Table 2.

Summary of Meta-Analysis Results

Effect of Health literacy	ka	Total Nb	Unweighted Median r (range)c	mean r [95% Confidence Interval]	mean r [95% Confidence Interval]	Fail safe Nd	Odds Ratio [95% Confidence Interval]e	Relative Risk [95% Confidence Interval]e
Health literacy and adherence correlationf	48	19072	0.10 (−0.60, 0.80)	0.12 [0.10, 0.13] **	0.14 [0.08, 0.19] **	3191 (tolerance level 250)	1.76 [1.38, 2.16]	1.33 [1.17, 1.47]
Health literacy interventions aimed at improving health literacyg	71	12691	0.20 (0.06, 0.56)	0.14 [0.12, 0.16] **	0.22 [0.18, 0.25] **	7922 (tolerance level 365)	2.45 [2.07, 2.78]	1.56 [1.44, 1.67]
Health literacy interventions aimed at improving patient adherenceh	101	20545	0.15 (−0.08, 0.49)	0.10 [0.09, 0.12] **	0.16 [0.14, 0.19] **	10431 (tolerance level 515)	1.91 [1.76, 2.16]	1.38 [1.32, 1.47]

Note.

^**p <.001

^aNumber of samples;

^btotal N across all samples;

^cfor each sample, a positive r indicates that patients who are more health literate are more likely to be adherent or health literacy interventions were effective in improving a patient’s level of health literacy or adherence to treatment. A negative r indicates that patients who are more health literate are less likely to be adherent or health literacy interventions were not effective in improving a patient’s level of health literacy or adherence to treatment;

^dsince the fail N exceeds the “level of tolerance for future null results” it is unlikely that the “file drawer problem” is a bias;

^ethe binomial effects size display from the unweighted mean effects in the random effects model was used to obtain the standardized odds ratio and relative risk;

^fthe heterogeneity test (k=48) for health literacy and adherence correlational studies is significant (X²= 591.36, p<.001);

^gthe heterogeneity test (k=78) for health literacy interventions aimed at improving health literacy is significant (X²=235.10, p<.001);

^hthe heterogeneity test (k=101) health literacy interventions aimed at improving patient adherence is significant (X²= 249.87, p<.001)