Characteristics of long COVID: a survey-based study in Brazilian primary health care

Abstract

In Brazil, the knowledge regarding Long COVID prevalence, its specific clinical outcomes and overall impact on population health is severely limited. To address these existing gaps, the PhD study aimed to describe the prevalence, risk factors and clinical outcomes of Long COVID, and its impact on health-related quality of life among adults diagnosed with mild to moderate during the 2021 COVID-19 pandemic in Brazilian primary care. A retrospective cross-sectional survey was conducted in six Family Health Care Units in João Pessoa, Paraiba, from May 2023 to July 2024, using two instruments: 1) a standardized questionnaire containing 18 validated clinical outcomes, and 2) a generic EQ-5D-5L instrument for measuring health-related quality of life (HRQOL). To define Long COVID, the study adopted the definition outlined by the WHO (2021). Descriptive statistical analyses were used to describe the sociodemographic characteristics of the study population, COVID-19 vaccination status, symptoms, and the presence of comorbidities. The overall prevalence of Long COVID along with symptom-specific prevalence adjusted for sex and age, was estimated and compared between adults with and without Long COVID. EQ-5D-5L health index values and visual analogue scale (VAS) scores were analyzed to compare health-related quality of life between the two groups. Binary logistic regression models were used to examine the associations between Long COVID and clinical outcomes, risk factors, and health states. Of 226 respondents, 69.0% met the definition of Long COVID and had at least one persistent symptom following SARS-CoV-2 infection. A total of 16 clinical outcomes were significantly associated with Long COVID. The largest adjusted odds ratios (aORs) were observed for short-term memory loss, anxiety, and impaired attention. The risk factors for Long COVID included five or more symptoms, female sex, age 40–49 years, and age 70 years or older. Individuals with Long COVID continued to experience significantly poorer health-related quality of life two years or more after mild-to-moderate infection compared with those without persistent illness, regardless of sex, age, ethnicity, educational level, or comorbidities. Adults with this condition are at higher risk of experiencing health issues related to anxiety or depression, pain or discomfort, and deterioration in usual activities. This thesis highlights the need to target multidisciplinary services in primary care for COVID-19 survivors experiencing long-term health issues after infection. Furthermore, understanding the long-lasting health effects of SARS-CoV-2 infection and identifying adults at higher risk for enduring health issues can help health professionals, caregivers, and policymakers better address aspects of patients’ lives that lack quality and develop a multidisciplinary approach in primary care for managing this condition.