Table 4. Predicted Hazard ratio for treatment failure occurrence and changes in prescription based on cox proportional hazard model.

Variables		Hazard ratio	95% confidence interval	p-value
Probability of treatment failure after adding sulfonylurea or DPP-4 inhibitor to metformin monotherapy
	MS (= reference)
	MD	0.665	0.470–0.942	0.022
	Age	0.98	0.970–0.993	0.002
	HbA1c level ≥ 8% before prescription	2.309	1.745–3.056	< 0.001
Probability of changes in prescription after adding sulfonylurea or DPP-4 inhibitor to metformin monotherapy
	MS (= reference)
	MD	0.581	0.440–0.767	< 0.001
	Sex (female)	1.303	1.029–1.650	0.031
	Age	0.987	0.976–0.997	0.012

MS, patients with addition of sulfonylurea to metformin monotherapy; MD, patients with addition of DPP-4 inhibitor to metformin monotherapy.