The Risk of Microscopic Colitis in Solid-Organ Transplantation Patients : A Population-Based Study

Background. Microscopic colitis (MC) has not been recognized as a complication of transplantation because patients are on immunosuppressant medications. The objective of this work was to describe the risk of developing MC after solid-organ transplantation. Methods. This population-based cohort study identified all cases of MC diagnosed after kidney, kidney and pancreas, or liver transplantation using pathology and transplantation databases. The annual incidence and point prevalence of MC after transplantation was calculated. The incidence rate of MC among transplantation patients was compared with the general population and presented as a Standardized Incidence Ratio (SIR) with 95% confidence intervals. Results. Seven cases (0.9%) of MC were diagnosed in kidney (n=2), kidney and pancreas (n=1), and liver (n=4) transplantation recipients. The point prevalence of MC was 8.8 per 1000 transplantation recipients. The annual incidence rate of MC in solid-organ transplantation patients was 5.0 cases per 1000 person-years. The SIR of developing MC after transplantation was 50.5 (95% confidence interval 13.6–131.8). The average age of diagnosis of MC was 49.4±5.3 years, average time of onset from transplantation was 67.4±27.0 months, and the average latency period was 30.1±9.0 months. Once diagnosed, all patients responded to MC-specific therapy. Conclusion. Physicians should have a low threshold to investigate for MC in solid-organ transplantation recipients who present with chronic diarrhea because this population is at an increased risk of developing MC.