Introduction Telemedicine applications, including teleconsultations, can potentially improve patient health outcomes, access to health care and to reduce health care costs. “Telemedicine” means “medicine delivered at a distance”, and the exchange of information can occur synchronously (when interactions happen in real time) or asynchronously (when there is a lag between the clinical information being transmitted and the response), and through different channels, including videoconferencing, mobile applications, and secure messaging. It is also possible that one telemedicine service has a store-andforward as well as a realtime component. Although telemedicine and telehealth have been conceptualised separately, with the latter being a broader term that also incorporates activities such as patient and provider education, they are often used synonymously. Also, the terms ehealth and telehealth are most often used interchangeably. Semantically, the difference between these two concepts is that ehealth applications are not limited to health care over a distance, as is the case with telehealth. Given continuing technological innovation and the emergence of a new generation of people in a digital world, it must be emphasised the importance of studying both patients and doctors perceptions on the impact of these changes in the doctor-patient relationship. The general aim of this thesis is to explore patients’ and physicians’ perceptions of the impact of teleconsultations on clinical practice and the organisation of care of a pilot project of interactive telecardiology in the Portuguese national health system (NHS). The specific objectives are to identify the facilitators and barriers to the uptake of teleconsultations; to explore the perceptions of participants on the doctorpatient relationship and the inter-professional collaboration in health care; and to assess the effects of mobile-based technologies versus usual care for supporting communication and consultations between health care providers on their performance, acceptability and satisfaction, health care use, patient health outcomes, costs, and technical difficulties. Methods The thesis contains four research manuscripts, divided in two parts. The first group includes a Cochrane systematic review of randomised trials developed in collaboration with the Nuffield Department of Population Health, University of Oxford. We searched CENTRAL, MEDLINE, Embase and three other databases from 1 January 2000 to 22 July 2019. We searched clinical trials registries, checked references of relevant systematic reviews and included studies, and contacted topic experts. For the data collection and analysis we followed standard methodological procedures expected by Cochrane and the EPOC group. We used the GRADE approach to assess the certainty of the body of evidence for the most important outcomes. The second group includes three qualitative studies embedded in a case study of the rollout of a new service model of teleconsultations between the primary and the secondary care levels. Semi-structured interviews to patients and physicians were transcribed, stored, coded and analysed following the steps for conventional content analysis. This type of study design facilitates the understanding of the phenomenon of teleconsultations that is both context-dependent and influenced by the individual’s characteristics. We reflected on the dynamics and process of introducing teleconsultations into health care with two of the most frequently used theories in telemedicine research, namely, normalisation process theory and the diffusion of innovations, although there is scarce integration of constructs belonging to different theories found in the literature. Both of these theories highlight that the ongoing use of technology is linked to flexibility to enable care models to meet end-users’ needs and expectations, which in turn will evolve as new challenges appear. We chose qualitative methods because they may help to identify unexpected experiences, or provide in-depth understandings of how participants’ interactions with interventions produce change. The Medical Research Council (MRC) emphasises the need for qualitative exploration of participant responses, during and after intervention, to understand how change is produced in the short and longer term. Exploring the way in which this intervention is implemented can provide insight into why it has unexpected consequences, or why it works and how it can be optimised. Results The systematic review included 19 trials (5766 participants), most were conducted in high-income countries. The most frequently used mobile technology was a mobile phone, often accompanied by training if it was used to transfer digital images. Trials recruited participants with different conditions, and interventions varied in delivery, components, and frequency of contact. We judged most trials to have high risk of performance bias, and approximately half had a high risk of detection, attrition, and reporting biases. Two studies reported data on technical problems, reporting few difficulties. The qualitative studies included a total of 29 participants interviewed between September 2019 and January 2020. The first qualitative study found that patients and physicians merged in their views on ‘process’ issues, i.e., those concerning a better prioritisation of patients and an improved collaborative practice, albeit with possible technological constraints. Physicians recognised that teleconsultations presented an educational opportunity for managing patients’ health problems. Our findings suggest that not all patients would require equally intensive collaborative activities across the health system. The barriers described included difficulties using the system (technical issues) and concerns about workload as a consequence of the disruption of traditional clinical routines. Increasing the range of collaborative strategies available to health care providers may require a broader assessment of the way that care processes are structured between levels of care. Patients revealed strong support for teleconsultation on the grounds of interprofessional collaboration and avoidance of unnecessary hospital visits. The second qualitative study found that patients and physicians presented clear views about the role of the general practitioner (GP) and the cardiologist and their function in overall structure of health care. GPs felt their role was to bring expertise in the patient which could supplement the cardiologists’ expertise on the condition. However, GPs had to renegotiate roles in the teleconsultations when they saw themselves in a new situation, together with another physician and the patient. The third qualitative study found that GPs and cardiologists recognised that telemedicine between levels of care could act as a continuing medical education tool (CME). Although they departed with different expectations, telemedicine helped them collaborate as a multidisciplinary team, exchanging feedback about clinical decisions, and constructing knowledge collaboratively. Telemedicine also supplemented existing learning meetings. Conclusions Interventions including a mobile technology component to support communication among health care providers may reduce the time between presentation and management of the health condition when primary care providers or emergency physicians use them to consult with specialists, and may increase the likelihood of receiving a clinical examination among participants with diabetes and those who required an ultrasound. They may decrease the number of people attending primary care who are referred to secondary or tertiary care in some conditions, such as some skin conditions and chronic kidney disease. The implementation of teleconsultations between levels of care may be facilitated when patients, caregivers and physicians see the added value of this service, that adequate resources are put in place and that there is flexible implementation. This work adds an in-depth understanding of participants’ perceptions of this intervention in a case study. Teleconsultations can promote continuity of care for patients in the primary-secondary care interface. Active coordination between physicians with delineation of roles throughout primary-secondary care interface is needed to manage selected patients who may benefit the most from shared care. Our findings suggest that, in the context of the Portuguese NHS, telemedicine as a CME tool helped to build multidisciplinary teams which exchanged feedback and constructed shared knowledge to improve patients’ outcomes. It also helped to identify practice-changing contents to be included in faceto-face educational meetings. Adequate organisational and financial support are necessary for this new collaborative practice to succeed.