Table 3.

Crude incidence rate of ESRD and (a) combined renal end point, and (b) according to serum phosphate quartiles and study arms (Ramipril versus placebo)

(a) Incidence rate of end stage renal disease (ESRD)
Crude Incidence Rate of ESRD Occurrence (events/100 person-years)*Crude Hazard Ratio, 95% CI, and P-value (Ramipril versus placebo)
Placebo groupRamipril group
First two quartiles (<3.45 g/dl)6.9 (4.0–11.2)0.42 (0.01–2.4)0.13 (0.04–0.39), P < 0.0001
Third quartile (3.45–4.00 mg/dl)13.8 (7.6–23.2)6.5 (3.0–12.3)0.32 (0.18–0.59), P < 0.001
Fourth quartile (> 4.00 mg/dl)26.8 (16.1–41.7)20.7 (11.6–34.2)0.82 (0.44–1.55), P = 0.54
P for effect modification = 0.008
(b) Incidence rate of the combined renal end point (ESRD and doubling of serum creatinine)
Crude Incidence Rate of Renal Outcomes (events/100 person-years)*Crude Hazard ratio, 95% CI, and P-value (Ramipril versus placebo)
Placebo groupRamipril group
First two quartiles (<3.45 g/dl)8.8 (5.3–13.7)1.3 (0.3–3.8)0.15 (0.06–0.39), P < 0.0001
Third quartile (3.45–4.00 mg/dl)18.6 (10.8–29.7)6.7 (3.1–12.7)0.37 (0.22–0.62), P < 0.001
Fourth quartile (> 4.00 mg/dl)27.9 (16.8–43.8)25.2 (14.7–40.4)0.90 (0.49–1.66), P = 0.73
P for effect modification = 0.004
  • Data are incidence rate and 95% confidence intervals.

  • *The crude hazard ratios of Ramipril treatment for study outcomes across serum phosphate quartiles were derived by Cox models including Ramipril treatment, serum phosphate strata, and their interaction term.