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BMJ Open. 2014 Jun 5;4(6):e005082. doi: 10.1136/bmjopen-2014-005082.

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

Author information

1
Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
2
Breast Clinic, Aalborg University Hospital, Aalborg, Denmark.
3
Department of Oncology, Uppsala University Hospital, Uppsala, Sweden.
4
Institute of Pathology, Aalborg University Hospital, Aalborg, Denmark.
5
Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.

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.

KEYWORDS:

Epidemiology; Oncology

PMID:
24902734
PMCID:
PMC4054647
DOI:
10.1136/bmjopen-2014-005082
[Indexed for MEDLINE]
Free PMC Article

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