- Three matched cohort studies compared the risk of venous thromboembolism (VTE) among patients with knee, hip or hand osteoarthritis (OA) with that of individuals without OA in the general U.K. population
- The risk of VTE was 38% higher among individuals with knee OA and 83% higher among individuals with hip OA, compared with the matched non-OA cohorts
- Knee and hip replacement surgery played an important role in the association: 25% of the knee OA effect on the risk of VTE and 28% of the hip OA effect was mediated through joint replacement
- Other factors that might increase the risk of VTE in these patients include those induced by prolonged physical inactivity, such as muscular and diaphragm dysfunction, venous stasis and a hypercoagulability state
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Limited mobility and total joint arthroplasty are known to be strong risk factors for venous thromboembolism (VTE). In previous research published in Arthritis & Rheumatology, Massachusetts General Hospital researchers detected an elevated risk of VTE lasting for up to years after knee or hip replacement for osteoarthritis (OA).
Now, extending that research, Chao Zeng, MD, PhD, from Xiangya Hospital, and Yuqing Zhang, DSc, director of Epidemiological and Biostatistical Methods at the Division of Rheumatology, Allergy and Immunology at Massachusetts General Hospital, and colleagues have linked the risk of VTE with OA itself. Their findings appear in Annals of the Rheumatic Diseases.
The researchers reviewed data from The Health Improvement Network, a prospectively gathered database that's nationally representative of the U.K. population that currently has about 17 million participants from 790 general practices. Eligible participants were age ≥50 and had been enrolled in their practice for at least one year between January 2000 and December 2017.
Three cohort studies were conducted, each comparing patients with a single type of OA with patients who didn't have OA at any site, matched by age, sex, year of OA diagnosis and body mass index. The cohorts were:
- 20,696 with knee OA vs. 81,137 without OA
- 10,411 with hip OA vs. 41,594 without OA
- 6,329 with hand OA vs. 25,206 without OA
- The knee OA cohort had a higher overall risk of VTE than its matched non-OA cohort (adjusted HR, 1.38; 95% CI, 1.23–1.56)
- The aHR was 1.21 for deep vein thrombosis and 1.65 for pulmonary embolism
- The risk of VTE was about 13-fold greater among those who underwent knee replacement than those who did not (15.8% vs. 1.2%)
- 25% of the effect of knee OA on the risk of VTE was mediated through knee replacement
- The hip OA cohort also had a higher risk of VTE than its matched non-OA cohort (aHR,1.83; 95% CI, 1.56–2.13)
- The aHR was 1.87 for deep vein thrombosis and 1.92 for pulmonary embolism
- The risk of VTE was about 12-fold greater among those who underwent hip replacement than those who did not (14.9% vs 1.2%)
- 28% of the effect of hip OA on the risk of VTE was mediated through hip replacement
There was no significant difference in the risk of VTE between the hand OA cohort and its matched non-OA cohort.
A Potential High-Risk Population
If these novel findings are confirmed by other studies, clinicians managing patients with knee or hip OA should have a high index of suspicion for VTE. This will be particularly important for patients with mobility limitations and those with non-specific symptoms and signs.
Besides joint replacement surgery, factors that increase the risk of VTE in these patients may include those induced by prolonged physical inactivity, such as muscular and diaphragm dysfunction, venous stasis and a hypercoagulability state. Patients with knee or hip OA should be encouraged to engage in physical exercise, and early mobilization after surgery remains important.
Refer a patient to the Rheumatology Unit