Fig. (1) Cumulative time-dependent probability of a second moderate/severe attack according to severity and duration of the first. The 3-year probabilities were: 21% (4-38) for patients with a severe first attack, 17% (4-31) for moderate, 29% (12-46) for mild, and 17% (0-38) for very mild (p=0.70); 23% (9-37) for patients with a long first attack, 24% (7-41) for intermediate and 18% (5-32) for short (p=0.81).