Table. 1.

Characteristics of 66 included studies

Study characteristic Category Frequency
Trial type Single center 30 (45.5)
Multi-center 36 (54.5)
Source of funding Industry 37 (56.1)
Non-industry 25 (37.9)
Both 1 (1.5)
Not reported 3 (4.5)
Primary outcome (pain) Yes 43 (65.2)
No 23 (34.8)
Post-hoc analysis Yes 37 (56.1)
No 29 (43.9)
Treatment effect of primary outcome (main trial) Positive 24 (36.4)
Negative 42 (63.6)
Risk of bias Higha 38 (57.6)
Lowb 28 (42.4)
Korean J Pain 2021;34:139~155 https://doi.org/10.3344/kjp.2021.34.2.139
© Korean J Pain