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Pain‐Related Outcome Domains and Measures in Randomized Controlled Trials of Treatment for Acute Abdominal Pain: A Systematic Review

Year: 2026

Type: review

Abstract: BACKGROUND AND OBJECTIVES: Acute abdominal pain frequently presents to emergency departments, yet outcome domains in randomized controlled trials (RCTs) remain poorly characterized. This review identified pain-related domains and outcome measures used in RCTs on acute abdominal pain. DATABASES AND DATA TREATMENT: This PRISMA-guided systematic review was registered in PROSPERO (CRD42025630171). PubMed, Embase, Scopus, and Web of Science were searched for RCTs (January 2000-February 2025). Eligible studies included adult and paediatric patients with acute abdominal pain reporting pain assessment. Outcome domains extracted included pain intensity, rescue analgesia, adverse effects, pain interference, quality of life (QoL), and psychological function. Bias was assessed using Cochrane RoB2. RESULTS: Of 826 records, 43 RCTs were included; eight included children. In adult trials, pain intensity was assessed using the visual analogue scale (n = 19) or the numeric rating scale (n = 15). Rescue analgesia (44%) and adverse effects (84%) were frequently reported. No study assessed pain interference or psychological function, and QoL was listed as an outcome in one trial. All were conducted in emergency settings, with short-term follow-up within the first hours. CONCLUSIONS: Pain assessment in acute abdominal pain RCTs is predominantly limited to intensity measures and short-term outcomes. While appropriate for immediate analgesic effects, this approach may be insufficient when broader treatment goals or longer follow-up are relevant. Context-specific outcome selection is needed, aligning domains with clinical purpose and time frame. SIGNIFICANCE: RCTs on acute abdominal pain assess pain incompletely, focusing predominantly on intensity rather than broader domains such as pain interference and psychological function. None adhered to the INTEGRATE framework for pain assessment. This review provides the first systematic mapping of outcome domains in this area, offering a foundation for context-specific outcome selection aligned with what matters to patients.

Source: European Journal of Pain

DOI: 10.1002/ejp.70445