Table 1

Baseline characteristics of the adult-onset and childhood-onset IgA vasculitis (IgAV) cohorts with corresponding controls. adult-onset patients include all incident and prevalent IgAV cases with a date of diagnosis after the age of 16 years

Baseline characteristics (SD or percentage)
Adult-onset IgAVChildhood-onset IgAV
ExposedUnexposedExposedUnexposed
Patients, n2828565510 40520 810
Median follow-up period (years)4.91 (IQR 2.07–9.08)4.99 (IQR 2.18–9.05)4.86 (IQR 2.06–9.08)4.98 (IQR 2.17–9.86)
Mean age at study entry (years)*43.33 (18.8)43.33 (18.7)17.57 (13.12)17.59 (13.13)
Mean age at IgAV diagnosis38.09 (18.8)N/A6.68 (3.41)N/A
Gender (male)1370 (48.4%)2739 (48.4%)5545 (53.29%)11 090 (53.29%)
Gender (female)1458 (51.6%)2916 (51.6%)4860 (46.71%)9720 (46.71%)
Mean body mass index26.9 (6.1)26.2 (5.5)N/AN/A
Smoking status
 Current smoker522 (18.5%)1289 (22.8%)1178 (11.32%)2102 (10.10%)
 Ex-smoker525 (18.6%)845 (14.9%)528 (5.07%)904 (4.34%)
 Non-smoker1525 (53.9%)2825 (50.0%)2751 (26.44%)5427 (26.08%)
 Not available256 (9.05%)696 (12.31%)5,948 (57.16%)12,377 (59.48%)
Hypertension523 (18.5%)734 (13.0%)185 (1.78%)236 (1.13%)
Diabetes mellitus149 (5.3%)210(3.7%)66 (0.63%)133 (0.64%)
VTE52 (1.8%)61 (1.1%)29 (0.28%)37 (0.18%)
IHD139 (4.9%)220 (3.9%)N/AN/A
Stroke and TIA68 (2.4%)107 (1.9%)N/AN/A
eGFR category
 >90 mL/min per 1.73 m2 639 (22.60%)856 (15.14%)116 (0.56%)100 (0.96%)
 60–90 mL/min per 1.73 m2 697 (24.65%)1160 (20.51%)121 (0.58%)157 (1.51%)
 30–59 mL/min per 1.73 m2 164 (5.80%)209 (3.70%)1339 (6.43%)707 (6.79%)
 <30 mL/min per 1.73 m2 30 (1.0620 (0.35%)1358 (6.53%)642 (6.17%)
 N/A1298 (45.90%)3410 (60.30%)17 876 (85.90%)8799 (84.57%)
Lipid-regulating medication use313 (11.1%)506 (5.0%)N/AN/A
Current contraceptive use†336 (23.1%)572 (19.6%)799 (16.44%)1,432 (14.73%)
Townsend deprivation quintile
 (Least deprived) 1622 (22.0%)1231 (21.8%)2216 (21.30%)4529 (21.76%)
 2542 (19.2%)1161 (20.5%)1927 (18.52%)3863 (18.56%)
 3557 (19.7%)1080 (19.1%)1968 (18.91%)4055 (19.49%)
 4476 (16.8%)955 (16.9%)1856 (17.84%)3633 (17.46%)
 5334 (11.8%)670 (11.9%)1293 (12.43%)2614 (12.56%)
 NA297 (10.5%)558 (9.9%)1145 (11.0%)2116 (10.17%)
Charlson comorbidity index
 01806 (63.86%)4176 (73.85%)N/AN/A
 1590 (20.86%)1063 (18.80%)N/AN/A
 2259 (9.16%)258 (4.56%)N/AN/A
 > 2173 (6.12%)158 (2.79%)N/AN/A
  • Childhood-onset patients include all incident and prevalent IgAV cases with a date of diagnosis before the age of 16 years. Controls were age-matched and sex-matched in a 2:1 ratio.

  • *Note that many patients had a IgAV diagnosis prior to study entry—prevalent cases. eGFR,estimated glomerular filtration rate; IHD, ischaemic heart disease; N/A, not available; VTE, venousthromboembolism.

  • †Current contraceptive use percentage reported for females only.