Determining Risk Factors That Affect Progression in Patients with Nonproliferative Diabetic Retinopathy

Table 1

Transition rate matrix at time t of the 5-state model.

From	To
	No retinopathy	Mild NPDR	Moderate NPDR	Severe NPDR	PDR
No retinopathy	−q11(t)	q12t	q13t	q14t	q15t
Mild NPDR	0	−q22t	q23t	q24t	q25t
Moderate NPDR	0	0	−q33t	q34t	q35t
Severe NPDR	0	0	0	−q44t	q45t
PDR	0	0	0	0	−q55t

NPDR = nonproliferative diabetic retinopathy; PDR = proliferative diabetic retinopathy.