Photoplethysmographic Measurement of Arterial Stiffness in Polish Patients with Long-COVID-19 Syndrome—The Results of a Cross-Sectional Study

The coronavirus disease 2019 (COVID-19) is associated with an increase in the incidence of cardiovascular diseases (CVD) that persists even several months after the onset of infection. COVID-19 may also have an impact on arterial stiffness, which is a risk factor for CVD. We aimed to analyze if and to what extent arterial stiffness measured by photoplethysmography differed among COVID-19 convalescents depending on the acute phase severity and time elapsed since disease onset. A total of 225 patients (mean age 58.98 ± 8.57 years, 54.7% women) were analyzed after COVID-19 hospitalization at the Cardiac Rehabilitation Department of the Ustron Health Resort (Poland). In the entire study population, no differences were found in the mean values of stiffness index (SI) and reflection index (RI) depending on the severity of the acute COVID-19 and the time since the onset of the disease. There were no differences in the heart rate (HR) according to the severity of acute COVID-19; the mean HR was higher in patients who had COVID-19 less than 12 weeks before the study than in convalescents more than 24 weeks after the acute disease (p = 0.002). The mean values of SI and RI were higher in men than in women (p < 0.001), while the heart rate (HR) was similar in both sexes (p = 0.286). However, multiple linear regression analyses after adjusting for factors influencing arterial stiffness, i.e., sex, age, body mass index, smoking status, hypertension, diabetes, the severity of the acute COVID-19, and the time from the disease onset, confirmed that age, sex, time from disease onset, and diabetes are the most important determinants that could influence arterial stiffness.