Accuracy of the volume-viscosity swallow test for clinical screening of dysphagia in post COVID-19 patients

Abstract

Up to 30% of patients hospitalized for COVID-19 had oropharyngeal dysphagia, particularly those in the ICU. Many cases remained underdiagnosed due to difficulties in conducting instrumental evaluations during the pandemic. Consequently, screening tests were mandatory during this period. To evaluate the accuracy of the volume-viscosity swallow test (V-VST), compared to gold standard videofluoroscopy, for screening dysphagia in a post-COVID cohort of patients. We conducted a prospective single-center study involving 58 post-COVID adult patients with no previous history of dysphagia. Blinded raters performed the index V-VST upon admission and a standardized videofluoroscopy (VFSS, the reference test) within 72h of patient intake. Oropharyngeal residue was considered a sign of impaired efficacy. Cough, decreased oxygen saturation, and voice changes were noted as signs of impaired safety. Accuracy, sensitivity, specificity, positive, and negative predictive values, and likelihood ratios were calculated for V-VST results and compared to the gold standard. Patients (aged 59.98 (SD11.53) years) spent a mean of 46.98 (SD 28.43) days in ICU, 33.76 (SD34.88) days with tracheostomy, and 19.46 (SD13.26) days in the NeuroRehabilitation Unit. The V-VST showed the following properties, compared to VFSS: sensitivity 55.6%, specificity 62.9%, positive predictive value 44.5%, negative predictive value 37.1%, and accuracy 61.5%. The V-VST showed mild accuracy, sensitivity, and specificity, compared to VFSS. Therefore, it should not be used as a stand-alone test for screening dysphagia in patients with a history of COVID.