Table 2.
Summary statistics of eGFRs from a series of two-year moving intervals
| CKD stage | Early 3 | Late 3 | Stage 4 | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Two-year moving interval | |||||||||||||||||||
| (−1,0) | (0,1) | (1,2) | (2,3) | (3,4) | All | (−1,0) | (0,1) | (1,2) | (2,3) | (3,4) | All | (−1,0) | (0,1) | (1,2) | (2,3) | (3,4) | All | ||
| eGFR | |||||||||||||||||||
| Variables | |||||||||||||||||||
| Variability | median | 6.0 | 6.2 | 5.7 | 5.3 | 5.3 | 5.8 | 5.5 | 5.7 | 4.8 | 4.4 | 4.4 | 5.1 | 4.6 | 4.6 | 3.4 | 3.1 | 3.2 | 4.0 |
| (SD) | Q1 | 3.8 | 4.4 | 4.1 | 3.7 | 3.6 | 4.0 | 3.5 | 3.8 | 3.4 | 3.0 | 2.9 | 3.4 | 2.8 | 3.0 | 2.4 | 2.0 | 2.1 | 2.6 |
| Q3 | 8.6 | 8.6 | 7.7 | 7.5 | 7.6 | 8.1 | 8.8 | 8.4 | 6.8 | 6.2 | 6.3 | 7.5 | 7.9 | 7.1 | 5.0 | 4.6 | 4.8 | 6.5 | |
| IQR | 4.8 | 4.2 | 3.6 | 3.8 | 4.0 | 4.1 | 5.3 | 4.6 | 3.4 | 3.2 | 3.4 | 4.1 | 5.1 | 4.1 | 2.6 | 2.6 | 2.7 | 3.9 | |
| Mean | median | 56.4 | 55.0 | 52.8 | 52 | 49.9 | 54.1 | 43.4 | 41.7 | 39.3 | 38.8 | 37.6 | 41.0 | 29.0 | 27.1 | 25.3 | 25.7 | 25.8 | 27.2 |
| Q1 | 51.9 | 50.5 | 47.7 | 45.8 | 43.3 | 48.8 | 38.5 | 37.0 | 34.3 | 33.0 | 31.3 | 35.7 | 24.6 | 22.9 | 20.8 | 20.9 | 20.7 | 22.7 | |
| Q3 | 60.9 | 59.2 | 57.6 | 58 | 56.7 | 59.1 | 48.7 | 46.5 | 44.2 | 44.8 | 44.2 | 46.3 | 34.2 | 31.4 | 29.7 | 31.1 | 31.8 | 32.2 | |
| IQR | 9.0 | 8.7 | 9.9 | 12.2 | 13.4 | 10.3 | 10.2 | 9.5 | 9.9 | 11.8 | 12.9 | 10.6 | 9.6 | 8.5 | 8.9 | 10.2 | 11.1 | 9.5 | |
| Coefficient of variation | median | 10.7 | 11.4 | 10.8 | 10.4 | 10.9 | 10.9 | 13.1 | 13.8 | 12.5 | 11.5 | 11.8 | 12.8 | 16.3 | 17.5 | 14.5 | 12.4 | 12.7 | 15.4 |
| Q1 | 7.1 | 8.2 | 7.7 | 7.1 | 7.2 | 7.5 | 8.7 | 9.7 | 8.8 | 7.8 | 8.0 | 8.7 | 10.9 | 12.0 | 10.1 | 8.5 | 8.6 | 10.5 | |
| Q3 | 14.9 | 15.6 | 14.9 | 14.8 | 15.7 | 15.1 | 18.9 | 19.4 | 17.4 | 16.3 | 17.2 | 18.1 | 24.3 | 25.1 | 20.2 | 17.6 | 17.8 | 22.5 | |
| IQR | 7.8 | 7.4 | 7.2 | 7.7 | 8.5 | 7.6 | 10.2 | 9.7 | 8.6 | 8.5 | 9.2 | 9.4 | 13.4 | 13.1 | 10.1 | 9.1 | 9.2 | 12.0 | |
| Slope | median | −3.6 | −2.7 | −1.3 | −1.5 | −1.2 | −2.2 | −5.9 | −3.7 | −1 | −1.5 | −1.2 | −2.8 | −6.8 | −4.2 | −1.1 | −1.4 | −1.2 | −3.5 |
| Q1 | −9.3 | −6.9 | −5.1 | −5.9 | −4.6 | −6.6 | −13 | −8.1 | −4.4 | −5.2 | −4 | −7.5 | −14 | −8.3 | −3.7 | −3.9 | −3.2 | −8.2 | |
| Q3 | 0.8 | 0.9 | 2.7 | 2.5 | 2 | 1.7 | −0.8 | −0.1 | 2.7 | 1.9 | 1.6 | 0.8 | −2.4 | −1.3 | 1.9 | 1.2 | 0.8 | −0.3 | |
| IQR | 10.1 | 7.8 | 7.8 | 8.4 | 6.6 | 8.3 | 12.2 | 8.0 | 7.1 | 7.1 | 5.6 | 8.3 | 11.6 | 7.0 | 5.6 | 5.1 | 4.0 | 7.9 | |
CKD: Chronic Kidney Disease; For two-year moving interval, 0 denotes the baseline year, −1 denotes the year prior to the baseline, and 1 to 4 denote the number of years in the follow-up period. eGFR: estimated Glomerular Filtration Rate. SD: standard deviation of an individual patient’s repeatedly measured eGFR values from a two-year interval. Q1: 1st quartile. Q3: 3rd quartile. IQR: Inter-Quartile Range (=Q3 minus Q1). The unit for the eGFR slope variable is ml/min/1.73 m2/year.