Table 4.

The extent of within-center correlation (ρ) and proportion of variation, R2, in dialysis adequacy explained by facility- and individual-level factors in Network 5 Study

ρ95% CIR2
aP < 0.001.
Unadjusted
facilities in total data set (n = 189)0.16(0.13, 0.19)a18.9%a
facilities in reduced data set (n = 149)0.20(0.15, 0.23)a23.6%a
facilities in reduced data set with random data0.00(0.00, 0.00)0%
Covariates
case-mix covariates12.3%a
dialysis-specific covariates11.3%a
Adjusted for case-mix and dialysis covariates
all facilities in reduced data set0.14(0.11, 0.18)a37.8%a
facilities by method and time of post-BUN measurement
sampling with slow flow method (n = 61)0.13(0.08, 0.20)a40.5%a
sampling <1 min postdialysis (n = 31)0.10(0.04, 0.18)a34.1%a
sampling >1 min postdialysis (n = 38)0.18(0.11, 0.28)a39.7%a
unknown postdialysis sampling time (n = 19)0.08(0.03, 0.18)a30.8%a