. Author manuscript; available in PMC: 2020 Jun 1.

Published in final edited form as: Am J Med. 2019 Jan 16;132(6):722–732.e7. doi: 10.1016/j.amjmed.2019.01.004

Table 4.

Pooled Incidence of Venous Thromboembolism and Bleeding Outcomes

	Any Outcome		Venous Thromboembolism			Major Bleeding			All Bleeding^*
Group	Studies, n	Procedures, n	Studies, n	Events/ Procedures, n	Pooled incidence, % (95% CI)	Studies, n	Events/ Procedures, n	Pooled incidence, % (95% CI)	Studies, n	Events/ Procedures, n	Pooled incidence, % (95% CI)
Main Analysis

All studies	28	6915^†	27	40.5 / 6886		15	41 / 3786		18	137.1/ 6494
With bridging	27	3448	26	25 / 3427	0.7 (0.4–1.2)	13	30 / 1702	1.8 (1.2–2.5)	16	114 / 3074	3.9 (2.0–7.4)
Without bridging	8	3459	8	15.5 / 3459	0.5 (0.3–0.8)^‡	5	11 / 2084	0.4 (0.1–1.5)	7	23.1 / 3420	0.4 (0.1–1.7)^§

Sensitivity analyses

Excluding studies without specific outcome reporting for population of interest ^\|\|	18	6648^†	17	40.5 / 6619		11	41 / 3557		14	137.1/ 6265
With bridging	18	3234	17	25 / 3213	0.8 (0.5–1.3)	11	30 / 1666	1.8 (1.3–2.6)	14	114 / 3038	4.4 (2.3–8.2)
Without bridging	6	3406	6	15.5 / 3406	0.5 (0.3–0.8)^‡	3	11 / 1891	0.5 (0.1–2.0)	5	23.1 / 3227	0.6 (0.1–2.4)^¶

Excluding conference abstracts	26	6725^†	25	38.5 / 6696		13	37 / 3620		16	111.1/ 6328
With bridging	25	3272	24	23 / 3251	0.7 (0.4–1.2)	12	26 / 1550	1.6 (0.8–3.2)	15	88 / 2922	3.4 (1.8–6.6)
Without bridging	7	3445	7	15.5 / 3445	0.5 (0.3–0.8)^‡	4	11 / 2070	0.4 (0.1–1.6)	6	23.1 / 3406	0.4 (0.1–1.8)^**

Excluding Sjögren, et al. ^†	27	4245	26	25 / 4224		15	41 / 3832		17	125 / 3878
With bridging	26	2117	25	15 / 2096	0.6 (0.3–1.3)	13	30 / 1702	1.8 (1.2–2.5)	15	104 / 1743	4.9 (2.7–8.7)
Without bridging	7	2128	7	10 / 2128	0.5 (0.2–1.2)	5	11 / 2084	0.4 (0.1–1.5)	6	21 / 2089	0.6 (0.1–2.8)

Excluding studies with <100 procedures	7	6173^†	7	35.5 / 6165		6	39 / 3481		7	113.1/ 6143
With bridging	7	2764	7	20 / 2764	0.7 (0.4–1.2)	5	28 / 1411	2.0 (1.4–2.9)	6	90 / 2742	4.0 (1.8–8.7)
Without bridging	5	3401	5	15.5 / 3401	0.5 (0.3–0.8)^‡	4	11 / 2070	0.4 (0.1–1.6)	5	23.1 / 3401	0.5 (0.1–1.9)

Subgroup analyses

High thromboembolic risk ^††	9	394	9	3 / 394					7	45 / 361
With bridging	9	373	9	3 / 373	0.8 (0.3–2.5)	NA	NA	NA	7	44 / 340	7.5 (3.1–17.4)
Without bridging	1	21	1	0 / 21	NA	NA	NA	NA	1	1 / 21	NA

LMWH dose ^††
Therapeutic dose	11	981	10	5 / 580	0.9 (0.4–2.1)	4	10 / 387	2.6 (1.4–4.7)	6	35 / 800	3.9 (2.0–7.5)
Prophylactic dose	6	362	5	3 / 208	1.4 (0.5–4.4)	3	4 / 188	2.1 (0.8–5.5)	4	32 / 342	4.4 (0.9–18.3)

includes major bleeding and any other bleeding outcomes that were specifically reported for patients with previous venous thromboembolism

^†

in the study by Sjögren et al,¹⁸ procedures in the non-bridging group were propensity score matched and weighted to equal the number of procedures in the bridging group; therefore, the number of procedures with bridging and without bridging does not add up to the exact number of overall procedures

^‡

the non-integer number of outcome events (5.5 venous thromboembolic events) in the study by Sjögren et al was rounded to the next integer for this analysis. When rounding down to the next lower integer, the results were similar (pooled incidence 0.4%, 95%CI 0.3–0.7%)

^§

the non-integer number of outcome events (2.1 events of any bleeding) in the study by Sjögren et al was rounded to the next integer for this analysis. When rounding up to the next higher integer, the results were similar (pooled incidence 0.5%, 95%CI 0.1–1.8%)

^||

some studies did not report results separately for patients with prior venous thromboembolism and could only be included because there were no venous thromboembolism ^{22, 23, 25, 27, 28, 30, 31, 36, 39, 42} or bleeding^{28–30, 40} outcomes in the overall population. As this might bias our study sample to studies with a low number of outcome events, we excluded these studies for this subgroup analysis.

^¶

^**

^††

for these analyses, we included only studies that reported outcomes separately for the specific subgroup of interest