How the clinical research community responded to the COVID-19 pandemic: An analysis of the COVID-19 clinical studies in ClinicalTrials.gov

Objective The novel coronavirus disease (COVID-19), broke out in December 2019, is a global pandemic. Rapidly in the past few months, a large number of clinical studies have been initiated worldwide to find effective therapeutics, vaccines, and preventive strategies. In this study, we aim to understand the landscape of COVID-19 clinical research and identify the gaps and issues that may cause difficulty in recruitment and the lack of population representativeness. Materials and Methods We analyzed 2,034 COVID-19 studies registered in the largest public registry - ClinicalTrials.gov . Leveraging natural language processing, descriptive analysis, association analysis, and clustering analysis, we characterized COVID-19 clinical studies by phase and design features. Particularly, we analyzed their eligibility criteria to understand: (1) whether they considered the reported underlying health conditions that may lead to severe illnesses, and (2) if these studies excluded older adults, either explicitly or implicitly, which may reduce the generalizability of these studies in older adults. Results The 5 most frequently tested drugs are Hydroxychloroquine (N=148), Azithromycin (N=46), Tocilizumab (N=29), Lopinavir (N=20), and Ritonavir (N=20). Most trials did not have an upper age limit and did not exclude patients with common chronic conditions such as hypertension and diabetes that are prevalent in older adults. However, known risk factors that may lead to severe illnesses have not been adequately considered by existing studies. Conclusions A careful examination of the registered COVID-19 clinical studies can identify the research gaps and inform future COVID-19 trial design towards balanced internal validity and generalizability.