Gastrointestinal bleeding is an important complication in dialysis patients, resulting in blood loss and high protein and potassium reabsorption in the intestines, and possibly leading to metabolic complications. The source of the bleed determines how much of the blood is dissolved in the gut versus passed in the stool and thereby recognized with a clinical diagnosis. Hematochezia, or bright red blood in the stool, is well-known as having sources in the lower gastrointestinal tract, including hemorrhoids, diverticular bleeding, colonic ulcers, and potentially, colonic polyps or cancers. Upper gastrointestinal tract bleeding is typically recognized by the melena color of the stool, as stomach acid reduces the hemoglobin content of the blood. This bleeding can lead to catabolism of the hemoglobin from pancreatic enzymes, raising the blood urea nitrogen (BUN) and creating a disproportionate BUN/serum creatinine ratio. Each 100 milliliters of packed cells contains approximately 10 grams of protein, which can be a significant load in addition to the recommended daily intake of one gram per kilogram. Gastrointestinal bleeding, therefore, has a relatively widespread impact, beyond direct blood loss and reduction of oxygen-carrying capacity.
First-year rates of hospitalization for a primary discharge diagnosis of gastrointestinal bleeding increased slightly during the study era among incident dialysis patients, but rose more meaningfully among prevalent patients between 2004 and 2011. Regional variation is apparent and, at least among prevalent dialysis patients, consistent with the nature of variation for many diagnoses of cardiovascular disease and infection. Specifically, admission rates are highest in the Middle Atlantic and East North Central divisions and lowest in the Mountain and Pacific areas.
Rates exhibit modest seasonality, but, perhaps more importantly, increased notably in 2011, coinciding with the introduction of the ESRD Prospective Payment System and the Food and Drug Administration’s later decision to add a ‘black box’ warning to erythropoiesis-stimulating agents. It is possible that, as hemoglobin levels fell in the dialysis patient population, and as more patients presented in acute care settings with very low hemoglobin concentrations, ascertainment of gastrointestinal bleeding also increased, as hospitalists sought to identify factors other than the anemia of chronic kidney disease that may engender especially low hemoglobin. Future reports will continue to monitor this outcome and assess the extent to which the incidence of gastrointestinal bleeding and the rate of red blood cell transfusions are related.