BACKGROUND: Increased proteinuria would lead to a larger risk for renal failure 
in the long term. Therefore, proteinuria requires immediate and thorough 
evaluation. This study was designed to evaluate the effects of pioglitazone on 
proteinuria in patients with non-diabetic renal disease.
METHODS: In this self-controlled clinical trial study, forty four non-diabetic 
patients aged 18 and more, who had renal disease and a stable proteinuria of 
over 0.5 g in 24 hour, were studied. All patients received 15 mg of daily 
pioglitazone for 4 months. Urine protein excretion was measured as a main end 
point prior to the study, at the end of the 2nd and 4th months of treatment, and 
2 and 4 months after the cessation of the active drug. Other evaluated variables 
included systolic blood pressure, serum creatinine, urea, alanine 
aminotransferase (ALT), aspartate aminotransferase (AST), fasting blood sugar 
(FBS), blood urea nitrogen (BUN) and glomerular filtration rate (GFR) levels.
RESULTS: Proteinuria (mean ± SEM) prior to the study, at the 2nd and 4th months 
of the treatment, and 2 and 4 months after the cessation of pioglitazone were 
1088.6 ± 131.1, 699.9 ± 118.3, 433.9 ± 68.7, 416.1 ± 54.9 and 646.9 ± 89.1, 
respectively (p < 0.001). In addition, the reduction of 24-hour urine protein 
was statistically significant for both male and female patients (p < 0.001 for 
both).
CONCLUSIONS: A reduction of proteinuria in patients with non-diabetic renal 
disease was observed during the 4-month treatment with pioglitazone which 
continued for 2 months after the cessation of the treatment. However, 4 months 
after the cessation of the treatment, a little increase was detected in the 
level of proteinuria.