Mean Baseline GFR (ml/min per 1.73 m^{2}) | Mean Slope (ml/min per 1.73 m^{2} per year) | Total Slope | Total Slope | Chronic Slope | ||||||
---|---|---|---|---|---|---|---|---|---|---|

No Acute Effect | Acute Effect =−1.25 ml/min per 1.73 m^{2} | Acute Effect =−1.25 ml/min per 1.73 m^{2} | ||||||||

Relative Efficiency | Required N for Clinical Outcome in a 4–6 yr RCT^{a} | Relative Efficiency | Required N for Clinical Outcome in a 4–6 yr RCT | Relative Efficiency | Required N for Clinical Outcome in a 4–6 yr RCT^{a} | |||||

Total Slope in 2 yr RCT versus Clinical Outcome in 4–6 yr RCT | Total Slope in 4–6 yr RCT versus Clinical Outcome in 4–6 yr RCT | Total Slope in 2 yr RCT versus Clinical Outcome in 4–6 yr RCT | Total Slope in 4–6 yr RCT versus Clinical Outcome in 4–6 yr RCT | Chronic Slope in 2 yr RCT versus Clinical Outcome in 4–6 yr RCT | Chronic Slope in 4–6 yr RCT versus Clinical Outcome in 4–6 yr RCT | |||||

27.5 | −1.5 | 1.14 | 1.07 | 4980 | 0.37 | 0.41 | 7140 | 1.27 | 0.76 | 7140 |

−3.25 | 1.51 | 1.58 | 2170 | 0.82 | 1.49 | 2190 | 1.29 | 1.81 | 2190 | |

−5.0 | 1.24 | 1.40 | 870 | 1.13 | 1.53 | 960 | 1.32 | 1.77 | 960 | |

42.5 | −1.5 | 0.71 | 1.11 | 4130 | 0.28 | 0.39 | 5010 | 0.71 | 1.68 | 5010 |

−3.25 | 1.41 | 1.71 | 1750 | 0.26 | 1.23 | 1940 | 1.13 | 2.32 | 1940 | |

−5.0 | 1.17 | 1.61 | 830 | 0.64 | 1.59 | 930 | 1.26 | 2.33 | 930 | |

67.5 | −1.5 | 1.06 | 1.83 | 6090 | 0.46 | 0.46 | 8240 | 1.18 | 2.83 | 8240 |

−3.25 | 1.28 | 2.16 | 2480 | 0.16 | 0.69 | 2940 | 1.42 | 3.65 | 2940 | |

−5.0 | 1.63 | 2.42 | 1310 | 0.09 | 1.25 | 1260 | 1.36 | 3.29 | 1260 |

All calculations assume a 25% intermediate long-term effect. Relative efficiencies are given by the ratio of sample size (

*N*) for the clinical end point over 4–6 yr versus the slope analysis over the indicated follow-up period. Relative efficiencies greater than one indicate that a smaller sample size is required to achieve the same statistical power with the slope outcome over the indicated follow-up period compared with the clinical end point over 4–6 yr. See Supplemental Figure 6 for additional detail including simulation SEM.↵a Increases in required

*N*for the clinical end point with baseline GFR=27.5 compared with 42.5 ml/min per 1.73 m^{2}are due to assumptions that the acute effect is smaller at lower GFR levels, a higher proportion of slow progressors reaching clinical events with smaller effect sizes under the intermediate long-term treatment effect model, and larger effects of random error in GFR measurements on end points requiring smaller GFR change.