Table 2.

Study characteristics potentially accounting for variability in outcome rates (per 100 persons per year) across independent studies of pediatric organ transplant recipients.

	Outcome Domain
	Immunosuppression Nonadherence			Clinic appointment and test nonadherence			Global nonadherence
Study Characteristica	rate (SE)	Nb	Z	rate (SE)	Nb	Z	rate (SE)	Nb	Z
Study design
Cross-sectional/retrospective	5.5 (0.6)	33	1.14	11.5 (2.7)	8	1.01	7.6 (1.6)	9	1.01
Prospective	14.7 (2.9)	8		24.0 (8.6)	2		16.1 (7.5)	2
Study quality
Lower (0–2)	4.9 (0.8)	28	4.27***	12.5 (3.5)	6	0.04	7.3 (2.3)	5	1.00
Higher (3–5)	8.4 (1.1)	13		12.7 (3.9)	4		9.5 (2.6)	6
Method of assessment
Clinical records review	4.2 (0.8)	19	(ref)	16.3 (4.0)	6	0.50	5.2 (1.4)	7	2.29**
Self-report	13.9 (8.5)	1c	---	24.1 (9.1)	2		---
Collateral	2.0 (2.7)	1c	---	2.7 (7.6)	1c	---	---
Indirect	13.8 (1.6)	14	5.90***	---			---
Multiple methods	8.0 (2.1)	6	3.56***	6.6 (7.6)	1c	---	18.7 (3.2)	4
Study sample age groupd
Children only	2.4 (1.4)	4	4.96***	---		---	---		---
Adolescents only	7.1 (1.1)	12		16.1 (3.5)	7		14.9 (4.3)	8

^aFor each nonadherence outcome domain, multivariate meta-regression tested the independent effects of study design, quality and method of assessment on nonadherence rate. Because fewer studies reported rates for specific age group, this variable could not be included in the multivariate analyses. A univariate test of this variable is provided (i.e., meta-regression with a single predictor variable).

^bNumber of studies included in each category of a given study characteristic, e.g., there were 32 studies that used a cross-sectional/retrospective design to examine immunosuppression nonadherence.

^cThere were too few studies in this category to be examined in the analyses.

^dStudies focused on specific age groups most commonly defined children as subjects aged ≤ 10 and adolescents as subjects aged > 10. See also footnote b, Table 1.

^*p < .05

^**p < .01

^***p < .001