Predictors of Abdominal Pain Duration in Henoch–Schönlein Purpura and Nomogram Model Development: A Retrospective Study of 220 Cases

Hong Huang, Xin Chen, Yun Pan, Yichi Zhang, Rentao Yu, Aijun Chen Department of Dermatology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People’s Republic of ChinaCorrespondence: Aijun Chen, Department of Dermatology, The First Affiliated Hospital of Chongqing Medical University, Youyi Road, Chongqing, CN 4000000, People’s Republic of China, Email [email protected] Rentao Yu, Department of Dermatology, The First Affiliated Hospital of Chongqing Medical University, Youyi Road, Chongqing, CN 4000000, People’s Republic of China, Email [email protected]: Our study aims to identify risk factors that predict an abnormally prolonged duration of abdominal pain relief (DAPR) in patients with abdominal Henoch–Schönlein purpura (A-HSP) and to construct a nomogram for early prediction.Methods: We reviewed data of all patients (n = 375) with confirmed A-HSP from the Chongqing Medical University platform, from 22 January 2011 to 18 November 2022. After applying rigorous inclusion and exclusion criteria, 220 patients were ultimately enrolled. We split them into two groups by the DAPR: < 1 week and ≥ 1 week. Multivariate relogit regression was performed to select factors associated with DAPR lasting ≥ 1 week, including demographics, symptoms, laboratory results, and treatment. We then constructed a nomogram to estimate risk probability and internally validated its performance via bootstrapping using discrimination, calibration, and clinical utility.Results: There were 220 patients in the training. Multivariate relogit regression analysis demonstrated that age, initial onset, neutrophil-to-lymphocyte ratio (NLR), and bowel wall thickening were independent risk factors for DAPR ≥ 1 week. The Area Under the Curve (AUC) of the nomogram constructed based on the above factors was 0.849. Both the Calibration curve and Decision Curve Analysis (DCA) of the nomogram showed that the model exhibited good fitness.Conclusion: The nomogram can effectively predict the prolonged duration of abdominal pain (≥ 1 week) in A-HSP patients, helping clinicians distinguish high-risk patients at an early stage and optimize treatment plans. However, external validation remains essential before clinical implementation.Plain Language Summary: What is already known about this topic?Abdominal Henoch–Schönlein purpura (A-HSP) typically presents with abdominal pain. Persistent pain raises the risk of dangerous digestive problems, severe illness, or death, resulting in poorer short-term outcomes, particularly in adults.Persistent abdominal pain also raises the risk of kidney involvement. Monitoring pain duration can help in the early detection of kidney damage.We currently lack reliable tools to predict cases of abnormally prolonged abdominal pain for A-HSP patients.What does this study add?Our study found that age, initial onset, bowel wall thickening, and elevated NLR blood levels were linked to abdominal pain lasting ≥ 1 week in A-HSP patients.A scoring tool based on these four factors could help doctors make early treatment decisions. However, it must first be tested in other patient groups before being used in practice.Keywords: IgA vasculitis, allergic purpura, gastrointestinal involvement, predictive model, prognostic factors