1. Missing or not reported data per variable, in order of percentage missing.
| Missing in ESA arm | Missing in control arm | |
| Total included | 7634 | 6299 |
| Sex | 0 | 0 |
| Age | 6 (0.1%) | 6 (0.1%) |
| Tumor type* | 17 (0.2%) | 25 (0.4%) |
| Region (country) | 231 (3.0%) | 170 (2.7%) |
| Hb at baseline | 252 (3.3%) | 274 (4.3%) |
| Cancer stage at study entry (free text entry) | 761 (10.0%) | 732 (11.6%) |
| Derived variable stage (metastatic/advanced versus not) | 1036 (13.6%) | 745 (11.8%) |
| Hct at baseline | 1493 (19.6%) | 1404 (22.3%) |
| Chemotherapy given during ESA study? | 1501 (19.7%) | 1252 (19.9%) |
| BMI baseline | 1515 (19.8%) | 973 (15.4%) |
| Documented history of cardiovascular event | 1932 (25.3%) | 1679 (26.7%) |
| Chemotherapy given before ESA study? | 1965 (25.7%) | 1736 (27.6%) |
| Baseline ECOG performance status** | 2035 (26.7%) | 1786 (28.4%) |
| Radiotherapy given during ESA study? | 2097 (27.5%) | 1766 (28.0%) |
| Documented history of thromboembolic events | 2272 (29.8%) | 2041(32.4%) |
| Documented history of hypertension | 2272 (29.8%) | 2041 (32.4%) |
| Radiotherapy given before esa study? | 2529 (33.1%) | 2216 (35.2%) |
| Documented history of diabetes mellitus | 3335 (43.7%) | 2573 (40.8%) |
| Baseline serum epo (mu/ml) | 4371 (57.3%) | 3911 (62.1%) |
| Cancer treatment status at study entry | 5366 (70.3%) | 4613 (73.2%) |
| Cancer stage at study entry | 6123 (80.2%) | 5069 (80.5%) |
*For an independent study we received tumor types based on French pathology terms. To date we have not transferred these data into the uniform coding system developed and used for the present study, the data of that study are coded as “other” for the time being.
**Baseline ECOG status: If other performance score systems such as Karnofsky scores were reported these were used for the analysis but are counted as missing for the present table.