Microproteinuria in patients with inflammatory bowel disease: Is it associated with the disease activity or the treatment with 5-aminosalicyclic acid?

AIM: To investigate whether microproteinuria in patients with inflammatory bowel disease (IBD) is associated with the disease activity or the treatment with 5-aminosalicylic acid (5-ASA). METHODS: We prospectively studied microproteinuria in 86 consecutive patients with IBD, 61 with ulcerative colitis (UC) and 25 with Crohn's disease (CD), before as well as 2 and 6 months after their inclusion in the study. Forty-six patients received 5-ASA for a period of 28.8 months (range 1-168 mo). Microalbuminuria (mALB) and urine levels of the renal tubular proteins beta(2)-microglobulin (beta(2)mGLB) and beta-N-acetyl-D-glucosamidase (beta-NAG) as well as the creatinine clearance were determined in a 12-h overnight urine collection. Tumor necrosis factor-alpha (TNF-alpha) serum levels were also measured. RESULTS: A total of 277 measurements (194 in UC patients and 83 in CD patients) were performed. The prevalence of abnormal microproteinuria in UC and CD patients was 12.9% and 6.0% for mALB, 22.7% and 27.7% for beta 2mGLB, and 11.3% and 8.4% for beta-NAG, respectively. mALB was not associated with IBD activity. beta 2mGLB and beta-NAG urine levels were correlated to UC activity (UCAI: P<0.01; UCEI: P<0.005). mALB in UC patients and beta-NAG urine levels in CD patients were related to TNF-a serum levels. An association was noticed between microproteinuria and smoking habit. Treatment with 5-ASA was not correlated to the severity of microproteinuria or to the changes of creatinine clearance. CONCLUSION: Microproteinuria is mainly associated with UC and its activity but not affected by 5-ASA. (C) 2006 The WJG Press. All rights reserved.