Has “D-dimeritis” worsened during the COVID-19 pandemic?

Abstract Background: This report describes how D-dimer testing pattern may have changed during the ongoing coronavirus disease 2019 (COVID-19) pandemic. Methods: Two independent analyses were conducted in this report. The first encompassed a digital search in Medline, using the keyword “D-dimer”, restricted to the past 40 years and with no language restriction. The second analysis was based on data provided by the management control unit of the University Hospital of Verona, concerning the number of D-dimer tests requested in the complete years 2019 (i.e., “pre-COVID-19”), 2021 and 2022 (i.e., “during COVID-19”). Results: The overall number of PubMed documents containing the word “D-dimer” has increased by 3.0-folds in 2020, 3.9-fold in 2021 and 3.1-fold in 2022 compared to the year 2019, respectively. Between 1992 and 2019 (i.e., pre-COVID-19), the increase was almost perfectly linear (r=0.989), while the linear fit was dramatically impaired after inclusion of the past three years. A good statistic power could be restored using a polynomial equation (r=0.941). The overall number of D-dimer tests requested at the local institution increased from 1885 in 2019, to 10449 in 2021 and 5803 in 2022, displaying a 5.5- (p=0.011) and 3.1-fold (p=0.027) increase. The surge was higher for COVID-19, intensive care and emergency medicine units, while the growth remained modest for all other hospital units. Conclusion: Clinicians have clear in mind that D-dimer is a key biomarker in COVID-19, but D-dimeritis may have been magnified by COVID-19.