21 July 2018

Australian General Practice

'Overcoming the data drought: exploring general practice in Australia by network analysis of big data' by Bich Tran, Peter Straka, Michael O Falster, Kirsty A Douglas, Thomas Britz and Louisa R Jorm in (2018) 209(2) Medical Journal of Australia 68-73 reports on investigation of the organisation and characteristics of medical general practice in Australia by applying novel network analysis methods to national Medicare claims data.

The authors analysed Medicare claims for general practitioner consultations during 1994–2014 for a random 10% sample of Australian residents, and applied hierarchical block modelling to identify provider practice communities (PPCs) covering around 1.7 million patients per year.

 They conclude that the number of PPCs fluctuated during the 21-year period; there were 7747 PPCs in 2014. The proportion of larger PPCs (six or more providers) increased from 32% in 1994 to 43% in 2014, while that of sole provider PPCs declined from 50% to 39%. The median annual number of claims per PPC increased from 5000 (IQR, 40–19 940) in 1994 to 9980 (190–23 800) in 2014; the proportion of PPCs that bulk-billed all patients was lowest in 2004 (21%) and highest in 2014 (29%).

Continuity of care and patient loyalty were stable; in 2014, 50% of patients saw the same provider and 78% saw a provider in the same PPC for at least 75% of consultations. The density of patient sharing in a PPC was correlated with patient loyalty to that PPC.

They argue
A strong primary care system that delivers appropriate care at the right time and in the right place is the bedrock of the Australian health care system. General practitioners are the major providers of primary care and serve as gatekeepers to specialist care and other components of the health care system. Almost all GP services are provided privately on a fee-for-service basis. Rebates are provided to patients by the national health insurance scheme according to the Medicare Benefits Schedule (MBS), and patients may seek care from several providers and at multiple locations. However, there is a dearth of information on the organisation and characteristics of Australian general practice. For example, the proportion of general practices that are accredited has not been reported since 2011,1 as the total number of practices is not known. 
Since the final Annual Survey of Divisions (ASD) in 2011–12,2 national data on the structure and characteristics of general practices have not been systematically reported. The Bettering the Evaluation and Care of Health (BEACH) survey3 was the only national study of general practice activity, describing the characteristics and activity of a representative sample (13% of practising GPs), but the program ended in 2016. The Medical Directory of Australia (MDA), published by the Australian Medical Publishing Company (http://www.ampco.com.au/mda-online), publishes estimates of the size of the GP workforce, but their data are based on mailing addresses, which do not necessarily match practice location. The National Health Workforce Dataset (NHWDS) includes data based on a survey voluntarily completed by practitioners during their annual registration, but it focuses on practitioners, not practices. Claims for subsidised services in the MBS are made on the basis of Medicare provider numbers, but, as practice location is not routinely linked, MBS data provide no information about practice activities. 
Efforts to understand the complex determinants of the quality of and variations in health care have led to the emergence of a new research approach, the application of data-driven methods to identifying and characterising networks of health care providers. A network is a set of people or groups of individuals, organisations, or other entities (“nodes”) with a pattern of interactions (“edges”). Administrative claims data have been analysed in the United States to investigate variations in the characteristics of patient-sharing networks,6,7 how these naturally occurring networks of providers are related to variations in health care costs, and quality of care.   
In this article, we report the first study to apply network analysis of national Medicare claims data in Australia to derive provider practice communities (PPCs); that is, groups of providers who share patients with each other to a greater extent than with other provider groups, as in group general practices (although a PPC does not necessarily correspond directly with a specific group practice). Using Medicare claims for the 21-year period 1994–2014 and a novel graph-partitioning algorithm, we examined trends in the number of PPCs and their characteristics, including size, bulk-billing rate, continuity of care, patient loyalty, and patient sharing.
In summary
During 1994–2014, Australian GP practice communities have generally increased in size, but continuity of care and patient loyalty have remained stable. Our novel approach to the analysis of routinely collected data allows continuous monitoring of the characteristics of Australian general practices and their influence on patient care.