#688 Major gastrointestinal bleeding in dialysis: influence of age, sex, race & comorbidities

Abstract Background and Aims Gastrointestinal bleeding (GIB) is considered the most common type of bleeding event in the dialysis population [1]. However, studies to date are small and not representative of the dialysis population, and the influence of patient characteristics has not been considered. We used a nationally representative sample of dialysis patients treated in the United States (US) to characterize the rates of major GIB episodes requiring hospitalization overall and by age, sex, race, and history of GIB comorbidity. Method We used data from a kidney care network from Jan 2018 through Mar 2021. We included data from adult dialysis patients (age ≥18 years) who were treated with dialysis for at least 30 days. We excluded patients who started dialysis on or after Jan 2021 to provide a three-month minimum follow up time for outcomes to occur. GIB hospitalizations were identified from international classification of diseases (ICD) diagnosis codes recorded as the primary, secondary, or tertiary discharge reason for hospitalization. ICD clusters defining GIB hospitalizations and lesion location were based on the US Healthcare Cost and Utilization Project [2]. We calculated proportion of patients with one or more GIB hospitalization, and the proportion of GIB observations per patient during the 3.25-year period by patient characteristics (GIB comorbidity, sex, age, race). Results Among 366,839 adult dialysis patients, 6.8% (n = 25,057) experienced one or more GIB hospitalization during the 3.25-year period. In total, there were 36,791 GIB hospitalization observations with 73.5% (n = 18,422) of patients with one GIB hospitalization, 16.8% (n = 4208) with two GIB hospitalizations, and 9.7% (n = 2,427) with three or more GIB hospitalizations. The lesion location was unspecified in diagnosis codes for 64.7% (n = 23,576) of GIB hospitalization observations. Among GIB hospitalization observations with a recorded lesion location, 60.3% (n = 7,968) were an upper GIB and 39.7% (n = 5,247) were a lower GIB. A baseline history of a GIB comorbidity was associated with a 2.9-fold higher rate for the occurrence of one or more GIB hospitalization in a unique patient, and a 3.5-fold higher rate of a GIB hospitalization event considering all observations (Fig. 1A). GIB hospitalization rates were relatively consistent between females and males on both a patient- and observation-level (Fig. 1B). There were positive increases in GIB hospitalization rates with older age categories, with about a 2-fold higher rate among those with an age ≥75 years compared to an age 18-44 years on both a patient- and observation-level (Fig. 2A). GIB hospitalization rates were relatively consistent for race groups, albeit there may be a trend for slightly higher rates among those with a black race, in particular on an observation level that accounts for multiple events per patient (Fig. 2B). Conclusion Major GIB events requiring hospitalization affect about 7% of dialysis patients. It appears about 60% of GIB hospitalizations were for an upper GIB, and about 40% were for a lower GIB. Patients who experienced one GIB hospitalization commonly had multiple GIB events, with more than 25% having two or more GIB hospitalizations during the observation period. Older age and a history of a baseline GIB comorbidity were associated with higher GIB hospitalization rates. Biological sex and race did not appear to be associated to GIB hospitalization rates. Ongoing analysis of GIB incidence accounting for person-years at risk is needed to confirm these observations.