Impact of comorbidity on risk of venous thromboembolism in patients with breast cancer: a Danish population-based cohort study

• Type of Material: Article
• Authors: Anne Gulbech Ording, Aarhus University Hospital; Erzsébet Horvath-Puho, Aarhus University Hospital; Jens Peter Garne, Aarhus University Hospital; Petra Witt Nystrom, Uppsala University Hospital; Mogens Vyberg, Aalborg University Hospital; Henrik Toft Sorensen, Aalborg University Hospital; Timothy Lash, Emory University
• Language: English
• Date: 2014-01-01
• Publisher: BMJ Publishing Group: Open Access
• Publication Version: Final Published Version
• Copyright Statement: Copyright © 2014, British Medical Journal
• License: Creative Commons Attribution 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.1136/bmjopen-2014-005082
• Title of Journal or Parent Work: BMJ Open
• ISSN: 2044-6055
• Volume: 4
• Issue: 6
• Start Page: e005082
• End Page: e005082
• Grant/Funding Information: The study was supported by the Danish Cancer Society (grant no. R73-A4284-13-S17); the Danish Agency for Science, Technology and Innovation (record number: 10-084581); Karen Elise Jensen Foundation; Aarhus University Research Foundation; the Clinical Epidemiology Research Foundation, Aarhus University; Aalborg Hospital, Region North Denmark
• Keywords: DENMARK; SURVIVAL; DISEASE; MEDICINE, GENERAL & INTERNAL; Medicine, General & Internal; Life Sciences & Biomedicine; THROMBOSIS; General & Internal Medicine; Science & Technology; REGISTRY; DATABASE
• Research Categories: Health Sciences, Oncology; Health Sciences, Public Health

Abstract

Objectives: To assess the interaction between comorbidity and breast cancer (BC) on the rate of venous thromboembolism (VTE) beyond what can be explained by the independent effects of BC and comorbidity. Design: Population-based matched cohort study. Setting: Denmark. Participants: Danish patients with BC (n=62 376) diagnosed in 1995-2010 and a comparison cohort of women without BC (n=304 803) from the general population were matched to the patients with BC on year of birth in 5-year intervals and on the specific diseases included in the Charlson Comorbidity Index (CCI) and atrial fibrillation and obesity. Measures: The rate ratios of VTE per 1000 person-years (PY) were computed by comorbidity levels using the CCI, and interaction contrasts (IC) were calculated as a measure of the excess or deficit VTE rate not explained by the independent effects of BC and comorbidity. Results: Among patients with BC with a CCI score of 1, the 0-1 year VTE rate was 12/1000 PY, and interaction accounted for 10% of the rate (IC=3.2, 95% CI 0.5 to 5.9). Among patients with BC with CCI ≥4, the VTE rate was 17, and interaction accounted for 8% of the rate (IC=1.2, 95% CI -1.8 to 4.2). There was no interaction during 2- 5 years of follow-up. Conclusions: There was only little interaction between BC and the CCI score on the rate of VTE.