History of congestive heart failure (CHF) is based on self-report. For any given cycle, this variable indicates reported CHF in past history or in at least one follow-up cycle up to and including that cycle. Participants are asked to respond "yes", "suspect or possible", or "no" to the following question:

Since your last interview on [date of last interview], have you been told by a doctor, nurse, or therapist that you had congestive heart failure?

Note: At baseline interview, the question reads: Have you ever been told by a doctor, nurse, or therapist that you had congestive heart failure?