Table 4.

Comparison of reporting quality of items of the PRISMA for abstracts of meta-analyses of RCT

Items	Univariable analysisa				Multivariable analysisb
	2014 versus 2012		2015 versus 2012		2014 versus 2012		2015 versus 2012
	Crude odds ratio (95 % CI)	p	Crude odds ratio (95 % CI)	p	Adjusted odds ratio (95 % CI)	p	Adjusted odds ratio (95 % CI)	p
Title	4.5 (0.52; 38.1)	0.240	4.6 (0.54; 39.4)	0.239	4.4 (0.55; 35.1)	0.163	4.5 (0.46; 43.7)	0.199
Objectives	0.76 (0.34; 1.7)	0.499	1.4 (0.56; 3.3)	0.499	0.78 (0.33; 1.8)	0.564	1.6 (0.66; 4.1)	0.286
Eligibility criteria	0.67 (0.24; 1.9)	0.451	0.70 (0.25; 2.0)	0.496	0.58 (0.17; 2.0)	0.390	0.75 (0.25; 2.3)	0.617
Information sources	2.3 (0.95; 5.4)	0.060	0.86 (0.31; 2.4)	0.770	2.0 (0.70; 5.5)	0.197	0.82 (0.26; 2.6)	0.740
Risk of bias	2.0 (1.003; 4.0)	0.048	0.92 (0.48; 1.8)	0.811	1.2 (0.55; 2.7)	0.625	0.79 (0.36; 1.7)	0.550
Included studies	0.81 (0.41; 1.6)	0.547	0.80 (0.41; 1.6)	0.519	1.1 (0.52; 2.2)	0.834	0.98 (0.50; 2.7)	0.956
Synthesis of results	1.2 (0.57; 2.4)	0.671	Not estimable	<0.001	1.1 (0.52; 2.5)	0.738	Not estimable
Description of the effect	0.88 (0.45; 1.7)	0.711	2.0 (0.96; 4.1)	0.063	0.93 (0.45; 1.9)	0.849	2.7 (1.2; 6.1)	0.014
Strengths and Limitations of evidence	0.68 (0.34; 1.4)	0.281	0.38 (0.18; 0.82)	0.012	0.23 (0.07; 0.71)	0.011	0.13 (0.03; 0.66)	0.013
Interpretation	1.4 (0.07; 2.8)	0.474	Not estimable	<0.001	1.9 (0.58; 5.9)	0.297	Not estimable
Funding	0.64 (0.29; 1.4)	0.264	1.6 (0.81; 3.3)	0.174	0.25 (0.07; 0.81)	0.021	1.5 (0.56; 4.0)	0.425
Registration	2.2 (0.36; 13.6)	0.404	12.2 (2.7; 56.1)	<0.001	1.9 (0.30; 12.4)	0.485	10.8 (2.3; 49.6)	0.002

CI confidence interval

^aChi-squared test

^bGeneralized estimation equations with journal as grouping variable: adjustment has been made for abstract word count (<300 versus ≥300), PRISMA endorser journal (yes versus no), abstract format (IMRAD versus 8-headings), publication on behalf a group (yes versus no), number of authors (≤6 versus >6)