The ownership of medical care providers outside of hospitals in many countries is private. Private owners of general practices have traditionally been self-employed GPs in small partnerships or working as solo-practitioners. However, this ownership model has been changing in some countries, with increasing numbers of practices owned by private corporate medical groups with non-GP shareholders [4,17,23]. Though all primary care providers need to earn revenue to cover their costs and ensure a preferred level of take-home pay for each GP partner, non-GP shareholders will also require a return on their investment and may be more strongly motivated to maximise profits.

Corporate medical groups are defined as GP practices which have non-GP shareholders (in Australia these are private companies but not partnerships, which allow private equity investment) and which operate across multiple locations. A more salient profit motive provides stronger incentives to increase organisational efficiency. This includes reducing waste and keeping costs low, by for example using a less costly skill-mix. Corporate medical groups may seek to be more efficient by exploiting economies of scale by spreading fixed costs, such as IT infrastructure, billing and administrative functions, across a group of practices. Lowering costs and reducing waste are key aspects of improving efficiency and high value healthcare [33]. Stronger motivation to increase profits may also result in strategies to increase revenue. This may include attracting more patients through increasing patient experience and quality of care as well as lower out of pocket costs. This could include providing a wider range of onsite services (including pathology, practice nurses and allied health professionals), shorter waiting times and more flexible appointment systems. Corporate medical groups could also increase performance management of staff which can influence the wellbeing and workload of GPs and their pay and conditions. They may offer different employment contracts for GPs and other staff (including pay, other benefits and working conditions) and seek to employ GPs and other staff at lower rates of pay (and of lower quality) as they seek to reduce costs. This could increase turnover of GPs and other staff, leading to lower continuity of care, a key defining element of providing high quality of care in general practice [36].

On the other hand, stronger profit motives could reduce aspects of quality that are not measured or not easily observable by patients. These may include health outcomes, but also process measures since patients may not be aware they are receiving low value care, since they may view a prescription and referral as high quality. Depending on whether there is patient enrollment/registration, corporate practices may be more likely to use their discretion as to which patients they will accept, with incentives to ‘cream skim’ and select only healthier (lower cost) patients, reducing access to primary healthcare for patients most in need and with complex conditions. This can also happen with adoption of e-health and online services which can exclude those who are not digitially literate, such as the elderly. Under fee-for-service, there are incentives to see a high volume of patients with shorter consultation lengths, which could potentially also increase inappropriate prescribing and referrals and the provision of low value care. These incentives can be amplified where there is competition [18,30,32]. Therefore, the effects of the payment system and higher levels of competition may interact to reduce quality of care

There is very little evidence on the effects of corporate ownership on physician practice styles, costs, or quality of care, compared to more traditional private ownership models such as partnerships wholly-owned by doctors [10]. In the U.S. there is a trend for physician practices to be owned by larger private hospital groups, commercial Health Maintenance Organisations or Accountable Care Organisations. These practices are larger, have lower use of quality improvement initiatives compared to federally-run practices (but higher than physician-owned practices), have similar levels of four cardiovascular preventive care measures, and provide lower value healthcare compared to federally run-practices and community health centres [23,[25], [26], [27]]. In the UK, patient satisfaction and continuity of care were lower at practices that were limited companies [7]. These studies did not examine aspects of organisational efficiency or physician wellbeing. In New Zealand, for-profit practices served younger and less vulnerable populations, charged higher fees, were less integrated into community planning, had more written policies, and employed less experienced GPs, compared to community owned primary care practices [8,9,19], providing some evidence on effects on costs and methods to raise revenue. In Australia, one study found no association between the quality of diabetes management between corporates and non-corporates [16].

There have been several attempts to summarise the issues and measure prevalence in Australia [10,14,15,21]. There are no administrative data on the number and type of GP practices in Australia [10]. The total number of general practices was estimated to be 8,147 in 2019 but there remain no other data on the total number of general practices in Australia [28]. The Department of Health [12] used self-reported corporate ownership and matching using contact details, Australian Company Number, and owner/trading names to determine if practices were ‘associated’ with one another, since multiple practices can be owned or partly owned by the same business entity. Data from surveys showed that around 12% of GPs worked in corporate practices in 2010/11 and around eight percent in 2011/12 [5]. Later surveys suggested this had reached 13.5% by 2015 [15]. The most recent survey data in 2020 found that 16% of GPs work in corporate practices [35], though this was based on a small and unrepresentative sample.

The aim of this paper is to fill the gaps in evidence by examining the association between being in a corporate medical group and a range of outcome measures organized into five broad groups: GP wellbeing, workload, patient access, organizational efficiency and service quality.