Longitudinal trajectories of long COVID among hospitalized patients with omicron infection in Changzhi, China.

BACKGROUND: Understanding the persistence of long COVID (LC) among discharged patients with Omicron infection remains limited. METHODS: The study used a retrospective longitudinal cohort to evaluate the dynamic trajectory of LC after hospital discharge and to identify factors associated with new-onset and persistent LC following Omicron infection. Patients admitted to Heping Hospital Affiliated to Changzhi Medical College and Changzhi People's Hospital for coronavirus disease 2019 between 15 December 2022 and 30 April 2024 were included. The first follow-up was conducted from 18 July to 20 August 2024, and the second from 9 May 2025 to 13 June 2025. RESULTS: Of the 3,777 discharged patients, 1,922 [median (IQR) age, 70.0 (59.0-78.0) years; 968 male individuals (50.4%)] who completed both follow-up visits were included in the final analysis. The median (IQR) time from discharge to the second follow-up was 727 (688-854) days. At the second follow-up, 292 patients (15.2%) were diagnosed with LC, including 121 (6.3%) with persistent LC and 171 (8.9%) with new-onset LC. The most common symptoms were muscle weakness, sleep difficulties, fatigue, cough, and dyspnea at rest. Notably, the proportions of muscle weakness, sleep difficulties, cough, arthralgia, and palpitations increased significantly, whereas brain fog decreased significantly from 2.8% at the first follow-up to 0.4% at the second follow-up. Overall, antiviral treatment (OR = 1.503; 95% CI: 1.063-2.126), female sex (OR = 3.729; 95% CI: 1.145-12.147), being a farmer as an occupation (OR = 4.695; 95% CI: 2.188-10.101), and BMI < 18.5 kg/m2 (OR = 5.291; 95% CI: 1.115-25.000) were associated with increased new-onset LC susceptibility, whereas having one or more complications was associated with decreased new-onset LC susceptibility (OR = 0.329; 95% CI: 0.125-0.865). CONCLUSION: Omicron-infected patients report a persistent burden of symptoms consistent with the WHO definition of LC after discharge. These findings provide valuable information on the dynamic trajectory of long-term health outcomes in patients infected with Omicron. However, the non-specific nature of the symptoms should be considered when interpreting these findings.