Fig. 1.

Transition probabilities for the 3-state model of disease severity. π probability, LL transition from low to low activity, LS transition from low to severe activity, LM transition from low to moderate activity, MM transition from moderate to moderate activity, ML transition from moderate to low activity, MS transition from moderate to severe activity, SM transition from severe to moderate activity, SL transition from severe to low activity, SS transition from severe to severe activity