A meta-analysis of controlled clinical trials comparing low-molecular weight heparins with unfractionated heparin in unstable angina.
BACKGROUND
Unfractionated heparin has been used extensively for the treatment of unstable angina/non-Q wave myocardial infarction but it has several disadvantages. Low-molecular weight heparins are now recommended although they are 3-5 times costlier than unfractionated heparin since they are convinient to administer and do not require activated thromboplastin time monitoring. Whereas enoxaparin, a low-molecular weight heparin, has been demonstrated to be superior to unfractionated heparin, the results of other low-molecular weight heparins have not been so convincing.


RESULTS
Through manual, MEDLINE and EMBASE search, we identified five randomized trials (excluding enoxaparin trials) that compared low-molecular weight heparins with unfractionated heparin in unstable angina. The prespecified efficacy end point of interest included a composite of death, myocardial infarction, recurrent angina and urgent revascularization. The safety end point was taken as a composite of major hemorrhage, minor hemorrhage, thrombocytopenia, allergic reaction and any other adverse event. We calculated odds ratio (95% confidence interval) for each trial for the composite end point, and the pooled odds ratio (95%) confidence interval) was calculated using two established methods of meta-analysis, the Mantel-Haenszel-Peto method and the DerSirmonian-Laird method. Both the methods yielded similar odds ratio (95% confidence interval). Separate odds ratio were calculated for efficacy and safety end points. There was a nonsignificant reduction in the incidence of the composite efficacy end point: the odds ratio (95% confidence interval) was 0.83 (0.70-0.99: p=0.08). The odds ratio (95% confidence interval) for the safety data was 0.78 (0.69-1.26: p=0.33).


CONCLUSIONS
No statistically significant difference was observed when the efficacy and safety of low-molecular weight heparins were compared with those of unfractionated heparin. A cost-effectiveness analysis of low-molecular weight heparins versus unfractionated heparin must be done urgently to establish more firmly the place of low-molecular weight heparins in the management of unstable angina.
Malhotra
S
S
Department of Pharmacology, Postgraduate Institute of Medical Education & Research, Chandigarh.
Karan
R S
RS
Bhargava
V K
VK
Pandhi
P
P
Grover
A
A
Sharma
Y P
YP
Kumar
R
R
D000328:Adult; D000368:Aged; D000789:Angina, Unstable / Q000188:drug therapy*; D016001:Confidence Intervals; D005260:Female; D005500:Follow-Up Studies; D006493:Heparin / Q000008:administration & dosage* / Q000031:analogs & derivatives*; D006495:Heparin, Low-Molecular-Weight / Q000008:administration & dosage*; D006801:Humans; D007194:India; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D016032:Randomized Controlled Trials as Topic; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
D006495:Heparin, Low-Molecular-Weight; C078918:ITF 300; D006493:Heparin