continuity and specialty care continuity.
  
  
  RESULTS
  After adjusting for covariates (demographics; baseline, primary, and specialty care visits; baseline outcomes; and morbidity burden), greater primary care continuity and greater specialty care continuity were each associated with a lower risk of inpatient admission (respective hazard ratios (95% CIs) = 0.97 (0.96, 0.99) and 0.95 (0.93, 0.98)) and a lower risk of emergency department visits (respective hazard ratios = 0.97 (0.96, 0.98) and 0.98 (0.96, 1.00)). For the subgroup with 3 or more primary care and 3 or more specialty care visits, specialty care continuity (but not primary care continuity) was independently associated with a decreased risk of inpatient admissions (hazard ratio = 0.94 (0.92, 0.97)), and primary care continuity (but not specialty care continuity) was associated with a decreased risk of emergency department visits (hazard ratio = 0.98 (0.96, 1.00)).
  
  
  CONCLUSIONS
  In an integrated delivery system with high informational continuity, greater continuity of care is independently associated with lower hospital utilization for seniors with multiple chronic medical conditions. Different subgroups of patients will benefit from continuity with primary and specialty care clinicians depending on their care needs.
authors.affiliation: Institute for Health Research, Kaiser Permanente Colorado, Denver, Colorado Department of Family Medicine, University of Colorado Denver, Aurora, Colorado elizabeth.bayliss@kp.org.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Bayliss
authors.affiliation: Institute for Health Research, Kaiser Permanente Colorado, Denver, Colorado.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Ellis
authors.affiliation: Institute for Health Research, Kaiser Permanente Colorado, Denver, Colorado.
authors.forename: Jo Ann
authors.initials: JA
authors.lastname: Shoup
authors.affiliation: Institute for Health Research, Kaiser Permanente Colorado, Denver, Colorado.
authors.forename: Chan
authors.initials: C
authors.lastname: Zeng
authors.affiliation: Institute for Health Research, Kaiser Permanente Colorado, Denver, Colorado.
authors.forename: Deanna B
authors.initials: DB
authors.lastname: McQuillan
authors.affiliation: Institute for Health Research, Kaiser Permanente Colorado, Denver, Colorado Department of Internal Medicine, University of Colorado Denver, Aurora, Colorado.
authors.forename: John F
authors.initials: JF
authors.lastname: Steiner
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease; D015331:Cohort Studies; D015897:Comorbidity; D003266:Continuity of Patient Care; D019033:Delivery of Health Care, Integrated; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D011320:Primary Health Care / Q000379:methods*; D016016:Proportional Hazards Models; D012189:Retrospective Studies
keywords: comorbidity; continuity of care; multimorbidity; older adults; physician-patient relations; utilization