Climate change represents a critical challenge for the healthcare sector, influencing operational efficiency, environmental comfort and the resilience of hospital facilities. This literature review analyses the intersection between hospital design, sustainability and energy efficiency, with a particular focus on climate change adaptation strategies for existing buildings. The healthcare building sector is responsible for a significant share of global greenhouse gas emissions, making the development of innovative and sustainable construction practices imperative. The literature review highlights the importance of a multidisciplinary approach in hospital design, integrating user-centred design, advanced technologies such as Building Information Modelling (BIM) and spatial syntax analysis, as well as retrofitting strategies for energy efficiency improvement. In addition, the growing adoption of the Digital Twin Immersive Design Process (DT-IDP) allows for more accurate modelling of healthcare environments, improving the quality of care and the patient experience. Despite progress, current research on climate resilience, energy efficiency and hospital design remains largely disjointed. The review emphasises the need for an integrated framework that combines climate adaptation strategies with a holistic approach to healthcare design. The adoption of predictive models for energy management, optimisation of hospital layout and the use of sustainable materials are essential to ensure resilient, efficient hospitals that are able to respond to future environmental challenges.