Suboptimal Quality and High Risk of Bias in Diagnostic Test Accuracy Studies on Chest Radiography and Computed Tomography in the Acute Setting of the COVID-19 Pandemic: A Systematic Review

Suchá, Dominika; van Hamersvelt, Robbert W.; van den Hoven, Andor F.; de Jong, Pim A.; Verkooijen, Helena M.

PURPOSE: Chest imaging techniques have been implemented for screening and diagnosis of COVID-19 patients, based on experience with other viral pneumonias and a handful of COVID-19 diagnostic test accuracy (DTA) studies. We performed a systematic review to synthesize the literature on DTA of chest radiography (CXR), computed tomography (CT) and ultrasound for diagnosis of COVID-19 in suspected patients in hospital setting and evaluated the extent of suboptimal reporting and risk-of-bias. METHODS: A systematic search was performed (April 26, 2020) in Embase, Pubmed and Cochrane to identify CXR, CT or ultrasound studies in adult patients with suspected COVID-19, using RT-PCR or clinical consensus as reference standard. 2x2 contingency tables were reconstructed and test sensitivity, specificity, positive predictive values (PPV) and negative predictive values (NPV) re-calculated. Reporting quality was evaluated by adherence to STARD and risk-of-bias by QUADAS-2. RESULTS: Thirteen studies were eligible (CT=12, CXR=1, US=0). Re-calculated CT sensitivity and specificity ranged between 0.57-0.97 and 0.37-0.94, respectively, PPV and NPV between 0.59-0.92 and 0.57-0.96, respectively. On average studies complied with only 35% of the STARD-guideline items. No study scored low risk-of-bias for all QUADAS-2 domains (patient selection, index test, reference test, flow and timing). High risk-of-bias in ≥one domain was scored in 10/13 studies (77%). CONCLUSION: Reported CT test accuracy for COVID-19 diagnosis varies substantially. Validity and generalizability of these findings is complicated by poor adherence to reporting guidelines and high risk-of-bias, which are most likely due to the need for urgent publication of findings in the first months of the COVID-19 pandemic.