Table 2.

Quality assessment of studies included in meta-analysis

Ref.	Study design	Selection bias	Confounders	Blinding	Data collection methods	Withdrawals and dropouts	Intervention integrity	Analyses	Quality assessment
Koch et al[25]	Retrospective Moderate	Moderate	Moderate	Weak	Strong	NA	Moderate	Moderate	Moderate
Rehman et al[24]	Retrospective Moderate	Moderate	Strong	Weak	Strong	NA	Strong	Moderate	Moderate
Perisetti et al[26]	Retrospective Moderate	Moderate	Weak	Weak	Strong	NA	Moderate	Moderate	Weak
Tang et al[27]	Retrospective Moderate	Moderate	Strong	Weak	Strong	NA	Moderate	Moderate	Moderate

NA: Data not available.