Table 2 Methodology quality of the included studies

Monotherapy

Laurin et al. [24]

Inadequate (no description)

No

5 vs. 5

2

Lindor et al. [25]

Inadequate (no description)

Yes

6 vs. 2

4

Dufour et al. [20]

Adequate (randomization list set up by pharmacy before study)

Yes

3 vs. 2

4

Kiyici et al. [26]

Inadequate (no description)

No

NM

2

Hong Qian, et al. [32]

Adequate (1:1 ratio)

NM

0 vs. 0

3

Zhu Hong-Juan [27]

Inadequate (no description)

No

0 vs. 0

2

Ratziu et al. [28]

Adequate (1:1 ratio in blocks of four)

Yes

7 vs. 3

5

Leuschner et al. [29]

Inadequate (no description)

Yes

39 in total

4

UDCA combined with other drugs

Dufour et al. [20]

Adequate

Yes

3 vs. 2

4

Zhuang Xue-shan [30]

Inadequate (no description)

NM

0 vs. 0

2

Sun Yan [31]

Inadequate (no description)

NM

NM

2

Lv Hong [33]

Inadequate (no description)

NM

NM

2

Liu Zhi-ye [34]

Inadequate (no description)

NM

NM

2