Demographic characteristics of participants and number of creatinine tests by location and phase of study
| Variables | Year 1 | Year 2 |
| Population* | 478 168 | 481 381 |
| Unique individuals† | 155 127 | 164 777 |
| Age | 61.7 (61.7 to 61.8) | 60.5 (60.5 to 60.6) |
| Male | 54.8% | 54.8% |
| Female | 45.2% | 45.2% |
| Creatinine testing location | ||
| Community inpatient | 4239 | 4807 |
| Community outpatient | 863 | 768 |
| ED/AMU/CDU | 47 200 | 53 769 |
| General practice | 203 580 | 224 103 |
| Hospital inpatient | 80 755 | 82 647 |
| Hospital outpatient | 60 964 | 64 046 |
| Combined community locales | 312 607 | 342 686 |
| Combined inpatient locales | 84 994 | 87 454 |
| Total | 397 601 | 430 140 |
Age=mean (95% CI).
*Population derived from Office for National Statistics Clinical Commissioning Group population estimates.20
†Number of unique individuals across both study years: 228 903.
ED/AMU/CDU, emergency department, acute medical unit and clinical decision units.