Table 3 TRIPOD adherence of included studies

Overall (excluding items 5c, 11, 14b, 10c, 10e, 12, 13, 17, and 19a)

481/812 (59.2)

Section 1: Title and Abstract

18/58 (31.0)

 1. Title—identify developing/validating a model, target population, and the outcome

2/29 (6.9)

 2. Abstract—provide a summary of objectives, study design, setting, participants, sample size, predictors, outcome, statistical analysis, results, and conclusions

16/29 (55.2)

Section 2: Introduction

36/58 (62.1)

 3a. Background—Explain the medical context and rationale for developing/validating the model

29/29 (100.0)

 3b. Objective—Specify the objectives, including whether the study describes the development/validation of the model or both

7/29 (24.1)

Section 3: Methods

218/277 (57.8)

 4a. Source of data—describe the study design or source of data (randomized trial, cohort, or registry data)

29/29 (100.0)

 4b. Source of data—specify the key dates

29/29 (100.0)

 5a. Participants—specify key elements of the study setting including number and location of centers

29/29 (100.0)

 5b. Participants—describe eligibility criteria for participants (inclusion and exclusion criteria)

22/29 (75.9)

 5c. Participants—give details of treatment received, if relevant (N = 25)

16/25 (64.0)

 6a. Outcome—clearly define the outcome, including how and when assessed

27/29 (93.1)

 6b. Outcome—report any actions to blind assessment of the outcome

3/29 (10.3)

 7a. Predictors—clearly define all predictors, including how and when assessed

10/29 (34.5)

 7b. Predictors—report any actions to blind assessment of predictors for the outcome and other predictors

4/29 (13.8)

 8. Sample size—explain how the study size was arrived at

3/29 (10.3)

 9. Missing data—describe how missing data were handled with details of any imputation method

6/29 (20.7)

 10a. Statistical analysis methods—describe how predictors were handled

29/29 (100.0)

 10b. Statistical analysis methods—specify type of model, all model-building procedures (any predictor selection), and method for internal validation

21/29 (72.4)

 10d. Statistical analysis methods—specify all measures used to assess model performance and if relevant, to compare multiple models (discrimination and calibration)

6/29 (20.7)

 11. Risk groups—provide details on how risk groups were created, if done (N = 0)

n/a

Section 4: Results

117/174 (67.2)

 13a. Participants—describe the flow of participants, including the number of participants with and without the outcome. A diagram may be helpful

16/29 (55.2)

 13b. Participants—describe the characteristics of the participants, including the number of participants with missing data for predictors and outcome

26/29 (89.7)

 14a. Model development—specify the number of participants and outcome events in each analysis

23/29 (79.3)

 14b. Model development—report the unadjusted association between each candidate predictor and outcome, if done (N = 5)

4/5 (80.0)

 15a. Model specification—present the full prediction model to allow predictions for individuals (regression coefficients, intercept)

21/29 (72.4)

 15b. Model specification—explain how to the use the prediction model (nomogram, calculator, etc.)

11/29 (37.9)

 16. Model performance—report performance measures (with confidence intervals) for the prediction model

20/29 (69.0)

Section 5: Discussion

86/87 (98.9)

 18. Limitations—Discuss any limitations of the study

28/29 (96.6)

 19b. Interpretation—Give an overall interpretation of the results

29/29 (100.0)

 20. Implications—Discuss the potential clinical use of the model and implications for future research

29/29 (100.0)

Section 6: Other information

6/58 (10.3)

 21. Supplementary information—provide information about the availability of supplementary resources, such as study

0/29 (0.0)

 22. Funding—give the source of funding and the role of the funders for the present study

6/29 (20.7))

Section 7: Validation for Model type 2a, 2b, 3, and 4 (N = 16)

32/64 (50.0)

 10c. Statistical analysis methods—describe how the predictions were calculated

15/16 (93.8)

 10e. Statistical analysis methods—describe any model updating (recalibration), if done (N = 0)

n/a

 12. Development versus validation—Identify any differences from the development data in setting, eligibility criteria, outcome, and predictors

10/16 (62.5)

 13c. Participants (for validation)—show a comparison with the development data of the distribution of important variables

2/16 (12.5)

 17. Model updating—report the results from any model updating, if done (N = 0)

n/a

 19a. Interpretation (for validation)—discuss the results with reference to performance in the development data and any other validation data

5/16 (31.3)