Table 2.
Characteristics of the patients in the 2 and 6 clusters found in the cluster analysis (n = 6,927)a
| 2 clusters | 6 clusters | |||||||
|---|---|---|---|---|---|---|---|---|
| Cluster A | Cluster B | Cluster 1 | Cluster 2 | Cluster 3 | Cluster 4 | Cluster 5 | Cluster 6 | |
| Jaccard index | 0.64 | 0.66 | 0.39 | 0.32 | 0.57 | 0.38 | 0.68 | 0.43 |
| No. of patients | 3,149 | 3,778 | 1,186 | 720 | 1,243 | 1,673 | 1,249 | 856 |
| Demographic characteristics | ||||||||
| Sex, female | 90 | 84 | 94 | 88 | 88 | 88 | 81 | 79 |
| Ethnicity | ||||||||
| White | 94 | 96 | 97 | 88 | 94 | 96 | 94 | 96 |
| Asian | 5 | 2 | 2 | 10 | 4 | 2 | 3 | 2 |
| Black | 2 | 2 | 1 | 2 | 2 | 2 | 3 | 2 |
| Age, mean ± SD years | 59.2 ± 13.3 | 58.2 ± 13.2 | 61.3 ± 12.9 | 60 ± 12.8 | 56.6 ± 13.5 | 61.2 ± 12.6 | 55.8 ± 13.2 | 55.9 ± 13.2 |
| Age at first non‐Raynaud's symptom, mean ± SD years | 47.9 ± 13.3 | 46.7 ± 13.3 | 48.9 ± 13.1 | 48.3 ± 12.8 | 46.7 ± 13.6 | 48.1 ± 13.1 | 46 ± 13.4 | 45.1 ± 13.4 |
| Disease duration, mean ± SD yearsb | 11.3 ± 8.2 | 11.5 ± 8.1 | 12.4 ± 8.1 | 11.8 ± 8.3 | 9.9 ± 7.9 | 13.2 ± 8.4 | 9.8 ± 7.6 | 10.8 ± 7.5 |
| Time from onset of Raynaud's phenomenon to first non–Raynaud's phenomenon symptom, mean ± SD years | 4.8 ± 8.7 | 3.1 ± 7.3 | 5.4 ± 8.7 | 4.4 ± 9.1 | 4.4 ± 8.5 | 3.9 ± 8.2 | 2.8 ± 6.6 | 2.2 ± 6.1 |
| Time from first non–Raynaud's phenomenon symptom to EUSTAR enrollment, mean ± SD years | 9.4 ± 7.9 | 9.3 ± 7.8 | 10.3 ± 7.9 | 9.8 ± 8.2 | 8.2 ± 7.4 | 10.5 ± 8.1 | 8.1 ± 7.4 | 8.6 ± 7.4 |
| Time from EUSTAR enrollment to last visit, mean ± SD years | 2.2 ± 2.3 | 2.8 ± 2.6 | 2.5 ± 2.3 | 2.3 ± 2.5 | 1.8 ± 2.2 | 3 ± 2.7 | 2.4 ± 2.5 | 2.9 ± 2.5 |
| Body mass index, mean ± SD kg/m2 | 24.1 ± 4.3 | 23.2 ± 4.2 | 24.3 ± 4.4 | 24.5 ± 4.6 | 23.6 ± 4 | 23.6 ± 4.4 | 23.3 ± 3.9 | 22.1 ± 4.2 |
| SSc characteristics | ||||||||
| Autoantibody status | ||||||||
| Antinuclear antibody positivec | 96 | 97 | 98 | 94 | 95 | 97 | 95 | 98 |
| Anticentromere antibody positivec | 54 | 22 | 79 | 24 | 48 | 29 | 20 | 12 |
| Anti–topoisomerase I antibody positivec | 21 | 54 | 8 | 35 | 24 | 46 | 50 | 77 |
| Anti–U1 RNP antibody positive | 5 | 5 | 3 | 8 | 5 | 7 | 3 | 4 |
| Anti‐PM/Scl antibody positive | 2 | 4 | 1 | 3 | 1 | 4 | 4 | 6 |
| Anti–RNA polymerase III antibody positive | 3 | 5 | 2 | 3 | 4 | 3 | 6 | 6 |
| Cutaneous involvement | ||||||||
| dcSSc | 19 | 61 | 11 | 29 | 21 | 37 | 72 | 92 |
| Peak MRSS, mean ± SDc | 6.6 ± 4.3 | 16.5 ± 9.8 | 6.6 ± 4.2 | 7.2 ± 4.6 | 6.3 ± 4.1 | 9.2 ± 5.3 | 19 ± 6.7 | 27.2 ± 8.7 |
| Gastrointestinal involvementd | ||||||||
| Esophageal symptomsc | 73 | 88 | 88 | 76 | 58 | 91 | 79 | 95 |
| Stomach symptomsc | 26 | 55 | 52 | 16 | 7 | 60 | 36 | 70 |
| Intestinal symptomsc | 33 | 50 | 64 | 21 | 11 | 57 | 34 | 63 |
| Joint involvement | ||||||||
| Joint contracturesc | 24 | 67 | 29 | 17 | 23 | 65 | 55 | 91 |
| Joint synovitisc | 14 | 37 | 15 | 13 | 15 | 37 | 25 | 53 |
| Tendon friction rubsc | 4 | 28 | 6 | 3 | 4 | 19 | 19 | 57 |
| Vascular involvement | ||||||||
| Raynaud's phenomenonc | 98 | 99 | 99 | 98 | 97 | 99 | 98 | 99 |
| History of or current digital ulcersc | 32 | 63 | 35 | 24 | 33 | 62 | 50 | 85 |
| Muscular involvement | ||||||||
| Muscle weaknessc | 16 | 59 | 27 | 8 | 10 | 69 | 33 | 77 |
| Muscle atrophyc | 6 | 35 | 9 | 3 | 6 | 38 | 17 | 57 |
| CK elevationc | 6 | 18 | 7 | 7 | 5 | 17 | 13 | 26 |
| Cardiac involvement | ||||||||
| Systemic arterial hypertensionc | 31 | 37 | 38 | 28 | 26 | 44 | 26 | 38 |
| Palpitationsc | 25 | 51 | 38 | 32 | 9 | 64 | 28 | 57 |
| Conduction blocksc | 12 | 30 | 16 | 14 | 6 | 39 | 16 | 34 |
| LVEF <50% | 3 | 7 | 3 | 3 | 2 | 6 | 5 | 10 |
| Abnormal diastolic functionc | 24 | 42 | 27 | 33 | 15 | 54 | 24 | 43 |
| Pericardial effusion | 7 | 14 | 7 | 11 | 4 | 15 | 9 | 18 |
| Pulmonary hypertension | ||||||||
| Pulmonary hypertension on echocardiographyc | 21 | 39 | 24 | 39 | 8 | 44 | 24 | 50 |
| Systolic PAP measured by echocardiography, mean ± SD mm Hg | 32.5 ± 13.7 | 36 ± 16.2 | 33 ± 14.3 | 36.7 ± 14.1 | 29.4 ± 12 | 37.2 ± 14.6 | 32.4 ± 12 | 38.1 ± 22.1 |
| Interstitial lung disease | ||||||||
| Lung fibrosis on plain radiographyc | 29 | 65 | 8 | 85 | 17 | 72 | 46 | 80 |
| Lung fibrosis on HRCT | 38 | 70 | 22 | 78 | 29 | 73 | 56 | 82 |
| Restrictive defect on PFTsc | 24 | 58 | 13 | 61 | 14 | 60 | 42 | 77 |
| FVC, mean ± SD % predicted | 97.8 ± 19.3 | 82.7 ± 21.1 | 101.2 ± 17.4 | 86.7 ± 21.9 | 99.9 ± 17.7 | 84.4 ± 20.8 | 87.5 ± 19.8 | 72.8 ± 20.3 |
| Dlco, mean ± SD % predicted | 68 ± 18.9 | 56.6 ± 19.7 | 69.8 ± 17.2 | 57.7 ± 19.3 | 72.3 ± 18 | 55.2 ± 18.8 | 62.5 ± 20.3 | 50.6 ± 18.1 |
| 6‐minute walking distance, mean ± SD meters | 411 ± 129 | 381 ± 136 | 400 ± 135 | 405 ± 130 | 427 ± 121 | 366 ± 133 | 418 ± 130 | 362 ± 138 |
| Renal involvement | ||||||||
| History of renal crisisc | 2 | 4 | 2 | 1 | 2 | 4 | 3 | 8 |
| Proteinuriac | 7 | 16 | 6 | 8 | 7 | 15 | 11 | 26 |
| Blood tests | ||||||||
| CRP elevation | 24 | 45 | 25 | 29 | 20 | 43 | 36 | 62 |
| Hypocomplementemia | 10 | 13 | 13 | 7 | 8 | 14 | 10 | 12 |
| Treatment | ||||||||
| Past or current steroids | 27 | 55 | 22 | 45 | 24 | 57 | 44 | 65 |
| Prednisone, mean ± SD mg/day | 2.8 ± 6.4 | 5.7 ± 7.9 | 2 ± 4.9 | 5.5 ± 9.3 | 2.3 ± 5.6 | 5.6 ± 7.6 | 4.6 ± 7.6 | 7.3 ± 8.8 |
| Past or current immunosuppressive drugs | 27 | 54 | 17 | 44 | 27 | 48 | 54 | 66 |
| Mortality | ||||||||
| Number of deaths per 1,000 patient‐years | 10.3 | 22.6 | 7.5 | 17.3 | 9.7 | 19.1 | 20.8 | 31.9 |
a
Except where indicated otherwise, values are the percent of patients. See Table 1 for definitions.
b
Time between the first non–Raynaud's phenomenon symptom and the last visit.
c
Clustering variables.
d
Esophageal symptoms included dysphagia and/or reflux, stomach symptoms included early satiety and/or vomiting, and intestinal symptoms included diarrhea, bloating, and/or constipation.