The efficiency of the EmERGE pathway to provide continuity of care for medically stable people living with HIV in Belgium.

The life-expectancy of people living with HIV (PLHIV) has increased due to the earlier and increased use of antiretroviral drugs (ARVs) [1]. The life-expectancy of PLHIV now approximates that of people not living with HIV [2]. Increased life-expectancy will increase the number of PLHIV including those aged 50 years or older [3]. NonHIV cancers, cardiovascular disease, and other noncommunicable diseases (NCDs) are the most common comorbidities in older PLHIV and the most common cause of death of PLHIV in high-income countries. These NCDs also are becoming more prevalent in lowand middle-income countries [4,5] and PLHIV will increasingly need to use HIV and non-HIV health and social services. As part of their HIV-response, many countries are monitoring and evaluating the use, cost, outcome and impact of health services for PLHIV and tracking them across sites [6], which can assist in developing more integrated and cost-effective health services [7]. Mobile Health (mHealth), or the use of wireless technology to deliver health services and information using mobile communication devices, such as mobile phones or other devices [8,9], plays an important role in linking and integrating health services. An increased use of mHealth has been seen in Belgium [10], the United States [11] and other countries as part of their respective responses to their 2020 COVID-19 epidemic. mHealth provides an increasingly important role to ensure continuity of medical and paramedical care in countries, including the management of acute and chronic diseases, such as cancer services [12]. The published studies on mHealth interventions, however, indicate the variable effectiveness of mHealth tools, for those that were HIV-specific [8,9,13] or mHealth tools for other chronic diseases [14,15]. Most of these studies were performed in high-income countries; however, mHealth is increasingly being used in lowand middle-income countries [16–21]. The Evaluating mHealth technology in HIV to improve Empowerment and healthcare utilisation: Research and innovation to Generate Evidence for personalised care (EmERGE) Project co-designed, developed and implemented a new digital mHealth Pathway, including a mobile health application (App) [22]. This allowed for the electronic transfer of personal health information to people living with medically stable HIV and communication with their caregivers [12]. A recent review identified nine functions that an mHealth App ought to fulfil [9]. These functions covered many of the communication aspects, but two important aspects were missing: firstly, that data collected, transmitted, and stored at either end are protected in terms of their confidentiality and security (Table 1); secondly such technology needs to be affordable and efficient [23]. Most studies to date have not included the cost for developing, implementing, and supporting these mHealth Apps, let alone assess their cost-effectiveness or potential cost-savings that mHealth potentially provides. The need for efficiency studies was recognized more than two decades ago [24,25], but few costeffectiveness, cost-minimization or cost–benefit studies have been performed since [8,9,26]. Such information gaps necessitate the development and implementation of long-term national research agendas on mHealth [26]. This study assessed the cost-effectiveness of developing and implementing the EmERGE Pathway across five HIV clinics in five European countries: England, Croatia, Portugal, Spain and Belgium. This study investigated the cost-effectiveness of implementing EmERGE at the Prince Leopold Institute for Tropical Medicine (ITM), Antwerp, Belgium. The objectives of this study were as follows: 1) to calculate the annual mean use of services per patient-year (MPPY) one-year preand post-implementation of EmERGE; 2) to calculate unit costs of outpatient services provided by departments to EmERGE participants; 3) to calculate the average annual costs per patient-year (PPY) one-