996
PARTICIPANTS : Two hundred thirty - five patients aged 76 and older admitted to a major healthcare network between July 1 , 2001 , and June 30 , 2002 , with atrial fibrillation on warfarin were enrolled .
 Disease: atrial fibrillation; Chemical: warfarin
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 Disease: atrial fibrillation; Chemical: warfarin