Fig. (2) Cumulative time-dependent probability of a second long attack according to severity and duration of the first. The 3-year probabilities were: 23% (7-39) for patients with a severe first attack, 15% (1-29) for moderate, 13% (0-26) for mild, and 17% (0-38) for very mild (p=0.61); 20% (7-33) for patients with a long first attack, 16% (2-31) for intermediate and 13% (1-26) for short (p=0.75).