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Table.1 Select baseline characteristics. The population for randomization included patients on hemodialysis as of April 1, 2013. The trial population included an open cohort of patients receiving in-center hemodialysis on April 1, 2014, or began receiving in-center hemodialysis during the trial period between April 1, 2014, and March 31, 2017

From: Simple compared to covariate-constrained randomization methods in balancing baseline characteristics: a case study of randomly allocating 72 hemodialysis centers in a cluster trial

Baseline characteristic

Value

Population for randomization

Trial population

Centers

Number of centers (n, patients)

72 (n=5812)

72 (n=11,832)

Center Size a

Mean ± standard deviation

81 (69)

164 (137)

15 to 73 patients

42 (58%)

N/A

74 to 131

19 (26%)

132 to 363

11 (15%)

The composite outcome of CV-related death or major CV-related hospitalization b

Historic rate per 100 person-years (cluster standard deviation)

10 (3.7)

11 (3.3)

0.00 to 6.60

11 (15%)

7 (10%)

6.70 to 9.90

14 (19%)

21 (29%)

10.0 to 13.2

26 (36%)

25 (35%)

13.3 to 23.1

21 (29%)

19 (26%)

  1. aPopulation for randomization included patients that were on hemodialysis as of April 1, 2013, index date. The trial population included patients on hemodialysis as of April 1, 2014, and any patient who started in-center hemodialysis at one of the 72 participating centers during the 3-year trial period. Follow-up ended on March 31, 2017. The index date was the first date patients entered the respective cohort. N/A = not applicable because the center’s trial population had an open cohort, so the size was larger by design
  2. bThe composite outcome of cardiovascular-related death or hospitalization for myocardial infarction, ischemic stroke, and congestive heart failure