NPPA and chronic kidney disease: At the endpoint, there was a significant increase in the serum urea level (#p < 0.05) and an increasing tendency in the serum creatinine level (p = 0.09) as well as a decreasing tendency in the creatinine clearance (p = 0.08) in the lower dose of KP-13-treated CKD group, compared to the CKD-only group (2A-2C).