Table 1

Characteristics of a severe chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) population

All dataYES CFS/MEYES/NO CFS/MENO CFS/ME
1a. Are you currently experiencing problems with fatigue?No0%0.00%0%0.00
Yes98.20%100.00%100%91.66%
*1.70%0.00%0%8.33%
1b. When did the fatigue begin (years ago)?Mean15.7213.0619.2221.18
SD10.369.8211.468.26
1c. What do you think the cause of your fatigue is?CFS/ME51.0%52.94%60%33.33%
Other37.50%41.17%30%50.00%
*10.00%5.88%10%16.66%
2. When your problem with fatigue began, did it develop.Within 24 hours16.07%8.80%10%25.00%
Over 1 week8.50%8.80%10%8.30%
Over 1 month5.10%5.80%0%8.30%
Over 2–6 months18.70%29.41%10%8.30%
Over 7–12 months11.90%11.76%0%25.00%
Over 1–2 years5.10%2.90%10%8.30%
>2 years17.00%17.60%20%16.66%
Since childhood10.20%0.0030%0.00%
NA—no fatigue problem3.40%0.0010%8.33%
3. In the past month, how many hours have you spent doing the following activities:HouseholdM 4.549 (SD7.8)M 3.77 (SD 6.05)M 5 (SD 10.5)M 4 (SD 4.45)
SocialM 2.83 (SD 4.07)M 2.79 (SD 4.14)M 3.33 (SD 4.4)M 3 (SD 3.354)
Work relatedM 2.83 (SD 5.1)M 0.375 (SD 2.08)M 3.7 (SD 4.4)M 4.43 (7.9)
4a. In the past 6 months have you reduced the time spent on activities due to health/fatigueNo27.2%32.35%40%8.33%
Yes61.20%64.70%60%75.00%
*6.80%2.90%0%1.66%
4b. If yes, which activities and by how many hours have you cut back?OccupationalM 8.73 (SD 8.1)M 9.1 (SD 9.2)M 7.5 (SD 2.5)M 8.33 (SD 6.2)
SocialM 3.68 (SD 4.1)M 4.29 (SD4.6)M 1.5 (SD 1.6)M 2.8 (SD 2.9)
FamilyM6.9 (SD13.8)M9.00 (SD 16.9)M 2 (SD 1.8)M 4.8 (SD 3.5)
4c. If you replied yes to 4d. How many hours did you use to spend on:OccupationalM 16.71 (SD13.0)M 14.50 (SD 13.7)M 16.66 (SD 12.4)M 18.25 (SD 3.2)
SocialM 5.08 (SD 3.3)M 5.6 (SD 3.3)M 3.91 (SD 3.9)M 4 (SD 0)
Family11.35 (SD 14.3)M 12.13 (SD 16.6)M 7.12 (SD 9.8)M 11.75 (SD4.8)
5a. Following rest, does your fatigue go away…A. Entirely0.00%0.00%0%0.00%
B. Partially37.40%52.94%70%50.00%
C. No effect49.30%47.05%30%41.66%
D. Other5.10%0.00%0%8.33%
5b. How long do you have to rest for your fatigue entirely or partially to go away?<2 hours31.76%0%16.66%
>2 hours1014.70%40%8.33%
>1 day30.00%10%8.33%
>2 days211.76%10%8.33%
>5 days15.88%0%*
Varies138.82%10%16.66%
*2447.05%30%50.00%
5c. Will your fatigue return if you stop and start doing something?No0%0.00%0%0.00
Yes54.40%55.88%70%50.00%
*42.80%44.11%30%50.00%
6. Do you restrict your activity levels to avoid experiencing severe fatigueNo1.70%2.09%0%0.00
Yes94.60%97.05%100%83.33%
*3.40%0.00%0%16.66%
7. Does physical activity make you feel:Worse96.40%100.00%100%83.33%
Better0.00%0.00%0%0.00%
Has no effect0.00%0.00%0%0.00%
*3.40%0.00%016.66%
8a. In the past 6 months, how often have you experienced a persistent or recurrent problem with Postexertional malaise (PEM). Do you feel worse after engaging in activities that require either physical or mental exertion?Never0.00%0.00%00.00%
Seldom0.00%0.00%0%0.00%
Often17.00%8.80%80%41.66%
Always78.50%91.17%20%41.66%
*3.40%0.00%0%16.66%
8b. If replied Often to 8a: How long does the PEM last for?<11.70%2.90%0%8.33%
1–3 hours8.90%5.80%0%25.00%
4–10 hours5.30%5.80%10%0.00%
11–13 hours3.40%2.90%0%8.33%
>13 hours1.70%2.90%0%0.00%
>24 hours85.00%70.58%90%41.66%
*7.10%5.80%0%16.66%
Other3.40%2.90%00.00%
8c,d,eNo one replied never or seldom to Q 8aNo one replied never or seldom to Q 8aNo one replied never or seldom to Q 8aNo one replied never or seldom to Q 8a
9. Past day rate perceived energyM 11.80 (SD 10.0)M 12.0 (SD 11.0)M 13 (SD 5.4)M 7.5 (SD 2.5)
10. Past day rate energy expendedM 32.142 (SD 25.9)M 23.40 (SD 26.7)M 16.33 (SD 12.8)M 26.4 (SD 35.4)
11. Past day rate fatigueM 82.53 (SD 15.54)M 84.97 (SD 11.5)M 76.5 (SD 13.4)M 77.5 (SD 28.9)
12. past week rate energyM 21 (SD 21.765)M 23.23 (SD 24.7)M 20 (SD 12.9)M 10 (SD 6.0)
13. Past week energy expendedM 26.71 (SD 27.6)M 27.48 (SD 28.4)M 17.77 (SD 11.2)M 36.64 (SD 33.4)
14. Past week rate fatigueM 82.04 (SD16.9)M 82.53 (SD 18.6)M 75.25 (SD 26.3)M 81.25 (SD 17.0)
15. How would describe the course of your illness/health problems:CGW33.90%26.47%70%25.00%
CI0.00%0.00%0%0.00%
Persisting19.60%23.52%10%16.66%
Relapsing8.90%5.88%20%8.33%
Fluctuating30.35%44.11%0%25.00%
*7.10%0.00%0%25.00%
  • *Data not completed.

  • CGW, constantly getting worse; CI, constantly improving; NA, not applicable.