Experience of 5-aminosalicylate nephrotoxicity in the United Kingdom

Aim: To study 5-aminosalicylate nephrotoxicity in patients with inflammatory bowel disease in the UK. Methods: A detailed postal questionnaire was sent to all 1298 names in the British Society of Gastroenterology database and 290 consultant members of the Renal Association. The British Society of Gastroenterology reported new cases monthly, the Renal Association 6 monthly. Results were expressed as estimated glomerular filtration rate. Results: Retrospective study: cases - British Society of Gastroenterology:Renal Association 202:87, aged 15-76 years. Median peak (range) creatinine (British Society of Gastroenterology:Renal Association) - 300:301 (78-1200) μ mol/L. Prospective study - 59 cases, median age 52 years (M:F ratio: 47:12). Median pre-treatment estimated glomerular filtration rate: 76.9 (123.9-39), at diagnosis 28.4 (80.5-3.6, creatinine range: 92-1361 μ mol/L), recovery 46.8 [111.2-end stage renal failure] mL/min/1.73 m(2). Recovery of renal function was significantly improved for patients treated for < 12 months [n = 10, median recovery estimated glomerular filtration rate 70.5 (92-26.9) vs. > 12 months 38.4 (111.2-end stage renal failure) mL/min/1.73 m(2), P = 0.028]. Conclusions: Regular monitoring of renal function may allow earlier detection of nephrotoxicity, particularly during the first year of therapy. Based on an inflammatory bowel disease prevalence in the United Kingdom of 412 x 10(5) with about 50% on treatment, we estimate that the incidence of clinical nephrotoxicity in patients taking 5-aminosalicylate therapy is approximately one in 4000 patients/year.