Risk factors and severity of functional impairment in long COVID: a single-center experience in Croatia

To determine the frequency of common symptoms in long COVID and their effect on the quality of life, and to determine the factors contributing to a more severe long COVID.

The study enrolled 266 patients who were either referred to long-COVID outpatient clinic or were inpatients undergoing rehabilitation. The data were collected between December 2020 and May 2021. We evaluated the symptoms experienced during acute and long COVID and comorbidities. Functional status was assessed with Post Covid Functional Status (PCFS).

The final sample consisted of 261 patients. After acute COVID-19 period (>4 weeks), almost 80% of patients had impaired functional status. Only 21.5% reported no functional impairment (0 on PCFS scale). A higher PCFS score was associated with female sex (P<0.001) and oxygen therapy requirement during acute disease (P=0.001). However, it was not associated with having a pre-existing lung disease (P=0.749). Disease severity did not pose a risk for developing a more severe long COVID.

Women were at greater risk for developing greater functional impairment in long COVID, although we have no explanation why. Malignant disease and hypertension also presented a risk factor for greater functional impairment. More studies are warranted to determine if patients with certain lung disease are more susceptible to long COVID.