Table 1.
Methodological and reporting quality of all studies
| Measures Pertaining to Methodological and Reporting Quality | All (N=602) | Development (n=415) | Validation (n=205) | Update (n=62) |
|---|---|---|---|---|
| Sample size, No. (%) | ||||
| Median (IQR) | 746 (262–3180) | 830 (276–3702) | 633 (261–2328) | 669 (345–3763) |
| 0–250 | 141 (23.4) | 97 (23.4) | 46 (22.4) | 8 (12.9) |
| 251–1500 | 242 (40.2) | 155 (37.3) | 90 (43.9) | 34 (54.8) |
| 1501–5000 | 107 (17.8) | 76 (18.3) | 40 (19.5) | 8 (12.9) |
| >5000 | 112 (18.6) | 87 (21.0) | 29 (14.1) | 12 (19.4) |
| Reference to TRIPOD statement, No. (%) | ||||
| Published before TRIPOD | 203 (33.7) | 150 (36.1) | 58 (28.3) | 18 (29.0) |
| Yes | 56 (9.3) | 36 (8.7) | 24 (11.7) | 0 (0) |
| No | 343 (57.0) | 229 (55.2) | 123 (60.0) | 44 (71.0) |
| Performance aspects, No. (%) | ||||
| Discrimination | 484 (80.4) | 335 (80.7) | 170 (82.9) | 50 (80.6) |
| Calibration | 261 (43.4) | 186 (44.8) | 90 (43.9) | 27 (43.5) |
| Reclassification measures | N.A. | N.A. | N.A. | |
| NRI | 8 (12.9) | |||
| IDI | 4 (6.5) | |||
| Both | 15 (24.2) | |||
| Model derivation method, No. (%) | N.A. | N.A. | N.A. | |
| Conventional regression model | 312 (75.2) | |||
| Machine learning | 59 (14.2) | |||
| Both | 44 (10.6) | |||
| Model presentation, No. (%) | N.A. | N.A. | N.A. | |
| Full regression formula | 120 (28.9) | |||
| Risk score | 71 (17.1) | |||
| Both | 34 (8.2) | |||
| Neither | 190 (45.8) |
Total No. of development, validation, and update studies adds up to more than the original number of included studies (n=602) because studies that combine multiple aims (e.g., development and external validation) were counted in all applicable categories. IDI, integrated discrimination improvement; IQR, interquartile range; N.A., not applicable; NRI, net reclassification index; TRIPOD, Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis.