Examining different measures of multimorbidity, using a large prospective cross-sectional study in Australian general practice

Abstract

ObjectivesPrevalence estimates of multimorbidity vary widely due to inconsistent definitions and measurement methods. This study examines the independent effects on prevalence estimates of how ‘disease entity’ is defined—as a single chronic condition or chapters/domains in the International Classification of Primary Care (V.2; ICPC-2), International Classification of Disease (10th revision; ICD-10) or the Cumulative Illness Rating Scale (CIRS), the number of disease entities required for multimorbidity, and the number of chronic conditions studied.DesignNational prospective cross-sectional study.SettingAustralian general practice.Participants8707 random consenting deidentified patient encounters with 290 randomly selected general practitioners.Main outcome measuresPrevalence estimates of multimorbidity using different definitions.ResultsData classified to ICPC-2 chapters, ICD-10 chapters or CIRS domains produce similar multimorbidity prevalence estimates. When multimorbidity was defined as two or more (2+) disease entities: counting individual chronic conditions and groups of chronic conditions produced similar estimates; the 12 most prevalent chronic conditions identified about 80% of those identified using all chronic conditions. When multimorbidity was defined as 3+ disease entities: counting individual chronic conditions produced significantly higher estimates than counting groups of chronic conditions; the 12 most prevalent chronic conditions identified only two-thirds of patients identified using all chronic conditions.ConclusionsMultimorbidity defined as 2+ disease entities can be measured using different definitions of disease entity with as few as 12 prevalent chronic conditions, but lacks specificity to be useful, especially in older people. Multimorbidity, defined as 3+, requires more measurement conformity and inclusion of all chronic conditions, but provides greater specificity than the 2+ definition. The proposed concept of “complex multimorbidity”, the co-occurrence of three or more chronic conditions affecting three or more different body systems within one person without defining an index chronic condition, may be useful in identifying high-need individuals.

An investigation of multimorbidity measures as risk factors for pneumonia in elderly frail patients admitted to hospital

“…Measuring the clinical complexity of multimorbid geriatric patients may in fact be sometimes challenging. The prevalence of multimorbidity itself in such patients may vary according to the chosen method of assessment [7,8]. However, there is a general consensus that the presence of multimorbidity is associated with a higher number of hospitalizations and medical visits [9][10][11].…”

Diverse Cumulative Impact of Chronic Diseases on Physical Health–Related Quality of Life: Implications for a Measure of Multimorbidity

“…Debate continues on the definition and measurement of multimorbidity for clinical care and research (4)(5)(6). Heterogeneity in the impact of chronic conditions is not characterized optimally, and this hampers consistent, systematic efforts to study multimorbidity.…”

Prioritising general practice research

“…61 This change in the age distribution of patients at GP encounters will affect all aspects of general practice as older patients are more likely to have more problems managed at encounters, more chronic conditions managed and are more likely to have multimorbidity. 23 There was a significant decrease in the proportion of encounters with patients who were new to the practice (from 9.1% in 2005-06 to 6.3% in 2014-15). This may be due to the need for continuity of care for chronic conditions.…”

“…Those interested in the prevalence of disease and multimorbidity should refer to the following papers: Estimating prevalence of common chronic morbidities in Australia, 20 Prevalence and patterns of multimorbidity in Australia, 21 Prevalence of chronic conditions in Australia, 22 and Examining different measures of multimorbidity, using a large prospective cross-sectional study in Australian general practice. 23 …”