Table 2.

Analysis of factors to explain heterogeneity between studies with respect to predialysis BPa

nSBPDBP
Bias95% CISDDQBias95% CISDDQ
Selection bias
    yes (7)2805.73.8 to 7.616.070.73.11.9 to 4.410.539.8
    no (11)41210.38.6 to 1217.369.21.90.8 to 2.910.762.2
Diabetes
    yes (12)4718.26.7 to 9.716.696.72.51.6 to 3.510.351
    no (6)2218.46.2 to 10.717.13312.00.47 to 3.511.641
ABPM
    SpaceLabs (11)4329.67.9 to 11.217.241.53.41.3 to 3.411.229.8
    non-SpaceLabs (7)2606.44.5 to 8.416.092.32.51.3 to 3.79.862.1
Dialysis unit BP measurements
    standardized (7)2307.04.6 to 9.418.533.91.5−0.01 to 2.911.456.9
    “routine” (11)4628.87.3 to 10.216.0100.22.81.8 to 3.710.340.2
  • a Bias, difference between dialysis unit BP and ABP; DBP, diastolic BP; Q, Q statistic for heterogeneity, all significant at P < 0.001; SBP, Systolic BP; SDD, SD of the difference.