# Analysis of Long COVID characteristics and risk factors in individuals infected with COVID-19: a follow-up study based on a cohort of 2,792 participants

## TL;DR

This study identifies risk factors and symptoms of Long COVID in a cohort of over 2,700 individuals, highlighting age and acute symptoms as key contributors.

## Contribution

The study introduces a novel use of hematological parameters as potential biomarkers for Long COVID and identifies specific risk factors through a large cohort.

## Key findings

- 6.52% of participants developed Long COVID, with common symptoms like fatigue and insomnia.
- Advanced age and severe acute symptoms were identified as independent risk factors for Long COVID.
- Long COVID patients showed altered hematological parameters, including higher red blood cell counts and lower hemoglobin-related indices.

## Abstract

Since the emergence of SARS-CoV-2 in 2019, Long COVID has emerged as a significant global public health challenge. The identification of accessible biomarkers and risk factors is critical to enabling early intervention and improving long-term outcomes.

This prospective cohort study enrolled 2,792 individuals with confirmed COVID-19 from Anhui Province in September 2024. A propensity score matching analysis was performed using a 1:4 ratio. Cases and matched controls were selected from cohort, serum sample were analyzed to assess hematological parameters. Multivariable logistic regression models were applied to identify independent risk factors associated with the development of Long COVID.

2,792 participants (average age 51.64 years) identified 182 (6.52%) long COVID patients during follow-up. Common symptoms included fatigue, cough, insomnia, throat discomfort, and appetite loss. After propensity score matching, risk factors were age, more severe acute symptoms. Long COVID patients exhibited higher red blood cell counts but lower hemoglobin-related indices and platelet count.

This study confirms the persistent risk of Long COVID following reinfection, with heightened susceptibility associated with advanced age, specific acute-phase symptoms. Alterations in routine hematological parameters may serve as valuable biomarkers for the monitoring and management of Long COVID.