title: Multimorbidity is strongly associated with long-term but not short-term mortality after cardiac valve replacement.
abstract: BACKGROUND
  The presence of multimorbidity is known to be related to adverse clinical outcomes. However, its association with mortality in patients undergoing cardiac valve replacement is not known.
  
  
  METHODS
  Multimorbidity (as a continuous variable) was characterized in adults receiving cardiac valve replacement surgery between 2008 and 2012 within Kaiser Permanente Northern California based on information from health plan electronic health records. Our primary outcome was 3-year all-cause mortality after surgery. We used Cox proportional hazards regression to evaluate the independent association of each additional comorbidity with mortality.
  
  
  RESULTS
  Among 3686 eligible patients, mean age was 67.9±13.5years and median comorbidity burden was 3 (IQR: 2). The presence of most individual comorbidities except hypertension and hyperlipidemia did not occur in isolation. The unadjusted annual incidence (per 100 person-years) of death increased with higher comorbidity burden: ≤1: 4.61 (95% CI: 3.29-6.45), 2-3: 13.7 (95% CI: 11.9-15.8), 4-5: 23.6 (95% CI: 20.6-26.9), and ≥6: 43.4(95% CI: 34.6-54.4). Advancing age, diabetes mellitus, cerebrovascular accident, heart failure, lung disease, urgent status and use of aldosterone-receptor antagonists were independently associated with an increased risk of mortality. In multivariable analyses, each additional comorbidity was significantly associated with an increased risk of long-term (adjusted hazard ratio (HR) 1.30, 95% CI: 1.22-1.39) but not short-term mortality (HR 0.92, 95% CI: 0.80-1.07).
  
  
  CONCLUSIONS
  Our study demonstrated that multimorbidity in patients undergoing cardiac valve replacement is significantly associated with long-term but not short-term mortality.
authors.affiliation: Division of Cardiology, Kaiser Permanente San Jose Medical Center, San Jose, CA, United States. Electronic address: ashok.krishnaswami@kp.org.
authors.forename: Ashok
authors.initials: A
authors.lastname: Krishnaswami
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, CA, United States; Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, United States; Department of Medicine, University of California, San Francisco, CA, United States; Department of Health Research and Policy, Stanford University, Stanford, CA, United States.
authors.forename: Alan S
authors.initials: AS
authors.lastname: Go
authors.affiliation: Division of Geriatric Cardiology, University of Pittsburgh, Pittsburgh, PA, United States; Geriatric Research, Education, and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, PA, United States.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Forman
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, CA, United States.
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Leong
authors.affiliation: Department of Cardiovascular Surgery, Kaiser Permanente Santa Clara Medical Center, Santa Clara, CA, United States.
authors.forename: Hon
authors.initials: H
authors.lastname: Lee
authors.affiliation: Division of Cardiology, Columbia University Medical Center, New York, NY, United States.
authors.forename: Mathew S
authors.initials: MS
authors.lastname: Maurer
authors.affiliation: Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, United States.
authors.forename: Charles E
authors.initials: CE
authors.lastname: McCulloch
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002140:California / Q000453:epidemiology; D015897:Comorbidity; D005260:Female; D019918:Heart Valve Prosthesis Implantation / Q000401:mortality*; D006801:Humans; D015994:Incidence; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors
keywords: Cardiac valve replacement; Mortality; Multimorbidity; Multiple chronic conditions; Proportional hazards models; Valvular heart disease