Impact of Telemedicine on the Follow-up of Chronic Diseases During the COVID-19 Pandemic: Experience of a Brazilian Public Tertiary Hospital

<b>Background:</b> The COVID-19 pandemic significantly impacted patients with chronic diseases (CDs), disrupting in-person consultations and health care services. In response, telemedicine was rapidly adopted to maintain continuity of care, especially in tertiary hospitals such as the Clinical Hospital of the Ribeirão Preto Medical School at the University of São Paulo, which became a leader in telemedicine in Brazil. The objective of this study was to describe the hospital's experience with telemedicine for managing CDs during the COVID-19 pandemic and evaluate its impact on hospital admissions and mortality. <b>Methods:</b> We conducted a retrospective cohort study analyzing 614,367 consultations from 2020 to 2021. Consultations were categorized as in-person or telemedicine, and patients with more than four consultations annually were included. Data were retrieved from electronic health records, and outcomes of interest included hospital admissions and mortality within 3 days of consultation. Telemedicine intensity was assessed by the percentage of teleconsultations per patient. <b>Results:</b> Of the 614,367 consultations, 52% met the inclusion criteria, representing 36,033 patients. The percentage of teleconsultations was 36.1%, with higher rates in 2020 (48.0%) compared with 2021 (28.8%). Psychiatry had the highest rate of teleconsultations (53.5%), while oncology had the lowest (11.2%). Patients with teleconsultations had lower hospital admission rates (0.15% for the Charlson Comorbidity Index [CCI] of 0) compared with in-person consultations. Mortality was inversely related to the intensity of telemedicine use, with teleconsultation rates above 16.7% associated with a significant reduction in mortality across all CCI levels. <b>Conclusion:</b> Telemedicine proved to be a crucial tool during the pandemic, restoring access to care and reducing hospital admissions and mortality for patients with CDs. Future studies using artificial intelligence techniques will further explore the impact of telemedicine on chronic disease management across specialties.