Open Access Open Badges Study protocol

High risk prescribing in older adults: prevalence, clinical and economic implications and potential for intervention at the population level

Danijela Gnjidic1234*, David G Le Couteur245, Sallie-Anne Pearson1, Andrew J McLachlan12, Rosalie Viney6, Sarah N Hilmer34, Fiona M Blyth24, Grace Joshy7 and Emily Banks78

Author Affiliations

1 Faculty of Pharmacy, University of Sydney, Bank Building A15, Science Rd, Sydney, NSW, Australia

2 Centre for Education and Research on Ageing and Concord RG Hospital, Sydney, NSW, Australia

3 Departments of Clinical Pharmacology and Aged Care, Royal North Shore Hospital and Kolling Institute of Medical Research, Sydney, NSW, Australia

4 Sydney Medical School, University of Sydney, Sydney, NSW, Australia

5 ANZAC Institute, Concord Hospital, Sydney, NSW, Australia

6 Centre for Health Economics Research & Evaluation, University of Technology, Sydney, NSW, Australia

7 National Centre for Epidemiology and Population Health, Australian National University, Canberra, ACT, Australia

8 Sax Institute, Sydney, NSW, Australia

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BMC Public Health 2013, 13:115  doi:10.1186/1471-2458-13-115

Published: 7 February 2013



High risk prescribing can compromise independent wellbeing and quality of life in older adults. The aims of this project are to determine the prevalence, risk factors, clinical consequences, and costs of high risk prescribing, and to assess the impact of interventions on high risk prescribing in older people.


The proposed project will utilise data from the 45 and Up Study, a large scale cohort of 267,153 men and women aged 45 and over recruited during 2006–2009 from the state of New South Wales, Australia linked to a range of administrative health datasets. High risk prescribing will be assessed using three indicators: polypharmacy (use of five or more medicines); Beers Criteria (an explicit measure of potentially inappropriate medication use); and Drug Burden Index (a pharmacologic dose-dependent measure of cumulative exposure to anticholinergic and sedative medicines). Individual risk factors from the 45 and Up Study questionnaire, and health system characteristics from health datasets that are associated with the likelihood of high risk prescribing will be identified. The main outcome measures will include hospitalisation (first admission to hospital, total days in hospital, cause-specific hospitalisation); admission to institutionalised care; all-cause mortality, and, where possible, cause-specific mortality. Economic costs to the health care system and implications of high risk prescribing will be also investigated. In addition, changes in high risk prescribing will be evaluated in relation to certain routine medicines-related interventions. The statistical analysis will be conducted using standard pharmaco-epidemiological methods including descriptive analysis, univariate and multivariate regression analysis, controlling for relevant confounding factors, using a number of different approaches.


The availability of large-scale data is useful to identify opportunities for improving prescribing, and health in older adults. The size of the 45 and Up Study, along with linkage to health databases provides an important opportunity to investigate the relationship between high risk prescribing and adverse outcomes in a real-world population of older adults.

High-risk prescribing; Prevalence; Clinical outcomes; Costs; Older adults