Globally, the retention of specialists in the public healthcare sector remains a major problem. The exodus of specialists from the government sector to the private sector is considered perilous to the public health sector since their skills and expertise are highly demanded to perform complex procedures to ensure the best treatment outcomes for patients [1]. They play an essential role in training the junior specialists by passing down their skills and knowledge to ensure sustainability in the provision of a high-quality, accessible, and equitable healthcare system [2].

Allowing specialists to take up dual practice is one of the common policy interventions to overcome attrition in low- and high-income countries [3]. Dual practice enables healthcare professionals to serve in private health settings without quitting the public sector [4,5,6]. Such a policy has been long adopted in many countries with a two-tier health system including Malaysia [5]. Other terms used to describe dual practice included ‘public-on-private’, ‘moonlighting’, or ‘multiple job holding’. However, the existing literature generally underlines the negative impacts of dual practice on the public healthcare system [6,7,8]. McPake et al. [9] highlighted the multifactorial and contextual differences on the impact of dual practice across countries, including regulatory environments and opportunities for such practice, and levels of demand for public and private healthcare services. Published studies reported on the different consequences of dual practice and the regulatory responses between high- and low-income countries [6,10,11].

It is crucial to distinguish the different types of dual practice to appreciate different arrangements implemented in numerous settings. In general, dual practice can be classified based on the locations of healthcare professionals attending to private patients as follows: (i) ‘outside’: in a separate private setting; (ii) ‘beside’: in a private ward or clinic physically connected with a public facility but run as a private business; (iii) ‘within’: in the same public facility but outside public service operating hours at extra fees, or (iv) ‘integrated’: in the same public facility with informal payment and no time restrictions [9,12]. In this context, ‘private patient’ refers to a patient who chooses and pays for their doctor and medical care, rather than using subsidized healthcare or the care provided for free by the government. The selection of dual practice type adopted in a country is closely linked to healthcare system governance and market demand for specialist services [12], even though the ‘outside’ type is the most discussed in the existing literature.

Full-time public servants who are solely dedicated to the public sector are no longer the norm. Dual practice is not limited to high-income countries and has also been widely adopted in low- and middle-income countries (LMIC) [4,10,11,13]. Dual practice within public hospitals (DPH), has been set up in developed and developing countries alike. The implementation of this model has been reported in Austria, Ireland, Italy, Australia, United Kingdom, France, and Germany [8,10,14,15], Indonesia [5], Vietnam [16], Ethiopia [17,18], and Uganda [19].

Multiple reasons for specialists taking up dual practice have been identified. According to Ferrinho et al. [4], the extent of specialist engagement in dual practice and their reasons are contextual in nature, even though additional incomes was often cited as the key motivation [10,17,20]. Ferrinho et al. [4] also highlighted dual practice as individual coping strategies against unrealistically low salaries. Socha and Bech [6] highlighted the possibility of different motivating factors for specialists who undertook dual practice in low- and high-income countries while García-Prado and González [10] discussed evidence to relate dual practice decisions with multiple factors such as working hour restrictions, job complementarities, as well as professional, institutional, and personal issues. Hipgrave and Hort [5] suggested that among non-financial reasons for dual practice in higher income countries are extra training to gain new skills and experience from private practice for self-improvement, to boost prestige, peer approval, and larger professional contact [10].

Both positive and negative consequences of DPH have been reported in the existing literature [5,6,14]. On a positive note, DPH enhanced the employer attractiveness of the public sector [14,21,22]. Such a policy was found to improve the retention of healthcare professionals in the public sector which successfully improved access to quality service delivery [17]. At the same time, DPH was also shown to generate additional income for public hospitals [14,21,22,23,24] and enhanced patient choice for treatment preference [14,23,25]. On the contrary, DPH has also been linked to negative consequences in terms of the service provision of public hospitals. Conceptually, DPH can lead to diminished healthcare responsiveness, distorted use of physical resources, and additional strain on the public hospital administration [14]. Consequently, it can lead to a conflict of interest, competition for specialists’ time and hospital resources, and limited access for non-private patients [4,5,14,24]. Worse still, it may also erode the public’s trust in the public healthcare system [14,23], especially if DPH is poorly regulated and managed. Within this context, Mueller and Socha-Dietrich [14] concluded that the net implications of DPH are ambiguous and are highly dependent on its governance.

In general, there is no single best method in the management of dual practice, with different strategies being adopted by governments [26]. In some countries, the government approach was to ban dual practice; for example, in China and Canada [10]. Prohibition as a means of controlling dual practice was deemed as highly ineffective, often resulting in an undesirable loss of valuable healthcare professionals [4,11,14]. In some countries such as Austria and the United Kingdom, dual practice is allowed but regulations are put in place to prevent or to alleviate the potential adverse consequences [11,13]. On the other extreme, dual practice without any restriction or regulation is generally not recommended because it will lead to various negative consequences [5].

Interestingly, the characteristic of DPH is viewed as one of the better option to facilitate the regulation of dual practice as it could be more easily controlled and governed [5,6,13,27]. To allay the concerns about conflicts of interest and competing priorities, some countries set a maximum amount of specialists’ earnings from DPH [13]. For example, public hospitals in France also shared a portion of the specialists’ earnings from DPH [14]. While previously, the National Health Service (NHS) in the UK limited the earnings from DPH to 10% of specialists’ incomes [14]. As González and Macho-Stadler [11] opined that limiting the activities of healthcare professionals rather than their incomes is likely to be more effective in regulating DPH, the NHS lifted the restriction in 2003 but emphasized specialists must ensure that their private practice does not result in a detrimental effect on NHS patients or services, nor diminish the public resources that are available for the NHS [28]. The plan to mandate income declarations was also cancelled in 2017 [14,29]. Apart from limiting the time devoted to DPH to less than 20% of worktime, France set a limit to the volume of services delivered [14]. DPH was also limited to senior physicians in some countries, such as Ireland [14], Kenya, and Zambia [8]. The types of enforcement are crucial as the arrangement of DPH has a larger implication in terms of higher risks of public resource mismanagement and conflict of interest [5,13,14].

In Malaysia, public specialists are allowed to perform both the ‘outside’ (locum at private hospitals) and ‘within’ types of dual practice [Full Paying Patient (FPP) Service]. Under the FPP, patients are treated by their specialists of choice in first-class wards and charged at full rate without receiving any government subsidies for the treatment [30]. Although FPP has long been offered since 2007, the information regarding its implementation is still limited. Therefore, this narrative review aimed to fill the gap by summarizing the evidence for the implementation of DPH in Malaysia, focusing on specialists serving in the public healthcare sector. We describe the extent of DPH, the motivations behind its implementation, the consequences of the practice, the service regulatory measures by the Ministry of Health (MOH) Malaysia, and the main challenges of this type of dual practice.

Malaysia is an upper-middle-income country with a two-tier health system. The public healthcare sector is funded predominantly through general taxation in co-existence with a market-driven private health sector that consists of mostly physician-owned clinics and hospitals [31]. All citizens in the country are entitled to a range of subsidized healthcare services, including both inpatient and outpatient care in the public system with nominal user charges [32]. The total expenditure on health (TEH) in Malaysia between 1997 to 2019 ranged from 3.04% to 4.30% of the Gross Domestic Product (GDP). In 2019, the TEH was 4.3% of GDP, 52% of which was contributed by the public sector [33]. As high as 99% of the health expenditure in the public sector was subsidized by the government and patients only co-pay 1–2% of the total cost [34]. More than half of the health expenditure in the public sector (55%) in 2019 was allocated to the wages for the employees of the MOH [35].

The 67th World Health Assembly adopted the Global Strategy on Human Resources for Health: Workforce 2030 with the aim to ensure universal availability, accessibility, acceptability, coverage, and quality of the health workforce through adequate investment to strengthen health systems and implementation of effective policies [36]. To pursue universal health coverage, all countries need adequate qualified medical specialists of multiple disciplines [9]. Nonetheless, the density of various clinical specialists in Malaysia is still relatively low (3.23 specialists per 10,000 populations). The selected member states of the Organization for Economic Co-operation and Development (OECD), for example, recorded an average density as high as 22.4 specialists per 10,000 populations [31].

Approximately 60% of the specialists in Malaysia serve in public hospitals [31]. They are responsible for the care provided to 70% of the inpatients in Malaysia, not to mention their role in training junior doctors [37]. The bed capacity in public hospitals is also nearly three times larger than that of private hospitals [38]. However, the rapid expansion of the private health sector catalyzes the loss of medical specialists in public hospitals. According to Amir and Ezat [2], 6.4% of MOH specialists left the public healthcare sector in 2000. They attributed the leaving of specialists from the public healthcare sector to job dissatisfaction due to suboptimal work environment, the lack of career paths, ineffective management and low salaries.

The Malaysian government has introduced multiple strategies to retain specialists in the public health sector, including offering financial incentives. Financial incentives play an important role in influencing individuals’ choice of workplace and have always been applied to address workforce shortage in healthcare worldwide [3,39]. While public sector health workforce under MOH receive fixed monthly salaries according to a salary scale with bands that vary by professional classification and grade, their counterparts in the private sector are mainly remunerated through fee-for-service payments [32,40]. On top of the fixed monthly salaries, they are entitled to specific allowances which make up approximately 20% and 50% of the total gross salary of non-specialists and specialists, respectively [40]. Currently, senior specialists in public hospitals could earn up to RM 14,000 excluding allowances and can make up to approximately RM 21,000 per month including allowances [41,42]. It has been claimed that private hospitals are often able to provide a 10-times-higher pay [43]. Regarding working hours, medical doctors in Malaysia generally need to work for at least 75 h weekly [44]. To reduce the attrition of specialists, time-based promotion and the permission to practice in private healthcare settings (locum) during out-of-office hours were also introduced [40]. Despite these initiatives, 30% of medical specialists in Malaysia had a tendency to quit the public sector within three years due to their discontentment with salaries, benefits and allowances, and location and facilities of workplaces being the significant contributing factors [45].

In many LMICs, seeking additional incomes by taking on fee-for-service private patients is common among healthcare workers [11,17]. Resorting to dual practice to meet their financial needs implied the inability of health ministries to ensure sufficient salaries [4]. In view of this, it may be more feasible and practical for the public sector to keep their skilled health workers at a low budgetary cost by allowing them to perform dual practice [10,46]. ‘FFP Service’ emerged against such a background in Malaysia [47].

According to Rahim and Mwanri [39], there is a paucity of evidence, particularly in the Malaysian context, on the long-term retention of health professionals. On top of that, despite the rapid expansion of mixed healthcare systems in the South and East Asia region, Hipgrave and Hort [5] highlighted the scanty evidence of dual practice in Southeast Asia. More research is required to inform health policies related to the recruitment and retention of healthcare professionals in the public sector. Therefore, this paper specifically discussed the various aspects of the FPP Service implementation as DPH in the Malaysian public healthcare sector.

It is noted that the FPP service is only available in 10 out of 146 public hospitals in Malaysia to date. The implementation of FPP Service reveals that the distinctive realms between public and private healthcare are progressively blurry in this country. FPP Service is a reflection that the Malaysian mixed public-private healthcare system has evolved to improve individual wellbeing by offering a greater choice of provider and care options, as well as faster access for elective treatments [70].

Conceptually, DPH is likely to improve the employer attractiveness of the public sector [14]. Therefore, it would help enhance the access to and quality of healthcare. The increasing number of participants of the FPP service also implies its effectiveness in retaining medical specialists in the public sector. Our review also found that the convenience of performing private practice within the same hospital setting and the attractiveness of government benefits such as special allowances, guaranteed seniority, and promotion with higher salary are the main reasons that specialists prefer to involve in the ‘within’ type of dual practice such as FPP compared to the ‘outside’ form of full private practice [51]. Similar to findings by Ferrinho et al. [4], García-Prado and González [10], and Abera et al. [17], some specialists in Malaysia still decided to stay in public hospitals and join DPH, as they highly value some of the elements in the public sector despite a lower pay. They expressed willingness to devote more efforts and time doing multiple jobs to benefit the ‘best of the two worlds’. Such findings indicated that DPH was effective in retaining public specialists to a certain extent. The review also discussed the growing demand for the FPP Service. Similar to Malaysia, the increasing trend of private patients in public hospitals was also reported in Australia [21] and the United Kingdom [22]. This can be attributed to the enhancement of patients’ choice of medical service delivery within public healthcare by providing alternatives to patients who can afford to pay without compromising the quality of care [23,25]. The freedom to choose an alternative arrangement of amenities such as executive or first class wards, and specialists of preference are among the key features of the dual practice, which makes it appealing to patients [14,25]. This is evidenced by the high satisfaction level reported by the patients under the FPP service [56]. On top of that, DPH improves the efficiency of hospitals, mainly through the optimal resource utilization [32]. However, a high demand for FPP service could exacerbate some of the existing problems in public hospitals, including overcrowding and long waiting time [71]. Waiting time is always used as an indicator of health service quality [72]. Conflicts of interest arising from DPH has also become a concern in Ireland, and the Sláintecare Report [73] called for the termination of DPH due to health inequalities. Another related issue which needs extra attention is the possibility of supplier-induced demand to happen. FPP specialists may perform more procedures or overtreat patients since they are now able to receive more incentives by performing via FPP Service. This may inflate the total healthcare expenditure in Malaysia in the long run. Hence, a further evaluation of the outcomes of the FPP service in Malaysia is warranted.

A portion of the revenue generated from DPH could be reinvested on public hospitals to improve the healthcare quality and alleviate the budgetary pressure [23]. Empirical evidence in certain countries, such as in Rwanda, demonstrated benefits of DPH in the form of upgraded public healthcare facilities and revenue flows [74]. DPH represents as important source of extra revenue for public hospital in Ireland, Australia, and the United Kingdom [14,21,22,23,24]. In fact, the NHS in the UK has encouraged hospitals to generate additional incomes from DPH [22,23]. The UK passed the Health and Social Care Act 2012, which increased the allowed amount to be earned from DPH from 2% to 49% of total hospital earnings [23,75]. Patients seeking subsidized care could also indirectly benefit from the improved healthcare quality [23]. However, as revenues generated from the FPP service is returned to the central treasury in Malaysia [34,54], it is important to ensure that they are used for healthcare. While poor financial planning and management for DPH have been reported [21,22,25], the issue of consumables not listed under the FPP Fee Schedule raised by Amir et al. [51] and Hairusnizan et al. [57] also warrants immediate attention.

Most of the challenges of the FPP Service are associated with the sharing of infrastructure and workforce. Ideally, the FPP service must be delivered effectively without compromising the level of responsiveness to patients seeking subsidized healthcare [13,14]. As argued by Kiwanuka et al. [8], the success of private care embedded within public facilities highly depends on adequate resource availability in terms of infrastructure, resources, and personnel to deliver private care on top of the routine service for public patients. Failing so, it is potentially likely that the resources are shifted to the private care sector within the public facility, whether intentionally or not [46], subsequently leading to the misuse of public resources [10,13] that will compromise the quality of public health services. If these challenges are not addressed, they can corrode public trust towards public service delivery as highlighted by Mueller and Socha-Dietrich [14].

DPH is complicated and reported to add additional burden to hospital administration [69], similar to as highlighted in the literature [14,24,25]. Hospital authorities need to deal with various aspects of DPH, including revenues, service delivery and resource management, if it is adopted. In several countries, hospitals are required to maintain a separate account for DPH to avoid cross-subsidization between public and private care [14]. While health authorities used different ways to cope with the challenges [19], it is important for policymakers to provide them with sufficient training and resources in addition to clear guidelines [23].

This review also highlighted the achievements of the FPP Service in ten public hospitals and suggested DPH expandability to other hospitals in Malaysia. Nevertheless, the concerns about the widening of health inequalities caused by DPH [18,22,73] should be addressed, as its impacts are often context-specific and multifactorial [9].

Undeniably, dual practice is a complex phenomenon with ambiguous effects on the healthcare sector’s performance [10]. In general, some of the criticisms surrounding dual practice was its negative impact on the quality, efficiency, and equity of the delivery of healthcare services [5], especially prevalent in low- and middle- income countries due to weak governance, suboptimal monitoring, and poor supervision [20]. Despite the increasing prominence of dual practice worldwide, there is still a lack of rigorous and scientifically reliable evidence to determine the net impact of this practice [6,10,12,14,20,26]. Therefore, it remains impossible to conclude if the benefits of dual practice outweigh its negative consequences. The achievement of universal healthcare coverage may be impeded by unregulated dual practice [9]. Many unanswered questions revolve around the effects and outcomes of dual practice. Thus, a more in-depth study is needed to analyze the consequences of DPH in Malaysia to facilitate decision makers in strategizing the best interventions to optimize the potentials of dual practice.

Dual practice policy and regulatory response continues to be a topic that generates wide interest among researchers [5,6,7,8,10,11,13,26,46]. González and Cuadrado [7] highlighted that it is still challenging to implement dual practice in most of the low- and middle-income countries due to the lack of regulations. Similarly, Hipgrave and Hort [5] as well as García-Prado and González [10] stated that weak governance and lax regulation of dual practice in developing countries led to a higher possibility of negative consequences. In Malaysia, the FPP service was regulated by limiting the specialists’ engagement, incomes, time spent and the number of patients. Although sharing facilities are likely to ease the governance of the FPP Service [10], the concerns of specialists about the misuse of resources should be addressed. The different viewpoints from the specialists regarding the FPP service monitoring need to be further explored [51]. If DPH is to be expanded in Malaysia, MOH should ensure adequate monitoring capacity for hospitals involved. A strong monitoring structure will ensure a good regulation and the eventual success of dual practice [8].