Table 3.

Meta-regression analyses

Factor	Ratio of odds ratio (95% CI)	P-value	Explained variance (%)
Country’s income group			0.0
High-income	1.10 (0.75 to 1.61)	0.632
Middle-income	0.83 (0.49 to 1.40)	0.489
Low-income	1 (reference)
Publication year			17.4
1993 to 2000	1 (reference)
2001 to 2005	1.97 (1.33 to 2.92)	0.001
2006 to 2010	1.97 (1.33 to 2.92)	0.001
2011 to 2013	2.07 (1.26 to 3.39)	0.004
Study design			1.0
Cross-sectional	0.87 (0.70 to 1.08)	0.208
Cohort	1 (reference)
Sample size			23.3
Less than 100	1 (reference)
100 to 500	1.48 (1.15 to 1.91)	0.002
500 or more	1.85 (1.39 to 2.47)	0.000
Depression rate			30.1
Less than 20%	1 (reference)
20 to 50 %	0.96 (0.68 to 1.35)	0.815
50% plus	0.68 (0.47 to 0.99)	0.044
Adherence rate			5.0
Less than 50%	1 (reference)
50 to 75%	1.34 (0.94 to 1.94)	0.102
75% plus	1.28 (0.89 to 1.84)	0.182
Adherence measure			0.0
Self-reported	1 (reference)
Pharmacy refills	1.09 (0.77 to 1.54)	0.628
Pill count	0.98 (0.57 to 1.68)	0.948
MEMS cap	0.82 (0.56 to 1.20)	0.299