Table 2. Secondary outcome results.

	App-based CBT-I, mean (SE)a	App-based HE, mean (SE)	Adjusted difference (95% CI)	p value	Cohen’s db
PHQ-9
Baseline	12.1 (0.2); n = 354	12.1 (0.2); n = 354
Post-session 2	7.6 (0.2); n = 291	7.7 (0.2); n = 285	−0.1 (−0.7, 0.5)	0.72	0.06
Post-session 4	6.1 (0.2); n = 256	7.0 (0.2); n = 264	−1.0 (−1.6, −0.4)	0.002	0.50
Post-intervention	5.1 (0.2); n = 314	6.2 (0.2); n = 319	−1.0 (−1.6, −0.5)	<0.001	0.53
6 months	5.4 (0.2); n = 273	6.3 (0.2); n = 268	−0.8 (−1.4, −0.2)	0.009	0.42
12 months	5.5 (0.2); n = 249	6.0 (0.2); n = 227	−0.5 (−1.1, 0.2)	0.14	0.24
PHQ-8 c
Baseline	9.6 (0.2); n = 354	9.6 (0.2); n = 354
Post-session 2	6.1 (0.2); n = 291	6.2 (0.2); n = 285	−0.1 (−0.6, 0.5)	0.83	0.03
Post-session 4	4.9 (0.2); n = 256	5.6 (0.2); n = 264	−0.7 (−1.2, −0.1)	0.02	0.39
Post-intervention	4.1 (0.2); n = 314	5.0 (0.2); n = 319	−0.9 (−1.4, −0.4)	0.001	0.51
6 months	4.5 (0.2); n = 273	5.1 (0.2); n = 268	−0.7 (−1.2, −0.1)	0.01	0.39
12 months	4.5 (0.2); n = 249	4.9 (0.2); n = 227	−0.4 (−1.0, 0.2)	0.18	0.23
ISI
Baseline	18.3 (0.2); n = 354	18.3 (0.2); n = 354
Post-session 2	11.5 (0.2); n = 291	12.1 (0.2); n = 285	−0.6 (−1.3, 0.1)	0.12	0.22
Post-session 4	9.0 (0.2); n = 256	10.7 (0.2); n = 264	−1.7 (−2.4, −1.0)	<0.001	0.66
Post-intervention	7.3 (0.2); n = 313	9.3 (0.2); n = 319	−2.0 (−2.7, −1.3)	<0.001	0.78
6 months	7.2 (0.2); n = 272	8.4 (0.2); n = 268	−1.1 (−1.9, −0.4)	0.002	0.45
12 months	7.3 (0.2); n = 249	8.2 (0.2); n = 227	−0.8 (−1.6, −0.1)	0.03	0.32

Abbreviations: CBT-I, cognitive behavioral therapy for insomnia; HE, health education; ISI, Insomnia Severity Index; PHQ, Patient Health Questionnaire.

^aAll values are adjusted for sex and insomnia severity at baseline.

^bCohen’s d is defined as the adjusted intervention effect divided by the square root of estimated sample variance derived from the linear mixed-effects model.

^cExcluding sleep item.