J. L. Goldstein et al. Similarities Differences 810 Aliment Pharmacol Ther 2011; 34: 808–816 ª 2011 Blackwell Publishing Ltd Figure 1 | Study designs for the (a) CLASS and (b) CONDOR trials. prescription of anti-inﬂammatory analgesic therapy for the management of their arthritis symptoms and who had increased GI risk were eligible for inclusion. For the CONDOR trial, increased GI risk was deﬁned as those patients aged ‡60 years or ‡18 years who had gastroduo- denal (GD) ulceration 90 days or more prior to screening. In contrast to CLASS, patients who were H. pylori posi- tive or using aspirin ⁄ other anti-platelet agents were excluded from the CONDOR trial. To make a parallel analysis in both trials, patients in the CLASS trial who were receiving aspirin (n = 882 and n = 445 in the celec- oxib and diclofenac groups, respectively) were excluded from this analysis. Furthermore, since only diclofenac (SR) was used in CONDOR as the nonselective NSAID whereas diclofenac and ibuprofen were used in CLASS, we only evaluated the pattern of clinically signiﬁcant decreases in haemoglobin ‡2 g ⁄ dL with diclofenac vs. cel- ecoxib (Table 1). While we are comparing diclofenac arms in the two trials it should be noted that the formu- lations of diclofenac differed, as shown in Table 1. Fur- thermore, a substantial difference between these trials that may have affected this analysis was the required use of PPIs in the CONDOR trial which was not allowed in the CLASS trial. For this analysis we made the assump- tion that injury beyond the upper GI tract would not be inﬂuenced by the administration of a PPI. Table 1 | Comparison of the CLASS and CONDOR trials CLASS CONDOR OA or RA Anticipated regular use of NSAID therapy for at least 6 months Use of NSAIDs, anti-ulcer drugs, sucralfate, misoprostol excluded Up to 15 months duration Age ‡18 years H. pylori negative or positive Aspirin (£325 mg) use allowed 6 months duration Increased GI risk (age ‡60 years or ‡18 years with history of GD ulcer) H. pylori negative No aspirin use Celecoxib 400 mg b.d. Diclofenac, ibuprofen; PPI use was not allowed Celecoxib 200 mg b.d. Diclofenac SR plus PPI (omeprazole) OA, osteoarthritis; RA, rheumatoid arthritis; NSAID, nonsteroidal anti-inﬂammatory drug; PPI, proton pump inhibitor.