Table 2.

Variables Associated With Adherence to Oral Mercaptopurine (N = 327)

Variable	Parameter Estimate*	95% CI	Estimated Adherence (%)	P
Intercept	3.85	3.34 to 4.35	—	< .001
Time on study, months				< .001
1	—		94.7	—
2	−0.29	−0.46 to −0.13	93.1	< .001
3	−0.41	−0.61 to −0.22	92.5	< .001
4	−0.52	−0.71 to −0.32	91.6	< .001
5	−0.59	−0.81 to −0.37	91.0	< .001
6	−0.66	−0.89 to −0.43	90.2	< .001
Age at study participation, years				< .001
< 12	—		93.1
≥ 12	−0.81	−1.28 to −0.34	85.8
Household structure				.001
Multiple caregivers	—		93.1
Single mother	−0.86	−1.39 to −0.33	80.6
Ethnicity				< .001
Non-Hispanic whites	—		94.8
Hispanics	−0.86	−1.20 to −0.52	88.4

NOTE. All models were adjusted for time from initiation of maintenance to study entry. Other variables examined but not found to be significantly associated with adherence included: sex (P = .51), National Cancer Institute criteria for disease risk (P = .44), chromosomal abnormalities (P = .51), parental education (P = .41), and annual household income (P = .93).

^*More negative values of the parameter estimates indicate worse adherence rate when compared with the referent level, which is indicated by —.