Introduction
Methods
Study design and database
Study population and definition of main variables and covariates
Statistical analysis
Results
Characteristics of the study population
Characteristic | Patients with HS (N = 6779) | Controls (N = 33,260) | p value |
---|---|---|---|
Age, years | |||
Mean (SD) | 33.1 (15.1) | 33.1 (15.1) | 0.817 |
Median (range) | 30.0 (0.6–88.7) | 30.0 (0.6–88.8) | |
Sex, N (%) | |||
Male | 2708 (39.9%) | 13,347 (40.1%) | 0.780 |
Female | 4071 (60.1%) | 19,913 (59.9%) | |
Ethnicity, N (%) | |||
Jews | 5607 (82.7%) | 27,413 (82.4%) | 0.768 |
Arabs | 1172 (17.3%) | 5846 (17.6%) | |
BMI, mg/kg2 | |||
Mean (SD) | 27.2 (6.5) | 24.7 (5.6) | < 0.001 |
Smoking, N (%) | 3591 (53.0%) | 11,469 (34.5%) | < 0.001 |
Diabetes Mellitus, N (%) | 698 (10.3%) | 2236 (6.7%) | < 0.001 |
Hyperlipidemia, N (%) | 1972 (29.1%) | 7690 (23.1%) | < 0.001 |
Hypertension, N (%) | 853 (12.6%) | 3220 (9.7%) | < 0.001 |
Charlson comorbidity score | |||
Mean score (SD) | 0.5 (1.2) | 0.4 (1.0) | < 0.001 |
None (0) | 4891 (72.1%) | 26,375 (79.3%) | < 0.001 |
Moderate (1–2) | 1469 (21.7%) | 5531 (16.6%) | < 0.001 |
Severe (≥ 3) | 419 (6.2%) | 1355 (4.1%) | < 0.001 |
The odds of hidradenitis suppurativa after rheumatoid arthritis (case–control design)
Subgroup | Preexisting RA in patients with HS N(%) (N = 6763)* | Preexisting RA in controls N(%) (N = 33,215)* | OR (95%CI) | Univariate p value |
---|---|---|---|---|
All | 33 (0.5%) | 102 (0.3%) | 1.59 (1.07–2.36) | 0.019 |
Age, years | ||||
< 20 | 4 (0.3%) | 7 (0.1%) | 2.80 (0.82–9.59) | 0.086 |
20–40 | 6 (0.2%) | 29 (0.2%) | 1.01 (0.42–2.44) | 0.976 |
≥ 40 | 23 (1.3%) | 66 (0.7%) | 1.73 (1.08–2.79) | 0.022 |
Gender | ||||
Male | 9 (0.3%) | 20 (0.1%) | 2.22 (1.01–4.89) | 0.041 |
Female | 117 (2.9%) | 438 (2.2%) | 1.44 (0.91–2.27) | 0.118 |
Ethnicity | ||||
Jews | 26 (0.5%) | 90 (0.3%) | 1.42 (0.91–2.19) | 0.118 |
Arabs | 7 (0.6%) | 12 (0.2%) | 2.93 (1.15–7.45) | 0.018 |
Latency after the diagnosis of RA | ||||
0–5 years | 7 (0.1%) | 29 (0.1%) | 1.19 (0.52–2.71) | 0.686 |
6–10 years | 11 (0.2%) | 36 (0.1%) | 1.50 (0.76–2.95) | 0.235 |
> 10 years | 15 (0.2%) | 37 (0.1%) | 1.99 (1.09–3.63) | 0.022 |
Multivariate analyses | ||||
Age- and sex-adjusted OR | 1.61 (1.08–2.38) | 0.019 | ||
Fully-adjusted OR** | 1.66 (1.11–2.49) | 0.014 |
The risk of rheumatoid arthritis in patients with hidradenitis suppurativa (retrospective cohort design)
HS (N = 6746)* | Control (N = 33,158)* | |
---|---|---|
Follow-up time, PY | 37,591.7 | 184,763.3 |
Median follow-up time, years (range) | 6.1 (0.1–18.7) | 6.1 (0.1–18.7) |
Number of new-onset RA events | 16 | 45 |
Incidence rate / 10,000 PY (95% CI) | 4.3 (2.5–6.8) | 2.4 (1.8–3.2) |
Unadjusted HR (95% CI) [p value] | 1.75 (0.99–3.90) [0.055] | Ref. |
Male-specific HR (95% CI) [p value] | 1.79 (0.57–5.62) [0.319] | Ref. |
Female-specific HR (95% CI) [p value] | 1.73 (0.90–3.34) [0.102] | Ref. |
< 30 years-specific HR (95% CI) [p value]a | 1.23 (0.35–4.34) [0.753] | Ref. |
≥ 30 years-specific HR (95% CI) [p value]a | 1.94 (1.02–3.69) [0.043] | Ref. |
Jews-specific HR (95% CI) [p value] | 1.50 (0.79–2.87) [0.216] | Ref. |
Arabs-specific HR (95% CI) [p value] | 3.36 (0.95–11.91) [0.061] | Ref. |
Age- and sex-Adjusted HR (95% CI) [p value] | 1.75 (0.99–3.09) [0.055] | Ref. |
Fully adjusted HR (95% CI) [p value]b | 1.45 (0.77–2.72) [0.249]a | Ref. |
Features of patients with hidradenitis suppurativa and comorbid rheumatoid arthritis
Coexistent HS and RA (n = 49) | HS without RA (n = 6730) | OR | 95% CI | p value | |
---|---|---|---|---|---|
Age at the onset of HS, years; mean (SD) | 48.5 (18.1) | 33.0 (15.0) | 1.70a | 1.46–1.98 | < 0.001 |
Female sex, n (%) | 36 (73.5%) | 4035 (60.0%) | 1.85 | 0.98–3.50 | 0.054 |
Jewish ethnicity, n (%) | 38 (77.6%) | 5569 (82.7%) | 0.72 | 0.37–1.41 | 0.338 |
Body mass index; Kg/m2, mean (SD) | 34.7 (23.8) | 27.5 (20.5) | 1.00b | 0.99–1.01 | 0.116 |
Modified Charlson Comorbidity index; mean (SD) | 1.3 (2.0) | 0.5 (1.1) | 1.35c | 1.18–1.54 | < 0.001 |
Diabetes mellitus, n (%) | 18 (36.7%) | 680 (10.1%) | 5.17 | 2.88–9.28 | < 0.001 |
Hypertension, n (%) | 18 (36.7%) | 835 (12.4%) | 4.10 | 2.28–7.36 | < 0.001 |
Hyperlipidemia, n (%) | 31 (63.3%) | 1941 (28.8%) | 4.25 | 2.37–7.61 | < 0.001 |
Smoking, n (%) | 26 (53.1%) | 3565 (96.9%) | 1.00 | 0.57–1.76 | 0.990 |