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±6.254.7±6.354.2±6.10.799
 BMI (kg/m2)31.7±5.829.9±5.1n=16; 28.5±3.00.133
Comorbidities
 Asthma12/41 (29.3%)4/36 (11.1%)0/17 (0.0%)0.025
 COPD4/41 (9.8%)2/36 (5.6%)0/17 (0.0%)0.640
 CVD5/40 (12.5%)15/36 (41.7%)7/17 (41.2%)0.018
 Diabetes1/41 (2.4%)6/36 (16.7%)8/17 (47.1%)<0.001
Symptom categories
 Fatigue41/42 (97.6%)23/36 (63.9%)2/17 (11.8%)<0.001
 Respiratory41/42 (97.6%)31/36 (86.1%)3/17 (17.6%)<0.001
 Neurological34/42 (81.0%)27/36 (75.0%)6/17 (35.3%)0.008
 Cardiovascular16/42 (38.1%)8/36 (22.2%)1/17 (5.9%)0.056
 Gastrointestinal21/42 (50.0%)5/36 (13.9%)3/17 (17.6%)0.004
 Other12/42 (28.6%)4/36 (11.1%)2/17 (11.8%)0.217
Lung function
 FEV1 % predn=40; 96.2±14.8n=35; 84.7±18.7n=15; 94.7±14.60.022
 FVC % predn=40; 94.6±17.4n=35; 83.5±18.9n=15; 91.9±13.90.052
 FEV1/FVCn=40; 80.7±7.9n=35; 79.5±9.3n=15; 80.0±4.90.811
 DLCO % predn=40; 85.9±17.0n=35; 69.3±20.0n=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±7.2n=28; 25.8±6.3n=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
 Mild9/42 (21.4%)1/36 (2.8%)0/17 (0.0%)0.063
 Moderate26/42 (61.9%)24/36 (66.7%)11/17 (64.7%)
 Severe7/42 (16.7%)11/36 (30.6%)6/17 (35.3%)
Acute phase duration/complications
 Hospital durationn=33; 8.0 (4.0, 11.0)n=34; 7.5 (5.2, 27.5)7.0 (3.0, 12.0)0.642
 Pulmonary embolism5/40 (12.5%)9/35 (25.7%)1/17 (5.9%)0.249
 Thrombosis3/40 (7.5%)7/34 (20.6%)4/17 (23.5%)0.249
Dominant virus type
 Alpha17/42 (40.5%)18/36 (50.0%)8/17 (47.1%)0.808
 Delta20/42 (47.6%)13/36 (36.1%)8/17 (47.1%)
 Omicron5/42 (11.9%)5/36 (13.9%)1/17 (5.9%)
CT abnormalities
 Ground-glass opacity/consolidations22/38 (57.9%)23/33 (69.7%)9/16 (56.2%)0.622
 Bronchiectasis6/38 (15.8%)8/33 (24.2%)5/16 (31.2%)0.496
 Subpleural reticulation7/38 (18.4%)10/33 (30.3%)6/16 (37.5%)0.347
 Honeycombing0/38 (0.0%)2/33 (6.1%)0/16 (0.0%)0.395
 Lymphadenopathy3/38 (7.9%)4/33 (12.1%)2/16 (12.5%)0.787
 Airtrapping9/38 (23.7%)0/33 (0.0%)1/16 (6.2%)0.013
SARS-CoV-2 vaccination
 No14/42 (33.3%)6/36 (16.7%)8/17 (47.1%)0.249
 Yes, 1 or more doses28/42 (66.7%)30/36 (83.3%)9/17 (52.9%)
Smoking status
 Never smoker15/42 (35.7%)16/36 (44.4%)9/17 (52.9%)0.139
 Ex-smoker27/42 (64.3%)16/36 (44.4%)8/17 (47.1%)
 Current smoker0/42 (0.0%)4/36 (11.1%)0/17 (0.0%)
Level of education
 Secondary education7/39 (17.9%)8/26 (30.8%)4/14 (28.6%)0.102
 Vocational education18/39 (46.2%)11/26 (42.3%)4/14 (28.6%)
 Bachelor13/39 (33.3%)3/26 (11.5%)3/14 (21.4%)
 Master1/39 (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.