The validation of the original and modified Caprini score in COVID-19 patients
Authors: Tsaplin Sergey , Schastlivtsev Ilya , Lobastov Kirill , Zhuravlev Sergey , Barinov Victor , Caprini Joseph A 
Published: June 2020

AbstractObjectiveThe study aimed to validate the original Caprini score and its modifications considering coronavirus disease (COVID-19) as a severe prothrombotic condition in patients admitted to the hospital with confirmed infection.MethodsThe relevant data were extracted from the electronic medical records with the implemented Caprini score and were evaluated retrospectively. The score was calculated twice: by the physician at the admission and by the investigator at discharge or after death. The second calculation at discharge, considered additional risk factors that occurred during inpatient treatment. Besides the original Caprini score (a version of 2005), the modified version added the elevation of D-dimer and specific scores for COVID-19 as follows: 2 points for asymptomatic, 3 points for symptomatic and 5 points for symptomatic infection with positive D-dimer, were evaluated in a retrospective manner. The primary endpoint was symptomatic venous thromboembolism (VTE) confirmed by appropriate imaging testing or dissection. The secondary endpoint included the unfavorable outcome as a combination of symptomatic VTE, admission to the intensive care unit, the requirement for invasive mechanical ventilation, and death. The association of eight different versions of the Caprini score with outcomes was evaluated.ResultsTotally 168 patients (83 males and 85 females at the age of 58.3±12.7 years old) were admitted to the hospital between April 30 and May 29, 2020, and were discharged or died up to the time of data analysis. The original Caprini score varied between 2-12 (5.4±1.8) at the admission and between 2-15 (5.9±2.5) at discharge or death. The presence of the virus increased these scores and resulted in an increased score with the maximal value for those including COVID-19 points (10.0±3.0). Patients received prophylactic (2.4%), intermediate (76.8%), or therapeutic (20.8%) doses of enoxaparin. Despite this, the symptomatic VTE was detected in 11 (6.5%) and unfavorable outcomes in 31 (18.5%) patients. The Caprini score of all eight versions demonstrated a significant association with VTE with the highest predictability for the original scale when assessed at discharge. Supplementation of the original score by elevated D-dimer improved predictability only at the admission. Four versions of the Caprini score calculated at the admission had a significant correlation with the unfavorable outcome with the minor advantages of specific COVID-19 points.ConclusionThe study identified a significant correlation between the Caprini score and the risk of VTE or unfavorable outcomes in COVID-19 patients. All models, including specific COVID-19 scores, showed high predictability with minor differences.ARTICLE HIGHLIGHTSType of ResearchA single-center retrospective analysis of prospectively collected data.Key FindingsThe original version of the Caprini score and its modifications considering the elevation of D-dimer and specific COVID-19 points demonstrated a significant association with symptomatic VTE and unfavorable outcome in 168 hospitalized COVID-19 patients, of whom 6.5% developed symptomatic VTE and 18.5% - unfavorable outcome despite routine pharmacoprophylaxis.Take Home MessageThe Caprini score allows stratification of COVID-19 inpatients according to their VTE risk and identification of subjects at extremely high risk.TABLE OF CONTENTS SUMMARYThis retrospective analysis of prospectively collected data demonstrates the significant association between the original and modified Caprini score and symptomatic VTE or unfavorable outcome in 168 patients with confirmed COVID-19. The Caprini score may be used for VTE risk assessment, and identification of persons at extremely high risk among COVID-19 patients admitted to the hospital.