In recent decades, health systems have faced the need to transform their vertical structure, conceived under the paradigm of fragmentation between various departments and different care levels, into a more horizontal structure in which healthcare organization is more consistent with the natural transfer of a patient between care levels and services or departments and caters to the needs of users. Mainly, continuity of care constitutes one of the mainstays on which care programs for chronic and multi-pathological patients are based. This type of patient has complex needs that require long-term care and specific guidelines to deal with the multiple transitions between care levels ¹.

The transformation of health services has developed and implemented new functional and care areas, such as home hospitalization units or chronic or multi-pathological patient care units, to respond to the growing health demand of chronic processes. These new resources are vital to promoting continuity of chronic care and show positive results at multiple levels, such as fewer rehospitalizations ². Besides, new nursing profiles, such as case management nurses or liaison nurses, and many other nursing initiatives and innovations are emerging to foster continuity of healthcare, avoid care fragmentation, obtain positive effects on the quality of care for chronic patients, and reduce hospital readmissions ³.

In this global commitment to attach further importance to continuity of care -understood as care coherent, connected, and consistent with the needs of the patient and their family-, there should be a strategic design that considers the three dimensions of continuity of care and maintains a hierarchical relationship between them, each being fundamental for the operation of the others ⁴. The relational dimension refers to the interaction between professionals and patients and their families over time; the informational dimension means the use and transmission of information, and the managerial dimension is related to the coordination between professionals and services. Thus, several challenges are associated with these three dimensions of continuity of care for nurses' professional practice, as addressed below.

Effective communication and collaboration among healthcare professionals are critical to appropriate continuity of care. One of the challenges for nurses, related to the relational dimension of continuity of care, is establishing collaborative relationships between the health professionals who care for the patient in multiple clinical contexts ⁵. Displaying leadership and trust is essential to make the rest of the professionals understand nurses' skills in continuity of care while recognizing and respecting the functions of other health workers. Another fundamental aspect of collaboration is shared access to complete patient information, which includes querying the patient's various electronic records and transmitting information in a systematic and structured manner when transferring the patient to other care levels.

The emergence of new professional profiles, such as the liaison nurse or case manager, facilitates the relationship of the patient and their family with health professionals. Thus, the therapeutic relationship must be established with the same person (liaison nurse or case manager) to build trust. In turn, professionals may gain more detailed patient knowledge to favor comprehensive care by meeting individual needs. The transmission of information and communication with the patient and their family will benefit from the bond forged between them.

Without a doubt, the digital transformation of health organizations is one of the tough challenges. It is about incorporating technological innovations -such as wearables or smart clothing to control and quickly obtain body data from the patient at home- and managing a change in guaranteeing adequate data reception, registration, use, security, and protection.

Furthermore, the COVID-19 pandemic accelerated our understanding of the potential technology for continuity of care. Indeed, the use of information and communication technologies (ICT) in health, known as e-health, to meet the needs of patients, families, communities, and health professionals is already a reality. Under the concept of "mobile health" or m-health, mobile devices -widely used in the worst moments of the pandemic- encourage communication among professionals and with the patient and their family.

Regarding ICT implementation in the health field, we cannot ignore the enormous challenge of educating and training nurses and other health professionals in innovation and ICT ⁶. Similarly, patients and families must be educated to maximize the potential for efficient health systems. Greater empowerment of the patient and their family stimulates participation in decision-making and, undoubtedly, optimizes the transmission of information between them, resulting in better management of the disease. The development of nurses' teaching skills is essential for adequate health literacy, identifying the degree of acceptance of these technologies by patients and families and their concerns about the use of applications, and offering strategies to improve access to ICT, especially by the most vulnerable groups.

Nurses, particularly those in formal leadership positions in organizations, play a crucial role in managing health services and the care provided. Nurse managers collaborate with other professionals and other knowledge domains and care levels. Thus, transformational nursing leadership is always sought to uphold positive work environments and the well-being of individuals.

In this context of nursing leadership, the advanced practice nurse (APN) has appeared to a greater or lesser extent in numerous countries. This nurse has expert knowledge, leadership, complex decision-making skills, and advanced clinical abilities to improve nursing practice ^7,8. Although these new professional profiles and roles are demonstrating high efficiency in user satisfaction and managing the demand and needs of patients with chronic diseases, it is complicated to implement and adapt current clinical management and coordination structures, such as the recognition and delimitation of responsibilities and an appropriate academic and economic as sessment of APNs. Therefore, this situation constitutes a significant challenge for nurse managers.

Finally, the COVID-19 pandemic has entailed the redesign of care management processes: defining new guidelines for action, redistributing staffing and staff rotation to care for COVID-19 patients without neglecting the rest of patients, promoting nurse training in record time for patient safety, and adapting nurses' work dynamics to respond to new health circumstances. Indisputably, this experience has been a worldwide pilot of creative, committed, and even resilient management in which nurse managers have become a cornerstone. Now it is time to recover and re-adapt to serve the increasing volume of patients with acute and chronic diseases due to the deficit of care and tackle the impact of a lack of physical activity in elderly, frail, or disabled people because of lockdown. We have a new challenge that requires implementing innovative organizational strategies that respond effectively and efficiently to the current healthcare context.

Continuity of care is critical in caring for individuals and families with complex health needs who require professional care over time. The digital transformation of health organizations supports a more continuous and closer relationship between the professional and the patients and their families, the better transmission of information, and the improved coordination between medical attention and nursing care. Thus, as usual, every challenge becomes an opportunity.

Nursing research is fundamental for the profession and necessary to promote innovative quality care and influence health policies. So, the inno-CARE research group on new nursing practices at the Universidad Pública de Navarra (Spain) is working to improve continuity of care, both from nursing innovation and new technologies and from knowledge generation, to develop new care models centered on the patient with complex chronic diseases and their family. We understand that translational research not only requires collaboration between diverse nursing profiles (care nurses, researchers, and managers) and between different health workers but also transformational leadership to produce a change in the health system, currently oriented to professionals, toward a user-centered care system, focused on the patient and their family at different healthcare levels. Unquestionably, this is a tremendous challenge for nurses across the globe.