This retrospective observational study was conducted exclusively at Jinhua Municipal Central Hospital from January 2019 to October 2022. Eligible participants for this study included patients who meeting the 2015 ACR/EULAR classification criteria for gout and concurrently experienced active gastrointestinal bleeding upon enrollment. Notably, patients presenting with swollen and painful joints at admission were excluded. Individuals with other forms of arthritis were also excluded from the study. A flow chart of this study is shown in Fig. 1. All of the patients included suffered from gout flares after gastrointestinal bleeding.

Flow chart of the study. 6030 hospitalized patients diagnosed as gout were reviewed, and based on the study criteria, 94 cases were ultimately included in the analysis

Ethical considerations were rigorously adhered to in accordance with the Declaration of Helsinki principles, and the study obtained ethical approval from the Ethics Committee of Jinhua Municipal Central Hospital (Approval No. [2022]366)

Clinical data was collected from electronic medical records according to the International Classification of Diseases (ICD) 11th revision code for gout and gastrointestinal bleeding, and was in full compliance with the protocols established by Jinhua Municipal Central Hospital. The dataset encompassed a range of variables, including age, gender, medical history, body mass index (BMI), comorbidities (such as hypertension, diabetes, renal insufficiency, heart failure, cardiovascular and cerebrovascular events, and cirrhosis), prior usage of uric acid-lowering medications and diuretics prior to admission, serum uric acid levels, hemoglobin levels, instances of blood transfusion, utilization of endoscopic procedures, intravenous fat emulsion therapy, length of hospital stays, recurrent bleeding episodes, gout attacks, and specific details pertaining to the gout attacks (including the site of flare, day of hospitalization, and the administration of anti-inflammatory drugs, among others). The intravenous fat emulsions included C8-24, C6-24, and C14-24, administered at a daily dose of 250 ml. Large amount of missing data resulted in the exclusion of information on tophus and fluid intake.

In this study, a gout flare was defined as a clinically evident episode of acute inflammation induced by monosodium urate crystals, a definition endorsed by the Gout, Hyperuricemia and Crystal-associated Disease Network (G-CAN) [13]. To be specific, all patients met at least 3 of the following criteria: (1) Patient-defined gout flare; (2) Pain at rest score >3 on a 0–10 numerical rating scale; (3) Presence of at least 1 swollen joint; (4) Presence of at least 1 warm joint [14]. The gout flares were confirmed by the rheumatologist. Besides, active gastrointestinal bleeding was defined based on the following criteria: (1) Hematemesis or hematochezia within the 24-h period preceding admission; (2) A positive result on the fecal occult blood test; (3) Absence of bleeding in the oral cavity and respiratory system.

The primary outcome measure in this study was the incidence of gout flares among patients experiencing active gastrointestinal bleeding during their hospitalization. For subsequent analysis, patients were categorized into two distinct groups: the “flare group” and the “stable group”.

Statistical analyses were conducted using SPSS software (version 26). Normality testing was performed using the Kolmogorov–Smirnov test. Normally distributed continuous variables were presented as mean ± SD and analyzed using the Student’s t-test, whereas non-normally distributed continuous variables were represented as median (interquartile range) and assessed via the Mann-Whitney test. Categorical data comparisons were conducted using the Pearson chi-square tests. Risk factor analysis was carried out using multivariate logistic regression, focusing on variables with P values either below 0.10 in the univariate analysis or deemed clinically significant. Hyperuricemia, ULT, intravenous fat emulsion, endoscopic procedure and transfusion were finally included as dependent variables in the model based on the above criterion. Statistical significance was determined at a threshold of p < 0.05.