. 2022 Dec 21;6:78. doi: 10.1186/s41927-022-00308-5

Table 3.

Relation between RDCI and the main disease characteristics

Parameter	Mean RDCI (SD)	IC à 95%	p-value
Age < 40 years 40–59 years 60–79 years > 80 years	0.3 (SD 0.9) 0.8 (SD 1.0) 1.5 (SD 1.2) 2.4 (SD 2.6)	-0.11-0.77 0.70–1.08 1.27–1.74 -0.84-5.64	< 0.001
Patient aged 65 years or over Yes No	2.1 (SD 1.4) 1.5 (SD 1.2)	1.56–2.40 0.70–1.91	0.009
Gender Male Female	1.8 (SD 1.3) 1.5 (SD 1.2)	0.89–1.73 0.88–1.21	0.058
Age at disease onset	-	-	0.001
Age at disease onset over 40 years Yes No	1.8 (SD 1.3) 1.5 (SD 1.2)	1.36–1.88 0.67–1.37	0.007
Disease duration	-	-	0.263
Seropositive RA Yes No	1.6 (SD 1.2) 1.4 (SD 1.1)	0.91–1.26 0.75–1.41	0.968
Immunopositive RA Yes No	1.6 (SD 1.2) 1.4 (SD 1.2)	0.83–1.21 0.96–1.49	0.887
DAS 28 (CRP)	-	-	0.719
HAQ	-	-	0.444
Extra-articular manifestations Yes No	2.1 (SD 1.4) 0.5 (SD 0.7)	0.97–1.97 0.27–0.85	< 0.001
Pulmonary involvement Presence Absence	2.2 (SD 1.5) 0.4 (SD 0.6)	1.04–2.11 0.27–0.8	0.001
Cardiac involvement Presence Absence	2 (SD 1.5) 1.4 (SD 1.3)	0.37–3.63 1.14–1.66	0.297
Ocular involvement Presence Absence	2.7 (SD 1.6) 0.8 (SD 0.9)	1.12–2.77 0.46–1.03	0.002
Kidney involvement Presence Absence	1.3 (SD 1.1) 1.9 ± 1.3	-0.54-5.2 1.19–1.74	0.858
Rheumatoid nodules Presence Absence	2 (SD 1.4) 1.7 (SD 1.3)	-11.71-13.71 0.76–1.44	0.309
Systemic vasculitis Presence Absence	1.6 (SD 2) 1.8 (SD 1.3)	-23.41-27.41 0.78–1.45	0.317
Radiographic erosions Presence Absence	1.6 (SD 1.2) 0.7 (SD 0.8)	0.95–1.35 0.66–1.28	0.006
Coxitis Yes No	2.4 (SD 1.5) 1.4 (SD 1.1)	0.63–1.79 0.88–1.18	0.029
Atlanto-axial dislocation Yes No	1.9 (SD 1.3) 1.5 (SD 1.2)	0.70-2.00 0.58–1.37	0.014
bDMARDs csDMARDs	2.8 (SD 1.6) 1.0 (SD 1.0)	1.25–2.45 0.82–1.14	0.021

Parameter

Mean RDCI (SD)

IC à 95%

p-value

Age

< 40 years

40–59 years

60–79 years

> 80 years

0.3 (SD 0.9)

0.8 (SD 1.0)

1.5 (SD 1.2)

2.4 (SD 2.6)

-0.11-0.77

0.70–1.08

1.27–1.74

-0.84-5.64

< 0.001

Patient aged 65 years or over

Yes

2.1 (SD 1.4)

1.5 (SD 1.2)

1.56–2.40

0.70–1.91

0.009

Gender

Male

Female

1.8 (SD 1.3)

1.5 (SD 1.2)

0.89–1.73

0.88–1.21

0.058

Age at disease onset

0.001

Age at disease onset over 40 years

Yes

1.8 (SD 1.3)

1.5 (SD 1.2)

1.36–1.88

0.67–1.37

0.007

Disease duration

0.263

Seropositive RA

Yes

1.6 (SD 1.2)

1.4 (SD 1.1)

0.91–1.26

0.75–1.41

0.968

Immunopositive RA

Yes

1.6 (SD 1.2)

1.4 (SD 1.2)

0.83–1.21

0.96–1.49

0.887

DAS 28 (CRP)

0.719

HAQ

0.444

Extra-articular manifestations

Yes

2.1 (SD 1.4)

0.5 (SD 0.7)

0.97–1.97

0.27–0.85

< 0.001

Pulmonary involvement

Presence

Absence

2.2 (SD 1.5)

0.4 (SD 0.6)

1.04–2.11

0.27–0.8

0.001

Cardiac involvement

Presence

Absence

2 (SD 1.5)

1.4 (SD 1.3)

0.37–3.63

1.14–1.66

0.297

Ocular involvement

Presence

Absence

2.7 (SD 1.6)

0.8 (SD 0.9)

1.12–2.77

0.46–1.03

0.002

Kidney involvement

Presence

Absence

1.3 (SD 1.1)

1.9 ± 1.3

-0.54-5.2

1.19–1.74

0.858

Rheumatoid nodules

Presence

Absence

2 (SD 1.4)

1.7 (SD 1.3)

-11.71-13.71

0.76–1.44

0.309

Systemic vasculitis

Presence

Absence

1.6 (SD 2)

1.8 (SD 1.3)

-23.41-27.41

0.78–1.45

0.317

Radiographic erosions

Presence

Absence

1.6 (SD 1.2)

0.7 (SD 0.8)

0.95–1.35

0.66–1.28

0.006

Coxitis

Yes

2.4 (SD 1.5)

1.4 (SD 1.1)

0.63–1.79

0.88–1.18

0.029

Atlanto-axial dislocation

Yes

1.9 (SD 1.3)

1.5 (SD 1.2)

0.70-2.00

0.58–1.37

0.014

bDMARDs

csDMARDs

2.8 (SD 1.6)

1.0 (SD 1.0)

1.25–2.45

0.82–1.14

0.021

RDCI: Rheumatic Disease Comorbidity Index; DAS28 (CRP): Disease activity scale (C-reactive protein); HAQ: Health assessment questionnaire; bDMARDs: biologic Disease-modifying antirheumatic drugs; csDMARDs: conventional synthetic Disease-modifying antirheumatic drugs p: statistical significance; SD: Standard deviation; IC: confidence interval