Table 1.
Socio-demographic and clinical characteristics
| Characteristics | All (n = 37) | ME/CFS + (n = 10) | ME/CFS − (n = 27) | P valuec |
|---|---|---|---|---|
| Socio-demographic | ||||
| Gender (men/women) | 25/12 | 5/5 | 20/7 | 0.17 |
| Agea | 51.9 ± 10.9, 54 | 50.7 ± 12.3, 55.5 | 52.3 ± 10.5 | 0.90 |
| Education (y)a | 12.9 ± 3.4, 13 | 14.5 ± 3.1, 15 | 12.3 ± 3.3, 13 | 0.07 |
| BMIa | 26.8 ± 4.3, 26.4 | 27.0 ± 4.4, 26.4 | 26.2 ± 4.2, 26.3 | 0.90 |
| Baseline Comorbidities (yes/no) | ||||
| Hypertension | 9/28 | 4/6 | 5/22 | 0.36 |
| Cardiac disease | 2/35 | 1/9 | 1/26 | 1.00 |
| Diabetes | 1/36 | 0/10 | 1/26 | 1.00 |
| Cancer | 1/36 | 0/10 | 1/26 | 1.00 |
| COPD | 2/35 | 1/9 | 1/26 | 1.00 |
| Kidney disease | 1/36 | 0/10 | 1/26 | 1.00 |
| Liver disease | 0/37 | 0/10 | 0/26 | 1.00 |
| Psychiatricb | 4/33 | 0/10 | 4/23 | 0.49 |
| SARS-CoV-2 infection—Clinical | ||||
| Hospitalization (yes/no) | 33/4 | 8/2 | 25/2 | 0.62 |
| Months since infectiona | 6.1 ± 0.3, 6.0 | 6.1 ± 0.4, 6.0 | 6.0 ± 0.1, 6.0 | 0.54 |
| ICU (yes/no) | 8/29 | 3/7 | 5/22 | 0.76 |
| O2 therapy (yes/no) | 22/15 | 4/6 | 18/9 | 0.28 |
| SARS-CoV-2 infection—Inflammatory | ||||
| C-reactive protein (mg/L) | 72.4 ± 52.1, 70 | 72.9 ± 68.2, 83 | 72.3 ± 48.0, 68 | 0.84 |
| Procalcitonin (µg/L) | 0.3 ± 0.4, 0.1 | 0.6 ± 0.6, 0.3 | 0.3 ± 0.4, 0.1 | 0.31 |
| White blood cells (1000/µL) | 7.5 ± 3.6, 7.1 | 8.5 ± 6.1, 6.1 | 7.2 ± 2.7, 7.1 | 0.81 |
| Neutrophil granulocytes (1000/µL) | 6.0 ± 4.0, 5.3 | 7.1 ± 4.2, 5.9 | 5.7 ± 4.0, 4.7 | 0.32 |
| Lymphocytes (1000/µL) | 0.9 ± 0.3, 0.9 | 1.0 ± 0.4, 1.1 | 0.9 ± 0.3, 0.9 | 0.27 |
| I nterleukin 6 (pg/mL) | 32.5 ± 23.2, 24.0 | 34.9 ± 25.1, 24.0 | 31.2 ± 24.5, 25.5 | 0.80 |
| Neuropsychiatric symptoms | ||||
| Sleep disorders (yes/no) | 19/18 | 9/1 | 10/17 | 0.013* |
| PSQI scorea | 5.8 ± 2.8, 6.0 | 7.0 ± 2.2, 6.0 | 5.3 ± 2.9, 5.0 | 0.037* |
| Fatigue | ||||
| MFI scorea | 42.5 ± 20.0, 36.0 | 64.4 ± 17.4, 64.0 | 34.3 ± 13.7, 30.0 | < 0.001* |
| MFI-FG scorea | 9.5 ± 4.8, 8.0 | 13.6 ± 4.6, 14.0 | 7.9 ± 3.9, 6.0 | 0.002* |
| MFI-FF scorea | 8.7 ± 4.7, 8.0 | 13.1 ± 5.0, 12.5 | 7.0 ± 3.4, 6.0 | 0.001* |
| MFI-RA scorea | 8.7 ± 4.8, 7.0 | 13.6 ± 4.7, 14.5 | 6.9 ± 3.4, 6.0 | < 0.001* |
| MFI-RM scorea | 7.5 ± 3.8, 6.0 | 10.9 ± 4.1, 11.0 | 6.3 ± 2.9, 5.0 | 0.001* |
| MFI-FM scorea | 8.0 ± 4.3, 6.0 | 13.2 ± 3.5, 14.0 | 6.0 ± 2.7, 5.0 | < 0.001* |
| Pain (yes/no) | 14/23 | 8/2 | 6/21 | 0.005* |
| NRS scorea | 1.8 ± 2.5, 0.0 | 4.2 ± 2.8, 5.0 | 0.9 ± 1.7, 0.0 | 0.001* |
| Anxiety (yes/no) | 10/27 | 4/6 | 6/21 | 0.51 |
| HADS score (anxiety)a | 4.6 ± 3.4, 5.0 | 5.9 ± 3.5 | 4.1 ± 3.5, 3.0 | 0.11 |
| Depression (yes/no) | 6/31 | 4/6 | 2/25 | 0.06 |
| HADS score (depression)a | 2.9 ± 3.5, 1.0 | 5.6 ± 2.8, 6.0 | 1.9 ± 2.9, 1.0 | 0.002* |
| Neuropsychological assessment | ||||
| Subjective complaints (yes/no) | 14/23 | 10/0 | 4/23 | < 0.001* |
| General (MoCA raw score)a | 26.0 ± 2.0, 26.0 | 27.0 ± 1.6, 27.0 | 25.6 ± 2.0, 26.0 | 0.05 |
| General (MoCA corrected score)a | 25.4 ± 2.4, 24.5 | 26.1 ± 2.2, 26.2 | 25.1 ± 2.4, 24.5 | 0.22 |
| Psychomotor speed (SDT score)a | 46.9 ± 10.4, 46.0 | 51.3 ± 8.7, 48.5 | 45.2 ± 10.7, 44.0 | 0.10 |
| Executive function (Stroop time)a | 18.5 ± 8.3, 17.5 | 16.2 ± 7.5, 16.9 | 19.4 ± 8.6, 17.8 | 0.39 |
| Neurofilament light chain (pg/mL) | 9.5 ± 4.9, 8.5 | 10.4 ± 7.7, 8.2 | 9.2 ± 3.5, 8.5 | 0.89 |
| Spirometry | ||||
| FEV1 (% predicted)a | 115.9 ± 15.6, 116.0 | 113.5 ± 11.2, 111.5 | 116.6 ± 16.9, 119.0 | 0.36 |
| FVC (% predicted)a | 120.8 ± 17.0, 120.0 | 114.8 ± 10.7, 117.0 | 122.7 ± 18.3, 126.0 | 0.17 |
| FEV/FVC (%)a | 100.5 ± 6.7, 101.0 | 103.9 ± 8.6, 107.0 | 99.4 ± 5.7, 100.0 | 0.10 |
| TLC (% predicted)a | 102.3 ± 13.0, 103.0 | 98.3 ± 12.1, 102.5 | 103.6 ± 13.3, 103.0 | 0.42 |
| DLCO (% predicted)a | 89.1 ± 13.3, 87.0 | 84.5 ± 15.0, 81.0 | 90.5 ± 12.7, 87.0 | 0.23 |
| KCO (% predicted)a | 95.4 ± 15.5, 93.0 | 97.6 ± 21.8, 89.5 | 94.7 ± 13.4, 94.0 | 0.85 |
| Arterial blood gas analysis | ||||
| pCO2 (mm Hg)a | 36.5 ± 7.2, 38.0 | 38.8 ± 1.5, 39.0 | 35.8 ± 8.2, 37.0 | 0.15 |
| pO2 (mm Hg)a | 97.0 ± 21.7, 99.0 | 99.3 ± 6.6, 100.0 | 96.2 ± 24.7, 99.0 | 0.95 |
| Six-minute walking test | ||||
| Distance walked (m)a | 589.4 ± 66.9, 600.0 | 602.9 ± 80.2, 608.0 | 584.9 ± 63.2, 576.0 | 0.27 |
| Distance walked (% predicted)a | 103.2 ± 17.8, 100.3 | 106.0 ± 18.1, 106.5 | 102.2 ± 17.9, 98.7 | 0.32 |
| SatO2 (baseline)a | 97.0 ± 1.1, 97.0 | 97.1 ± 0.8, 97.0 | 97.0 ± 1.1, 97.0 | 0.84 |
| SatO2 (end-effort)a | 96.6 ± 1.8, 97.0 | 96.8 ± 1.7, 97.0 | 96.5 ± 2.0, 96.5 | 0.77 |
| Borg dyspnea scale (baseline)a | 0.16 ± 0.45, 0.0 | 0.50 ± 0.76, 0.3 | 0.04 ± 0.20, 0.0 | 0.014* |
| Borg fatigue scale (baseline)a | 0.09 ± 0.30, 0.0 | 0.25 ± 0.46, 0.0 | 0.04 ± 0.20, 0.0 | 0.085 |
| Borg dyspnea scale (end-effort)a | 2.16 ± 1.54, 3.0 | 2.38 ± 0.92, 3.0 | 2.08 ± 1.72, 2.0 | 0.55 |
| Borg fatigue scale (end-effort)a | 1.69 ± 1.38, 1.0 | 2.13 ± 1.73, 2.0 | 1.54 ± 1.25, 1.0 | 0.36 |
BMI body mass index, COPD chronic obstructive pulmonary disease, DLCO diffusing capacity of the lungs for carbon monoxide, FEV1 forced expiratory volume in the first second, FVC forced vital capacity, HADS Hospital Anxiety and Depression Scale, ICU intensive care unit, KCO carbon monoxide transfer coefficient, ME/CFS + patients with myalgic encephalomyelitis/chronic fatigue syndrome-like symptoms, ME/CFS − patients without myalgic encephalomyelitis/chronic fatigue syndrome-like symptom, MFI Multidimensional Fatigue Inventory, MFI-FG general fatigue, MFI-FF physical fatigue, MFI-RA reduced activity, MFI-RM reduced motivation, MFI-FM mental fatigue, MoCA Montreal Cognitive Assessment, NRS numerical rating scale, pCO2 partial pressure of arterial carbon dioxide, pO2 partial pressure of oxygen, PSQI Pittsburgh Sleep Quality Index, SatO2 oxygen saturation, SDT Symbol Digit Test, TLC total lung capacity
aMean ± SD, median
bMild severity
cNon-parametric Mann–Whitney U test for continuous variables; chi square test for categorical variables
*P < 0.05 for ME/CFS + vs ME/CFS - comparison