Introduction Many patients presenting with abdominal pain to emergency departments (EDs) are discharged without a definitive diagnosis. For these patients, often designated as having non-specific abdominal pain, re-evaluation is often advocated. We aimed to investigate how often re-evaluation changes the diagnosis and clinical management and discern factors that could help identify patients likely to benefit from re-evaluation.

Methods This was a retrospective study conducted in the Netherlands between 1 January 2014 and 31 December 2015 of patients asked to return to the ED after an initial presentation with acute non-traumatic abdominal pain. The primary outcome was a clinically relevant change in treatment (surgery, endoscopy during admission and/or hospitalisation) and diagnosis at ED re-evaluation within 30 hours.

Results During the 2-year study period, 358 ED patients with non-specific abdominal pain were scheduled for re-evaluation. Of these, 14% (11%–18%)) did not present for re-evaluation. Re-evaluation resulted in a clinically relevant change in diagnosis and treatment in, respectively, 21.3% (17%–29%)) and 22.3% (18%–27%)) of the subjects. Of the clinical, biochemical and radiological factors available at the index visit, C reactive protein (CRP) at the index visit predicted a change in treatment (CRP >27 mg/L likelihood ratio (LR)+ 1.69 (1.21–2.36)), while an increase in CRP of >25 mg/L between index and re-evaluation visit (LR+ 2.85 (1.88–4.32)) and the conduct of radiological studies at the re-evaluation visit were associated with changes in treatment (LR+ 3.05 (2.41–3.86)).

Conclusion Re-evaluation within 30 hours for ED patients discharged with non-specific abdominal pain resulted in a clinically relevant change in diagnosis and therapy in almost one-quarter of patients. Elevated CRP at the index visit might assist in correctly identifying patients with a greater likelihood of needing treatment in follow-up, and a low threshold for radiological studies should be considered during re-evaluation.