Meta regression analysis to indirectly compare dalteparin to enoxaparin for the prevention of venous thromboembolic events following total hip replacement

Table 2 Summary of meta regression analysis on the risk of VTE and adverse events in THR patients

Outcome	LMWH (D or E) vs. Control	SE	P-Value	Impact on Risk
VTE Risk in Placebo Trials	Relative Risk
Both drugs vs. placebo	0.50 (0.40 - 0.61)		<0.001	↓by 50%
RR difference between drugs (E vs. D)	0.23 (i.e. 12%)	0.25	0.36	NS
Region (vs. North American)
European trial	0.33	0.49	0.50	NS
Global trial	0.20	0.58	0.73	NS
LMWH dosing¹	-0.09	0.53	0.87	NS
LMWH treatment duration²	-0.21	0.31	0.51	NS
Year of publication	0.04	0.04	0.34	NS
Risk of Major Bleeds
Both drugs vs. placebo	1.19(0.39 - 3.55)		0.76	NS
Risk difference between Drugs (E vs. D)	-0.94	1.25	0.45	NS
Risk of HIT
Both drugs vs. placebo	1.13 (0.36 - 3.53)		0.83	NS
RR difference between Drugs (E vs. D)	-0.85	2.0	0.48	NS
Risk of Death
Both drugs vs. placebo	0.72 (0.22-2.34)		0.59	NS
RR difference between Drugs (E vs. D)	0.22	1.28	0.86	NS
VTE Risk in UH Trials
Both drugs vs. UH	0.83 (0.66-1.05)		0.12	NS
RR difference between drugs (E vs. D)	-0.24 (i.e. - 22%)	0.61	0.66	NS
Risk of Major Bleeds
Both drugs vs. UH	0.70 (0.35-1.38)		0.30	NS
RR difference between Drugs (E vs. D)	NA
Risk of HIT
Both drugs vs. UH	0.61 (0.21-1.77)		0.36	NS
RR difference between Drugs (E vs. D)	0.56	1.53	0.71	NS
Risk of Death
Both drugs vs. UH	0.59 (0.12-3.1)		0.53	NS
RR difference between Drugs (E vs. D)	NA

Abbreviations: LMWH = low molecular weight heparin, D = dalteparin, E = enoxaparin, P = placebo, UH = unfractionated heparin, THR = total hip replacement, VTE = venous thromboembolic events, HIT = heparin induced thrombocytopenia, NS = not significant, DVT = deep vein thrombosis, PE = pulmonary embolism, NA = data not available for calculation.
¹Pre vs. post surgical initiation. ²Short duration (i.e. < 15 days) vs. extended duration.

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