The original and modified Caprini score equally predicts venous thromboembolism in COVID-19 patients

Abstract

Objective: The 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.

Methods: The relevant data were extracted from the electronic medical records with an implemented Caprini score and were retrospectively evaluated. The score was calculated twice: by the physician on admission and by the investigator at discharge (death). The final assessment 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: two points for asymptomatic, three points for symptomatic, and five points for symptomatic infection with positive D-dimer. Cases were evaluated retrospectively. The primary end point was symptomatic venous thromboembolism (VTE) detected during inpatient treatment and confirmed by appropriate imaging testing or autopsy. The secondary end points included those observed during hospitalization (admission to the intensive care unit, a requirement for invasive mechanical ventilation, death, bleeding), and those assessed at 6-month follow-up (symptomatic VTE, bleeding, death). The association of eight different versions of the Caprini score with VTE events was evaluated.

Results: A total of 168 patients (83 males and 85 females at the age of 58.3 ± 12.7 years) were admitted to the hospital between April 30 and May 29, 2020, and were discharged or died to the time of data analysis. The original Caprini score varied between 2 and 12 (5.4 ± 1.8) at the admission and between 2 and 15 (5.9 ± 2.5) at discharge or death. The maximal score was observed with modification including specific COVID-19 points of 5 to 20 (10.0 ± 3.0). Patients received prophylactic (enoxaparin 40 mg once daily: 2.4%), intermediate (enoxaparin 80 mg once daily: 76.8%), or therapeutic (enoxaparin 1 mg/kg twice daily: 20.8%) anticoagulation. Despite this, symptomatic VTE was detected in 11 (6.5%) inpatients. Of the 168 individuals, 28 (16.7%) admitted to the intensive care unit, 8 (4.8%) required invasive mechanical ventilation, and 8 (4.8%) died. Clinically relevant nonmajor bleeding was detected in two (1.2%) cases. The Caprini score of all eight versions demonstrated a significant association with inpatient VTE frequency. The highest predictability was observed for the original scale when assessed at discharge (death). Only symptomatic VTE was reported after discharge with a cumulative incidence of 7.1%. This did not affect the predictability of the Caprini score. Extended antithrombotic treatment was prescribed to 49 (29%) patients with a cumulative incidence of bleeding of 1.8% at 6 months.

Conclusions: The study identified a significant correlation between the Caprini score and the risk of VTE in patients with COVID-19. All models including specific COVID-19 scores showed equally high predictability, and use of the original Caprini score is appropriate for patients with COVID-19.

Keywords: COVID-19; Caprini score; Prophylaxis; Risk assessment; Venous thromboembolism.

Fig 1

The incidence of symptomatic inpatient venous thromboembolism (VTE) according to the different modifications of the Caprini score assessed at the time of admission. Caprini[COVID-19:adm]: Considering two points for asymptomatic infection, three points for symptomatic infection, five points for symptomatic infection with positive D-dimer, score assessed at admission (V = 0.525; P < .001); Caprini[Dd>3ULN:adm]: considering three points if D-dimer increased >3 times over ULN, score assessed at admission (V = 0.493; P < .001); Caprini[Dd>ULN:adm]: considering three points if D-dimer increased over ULN, score assessed at admission (V = 0.531; P < .001); Caprini[orig:adm]: the original score assessed at admission (V = 0.505; P < .001); ULN: upper limit of normal; V: Cramer's V.

Fig 2

The incidence of symptomatic inpatient venous thromboembolism (VTE) according to the different modifications of the Caprini score assessed at the time of discharge or death. Caprini[COVID-19:fin]: Considering two points for asymptomatic infection, three points for symptomatic infection, five points for symptomatic infection with positive D-dimer, score assessed at discharge or death (V = 0.706; P < .001); Caprini[Dd>3ULN:fin]: considering three points if D-dimer increased >3 times over ULN, score assessed at discharge or death (V = 0.645; P < .001); Caprini[Dd>ULN:fin]: considering three points if D-dimer increased over ULN, score assessed at discharge or death (V = 0.707; P < .001); Caprini[orig:fin]: the original score assessed at discharge or death (V = 0.664; P < .001); ULN: upper limit of normal; V: Cramer's V.

Fig 3

The cumulative incidence of symptomatic venous thromboembolism (VTE) at 6 months according to the different modifications of the Caprini score assessed at the time of discharge or death. Caprini[orig:fin]: The original score assessed at discharge or death (V = 0.634; P < .001); Caprini[Dd>ULN:fin]: considering three points if D-dimer increased over ULN, score assessed at discharge or death (V = 0.677; P < .001); Caprini[Dd>3ULN:fin]: considering three points if D-dimer increased >3 times over ULN, score assessed at discharge or death (V = 0.616; P < .001); Caprini[COVID-19:fin]: considering two points for asymptomatic infection, three points for symptomatic infection, five points for symptomatic infection with positive D-dimer, score assessed at discharge or death (V = 0.678; P < .001); ULN: upper limit of normal; V: Cramer's V.

Supplementary Fig 1 (online only)

Predictability of different versions of the Caprini score for symptomatic venous thromboembolism (VTE) detected during inpatient treatment by the receiver operating characteristic (ROC) curves. Caprini[COVID-19:adm], Considering two points for asymptomatic infection, three points for symptomatic infection, five points for symptomatic infection with positive D-dimer, score assessed at admission; Caprini[COVID-19:fin], considering two points for asymptomatic infection, three points for symptomatic infection, five points for symptomatic infection with positive D-dimer, score assessed at discharge or death; Caprini[Dd>3ULN:adm], considering three points if D-dimer increased >3 times over ULN, score assessed at admission; Caprini[Dd>3ULN:fin], considering three points if D-dimer increased >3 times over ULN, score assessed at discharge or death; Caprini[Dd>ULN:adm], considering three points if D-dimer increased over ULN, score assessed at admission; Caprini[Dd>ULN:fin], considering three points if D-dimer increased over ULN, score assessed at discharge or death; Caprini[orig:adm], the original score assessed at admission; Caprini[orig:fin], the original score assessed at discharge or death; ULN, upper limit of normal.

Supplementary Fig 2 (online only)

Predictability of different versions of the Caprini score for symptomatic venous thromboembolism (VTE) detected 6 months after discharge by the receiver operating characteristic (ROC) curves. Caprini[COVID-19:fin], Considering two points for asymptomatic infection, three points for symptomatic infection, five points for symptomatic infection with positive D-dimer, score assessed at discharge or death; Caprini[Dd>3ULN:fin], considering three points if D-dimer increased >3 times over ULN, score assessed at discharge or death; Caprini[Dd>ULN:fin], considering three points if D-dimer increased over ULN, score assessed at discharge or death; Caprini[orig:fin], the original score assessed at discharge or death; ULN, upper limit of normal.