Table 2.

Metaregression analyses of the association of ESA dose with all-cause and cardiovascular mortality.

Outcome / predictor	No. patients	No. trials	IRR (95% CI)	P
All-cause mortality
First-3-month mean ESA dose
Unadjusted	4565	11	1.42 (1.10–1.83)	0.007
Adjusted for target Hb	4385	10	1.71 (0.90–3.24)	0.1
Adjusted for first-3-month achieved mean Hb	4565	11	1.48 (1.02–2.14)	0.04
Total-study-period mean ESA dose
Unadjusted	11,285	21	1.09 (1.02–1.18)	0.02
Adjusted for target Hb	11,105	21	1.41 (1.08–1.82)	0.01
Adjusted for total-study-period achieved mean Hb	11,285	21	1.27 (0.97–1.65)	0.08
Cardiovascular mortality
First-3-month mean ESA dose
Unadjusted	2085	6	1.31 (0.92–1.86)	0.1
Adjusted for target Hb	1979	5	Not performed*	-
Adjusted for first-3-month achieved mean Hb	2085	6	Not performed*	-
Total-study-period mean ESA dose
Unadjusted	7148	10	1.07 (0.97–1.17)	0.2
Adjusted for target Hb	7042	10	Not performed†	-
Adjusted for total-study-period achieved mean Hb	7148	10	1.38 (0.93–2.03)	0.1

ESA dose is per epoetin alfa--equivalent 10,000-U/wk increment. IRR, incidence rate ratio; CI, confidence interval; Hb, hemoglobin; ESA, erythropoiesis-stimulating agent.

^*The analysis was not performed due to insufficient observations.

^†The analysis was not performed due to collinearity.