Table 2. Primary and Secondary Outcomes in a Study of the Effect of Oral Methylprednisolone on Kidney Function Decline in Patients With IgA Nephropathy.
| Outcome | Methylprednisolone (n = 257)a,b | Placebo (n = 246)a,b | Rate difference (95% CI), %b | Hazard ratio (95% CI)c | P valuec | ||
|---|---|---|---|---|---|---|---|
| No. of events | Annual event rate (95% CI), % | No. of events | Annual event rate (95% CI), % | ||||
| Primary | |||||||
| 40% eGFR reduction, kidney failure, or death due to kidney diseased,e | 74 | 7.3 (5.7 to 9.4) | 106 | 12.1 (9.7 to 15.1) | −4.8 (−8.0 to −1.6) | 0.53 (0.39 to 0.72) | <.001 |
| Secondary | |||||||
| 30% eGFR reduction, kidney failure, or all-cause death | 86 | 8.4 (6.7 to 10.6) | 113 | 12.8 (10.3 to 15.8) | −4.4 (−7.7 to −1.0) | 0.56 (0.42 to 0.75) | <.001 |
| 40% eGFR reduction, kidney failure, or all-cause death | 78 | 7.7 (6.1 to 9.8) | 106 | 12.2 (9.8 to 15.2) | −4.5 (−7.7 to −1.2) | 0.56 (0.42 to 0.76) | <.001 |
| 50% eGFR reduction, kidney failure, or all-cause death | 71 | 7.0 (5.5 to 9.1) | 94 | 10.8 (8.6 to 13.7) | −3.8 (−6.9 to −0.7) | 0.62 (0.46 to 0.85) | .003 |
| Kidney failure requiring dialysis/transplant | 50 | 4.9 (3.7 to 6.6) | 67 | 7.8 (5.9 to 10.2) | −2.9 (−5.4 to −0.3) | 0.59 (0.40 to 0.87) | .008 |
| eGFR reduction | |||||||
| 30% | 67 | 6.7 (5.2 to 8.7) | 98 | 11.4 (9.1 to 14.3) | −4.7 (−7.8 to −1.6) | 0.47 (0.34 to 0.65) | <.001 |
| 40% | 57 | 5.8 (4.4 to 7.7) | 91 | 10.9 (8.6 to 13.7) | −5.0 (−8.0 to −2.0) | 0.44 (0.31 to 0.62) | <.001 |
| 50% | 49 | 5.0 (3.7 to 6.7) | 76 | 9.1 (7.0 to 11.7) | −4.1 (−6.8 to −1.3) | 0.52 (0.36 to 0.74) | <.001 |
| Death due to kidney failuref | 1 | 0 | 1 | 0 | 0 | NA | NA |
| Death due to any cause | 6 | 0.5 (0.2 to 1.3) | 3 | 0.3 (0.1 to 1.0) | 0.2 (−0.4 to 0.8) | 2.62 (0.53 to 13.05) | .24 |
| Rate of eGFR decline, mL/min/1.73 m2/y | Mean (95% CI)g | Mean difference (95% CI)g | P valueg | ||||
| Using all visits | −2.50 (−3.56 to −1.44) | −4.97 (−6.07 to −3.87) | 2.46 (0.94 to 3.99) | .002 | |||
| Excluding values from those receiving high-exposure treatment | −2.18 (−3.16 to −1.20) | −4.94 (−6.01 to −3.87) | 2.76 (1.32 to 4.21) | <.001 | |||
| Excluding values from those receiving treatment | −2.11 (−3.03 to −1.20) | −4.76 (−5.81 to −3.72) | 2.65 (1.27 to 4.03) | <.001 | |||
| Time-averaged proteinuria, g/d | 1.70 (1.54 to 1.86) | 2.39 (2.15 to 2.63) | −0.69 (−0.98 to −0.41) | <.001 | |||
Median (IQR) follow-up was 3.5 (2.4-6.2) years.
Yearly event rates (per 100 patients) and rate differences were obtained from a Poisson model adjusted for the stratification factors as fixed effects but without site as a random effect.
Hazard ratios and corresponding P values were obtained from a Cox model adjusted for stratification factors as fixed effects and site as a random effect.
Persistent ≥40% estimated glomerular filtration rate (eGFR) reduction was confirmed by a repeated reading at least 30 days later.
Kidney failure requiring maintenance dialysis or kidney transplant.
Too few events to derive CIs, estimates of effect, and P values.
Means, mean differences, and corresponding P values were obtained from a linear model adjusted for stratification factors as fixed effects and site as a random effect. Yearly event rates (per 100 patients) and rate differences were obtained from a Poisson model adjusted for site as a random effect and proteinuria, eGFR, and kidney biopsy findings as fixed effects.