Table 2. Multivariable Cox model measured hazard ratios and 95% confidence intervals for recurrent depressive disorder in the interferon-α-induced depression.

	IFN-α-treated cohort				Matched cohort
	HR	95% CI	Adjusted HRa	95% CI	HR	95% CI	Adjusted HRa	95% CI
IFN-α-induced depression	14.4	10.6–19.4	13.5	9.9–18.3	19.0	10.6–34.3	22.2	11.2–44.2
Past depression history
No	14.6	10.6–20.2	13.8	9.9–19.0	17.4	9.4–32.3	20.1	9.7–41.6
Yes	12.9	5.8–28.9	11.8	5.2–26.5	41.7	5.0–348.4	46.1	5.1–418.0
Onset day of IFN-α-induced depression
⩽45	15.4	9.6–24.6	15.3	9.5–24.7	13.1	5.7–30.5	16.0	6.2–40.9
45–90	9.8	5.4–17.8	8.9	4.9–16.3	18.2	5.7–58.3	19.9	5.2–76.3
>90	16.9	10.5–27.5	14.4	9.4–25.0	36.2	10.5–124.7	45.5	11.7–177.3
Post-depression IFN-α doses
⩽2	13.6	8.4–22.1	13.0	8.0–21.2	33.0	9.6–113.4	40.0	11.4–155.2
2–5	10.5	5.9–18.5	9.6	5.4–17.1	8.5	3.4–21.4	9.7	3.5–27.2
>5	18.9	11.6–30.6	17.5	10.8–28.6	29.7	9.9–88.9	31.0	9.6–100.4
Antidepressant therapy
No	15.6	8.8–27.6	15.5	8.7–27.6	13.9	5.2–37.3	16.1	5.2–49.3
Yes	14.0	9.9–19.8	12.9	9.1–18.3	22.3	10.6–47.0	25.8	11.3–58.5

Abbreviations: CI, confidence interval; HR, hazard ratio; IFN, interferon.

^aAdjusted for age, sex, income, urbanization, hypertension, diabetes, hypercholesterolemia, chronic obstructive pulmonary disease, liver cirrhosis, coronary heart disease, anemia and thyroid disease.