Long COVID Following Mild SARS-CoV-2 Infection: A Retrospective Study in a Portuguese Primary Health Care Unit

Introduction: Long COVID is a recent pathological entity. Its manifestations and impact on health and quality of life and, on a larger scale, at an economic and social level may be very significant, reflecting a challenge for the future. The family doctor plays a major role in the care of these patients and must be aware of this new reality. With this study, we aim to determine the prevalence of long COVID in the adult population registered in a Portuguese Primary Healthcare Unit, called USF Amatus, and identify the most frequent symptoms, its duration, and impact on the quality of life of individuals.

Methods: This is a retrospective study based on the analysis of the national database of COVID-19 (Trace COVID-19), selecting patients ≥ 18 years old registered in USF Amatus, diagnosed with mild COVID-19, in the period between March 2020 and March 2022. The selected patients were submitted to a telephone interview to fill a questionnaire adapted from the World Health Organization "Report Form for Post COVID Condition" to the Portuguese population by the Directorate-General of Health (DGS). The collected data were analyzed using statistical software (R Development Core Team; Vienna, Austria) and the package "ggplot2".

Results: A total sample of 334 (56% female) was recruited for this study. The prevalence of long COVID was found to be 145 (43.4%) cases in the near months (≥ 3 months) following COVID-19 and 57 (17.1%) cases after two years. The most frequently reported symptoms were fatigue, persistent muscle pain, post-exercise malaise, memory loss, leg/arm weakness, and dizziness/lightheadedness. About 58 (17.4%) patients reported that their self-care capacity became worse after COVID-19. In the further evaluation of functional status, 56 (16.8%) patients reported that walking a distance of at least 1 km is more difficult nowadays, and 29 (8.7%) reported that performing household tasks became harder.

Conclusion: This study demonstrates the relevance of long COVID. The findings reveal a significant prevalence of symptomatic patients even two years after the infection with SARS-CoV-2. The most commonly reported symptom was fatigue. Other prevalent symptoms were neurocognitive, muscular, and physical exercise intolerance. It is also important to mention the relevant impact of long COVID on the quality of life of these patients. Further research is needed in order to better understand long COVID and, consequently, develop more directed and effective interventions for these patients, contributing to their well-being at an individual, familial, and social level.