Modelling the incidence of admission of older women to hospital, and the impact of comorbidity and frailty on hospital use

Australians have one of the highest life expectancies in the world, the proportion of the population over 60 years is increasing, and these older people account for a large proportion of health service users. In addition, at these ages, women outnumber men due to their longer life expectancy. However, women are more likely to be frail, and are more likely to require hospital service than men in later life. Even though hospital care should not be denied for older people, prevention of avoidable hospital admission and reduction in length of hospital stays are important in decreasing adverse health outcomes and the subsequent burden on the healthcare system. This study identified the frailty and chronic disease burden among older women and examined the impact on hospitalisations, unplanned readmission, length of hospital stay, and mortality. This study linked data from women in the 1921–1926 birth cohort of the Australian Longitudinal Study on Women’s Health (ALSWH) with New South Wales (NSW) Admitted Patient Data Collection (APDC) and the National Death Index (NDI), to identify hospitalisations (admission and discharge dates) and death dates. Using the International Statistical Classification of Diseases Australia Modification (ICD-10-AM) diagnostic codes, scores were calculated for the Charlson Comorbidity Index (CCI), and the Hospital Frailty Risk Score. Self-report survey data were used to calculate the Frail Scale (HFRS) and to provide other demographic, health and social information. Predictors of unplanned and planned hospitalisations were independently assessed according to the Andersen Newman healthcare utilisation model, showing predisposing and need factors were associated with unplanned admission. In contrast, predisposing and enabling factors were associated with planned admission. Women with a higher CCI had increased risk of repeated hospital admissions and mortality. More women were identified as frail through the Frail Scale compared to the HFRS. This finding highlighted that a single score may be inadequate to prognosticate for all poor outcomes associated with frailty in older people.