End points For both trials, a decrease in haemoglobin of ‡2 g ⁄ dL was used to deﬁne the clinically meaningful end point as previously described by us and others.16–18 In addition, a post hoc analysis was performed for patients who had a decrease in haemoglobin ‡2 g ⁄ dL that resulted in labora- tory-deﬁned anaemia (haemoglobin level £11.5 g ⁄ dL). While the CLASS trial followed patients for up to 15 months, for purposes of this analysis, we chose the 6- month time frame to allow us to make parallel compari- sons between the two studies. Statistical analysis The proportions of patients in the CLASS and CONDOR trials with a haemoglobin drop of ‡2 g ⁄ dL were estimated using the laboratory data collected at scheduled and unscheduled visits; odds ratio and conﬁdence intervals (CI) have also been presented. The time to haemoglobin drop of ‡2 g ⁄ dL was analysed using a log-rank test and summar- ised using Kaplan–Meier curves; the proportion of patients with haemoglobin drops of ‡2 g ⁄ dL by day 180 (6 months) were also estimated from the Kaplan–Meier curve. RESULTS Patient populations and demographics Overall 1845 and 1730 non-aspirin users receiving celec- oxib and 890 and 1621 non-aspirin users receiving Haemoglobin decreases in NSAID users diclofenac completed the CLASS and CONDOR trials, respectively (Figure 2). In CLASS, 41.3% of patients withdrew from the trial in the celecoxib and diclofenac arms by 6 months for reasons including treatment fail- ure, protocol violation, noncompliance, laboratory abnor- malities, adverse events and death (Table S1); in CONDOR, 25.3% withdrew for similar reasons (Table S2).16 For the purposes of this analysis, only the baseline demographics for those patients who were non-aspirin users in the CLASS trial are displayed (Table 2). The baseline demographics for the complete total population in CLASS have previously been reported by Silverstein et al.8 There were more women and more patients with OA or a previous history of GD ulcers in the CONDOR trial than in CLASS, while more patients in the CLASS trial were white. Although patients with H. pylori infection at baseline were excluded from the CONDOR trial (patients had to test negative for H. pylori at the screen- ing visit or to have conﬁrmed eradication of the infec- tion at a re-screening visit to be included), they were included in the CLASS trial; the patient population used in this secondary analysis included participants regard- less of their H. pylori status. In the CLASS trial 38.2% and 37.3% of patients were H. pylori positive in the cel- ecoxib and diclofenac treatment arms respectively (Table 2). Figure 2 | Study disposition (non-aspirin users in the CLASS and CONDOR trials). Aliment Pharmacol Ther 2011; 34: 808–816 ª 2011 Blackwell Publishing Ltd 811