Table 2.

Baseline characteristics of patients with rheumatic immune-mediated inflammatory diseases and healthy controls with a confirmed diagnosis of COVID-19

Patient characteristics	Patients (n=347)	Healthy controls (n=133)
Age, years—mean (SD)	56 (13)	54 (13)
Female sex—no. (%)	240 (69)	102 (77)
Male sex—no. (%)	107 (31)	31 (23)
Body mass index, kg/m2—mean (SD)	25 (5)	25 (4)
Caucasian race—no. (%)	282 (83)	122/131 (93)
Educational level—no. (%)
High	149 (45)	68 (53)
Middle	114 (35)	39 (30)
Low	67 (20)	21 (16)
Current smoking status—no. (%)	27 (8)	2 (2)
Coexisting conditions—no. (%)
Cardiovascular disease	34 (10)	7 (5)
Chronic pulmonary disease	42 (12)	9 (7)
Diabetes	14 (4)	0 (0)
Obesity	65 (19)	14 (10)
COVID-19-related symptoms—no. (%)
Sore throat	154 (44)	54 (41)
Cough	183 (53)	66 (50)
Rhinorrhoea	206 (59)	81 (61)
Dyspnoea	124 (36)	39 (29)
Fever	138 (40)	58 (44)
Loss of taste or smell	163 (47)	69 (52)
Headache	192 (55)	59 (44)
Excessive tiredness	229 (66)	70 (53)
General malaise	148 (43)	56 (42)
Vomiting and/or diarrhoea	46 (13)	11 (8)
Diagnosis of COVID-19—no. (%)
PCR test	249(72)	95 (71)
Solely negative results	50 (14)	29 (22)
At least one positive result	199 (57)	66 (50)
RBD-Ab bridging ELISA	296 (85)	125 (94)
Solely negative results	30 (9)	9 (7)
At least one positive result	291 (84)	120 (90)
Disease severity of COVID-19
Asymptomatic—no. (%)	45 (13)	10 (8)
Hospitalisation—no. (%)	23 (7)	1 (0.7)
Duration, days—median (IQR)	10 (2–11)	15 N.A.
ICU admission—no. (%)	3 (0.9)	0 (0)
Deceased—no. (%)	1 (0.3)	0 (0)

Data are mean (SD), median (IQR) or n (%).

Only data on educational level and race had missing values, valid percentages are shown. Duration of hospitalisation was only assessed in patients who survived COVID-19.

ICU, intensive care unit; N.A., not available; RBD-Ab, receptor binding domain antibody.