OBJECTIVES: In the assessment of NSAID related GI events, many authors focus on severe events leading to hospitalisation. This study aimed at describing medical practice, resource utilisation and costs of different GI events related to chronic NSAID use in osteo-arthritis (OA) and rheumatoid arthritis (RA) patients in Belgium. METHODS: A random sample of 231 OA and RA patients with GI events associated with NSAID use was included in a multicenter GP level chart review. Charts were assessed by the GP and monitored by an independent researcher for all medical resource use related to the event. Direct medical costs were calculated by multiplying resource use with standard costs for the health insurance. GI events were categorised as GI discomfort (=minor event), symptomatic ulcer, anaemia with occult bleeding and severe (i.e. hospitalised) gastro-intestinal pathologies. RESULTS: Thirty-five patients (15.2%) were RA patients, 196 (84.8%) OA. The average age of the sample was 61.0y (st.dev 14.7y). 45% were male. The median duration of a GI event was 10 days, the average was 23 days. The average cost per patient was €284. The cost per type of event (in €) was as follows (p<0.001 Kruskal Wallis): GI Discomfort (n=155): 198 (SE=41); Ulcer (n=66): 364 (SE=28); Anaemia (n=7): 756 (SE=234); Severe GI (n=3): 1,896 (SE=1,585). Total cost (n x mean) was: GI Discomfort: 30,657 (46.7%); Ulcer: 24,020 (36.6%); Anaemia: 5,293 (8.1%); Severe GI: 5,688 (8.7%). It was thus shown that GI discomfort, due to the relative high number of patients, leads to 47% of total GI related costs. CONCLUSIONS: Many patients with minor NSAID related GI events visit a physician. The resulting use of healthcare resources to manage these events should be taken into account in economic evaluations of measures to prevent GI events.