The Effect of Metformin on Adolescents with Type 1 Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Table 2

Quality assessment of individual studies.

Study and publication year	Randomization	Double blinding	Dropouts	Jadad score	Concealment of allocation^#
Libman et al., 2015 [15]	2	2	1	5	Adequate
Nwosu et al., 2015 [13]	2	2	1	5	Adequate
Nadeau et al., 2015 [14]	2	2	1	5	Adequate
Särnblad et al., 2003 [6]	1	1	1	3	Unclear
Hamilton et al., 2003 [17]	2	2	1	5	Unclear

The Jadad scale consists of three items related to descriptions of randomization (0–2 points), double blinding (0–2 points), and dropouts and withdrawals (0-1 point) for a total of five scores. Higher scores indicate better quality. High-quality trials were defined as those that scored more than 2. Low-quality trials were defined as those that scored 2 or less.
^#Concealment of allocation was assessed as adequate, inadequate, or unclear based on the criteria described by Schulz et al. [18].