First author, year [ref.] | Randomisation | Allocation concealment | Blinding | Follow-up | Selective reporting | Statistical analysis plan |
Tashkin, 2007 [12] | Yes | Unclear | Yes | No | No | Unclear |
Tashkin, 2016 [13] | Yes | Unclear | Yes | No | No | Yes |
Sircar, 2017¶ [14] | Yes | Unclear | No | Unclear | No | Unclear |
Pérez Campos, 2012 [15] | Yes | Yes | Yes | No | No | Unclear |
Seibold, 2010 [16] | Unclear | Unclear | Yes | No | No | Unclear |
#: a further study was underpowered and therefore not rated at the same evidence level [11]; ¶: please note that since the date of the literature search, this reference (abstract) has been published in full.