INR self-testing associated with improved quality of life for patients on warfarin vs. clinic testing
Matchar D. N Engl J Med. 2010;363:1608-1620.
Weekly self-testing of the international normalized ratio for patients on warfarin did not delay the time to a first stroke, major bleeding episode or death when compared with high-quality clinic testing to the extent suggested by prior studies, new data from the THINRS trial indicated. However, statistically significant improvements in patient satisfaction and quality of life for self-testing were reported by researchers.
In the prospective, randomized, nonblinded trial, 2,922 patients taking warfarin (Coumadin, Bristol-Myers Squibb) were randomly assigned to either self-testing (n=1,465) or high-quality testing of INR in a clinic (n=1,457). The primary endpoint was the time to a first major event — stroke, major bleeding episode or death — and the secondary endpoints were time within the INR target range, patient satisfaction and quality of life.
During 8,730 patient-years of follow-up (time range, 2-4.75 years), study data revealed no significantly longer time to the first primary event in the self-testing group than in the clinic-testing group (self-testing HR= 0.88; 95% CI, 0.75-1.04). Clinical outcomes were similar between arms, with the exception of more minor bleeding episodes in the self-testing group (540 vs. 401, P<.001).
At 2 years, the self-testing arm showed improvements in patient satisfaction (P=.002) and quality of life (P<.001) with anticoagulation therapy vs. the clinic-testing arm, whereas during the entire follow-up, an improvement in the percentage of time INR was within target range was also noted in the self-testing group (P<.001).
“The results of THINRS do not establish the superiority of self-testing over high-quality clinic testing in preventing major clinical outcomes but do provide evidence of modest improvements in time within the therapeutic INR range, patient satisfaction with anticoagulation therapy and quality of life,” the researchers concluded.
Based on the findings of this study, they added, self-testing should be considered for patients whose access to high-quality anticoagulation care is limited by disability, geographic distance or other factors, if the alternative would be to withhold a highly effective treatment.
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TRACS: Differing blood transfusion strategies yield similar complication, death rates in cardiac surgery patients
Hajjar L. JAMA. 2010;304:1559-1567.
A liberal strategy for initiating perioperative blood transfusions resulted in statistically similar clinical complication and mortality rates compared with a more restrictive strategy, results from a study indicated. Regardless of treatment strategy, blood transfusions were associated with higher death and complication rates.
Some researchers have suggested the use of perioperative transfusion for the maintenance of hemoglobin levels of 10 g/dL and 30% hematocrit concentrations, according to the study. Other researchers have recently questioned these thresholds, however, as the risks of transfusion and the highly individualized nature of a patient’s response to anemia have become better understood.
A prior study of critically ill patients found that maintaining hemoglobin concentrations between 7 and 9 g/dL may result in fewer patient deaths than a more liberal strategy of sustaining hemoglobin between 10 and 12 g/dL. Ludhmila A. Hajjar, MD, PhD, and colleagues compared similar strategies in 502 patients undergoing elective cardiac surgery with cardiopulmonary bypass at a cardiac surgery referral center in Brazil.
Before surgery, patients were randomly assigned in a prospective fashion to two groups. Patients in the restrictive group received red blood cell transfusions if their hematocrit values were less than 24% at any point from the start of surgery until discharge from the ICU. For patients in the liberal group, the transfusion trigger was hematocrit levels of less than 30%.
Significantly more patients in the liberal group received red blood cell transfusions. In this group, 198 of 253 patients (78%) received a transfusion, compared with 118 of 249 (47%) patients in the restrictive group (P<.001).
Average hemoglobin concentrations were kept at 10.5 g/dL (95% CI, 10.4-10.6) in the liberal group vs. 9.1 g/dL (95% CI, 9.0-9.2) in the restrictive group (P<.001).
The researchers defined their composite endpoint as 30-day all-cause mortality and severe morbidity, including acute respiratory distress syndrome, cardiogenic shock or acute renal injury requiring dialysis or hemofiltration. In the liberal group, 10% of patients reached the endpoint vs. 11% of patients in the restrictive group (95% CI, –6% to 4%). There were no significant differences in cardiac complications, neurologic complications, infection or severe bleeding requiring reoperation.
In their conclusion, the researchers posited that the reported similarity in complication rates “occurred because the restrictive strategy did not result in reduced oxygen availability to the cells. This is supported by the lack of difference in lactate levels between the two groups during the study period”
Although neither transfusion strategy was associated with greater risk, the total number of transfused red blood cell units was an independent risk factor for complications or death at 30 days (HR for each additional unit transfused, 1.2; 95% CI, 1.1-1.4).
“These findings suggest that the primary strategy in patients undergoing cardiac surgery should be to avoid giving [red blood cell] transfusion solely to correct low hemoglobin levels. The increased risk of mortality related to the number of transfused [red blood cell] units supports a restrictive therapy in cardiac surgery,” the researchers wrote. “In addition, clinicians caring for patients after cardiac surgery should administer only one [red blood cell] unit at a time because this may result in less exposure to risks but similar benefits.”