Fig 1.

CONSORT diagram. Details of patients randomly assigned, treated, and followed up in the study. Data were not collected regarding eligibility screening before randomization. Changes to cytoreductive treatment are shown. In the aspirin-alone arm, 71 patients started hydroxycarbamide (HC) and 11 started anagrelide; 23 patients subsequently received one or more additional agents (hydroxycarbamide [14], anagrelide [11], interferon-alfa [1], thalidomide [1]). In the hydroxycarbamide-plus-aspirin arm, nine patients were randomly assigned to hydroxycarbamide but never started it; 13 patients stopped hydroxycarbamide without simultaneously starting a second-line agent; 14 patients switched to an alternative cytoreductive agent (anagrelide [12], interferon-alfa [1], busulphan [1]), and 3 started anagrelide without stopping hydroxycarbamide. PV, polycythemia vera.