Fig 1.

Study analysis. The observation period coincided with the inclusion period for the Multiple Environmental and Genetic Assessment of Risk Factors for Venous Thrombosis (MEGA) study (between February 1999 and September 2004). Periods with treatment were defined according to the day of prescription. Six risk periods were defined: (i) baseline (unexposed) period (without oral glucocorticoids); (ii) 7‐day pre‐exposure period; (iii) first 7 days with oral glucocorticoids treatment; (iv) 8–30 days with oral glucocorticoids; (v) 31–180 days with oral glucocorticoids and (vi) >180 days with oral glucocorticoids (not drawn to scale). A new baseline period started the day after the end of prescription.