132.
Increased one year risk of venous thromboembolism following total
hip replacement: A nationwide cohort study
Alma B Pedersen, Søren P Johnsen, Henrik T Sørensen
Department of Clinical Epidemiology Aarhus Universityhospital Aarhus ;
Department of Clinical Epidemiology, Aarhus Universityhospital Aarhus ;
Department of Clinical Epidemiology, Aarhus Universityhospital Aarhus
Background:
Comparing persons with total hip replacement (THR) and those
without THR is important in order to understand the excess venous
thromboembolism (VTE) risk conferred by the THR surgery itself in addition
to VTE risk in general. To our knowledge, only one study among middle aged
women has compared VTE risk in THR patients with the VTE risk of the
general population within 12 weeks after surgery
Purpose / Aim of Study:
We examined the one year risk of VTE following
primary THR surgery among Danish patients and comparison cohort from the
general population.
Materials and Methods:
From the Danish Hip Arthroplasty Registry, we
identified all primary THRs performed in Denmark from 1995 to 2006
(
n=85,965). 97% of THR patients received low molecular weight heparin
products during hospitalization. Through the Danish Civil Registration System
we sampled a comparison cohort without THR from the general population
(
n=257,895). We used the National Registry of Patients to obtain information
on all THR patients and comparison cohort members, who were treated for
VTE (including deep venous thrombosis and pulmonary embolism) at an
outpatient clinic or hospitalized with VTE, after the index date.
Findings / Results:
Among THR patients, the risk of symptomatic VTE was
0.79% 0-90
days after surgery and 0.29% 91-365 days after surgery. In the
comparison cohort, the corresponding risks were 0.05% and 0.12%,
respectively. The adjusted relative risks of symptomatic VTE among THR
patients were 15.84 (95% confidence interval (95% CI): 13.12-19.12) during
the first 90 days after surgery and 2.41 (95% CI: 2.04- 2.85) during 91-365
days after surgery, compared with the comparison cohort. The relative VTE
risk was elevated irrespective of the THR patients’ gender, age and
comorbidity level at the time of surgery.
Conclusions:
THR surgery was associated with an increased risk of
symptomatic VTE up to one year after surgery compared to the general
population, although the absolute risk is small.
