Table 2.
Baseline characteristics of the P4O2 COVID-19 cohort with cluster separation
| Cluster 1 (N=42) | Cluster 2 (N=36) | Cluster 3 (N=17) | Adj p value | |
| General characteristics | ||||
| Sex (female) | 39/42 (92.9%) | 6/36 (16.7%) | 2/17 (11.8%) | <0.001 |
| Age (years) | 53.6±6.2 | 54.7±6.3 | 54.2±6.1 | 0.799 |
| BMI (kg/m2) | 31.7±5.8 | 29.9±5.1 | n=16; 28.5±3.0 | 0.133 |
| Comorbidities | ||||
| Asthma | 12/41 (29.3%) | 4/36 (11.1%) | 0/17 (0.0%) | 0.025 |
| COPD | 4/41 (9.8%) | 2/36 (5.6%) | 0/17 (0.0%) | 0.640 |
| CVD | 5/40 (12.5%) | 15/36 (41.7%) | 7/17 (41.2%) | 0.018 |
| Diabetes | 1/41 (2.4%) | 6/36 (16.7%) | 8/17 (47.1%) | <0.001 |
| Symptom categories | ||||
| Fatigue | 41/42 (97.6%) | 23/36 (63.9%) | 2/17 (11.8%) | <0.001 |
| Respiratory | 41/42 (97.6%) | 31/36 (86.1%) | 3/17 (17.6%) | <0.001 |
| Neurological | 34/42 (81.0%) | 27/36 (75.0%) | 6/17 (35.3%) | 0.008 |
| Cardiovascular | 16/42 (38.1%) | 8/36 (22.2%) | 1/17 (5.9%) | 0.056 |
| Gastrointestinal | 21/42 (50.0%) | 5/36 (13.9%) | 3/17 (17.6%) | 0.004 |
| Other | 12/42 (28.6%) | 4/36 (11.1%) | 2/17 (11.8%) | 0.217 |
| Lung function | ||||
| FEV1 % pred | n=40; 96.2±14.8 | n=35; 84.7±18.7 | n=15; 94.7±14.6 | 0.022 |
| FVC % pred | n=40; 94.6±17.4 | n=35; 83.5±18.9 | n=15; 91.9±13.9 | 0.052 |
| FEV1/FVC | n=40; 80.7±7.9 | n=35; 79.5±9.3 | n=15; 80.0±4.9 | 0.811 |
| DLCO % pred | n=40; 85.9±17.0 | n=35; 69.3±20.0 | n=14; 89.7±15.8 | <0.001 |
| Questionnaires | ||||
| FSS (↓) | n=39; 6.0 (5.1, 6.6) | n=33; 5.6 (5.1, 6.2) | n=15; 2.2 (1.6, 3.1) | <0.001 |
| PROMIS (↑) | n=39; 26.7±7.2 | n=28; 25.8±6.3 | n=15; 39.5±1.3 | <0.001 |
| PC-PTSD-5 (↓) | n=39; 1.0 (0.0, 3.0) | n=29; 1.0 (0.0, 1.0) | n=15; 0.0 (0.0, 0.0) | 0.003 |
| EQ5D (↓) | n=40; 11.0 (8.0, 12.2) | n=28; 9.5 (7.8, 11.0) | n=15; 5.0 (5.0, 6.0) | <0.001 |
| CLC-IC (↓) | n=37; 6.0 (3.0, 8.0) | n=29; 5.0 (3.0, 9.0) | n=14; 0.5 (0.0, 1.0) | <0.001 |
| USER-P (↑) | n=39; 73.3 (56.4, 88.9) | n=29; 72.7 (53.3, 83.3) | n=15; 100.0 (100.0, 100.0) | <0.001 |
| HADS Depression (↓) | n=35; 4.0 (2.0, 8.5) | n=28; 5.0 (2.8, 9.0) | n=15; 0.0 (0.0, 1.0) | <0.001 |
| HADS Anxiety (↓) | n=36; 5.5 (1.0, 10.0) | n=29; 3.0 (2.0, 8.0) | n=15; 2.0 (1.0, 4.5) | 0.273 |
| Acute phase WHO severity | ||||
| Mild | 9/42 (21.4%) | 1/36 (2.8%) | 0/17 (0.0%) | 0.063 |
| Moderate | 26/42 (61.9%) | 24/36 (66.7%) | 11/17 (64.7%) | |
| Severe | 7/42 (16.7%) | 11/36 (30.6%) | 6/17 (35.3%) | |
| Acute phase duration/complications | ||||
| Hospital duration | n=33; 8.0 (4.0, 11.0) | n=34; 7.5 (5.2, 27.5) | 7.0 (3.0, 12.0) | 0.642 |
| Pulmonary embolism | 5/40 (12.5%) | 9/35 (25.7%) | 1/17 (5.9%) | 0.249 |
| Thrombosis | 3/40 (7.5%) | 7/34 (20.6%) | 4/17 (23.5%) | 0.249 |
| Dominant virus type | ||||
| Alpha | 17/42 (40.5%) | 18/36 (50.0%) | 8/17 (47.1%) | 0.808 |
| Delta | 20/42 (47.6%) | 13/36 (36.1%) | 8/17 (47.1%) | |
| Omicron | 5/42 (11.9%) | 5/36 (13.9%) | 1/17 (5.9%) | |
| CT abnormalities | ||||
| Ground-glass opacity/consolidations | 22/38 (57.9%) | 23/33 (69.7%) | 9/16 (56.2%) | 0.622 |
| Bronchiectasis | 6/38 (15.8%) | 8/33 (24.2%) | 5/16 (31.2%) | 0.496 |
| Subpleural reticulation | 7/38 (18.4%) | 10/33 (30.3%) | 6/16 (37.5%) | 0.347 |
| Honeycombing | 0/38 (0.0%) | 2/33 (6.1%) | 0/16 (0.0%) | 0.395 |
| Lymphadenopathy | 3/38 (7.9%) | 4/33 (12.1%) | 2/16 (12.5%) | 0.787 |
| Airtrapping | 9/38 (23.7%) | 0/33 (0.0%) | 1/16 (6.2%) | 0.013 |
| SARS-CoV-2 vaccination | ||||
| No | 14/42 (33.3%) | 6/36 (16.7%) | 8/17 (47.1%) | 0.249 |
| Yes, 1 or more doses | 28/42 (66.7%) | 30/36 (83.3%) | 9/17 (52.9%) | |
| Smoking status | ||||
| Never smoker | 15/42 (35.7%) | 16/36 (44.4%) | 9/17 (52.9%) | 0.139 |
| Ex-smoker | 27/42 (64.3%) | 16/36 (44.4%) | 8/17 (47.1%) | |
| Current smoker | 0/42 (0.0%) | 4/36 (11.1%) | 0/17 (0.0%) | |
| Level of education | ||||
| Secondary education | 7/39 (17.9%) | 8/26 (30.8%) | 4/14 (28.6%) | 0.102 |
| Vocational education | 18/39 (46.2%) | 11/26 (42.3%) | 4/14 (28.6%) | |
| Bachelor | 13/39 (33.3%) | 3/26 (11.5%) | 3/14 (21.4%) | |
| Master | 1/39 (2.6%) | 4/26 (15.4%) | 3/14 (21.4%) | |
P values were calculated using the analysis of variance or Kruskal-Wallis tests for numerical data, and a Fisher’s exact test for categorial data. Data are shown as mean±SD or median (IQR) for numerical data and as n (%) for categorical data. When not all data are available, the number of patients with data available is given. For each questionnaire it is indicated with an arrow if a higher or lower score is considered better. P values below 0.05 are highlighted in bold. Adj p value: adjusted p value (Benjamini and Hochberg).
BMI, body mass index; CLC-IC, Checklist for Cognitive Consequences after an ICU Admission; COPD, chronic obstructive pulmonary disease; CVD, cardiovascular disease; DLCO, diffusion capacity of the lungs for carbon monoxide; EQED, EuroQoL 5D-5L; FEV1, forced expiratory volume in 1 s; FSS, Fatigue Severity Scale; FVC, forced vital capaticy; HADS, Hospital Anxiety and Depression Scale; PC-PTSD-5, Primary Care PTSD Screen for DSM-5; PROMIS, Patient-Reported Outcomes Measurement Information System; USER-P, Utrecht Scale for Evaluation of Revalidation-Participation.