Impact of the COVID-19 Pandemic on Clinical Findings in Medical Imaging Exams in a Nationwide Israeli Health Organization: Observational Study

BACKGROUND The outbreak of the COVID-19 pandemic had a major effect on consumption of healthcare services. Changes in the use of routine diagnostic exams, increased incidences of post-acute COVID-19 syndrome (PCS), and other pandemic-related factors, may have influenced detected clinical conditions. OBJECTIVE The study aimed to analyze the impact of COVID-19 on the use of outpatient medical imaging services and clinical findings therein, specifically focusing on the time period after the launch of the Israeli COVID-19 vaccination campaign. In addition, the study tested whether the observed gains in abnormal findings may be linked to PCS or COVID-19 vaccination. METHODS Our dataset included 572,480 ambulatory medical imaging patients in a national health organization, from January 1, 2019 to August 31, 2021. We compared different measures of medical imaging utilization and clinical findings therein, before and after the surge of the pandemic, to identify significant changes. We also inspected the changes in the rate of abnormal findings during the pandemic after adjusting for changes in medical imaging utilization. Finally, for imaging classes that showed increased rates of abnormal findings, we measured the causal associations between COVID-19 infection, hospitalization (indicative of COVID-19 complications), and vaccination and future risk for abnormal finding. To allow adjustment for a multitude of confounding factors, we used causal inference methodologies. RESULTS After the initial drop in the utilization of routine medical imaging due to the first COVID-19 wave, the number of these exams has increased, but with lower proportions of older patients, patients with comorbidities, women, and vaccine-hesitant patients. Furthermore, we observed significant gains in the rate of abnormal findings, specifically in musculoskeletal magnetic resonance (MR-MSK) and brain computed tomography (CT-brain) exams. These results also persisted after adjusting for the changes in medical imaging utilization. Demonstrated causal associations included: COVID-19 infection increasing the risk for an abnormal finding in a CT-brain exams (odds ratio [OR] of 1.4, with 95% confidence interval [CI] 1.1 to 1.7); and COVID-19-related hospitalization increasing the risk for abnormal findings in an MR-MSK exam (OR 3.1, 95% CI 1.9 to 5.3). CONCLUSIONS COVID-19 impacted the use of ambulatory imaging exams, with greater avoidance among patients at higher risk for COVID-19 complications: older patients, patients with comorbidities, and non-vaccinated patients. Causal analysis results imply that PCS may have contributed to the observed gains in abnormal findings in MR-MSK and CT-brain exams, respectively. CLINICALTRIAL