title: Patterns of multimorbidity in working Australians.
abstract: BACKGROUND
  Multimorbidity is becoming more prevalent. Previously-used methods of assessing multimorbidity relied on counting the number of health conditions, often in relation to an index condition (comorbidity), or grouping conditions based on body or organ systems. Recent refinements in statistical approaches have resulted in improved methods to capture patterns of multimorbidity, allowing for the identification of nonrandomly occurring clusters of multimorbid health conditions. This paper aims to identify nonrandom clusters of multimorbidity.
  
  
  METHODS
  The Australian Work Outcomes Research Cost-benefit (WORC) study cross-sectional screening dataset (approximately 78,000 working Australians) was used to explore patterns of multimorbidity. Exploratory factor analysis was used to identify nonrandomly occurring clusters of multimorbid health conditions.
  
  
  RESULTS
  Six clinically-meaningful groups of multimorbid health conditions were identified. These were: factor 1: arthritis, osteoporosis, other chronic pain, bladder problems, and irritable bowel; factor 2: asthma, chronic obstructive pulmonary disease, and allergies; factor 3: back/neck pain, migraine, other chronic pain, and arthritis; factor 4: high blood pressure, high cholesterol, obesity, diabetes, and fatigue; factor 5: cardiovascular disease, diabetes, fatigue, high blood pressure, high cholesterol, and arthritis; and factor 6: irritable bowel, ulcer, heartburn, and other chronic pain. These clusters do not fall neatly into organ or body systems, and some conditions appear in more than one cluster.
  
  
  CONCLUSIONS
  Considerably more research is needed with large population-based datasets and a comprehensive set of reliable health diagnoses to better understand the complex nature and composition of multimorbid health conditions.
authors.affiliation: School of Medicine, Griffith University; University Drive Meadowbrook, Queensland 4131, Australia.
authors.forename: Libby
authors.initials: L
authors.lastname: Holden
authors.affiliation: School of Medicine, Griffith University; University Drive Meadowbrook, Queensland 4131, Australia.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Scuffham
authors.affiliation: Queensland Centre for Mental Health research, Queensland Health; Level 3 Dawson house, The Park, Wacol, Queensland 4076, Australia.
authors.forename: Michael F
authors.initials: MF
authors.lastname: Hilton
authors.affiliation: University of Queensland, School of Population Health; Herston Road Herston, Queensland 4006, Australia.
authors.forename: Alexander
authors.initials: A
authors.lastname: Muspratt
authors.affiliation: School of Medicine, Griffith University; University Drive Meadowbrook, Queensland 4131, Australia.
authors.forename: Shu-Kay
authors.initials: SK
authors.lastname: Ng
authors.affiliation: Queensland Centre for Mental Health research, Queensland Health; Level 3 Dawson house, The Park, Wacol, Queensland 4076, Australia.|University of Queensland, School of Population Health; Herston Road Herston, Queensland 4006, Australia.
authors.forename: Harvey A
authors.initials: HA
authors.lastname: Whiteford