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Table 1 Characteristics of U.S. patients initiating peritoneal dialysis from 2007 to 2011 with Medicare Part D coverage

From: Renin-angiotensin system blockers and residual kidney function loss in patients initiating peritoneal dialysis: an observational cohort study

  Full cohort IPTW Cohort
Variable Non-users
N = 497
ACEI/ARB users
N = 389
Std. diff. Non-users ACEI/ARB users Std. diff.
Demographics
 Age (yr, mean ± SD) 67 ± 14 64 ± 13 0.22 66 ± 19 65 ± 19 0.05
 Male sex 56 56 0.00 56 57 0.02
 Race
  Black 16 17 0.03 16 16 0.00
  White 79 76 0.07 78 77 0.02
  Other 5 7 0.08 6 7 0.04
 Hispanic ethnicity 10 16 0.18 12 12 0.00
 Medicaid at time of dialysis initiation 26 34 0.18 28 28 0.00
Reported comorbidities
 Cancer 11 6 0.18 9 8 0.04
 Cardiac disease, othera 21 20 0.02 20 22 0.05
 Cerebrovascular disease 9 11 0.07 9 9 0.00
 Coronary artery disease 21 23 0.05 21 22 0.02
 Diabetes mellitus 55 64 0.18 60 58 0.04
 Heart failure 29 25 0.09 28 28 0.00
 Hyperkalemia 3 3 0.00 3 3 0.00
 Hyperlipidemia 18 18 0.00 18 18 0.00
 Hypertension 92 96 0.17 93 94 0.04
 Liver disease 2 1 0.08 1 2 0.08
 Peripheral vascular disease 15 16 0.03 15 15 0.00
 Pulmonary disease 15 13 0.06 14 14 0.00
 Tobacco use 7 7 0.00 7 7 0.00
 Days hospitalized in in the first 90 days of dialysis (median, IQR) 0 (0–0) 0 (0–0) 0.00 0 (0–0) 0 (0–0) 0.00
Baseline medication use
 ACEI or ARB
  ACEI 0 65 NA 0 65 NA
  ARB 0 42 NA 0 41 NA
  Both 0 6 NA 0 6 NA
 Beta blocker 63 61 0.04 63 62 0.02
 Calcium channel blocker 46 64 0.37 54 57 0.06
 Diuretic 56 66 0.21 61 59 0.04
 Other antihypertensiveb 40 48 0.16 43 44 0.02
 Statin 49 61 0.24 54 56 0.04
 Clopidogrel 12 13 0.03 13 14 0.03
 Warfarin 10 6 0.15 9 8 0.04
 Other cardiovascular medc 19 25 0.15 21 23 0.05
 Levothyroxine 17 18 0.03 18 18 0.00
Dialysis characteristics
 Saw nephrologist prior to dialysis initiation 88 88 0.00 87 89 0.06
 Year initiated dialysis
  2007 14 18 0.11 15 16 0.03
  2008 17 21 0.10 18 21 0.08
  2009 15 18 0.08 17 16 0.03
  2010 29 25 0.09 28 27 0.02
  2011 25 18 0.17 22 20 0.05
 CAPD (vs. CCPD) 32 40 0.17 35 36 0.02
Vital signs and laboratory measurements
 BMI (mean ± SD)d 28.3 ± 6 29.0 ± 6.4 0.11 28.4 ± 8 28.8 ± 9.7 0.04
 Hemoglobin (g/dL, mean ± SD) 10.7 ± 1.4 10.9 ± 1.5 0.14 10.7 ± 1.9 10.9 ± 2.2 0.10
 Albumin (g/dL, mean ± SD) 3.8 ± 0.5 3.8 ± 0.5 0.00 3.8 ± 0.6 3.8 ± 0.8 0.00
 Baseline rGFR (ml/min, mean ± SD) 8.4 ± 4.8 8.5 ± 4.7 0.02 8.3 ± 6.3 8.6 ± 7.2 0.07
 24 h urine volume (ml, median, IQR) 900 (550–1400) 1000 (600–1500) 0.07 850 (600–1400) 900 (600–1400) 0.01
Facility characteristics
 Number of PD patients (median, IQR)e 24 (14–39) 25 (14–39)   24 (14–39) 25 (14–39)  
  ≥20 62 65 0.06 62 62 0.00
 Ruralf 14 15 0.03 15 15 0.00
 Geographic location (U.S. census division)g
  East North Central 12 13 0.03 13 12 0.03
  East South Central 7 8 0.04 8 7 0.04
  Middle Atlantic 8 6 0.08 7 8 0.04
  Mountain 5 3 0.10 4 5 0.05
  New England 5 3 0.10 5 3 0.10
  Pacific 10 16 0.18 13 14 0.03
  South Atlantic 29 27 0.04 28 27 0.02
  West North Central 10 8 0.07 10 10 0.00
  West South Central 13 15 0.06 13 14 0.03
  1. All numbers are percentages unless indicated otherwise. ACEI angiotensin-converting enzyme inhibitor, ARB angiotensin-II receptor blocker, BMI body mass index, CAPD continuous ambulatory peritoneal dialysis, CCPD continuous cycling peritoneal dialysis, eGFR estimated glomerular filtration rate, IQR interquartile range, IPTW inverse probability of treatment weighted, PD peritoneal dialysis, SD standard deviation, Std. Diff. standardized difference
  2. aIncludes atrial fibrillation, arrhythmias, implanted cardiac defibrillators, pacemakers, and valvular disease
  3. bIncludes alfuzosin, aliskiren, clonidine, doxazosin, guanfacine, hydralazine, isosorbide, methyldopa, minoxidil, prazosin, ranolazine, and terazosin
  4. cIncludes ezetimibe, simvastatin, niacin, amiodarone, aspirin/dipyridamole, colesevelam, colestipol, digoxin, dipyridamole, dronedarone, fenofibrate, flecainide, gemfibrozil, mexiletine, nitroglycerin, omega-3 acid ethyl esters, procainamide, propafenone, and quinidine
  5. dMissing for 11% of non-users and 1% of users
  6. eBased on the year the patient initiated dialysis
  7. fFacilities were considered urban if they were classified as a metropolitan area in the Rural–Urban Commuting Area (RUCA) Codes version 2.0, which are based on 2000 Census commuting data and 2004 zip codes; all other areas were considered to be rural [24]
  8. gFacilities were categorized into one of nine U.S. Census Bureau Divisions based on their state [25]