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Table 1 Quality assessment of prognostic models

From: Systematic review of prognostic models in traumatic brain injury

INTERNAL VALIDITY All models Logistic regression Other analysis
  N:66 N:31 N:35
STUDY    
Loss to follow-up    
   < 10% 10 (15%) 5 (16%) 5 (14%)
   >10% 19 (29%) 7 (23%) 12 (34%)
   Not reported 37 (56%) 19(61%) 18 (52%)
VARIABLES    
Discussion about predictors    
   Yes 21(32%) 11 (35%) 10(29%)
   No 45(68%) 20 (65%) 25 (71%)
Description of measurement of predictors    
   Yes 12 (18%) 8 (26%) 3 (9%)
   No 54 (82%) 23(74%) 32 (91%)
Validity of outcome reported    
   Yes 31 (47%) 14 (45%) 17(49%)
   No 20 (30%) 7 (23%) 13 (37%)
   Not applicable 15(23%) 10 (32%) 5 (14%)
Handling of missing data    
   Estimated statistically 4 (6%) 4 (13%) 0
   Excluded 36(55%) 16(52%) 20 (57%)
   Not reported 26(39%) 11(35%) 15 (43%)
ANALYSIS    
Multivariable analysis Stepwise    
   Backwards - 12 (39%) N/A
   Forwards - 3 (10%)  
   Not specified - 10 (32%)  
Not reported - 5 (16%)  
Other - 1 (3%)  
Interactions examined    
   Yes - 4 (13%)  
   Not reported - 27 (87%)  
Handling of predictors variables    
   Continuous - 6 (19%)  
   Categorical - 16 (52%)  
   Not clear - 9 (29%)  
More than 10 events per variable    
   Yes - 9 (29%)  
   No - 16 (52%)  
   Not reported - 6 (19%)  
EXTERNAL VALIDITY All models Logistic regression Other analysis
Description of the sample    
   Yes 55 (83%) 28 (90%) 27 (77%)
   No 11(17%) 3 (10%) 8 (23%)
Presentation of the prognostic model    
   Normogram 1 (1%) 1 (3%) 0
   Simplified score 8 (12%) 4 (13%) 4 (11%)
   Figure 13 (20%) 1 (3%) 12 (34%)
   Regression formula 15 (23%) 12(39%) 3 (9%)
   Not explained 29 (44%) 13(42%) 16 (46%)
EXTERNAL VALIDITY All models Logistic regression Other analysis
  N:66 N:31 N:35
Performance reported A.U.C (Discrimination)    
   Yes - 18 (58%) NA
   No - 13(42%)  
   C.I. presented - 8 out of 18 (44%)  
H-L (Calibration)    
   Yes - 7 (23%) NA
   No - 23(74%)  
   Other - 1 (3%)  
Overall accuracy    
   Yes 37 (56%) 15 (48%) 22 (63%)
   No 29 (44%) 16 (52%) 13 (17%)
Validation    
   Yes 25 (38%) 17 (55%) 8 (23%)
   External 7 (11%) 7 (23%) 0
   No 41 (62%) 14 (45%) 27 (77%)