The prevalence of complex multimorbidity in Australia.

OBJECTIVE: To measure prevalence of multimorbidity and complex multimorbidity in the Australian population from a nationally representative prospective study and to identify the most prevalent patterns of chronic conditions and body systems affected.

METHODS: A sub-study of the nationally representative BEACH program, using a random sample of 8,707 patients at encounters with 290 general practitioners. All diagnosed chronic conditions were recorded for each patient. Multimorbidity was defined as co-occurrence of 2+ chronic conditions, while complex multimorbidity was defined as 3+ body systems each affected by at least one chronic condition.

RESULTS: We estimated: 47.4% of patients at GP encounters and one-third (32.6%) of the population had multimorbidity; and 27.4% of patients at GP encounters and 17.0% of the Australian population had complex multimorbidity. The most prevalent combination pattern of three conditions was hypertension+hyperlipidaemia+ osteoarthritis (5.5% of patient at encounters and 3.3% of the population). Most prevalent combination of three body systems affected was circulatory+musculoskeletal+endocrine / nutritional/metabolic systems (11.1% of patients at encounters and 7.0% of the population).

CONCLUSIONS AND IMPLICATIONS: A significant proportion of Australians have not only multimorbidity, but complex multimorbidity. To meet the challenge posed by complex multimorbidity, the single disease focus of our healthcare system needs to be re-evaluated.