INS and diabetic retinopathy: Covariates with standardized difference >10% included age, diabetes duration, dyslipidemia, obesity, nephropathy, peritoneal dialysis/hemodialysis, diabetes with ophthalmic manifestations/diabetic retinopathy, stroke, insulin, sulfonylurea, meglitinide, acarbose, rosiglitazone, heart failure, gingival and periodontal diseases, pneumonia, liver cirrhosis, organ transplantation, statin, and fibrate.