adding roflumilast to the standard therapy for diabetic nephropathy and studying the progression of many outcomes including urinary albumin to creatinine ratio, estimated GFR, biomarkers of diabetic nephropathy

Inclusion Criteria: diabetic patients with persistent micro- or macroalbuminuria despite treatment with the maximum tolerated dose of ACE inhibitors for at least 8 weeks before the screening and randomization

• Type I or II diabetic patient with stage 2 CKD (eGFR = 60 - 89 ml/min) ,stage 3 CKD (eGFR = 30 - 59 ml/min) or stage 4 (eGFR 15-29 ml/min)

Exclusion Criteria:

• moderate to severe hepatic disease (Child-Pugh B or C) severe renal disease (eGFR<15 ml/min) body-mass index below 25 kg/m2 concomitant use of strong cytochrome P450 inducers (e.g. rifampicin, phenobarbital, carbamazepine, phenytoin) known psychiatric illness, congestive heart disease patients with allergy for roflumilast pregnant and lactating women

data of outcomes and other research but not personal data are intended to be published in application to scientific journals