Cluster patients lost to follow-up for a period of from three to eight years were the subject of this study. One hundred and forty-nine/169 drop-outs or their relatives were contacted via mailings, telephone calls, or professional missing-person searchers; and questioned regarding headache status and serious illness.
Of the 149 drop-out patients, 75 (50.3%) reported no change in headache. Eleven (7.4%) had experienced a shift in headache type, that is, from chronic to episodic or episodic to chronic, equally. Fifty-one (34.2%) had experienced a prolonged (permanent ?) remission, and twelve (8.1%) had died. Thus, the major determinants of drop-out status included prolonged remission (longer than usual remission duration) and death (42.3%). Remission and mortality rates increased with duration of cluster disorder.
Prolonged (permanent ?) remission rates were highest among patients who had previously experienced usual remission period durations of one year or longer.
Mortality increased with age. Cancer mortality, however, was found to be twice that of coronary artery disease and stroke combined. There was a proportionately higher representation of women and chronic types in the cancer mortality group. Although all patients in this group had smoked cigarettes and drank alcohol, no correlation could be made between extent of these habits and site of cancer.