M. Reyes, et. al.
“Chronic Fatigue Syndrome Progression and Self-Defined Recovery: Evidence from the CDC Surveillance System.”
155 patients from the CFS surveillance study undertaken from 1989 through 1993 were followed through 1997. The CDC researchers determined that the cumulative probability of recovery was 31% during the first five years of illness and 48% during the first ten years.
Patients reporting recovery and those remaining ill were similar, with no significant differences with respect to age at onset, race, gender, education, presence of children, income or prior hospitalizations. Recovery rates were similar for those with sudden and gradual onset. All patients, including those who reported recovery, continued to have some CFS-defining symptoms. While sudden onset cases reported many more symptoms at onset than gradual onset cases, particularly sore throats and fevers, over time the two groups reported similar symptom profiles. The researchers recommended that a standard definition of recovery in CFS be developed and that studies take into account the variable duration of illness.