Microalbuminuria in inflammatory bowel disease

Abstract

Microalbuminuria independently predicts the development of nephropathy and increased cardiovascular morbidity and mortality in diabetic patients, but it may be an indicator of the acute phase response. This study examined microalbuminuria as a marker of the acute phase response in patients with inflammatory bowel disease and correlated it with the disease activity in 95 patients with inflammatory bowel disease (ulcerative colitis (n=52), Crohn's disease (n=43)) determined by the simple index of Harvey and Bradshaw. Fifty patients were in complete clinical remission and 45 patients had active disease. Microalbuminuria was detected in all patients with inflammatory bowel disease (147 (17) v 18 (2) μg/min, inflammatory bowel disease v controls mean (SEM), p<0.007). Patients with active inflammatory bowel disease had higher concentrations of microalbuminuria compared with patients in remission (206 (19) v 65 (8) μg/min, mean (SEM), p<0.0001). Eight patients with active inflammatory bowel disease who were sequentially followed up with measurements of micro-albuminuria had significantly lower values, when the disease was inactive (active inflammatory bowel disease 192 (44) v inactive inflammatory bowel disease 64 (14) μg/min, p<0.03). There was a significant correlation with the simple index of Harvey and Bradshaw (r=0.818, p<0.0001). Microalbuminuria values were significantly lower in inflammatory bowel disease patients in remission, maintained with olsalazine compared with those patients maintained with mesalazine and salazopyrine, but no significant difference was seen in values of microalbuminuria in active inflammatory bowel disease patients receiving different salicylates. This study also measured serum amyloid-A as an indicator of the acute phase response in the same patients. Serum amyloid-A was significantly increased in active disease compared with inactive disease (151 (43) v 33 (7) or controls 11 (2) μg/ml, p<0.05). In conclusion microalbuminuria is present in abnormal amounts in all patients with active inflammatory bowel disease, and values fall when the disease is quiescent. Microalbuminuria is probably a consequence of an acute phase response and provides a simple, rapid, and inexpensive test, which has the potential to monitor inflammatory bowel disease activity and response to treatment.