Figure 3.
Person-level variation across different disease conditions. This figure depicts the results of 46 different N-of-1 trials of cimetidine as reported by Johanessen et al.12 The effect of cimetidine versus placebo was measured in each subject across 12 crossover periods over the span of 184 days. While cimetidine had a similar average effect regardless of the index condition, there was far greater consistency of effect in patients with peptic ulcer disease and much more variation in effect among patients with non-ulcer dyspepsia.