Heart attacks may be twice as likely to lead to critical illness insurance claims as cases of cancer are.

Colonial Life & Accident Insurance Company, Columbia, S.C., a unit of UnumProvident Corp., Chattanooga, Tenn., has reported that finding in a review of critical illness claims filed with Colonial from Jan. 1, 2005, through June 30, 2006.

About 40% of the critical illnesses resulting in paid claims were heart attacks, Colonial says.

Cancer triggered 20% of the paid claims; stroke, 19%; bypass surgery, 13%; and renal failure, 3%.