title: Medical comorbidity, acute medical care use in late-life bipolar disorder: a comparison of lithium, valproate, and other pharmacotherapies.
abstract: OBJECTIVE
  Bipolar disorder is associated with high rates of medical comorbidity, particularly in late life. Little is known about medical health service utilization and potential effects of bipolar pharmacotherapy. We hypothesized that lithium use would not be associated with higher rates of medical hospitalization.
  
  
  METHODS
  Population-based retrospective cohort study of 1388 bipolar disorder patients aged ≥66years discharged from a psychiatric hospitalization in Ontario, Canada, between 2006 and 2012. Patients were divided into lithium users, valproate users, and non-lithium/non-valproate users. The main outcome was acute non-psychiatric, medical/surgical hospitalization during 1-year follow-up.
  
  
  RESULTS
  The rate of medical hospitalizations was 0.22 per patient-year. Time-to-medical hospitalization did not differ among lithium, valproate, and non-lithium/non-valproate users after adjusting for age, sex, past medical hospitalization, and antipsychotic use. Lithium, valproate, and non-lithium/non-valproate users did not differ markedly in terms of reason for medical hospitalization, 1-year acute medical health utilization outcomes, and medical comorbidity rates.
  
  
  CONCLUSIONS
  There were high rates of health service use for medical conditions among older adults with bipolar disorder, but this did not appear to be associated with lithium use, compared to valproate and other medication use (e.g., antipsychotics). A proactive collaborative care approach may prevent medical service utilization in severe late-life bipolar disorder.
authors.affiliation: Department of Psychiatry, Sunnybrook Health Sciences Centre, University of Toronto, 2075 Bayview Avenue, Toronto, ON, Canada M4N 3M5; Geri-PARTy Research Group, Department of Psychiatry, Jewish General Hospital, McGill University, 3755 Chemin de la Côte-Sainte-Catherine, Montreal, QC, Canada H3T 1E2. Electronic address: soham.rej@mail.mcgill.ca.
authors.forename: Soham
authors.initials: S
authors.lastname: Rej
authors.affiliation: Geri-PARTy Research Group, Department of Psychiatry, Jewish General Hospital, McGill University, 3755 Chemin de la Côte-Sainte-Catherine, Montreal, QC, Canada H3T 1E2.
authors.forename: Ching
authors.initials: C
authors.lastname: Yu
authors.affiliation: Department of Psychiatry, Sunnybrook Health Sciences Centre, University of Toronto, 2075 Bayview Avenue, Toronto, ON, Canada M4N 3M5.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Shulman
authors.affiliation: Department of Psychiatry, Sunnybrook Health Sciences Centre, University of Toronto, 2075 Bayview Avenue, Toronto, ON, Canada M4N 3M5.
authors.forename: Nathan
authors.initials: N
authors.lastname: Herrmann
authors.affiliation: Institute for Clinical Evaluative Sciences, 2075 Bayview Avenue, Toronto, ON, Canada M4N 3M5.
authors.forename: Hadas D
authors.initials: HD
authors.lastname: Fischer
authors.affiliation: Institute for Clinical Evaluative Sciences, 2075 Bayview Avenue, Toronto, ON, Canada M4N 3M5; Women's College Research Institute, Women's College Hospital, 790 Bay Street, 7th Floor, Toronto, ON, Canada M5G 1N8.
authors.forename: Kinwah
authors.initials: K
authors.lastname: Fung
authors.affiliation: Institute for Clinical Evaluative Sciences, 2075 Bayview Avenue, Toronto, ON, Canada M4N 3M5; Women's College Research Institute, Women's College Hospital, 790 Bay Street, 7th Floor, Toronto, ON, Canada M5G 1N8; Institute of Health Policy, Management and Evaluation, University of Toronto, 4th Floor, 155 College Street, Toronto, ON, Canada M5T 3M6; Department of Family Medicine, University of Alberta, 6-40 University Terrace, Edmonton, AB, Canada T6G 2T4.
authors.forename: Andrea
authors.initials: A
authors.lastname: Gruneir
mesh_terms: D000368:Aged; D018692:Antimanic Agents / Q000627:therapeutic use*; D001714:Bipolar Disorder / Q000188:drug therapy*; D015897:Comorbidity; D005260:Female; D006760:Hospitalization; D006801:Humans; D018020:Lithium Compounds / Q000627:therapeutic use*; D008297:Male; D009864:Ontario; D012189:Retrospective Studies; D016019:Survival Analysis; D014635:Valproic Acid / Q000627:therapeutic use*
chemical_list: D018692:Antimanic Agents; D018020:Lithium Compounds; D014635:Valproic Acid
keywords: Bipolar disorder; Health care utilization; Lithium; Medical comorbidity; Older adults; Severe mental illness