TABLE 1

Incidence, Point Prevalence, and Course of Fatigue, CF, and CFS During a 4- to 6-Month Period

Total Classifications at Time 1Classification at Time 2 Divided According to Classification at Time 1Total Classifications at Time 2 (4–6 mo Later)
Fatigue
    283 (34.1%) fatigued151 (53.4%) fatigued317 (38.1%) fatigued
132 (46.6%) not fatigued
    548 (65.9%) not fatigued166 (30.3%) fatigueda514 (61.9%) not fatigued
382 (69.7%) not fatigued
CFb
    3 (0.4%) CF0 (0%) CF9 (1.1%) CF
3 (100%) no CF
    839 (99.6%) no CF9 (1.1%) CFa833 (98.9%) no CF
830 (98.9%) no CF
CFSc
    1 (0.1%) CFS0 (0%) CFS4 (0.5%) CFS
1 (100%) No CFS
    841 (99.9) no CFS4 (0.5%) CFSa838 (99.5%) no CFS
837 (99.5%) no CFS
  • a New cases.

  • b Defined as severe fatigue of 6 months' duration with nonrestorative rest and functional impairment.

  • c According to CDC criteria.