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Table 3 Results of the first stage of two-stage clustering of chest pain data

From: Could the clinical interpretability of subgroups detected using clustering methods be improved by using a novel two-stage approach?

Response option  
Domain: Demographic        
2 clusters   Cluster1 Cluster2     
Scoring pattern label   Older Younger     
Cluster Size   51 % 49 %     
Cluster membership probability Median (interquartile range) 90 % (79 % to 96 %) 93 % (78 % to 100 %)     
Age (years) Mean (SD) 62.6 (5.2) 45.3 (6.3)     
Gender Female 43 % 39 %     
Domain: Previous history
1 cluster   Previous history did not discriminate subgroups in two-stage clustering
Domain: Psychological
5 clusters   Cluster1 Cluster2 Cluster3 Cluster4 Cluster5  
Scoring pattern label   Uncertain of cause of pain and fearful Believes cause from heart Believes both from heart and musculoskeletal Believes cause from musculoskeletal and less fearful Believes cause from other cause and less fearful  
Cluster Size   44 % 23 % 16 % 11 % 6 %  
Cluster membership probability Median (interquartile range) 100 % (92 % to 100 %) 99. % (99 % to 100 %) 100 % (100 % to 100 %) 95 % (95 % to 96 %) 77 % (77 % to 100 %)  
Self-perceived ‘Pain from muscle or joints’ No 10 % 100 % 0 % 0 % 75 %  
  Possibly 85 % 0 % 1 % 13 % 25 %  
  Yes 5 % 0 % 99 % 87 % 0 %  
Self-perceived ‘Pain from heart’ No 15 % 0 % 0 % 99 % 94 %  
  Possibly 83 % 1 % 1 % 1 % 6 %  
  Yes 3 % 99 % 99 % 0 % 0 %  
Self-perceived ‘Afraid’ Yes 99 % 71 % 83 % 56 % 50 %  
Domain: Pain
2 clusters   Cluster1 Cluster2     
Scoring pattern label   Crushing pain Not crushing pain     
Cluster Size   77 % 23 %     
Cluster membership probability, median (interquartile range)   97 % (94 % to 97 %) 99 % (96 % to 99 %)     
Episode duration < 10 min 59 % 50 %     
  10 min-1 hour 20 % 20 %     
  > 1 hour 5 % 7 %     
  Continuous 16 % 24 %     
Pain description ‘crushing pain’ Yes 100 % 25 %     
Pain description ‘tenderness’ Yes 3 % 3 %     
Pain description ‘sharp pains’ Yes 14 % 52 %     
Pain description ‘well defined’ Yes 3 % 6 %     
Pain description ‘diffuse’ Yes 6 % 5 %     
Pain description ‘burning’ Yes 4 % 8 %     
Pain description ‘tingling’ Yes 8 % 19 %     
Domain: Activity limitation
3 clusters   Cluster1 Cluster2 Cluster3    
Scoring pattern label   None or light activity limitation Moderate activity limitation Severe activity limitation    
Cluster Size   82 % 11 % 8 %    
Cluster membership probability, median (interquartile range)   100 % (100 % to 100 %) 86 % (86 % to 86 %) 99 % (82 % to 100 %)    
SF36 physical function sum-score Mean (SD) 71.2 (7.4) 49.0 (4.6) 27.1 (6.9)    
Domain: Diagnostic classification
3 clusters   Cluster1 Cluster2 Cluster3    
Scoring pattern label   Not heart Typical angina Maybe angina    
Cluster Size   37 % 35 % 28 %    
Cluster membership probability Median (interquartile range) 100 % (94 % to 100 %) 100 % (85 % to 100 %) 97 % (81 % to 100 %)    
Danish Cardiologist’s Society No angina 64 % 3 % 2 %    
classification ‘angina’ Typical 0 % 89 % 4 %    
  Atypical 1 % 8 % 65 %    
  Uncharacteri-stic 34 % 0 % 29 %    
  Unstable 0 % 1 % 0 %    
Canadian Cardiovascular Society Grade 0 87 % 0 % 8 %    
classification Grade 1 13 % 17 % 84 %    
  Grade 2 0 % 76 % 8 %    
  Grade 3 0 % 7 % 0 %    
Domain: Palpation
6 clusters   Cluster1 Cluster2 Cluster3 Cluster4 Cluster5 Cluster6
Scoring pattern label   No palpation findings Local 5/6 signs and intercostal tenderness Local 2/3/4 signs and pectoral tenderness Pectoral tenderness Paraspinal and pectoral tenderness Generalised tenderness
Cluster Size   22 % 19 % 18 % 16 % 16 % 8 %
Cluster membership probability, median (interquartile range)   100 % (100 % to 100 %) 100 % (100 % to 100 %) 100 % (100 % to 100 %) 100 % (100 % to 100 %) 100 % (100 % to 100 %) 100 % (100 % to 100 %)
Sternoxiphoid springing tenderness Yes 10 % 22 % 1 % 1 % 10 % 34 %
Costosternal tenderness 2/3 right Yes 0 % 5 % 1 % 4 % 16 % 52 %
Costosternal tenderness 2/3 left Yes 1 % 7 % 0 % 2 % 19 % 56 %
Costosternal tenderness 3/4 right Yes 2 % 13 % 1 % 3 % 12 % 52 %
Costosternal tenderness 3/4 left Yes 2 % 25 % 0 % 0 % 18 % 54 %
Costosternal tenderness 4/5 right Yes 1 % 28 % 1 % 1 % 4 % 51 %
Costosternal tenderness 4/5 left Yes 2 % 77 % 1 % 1 % 10 % 52 %
Costosternal tenderness 5/6 right Yes 1 % 27 % 1 % 1 % 0 % 51 %
Costosternal tenderness 5/6 left Yes 3 % 55 % 0 % 0 % 6 % 51 %
sternoxiphoid springing pain Yes 4 % 3 % 0 % 0 % 4 % 4 %
Costosternal springing pain 2/3 right Yes 0 % 0 % 0 % 4 % 1 % 8 %
Costosternal springing pain 2/3 left Yes 0 % 1 % 0 % 1 % 4 % 10 %
Costosternal springing pain 3/4 right Yes 0 % 2 % 1 % 2 % 2 % 10 %
Costosternal springing pain 3/4 left Yes 1 % 7 % 0 % 0 % 5 % 10 %
Costosternal springing pain 4/5 right Yes 0 % 8 % 1 % 0 % 1 % 6 %
Costosternal springing pain 4/5 left Yes 1 % 36 % 0 % 0 % 0 % 4 %
Costosternal springing pain 5/6 right Yes 0 % 9 % 0 % 0 % 0 % 4 %
Costosternal springing pain 5/6 left Yes 0 % 29 % 0 % 1 % 2 % 6 %
Muscle tenderness pectoralis major left Tenderness 1 % 19 % 78 % 62 % 38 % 54 %
  Pain 0 % 3 % 20 % 28 % 4 % 24 %
Muscle tenderness pectoralis minor left Tenderness 2 % 31 % 83 % 75 % 40 % 66 %
  Pain 0 % 6 % 13 % 8 % 4 % 20 %
Muscle tenderness intercostal 2/3 left Tenderness 1 % 6 % 58 % 42 % 24 % 84 %
  Pain 1 % 0 % 3 % 1 % 0 % 12 %
Muscle tenderness intercostal 3/4 left Tenderness 1 % 20 % 36 % 20 % 18 % 90 %
  Pain 1 % 2 % 0 % 0 % 1 % 8 %
Muscle tenderness intercostal 4/5 left Tenderness 3 % 46 % 12 % 10 % 5 % 91 %
  Pain 1 % 15 % 0 % 1 % 1 % 6 %
Muscle tenderness intercostal 5/6 left Tenderness 2 % 57 % 5 % 3 % 4 % 89 %
  Pain 0 % 21 % 0 % 0 % 0 % 6 %
Muscle tenderness intercostal 6/7 left Tenderness 1 % 42 % 1 % 1 % 0 % 82 %
  Pain 0 % 14 % 0 % 1 % 1 % 8 %
Muscle tenderness pectoralis major right Tenderness 0 % 16 % 75 % 74 % 28 % 56 %
  Pain 0 % 0 % 21 % 16 % 4 % 24 %
Muscle tenderness pectoralis minor right Tenderness 1 % 17 % 80 % 68 % 33 % 66 %
  Pain 0 % 0 % 11 % 7 % 1 % 20 %
Muscle tenderness intercostal 2/3 right Tenderness 0 % 9 % 59 % 38 % 16 % 90 %
  Pain 0 % 1 % 0 % 1 % 1 % 8 %
Muscle tenderness intercostal 3/4 right Tenderness 1 % 15 % 32 % 15 % 9 % 90 %
  Pain 0 % 0 % 0 % 1 % 1 % 6 %
Muscle tenderness intercostal 4/5 right Tenderness 0 % 27 % 10 % 4 % 4 % 90 %
  Pain 0 % 2 % 0 % 0 % 0 % 4 %
Muscle tenderness intercostal 5/6 right Tenderness 0 % 30 % 3 % 1 % 0 % 89 %
  Pain 0 % 4 % 0 % 0 % 0 % 4 %
Muscle tenderness intercostal 6/7 right Tenderness 0 % 17 % 2 % 2 % 0 % 84 %
  Pain 0 % 5 % 0 % 0 % 0 % 4 %
Tenderness c4/5 paraspinal posterior Yes 3 % 6 % 6 % 1 % 17 % 27 %
Tenderness c5/6 paraspinal posterior Yes 4 % 13 % 11 % 3 % 20 % 26 %
Tenderness c6/7 paraspinal posterior Yes 3 % 13 % 8 % 3 % 12 % 19 %
Tenderness c7/th1 paraspinal posterior Yes 1 % 8 % 18 % 0 % 9 % 21 %
Tenderness th1/2 paraspinal posterior Yes 2 % 14 % 50 % 0 % 20 % 31 %
Tenderness th2/3 paraspinal posterior Yes 3 % 27 % 89 % 0 % 46 % 51 %
Tenderness th3/4 paraspinal posterior Yes 1 % 33 % 78 % 0 % 54 % 61 %
Tenderness th4/5 paraspinal posterior Yes 1 % 38 % 40 % 1 % 59 % 59 %
Tenderness th5/6 paraspinal posterior Yes 1 % 45 % 13 % 0 % 53 % 41 %
Tenderness th6/7 paraspinal posterior Yes 1 % 43 % 1 % 0 % 45 % 35 %
Tenderness th7/8 paraspinal posterior Yes 3 % 27 % 2 % 0 % 26 % 33 %
Tenderness th8/9 paraspinal posterior Yes 2 % 12 % 0 % 0 % 17 % 25 %
Posterior vertebral springing th1/2 Yes 0 % 8 % 10 % 2 % 4 % 2 %
Posterior vertebral springing th2/3 Yes 1 % 7 % 41 % 11 % 18 % 17 %
Posterior vertebral springing th3/4 Yes 0 % 21 % 51 % 11 % 21 % 26 %
Posterior vertebral springing th4/5 Yes 0 % 15 % 31 % 5 % 18 % 28 %
Posterior vertebral springing th5/6 Yes 0 % 14 % 12 % 0 % 24 % 17 %
Posterior vertebral springing th6/7 Yes 1 % 19 % 2 % 0 % 19 % 11 %
Posterior vertebral springing th7/8 Yes 2 % 12 % 1 % 2 % 14 % 11 %
Posterior vertebral springing th8/9 Yes 5 % 9 % 1 % 0 % 10 % 19 %