Preventing venous thromboembolism in long-term care residents: Cautious advice based on limited data
ABSTRACTIn hospitalized medical patients, randomized trials have established that anticoagulant prophylaxis has an acceptable benefit-to-risk ratio: ie, it lowers the incidence of clinically silent and symptomatic venous thromboembolism (VTE), including fatal pulmonary embolism, more than it raises the risks of bleeding and other complications. However, no similar trials have been done in long-term care residents. More research is needed to ascertain which long-term care residents would benefit most from VTE prophylaxis. In the absence of evidence-based guidelines, we advocate a selective approach.
KEY POINTS
- Assessment of VTE risk and consideration of need for anticoagulant prophylaxis in long-term care residents are based on indirect data, derived primarily from studies of acutely ill hospitalized medical patients.
- Drugs and devices for thromboprophylaxis have been studied in medical and surgical populations, but issues of efficacy and safety are likely to also pertain to long-term care residents.
- Thromboprophylaxis should be considered for long-term care residents if they are definitely at increased risk of VTE—ie, if they have an acute exacerbation of congestive heart failure or chronic obstructive pulmonary disease; acute inflammatory disease; acute infection; active cancer; or immobility and prior VTE.
Heparin-induced thrombocytopenia
The other major risk of anticoagulant prophylaxis is heparin-induced thrombocytopenia, an infrequent but life-threatening complication caused by the formation of antibodies to the heparin-derived anticoagulant and a platelet surface antigen. It is associated with moderate thrombocytopenia and an incidence of venous or arterial thrombosis that is over 50%.26
No study has assessed the incidence of heparin-induced thrombocytopenia in long-term care residents. A meta-analysis reported that the risk with anticoagulant prophylaxis was 1.6% with unfractionated heparin (95% confidence interval [CI] 1.2%–2.1%) and 0.6% with low-molecular-weight heparin (95% CI 0.4%–0.9%), and that this risk increased with the duration of prophylaxis.27 If anticoagulant prophylaxis were given to all long-term care residents for extended durations (eg, for the duration of reduced mobility), the incidence and prevalence of heparin-induced thrombocytopenia would likely become a major concern.
Whenever anticoagulant prophylaxis is considered, the risks of both thrombosis and bleeding should be considered. Patients who are receiving anticoagulant prophylaxis should also be monitored for bleeding and heparin-induced thrombocytopenia. This is particularly true in long-term care residents, in whom the risks and benefits of anticoagulant prophylaxis are extrapolated from data from other populations.
MORE RESEARCH IS NEEDED
To date, we lack audits of thromboprophylaxis, clinical practice guidelines, and clear indications and contraindications for anticoagulant prophylaxis in long-term care residents. In the absence of such data, extrapolating the efficacy and safety of thromboprophylaxis from hospitalized patients to long-term care residents is difficult.
Clearly, additional research is needed to identify which long-term care residents would benefit most from thromboprophylaxis. In the meantime, a selective approach to identifying patients who should be considered for thromboprophylaxis should be adopted.
