OC 03.2 - External Validation of the Modified Michigan Risk Score to Predict Upper Extremity Deep Vein Thrombosis in Patients Receiving Chemotherapy Through a Peripherally Inserted Central Catheter

Saturday, June 22, 2024

13:15 – 13:30 ICT

Room: Ballroom B3

Presenting Author(s)

Scott Kaatz, DO, MSc

Co-director, Anticoagulation Clinics
Division of Hospital Medicine; Anticoagulation Services, Henry Ford Health, Detroit, MI
Detroit, Michigan, United States

Co-Author(s)

DP

David Paje

Clinical Associate Professor
Michigan Medicine
Ann Arbor, Michigan, United States
MH

Megan Heath

Statistician Lead
Michigan Medicine
Ann Arbor, Michigan, United States
JH

Jennifer K. Horowitz

Senior Area Research Lead
Michigan Medicine
Ann Arbor, Michigan, United States
EM

Elizabeth McLaughlin

Program Manager, Michigan Hospital Medicine Safety Consortium
Michigan Medicine
Ann Arbor, Michigan, United States
CT

Caitlin Tatarcuk

Quality Assurance Coordinator
Michigan Medicine
Ann Arbor, Michigan, United States
RS

Renee Salem

Medical Student
Michigan State University, College of Osteopathic Medicine
East Lansing, Michigan, United States
LS

Lakshmi Swaminathan

Division Head, Hospital Medicine
Trinity Health IHA Medical Group
Ann Arbor, Michigan, United States
SB

Steven J. Bernstein

Professor
Michigan Medicine
Ann Arbor, Michigan, United States
Hiu Lam Agnes Yuen

Consultant Haematologist
Monash Medical Centre
Clayton, Victoria, Australia
SC

Sanjeev Chunilal

Director, Laboratory Haematology
Monash Health
Clayton, Victoria, Australia
Huyen Tran, MBBS (Hons), MClinEpi, FRACP, FRCPA

Head of the Thrombosis & Hemostasis Unit and Director of the Hemophilia Treatment Centre
Ronald Sawyers Haemophilia Centre, The Alfred Hospital, Melbourne, Victoria, Australia
Melbourne, Victoria, Australia
SF

Scott Flanders

Program Director, Michigan Hospital Medicine Safety Consortium
Michigan Medicine
Ann Arbor, Michigan, United States
VC

Vineet Chopra

Professor and Chairman
University of Colorado Anschutz Medical Campus
Aurora, Colorado, United States

Background: Peripherally inserted central catheters (PICC) and cancer are each associated with venous thromboembolism (VTE). The Michigan Risk Score (MRS) was designed to predict VTE in hospitalized patients with PICCs whereas the Khorana Risk Score (KRS) evaluates the risk of developing VTE in ambulatory cancer patients. The modified MRS (mMRS), which added an element from the KRS (platelet count > 350,000) to MRS has been shown to improve discrimination compared to the MRS (c-statistic 0.72 vs. 0.63) in predicting upper extremity deep vein thrombosis (UE-DVT) in hospitalized patients receiving chemotherapy through a PICC. External validation of the mMRS was proposed at the Dragons’ Den Competition during the International Society of Thrombosis and Hemostasis 2023 Congress in Montreal. Although not chosen as the winner, the meeting facilitated networking to externally validate the mMRS in a subset of the Michigan Hospital Medicine Safety Consortium PICC database.

Aims: To externally validate the mMRS in predicting PICC-related UE-DVT in patients receiving chemotherapy.

Methods: Between July 2014 and October 2023, the Michigan Hospital Medicine Safety (HMS) consortium collected patient-level data on a sample of patients who received a PICC while admitted to 49 participating hospitals. From this database, we identified hospitalized patients receiving chemotherapy via PICCs to validate the mMRS. Discrimination was measured by the area under the receiver operator characteristic curve (AUC).

Results: Of 2,541 hospitalized patients receiving chemotherapy through PICCs, 80 (3.15%) developed UE-DVT. The AUC of the mMRS (0.61) for predicting UE-DVT was not different from that of the MRS (0.62, 95% CI: [0.56,0.67]).

Conclusion(s): In this external validation, modification of the MRS by adding elevated platelet count, an element of the Khorana score, did not improve the predictability of upper extremity DVT in patients receiving chemotherapy through a PICC line despite the observation shown in the model’s derivation.