Table 3.

Effect of engagement level* on HbA1c levels over time based on multivariable longitudinal linear regression models (n=292)

Variable	Adjusted†
	Mean difference (95% CI)	P value
Intervention effect
Low engagement vs control at each month‡
At month 0	−0.17 (−0.57 to 0.24)	0.4219
At month 6	−0.20 (−0.77 to 0.37)	0.4940
At month 12	0.05 (−0.53 to 0.63)	0.8665
High engagement vs control at each month‡
At month 0	−0.03 (−0.43 to 0.37)	0.8783
At month 6	0.08 (−0.38 to 0.53)	0.7471
At month 12	−0.16 (−0.67 to 0.34)	0.5272
High engagement vs low engagement at each month‡
At month 0	0.14 (−0.34 to 0.61)	0.5756
At month 6	0.28 (−0.36 to 0.91)	0.3972
At month 12	−0.21 (−0.85 to 0.42)	0.5106
Time effect
Month 6 vs month 0 for each group‡
For control group	−0.55 (−0.79 to −0.30)	<0.0001
For high engagement group	−0.44 (−0.80 to −0.08)	0.0177
For low engagement group	−0.58 (−1.01 to −0.15)	0.0087
Month 12 vs month 0 for each group‡
For control group	−0.48 (−0.76 to −0.19)	0.0011
For high engagement group	−0.61 (−0.96 to −0.26)	0.0007
For low engagement group	−0.26 (−0.67 to 0.15)	0.2120
Age (years)	−0.02 (−0.04 to −0.01)	0.0095
Sex: female vs male	−0.23 (−0.57 to 0.10)	0.1894
Language Spanish vs other	0.34 (−0.05 to 0.72)	0.0812
Mexican American: White vs other	0.29 (−0.24 to 0.83)	0.2039
Employment
Unemployed vs other	0.24 (−0.28 to 0.75)	0.3620
Employed vs other	−0.03 (−0.39 to 0.33)	0.8748
Marital status married vs other	−0.04 (−0.34 to 0.57)	0.8410
Insurance: yes vs no	−0.09 (−0.42 to 0.23)	0.5668
Education: high school or higher vs other	0.17 (−0.21 to 0.54)	0.4078

*High engagement, if total number of visits≥2; low engagement, if total number of visits<2

†Multivariable longitudinal linear regression model after adjusting for age, sex, preferred language, race, employment status, marital status, type of insurance, and years in school.

‡Based on interactive models where interactions between study group and follow-up visit (month) were included and tested.