In the enoxaparin group, 3.7% of patients experienced the primary outcome. This decreased to 1.1% in the rivaroxaban group. Approximately one-third of events were symptomatic. Major bleeding occurred in 0.1% and 0.3% (p=NS) of patients in the enoxaparin and rivaroxaban groups, respectively.
The study is limited by the exclusion of 1,388 of the 4,541 patients (30.6%) randomized, primarily due to having inadequate venography. Also, because the majority of thromboembolic events were asymptomatic, the primary outcome overemphasizes the clinical difference.
Bottom line: Oral rivaroxaban without monitoring is more efficacious than, and as safe as, subcutaneous enoxaparin when used for VTE prophylaxis for THR.
Citation: Eriksson B, Borris LC, Friedman RJ, Hass S, Huisman MV, Kakkar AK, et al. Rivaroxaban versus enoxaparin for thromboprophylaxis after hip arthroplasty. N Engl J Med. 2008;358:2765-75.
Background: Patients with cancer are at increased risk for VTE and require prophylaxis to prevent this complication postoperatively. Low molecular weight heparin (LMWH) has proven more efficacious than subcutaneous unfractionated heparin (UFH) in other settings (e.g., DVT treatment). However, it is still unknown whether LMWH offers better prophylaxis compared to UFH for cancer patients undergoing surgery.
Study design: Systematic review and meta-analysis.
Setting: 14 randomized controlled trials.
Synopsis: Eleven trials exclusively examined patients with cancer (n=4006) and three trials reported data for cancer patients as subgroups (n=1816). There were in differences in mortality, pulmonary embolism, and symptomatic DVT rates between the two groups.
LMWH was associated with a decrease in total (asymptomatic or symptomatic) DVT (RR, 0.72; 95% CI, 0.55-0.94). Rates of major bleeding, minor bleeding, and intraoperative blood loss were similar between the two treatments.
This meta-analysis is limited because 12 remaining trials (n=3185) also enrolled cancer patients but did not provide specific data for the cancer patient subgroup. The study also is limited by the heterogeneity of the original trials, including utilizing varying LMWHs and dosing regimens, numerous types of surgeries, and a wide range of neoplasms.
Bottom line: LMWH does not decrease mortality, pulmonary embolism, or symptomatic DVT compared to UFH in cancer patients undergoing surgery.
Citation: Akl EA, Terrenato I, Barba M, Sperati F, Sempos EV, Muti P, et al. Low-molecular-weight heparin vs. unfractionated heparin for perioperative thromboprophylaxis in patients with cancer. Arch Intern Med. 2008;168:1261-9.
Background: Asthma is a chronic disease causing major morbidity and mortality worldwide. Disease guidelines recommend all patients with persistent asthma be treated with inhaled corticosteroids. These same guidelines recommend adding a long-acting beta-agonist for patients whose symptoms persist. However, the safety of this practice has come under scrutiny.
Study design: Meta-analysis.
Setting: Sixty-six randomized, controlled trials conducted worldwide.
Synopsis: Analysis included 66 GlaxoSmithKline trials with a total of 20,966 patients with persistent asthma. Patients used either salmeterol (50mcg twice daily) plus inhaled corticosteroid (10,400 patients) or inhaled corticosteroid alone (10,566 patients).
Results showed no differences in asthma-related hospitalizations, asthma-related intubations, or deaths between the two groups. However, due to the low number of events, definitive conclusions are difficult to make. Severe asthma exacerbations requiring systemic corticosteroids significantly decreased in the inhaled corticosteroid plus salmeterol group.
The study is limited by it inclusion of only those trials sponsored by GlaxoSmithKline and by the short duration of most of the studies. Additionally, the studies included in the analysis used clinical outcomes as secondary endpoints.
Bottom line: Adding salmeterol to inhaled corticosteroid decreases severe asthma exacerbations and is likely safe, but does not have an effect on asthma-related hospitalization or death.