Table 2.

Mean number of episode days, corrected for age, sex, and practice

Variable	Coefficient	SE	P-value	95% CI
Age	0.20	0.13	0.12	−0.05 to −0.46
Sex	5.69	4.34	0.19	−2.82 to 14.21
Patient group
Depression (ref)	–
Anxiety	−102.87	9.66	0.000	−121.80 to −83.94
Emotional distress	−122.73	12.69	0.000	−147.60 to −97.87
Year
2007 (ref)	–
2008	−128.01	9.47	0.000	−146.56 to −109.46
2009	−136.89	9.47	0.000	−155.45 to −118.34
2010	−126.34	9.47	0.000	−144.89 to −107.78
2011	−130.39	9.47	0.000	−148.94 to −111.83
Group × year
Anx × 2008	87.63	13.47	0.000	61.23 to 114.03
Anx × 2009	83.08	13.47	0.000	56.68 to 109.48
Anx × 2010	77.27	13.47	0.000	50.87 to 103.68
Anx × 2011	92.63	13.47	0.000	66.23 to 119.04
Emo × 2008	83.4	17.58	0.000	48.95 to 117.86
Emo × 2009	91.17	17.58	0.000	56.71 to 125.62
Emo × 2010	85.04	17.58	0.000	50.58 to 119.5
Emo × 2011	86.53	17.58	0.000	52.07 to 121.00
Constant	165.16	8.56	0.000	148.39 to 181.94

Anx = anxiety. Emo = emotional distress. SE = standard error. For example, an 18-year-old male with depression in 2007 is the reference: on average he had 165 illness days (constant). For females, 5.69 days should be added; for each year’s increase in age, 0.2 days should be added. For anxiety, 103 days should be subtracted. For the same male with depression in 2008, 128 days should be subtracted. Whereas for a male of 18 years with anxiety in 2008, 103 days + 128 days should be subtracted; however, the interaction effect means that 88 days should be added. The 88 days refers to the 87.63 coefficient in the group year × year column.