title: Cluster analysis: a useful technique to identify elderly cardiac patients at risk for poor quality of life.
abstract: OBJECTIVE
  The purposes of this study are (1) to examine the frequency of cardiac symptoms in elderly people one year after acute myocardial infarction (AMI) and/or coronary artery bypass surgery (CABG); (2) to identify patient subgroups (cluster solutions) based on cardiac symptoms after cardiac events and (3) to determine if these subgroups vary based on health related quality of life and psychological distress.
  
  
  METHODS
  A sample of 206 elderly, unpartnered, patients (age > or = 65) were interviewed one year after AMI and/or CABG by telephone. Cardiac symptoms, SF-36, POMS, and QOL-I were measured. A hierarchical cluster analysis was used to identify patient subgroups based on cardiac symptoms, using a combination of dendrograms and stopping rules.
  
  
  RESULTS
  Three subgroups were identified: (1) the Weary (19.4%), (2) the Diffuse symptom (68.4%), and (3) the Breathless groups (12.2%). The Weary group had significantly lower scores on all of SF-36 subscales (except for social functioning) and higher scores on all of POMS subscales (except for Anger/hostility and Confusion/Bewilderment) compared to the Diffuse symptom group.
  
  
  CONCLUSIONS
  The cluster analysis was useful to identify the subgroup with poorer recovery. Patients in the Weary group need more attention and intervention strategies to improve their health.
authors.affiliation: School of Nursing, University of California San Francisco, San Francisco, CA 94143, USA. Yoshimi.Fukuoka@nursing.ucsf.edu
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Fukuoka
authors.forename: Teri G
authors.initials: TG
authors.lastname: Lindgren
authors.forename: Sally H
authors.initials: SH
authors.lastname: Rankin
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Cooper
authors.forename: Diane L
authors.initials: DL
authors.lastname: Carroll
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002318:Cardiovascular Diseases; D016000:Cluster Analysis; D001026:Coronary Artery Bypass; D003863:Depression; D005260:Female; D006304:Health Status; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D009203:Myocardial Infarction; D011788:Quality of Life / Q000523:psychology*; D013315:Stress, Psychological; D011795:Surveys and Questionnaires; D014481:United States