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Table 1 Patient characteristics in the Get With The Guideline – Stroke after post-stratification weights using raking or Bayesian approach

From: National surveillance of stroke quality of care and outcomes by applying post-stratification survey weights on the Get With The Guidelines-Stroke patient registry

  GWTG Unweighted NIS GWTG Raking Weights GWTG Bayesian Weights Standardized Differences, %
N = 726,390 N = 1,388,295 N = 1,388,295 N = 1,388,296 NIS vs Raking NIS vs Bayesian Raking vs Bayesian
Hospital Characteristics
 *Census divisions      0.0 3.9 3.9
  Division 1 New England 40,284 (5.55) 59,960 (4.32) 59,960 (4.32) 61,260 (4.41)    
  Division 2 Mid-Atlantic 141,026 (19.41) 190,045 (13.69) 190,045 (13.69) 191,365 (13.78)    
  Division 3 East North Central 98,744 (13.59) 215,585 (15.53) 215,585 (15.53) 217,076 (15.64)    
  Division 4 West North Central 41,280 (5.68) 90,955 (6.55) 90,955 (6.55) 83,707 (6.03)    
  Division 5 South Atlantic 159,799 (22.00) 303,745 (21.88) 303,745 (21.88) 314,341 (22.64)    
  Division 6 East South Central 39,350 (5.42) 114,565 (8.25) 114,565 (8.25) 107,499 (7.74)    
  Division 7 West South Central 66,934 (9.21) 158,475 (11.42) 158,475 (11.42) 160,105 (11.53)    
  Division 8 Mountain 37,864 (5.21) 72,795 (5.24) 72,795 (5.24) 66,735 (4.81)    
  Division 9 Pacific 101,109 (13.92) 182,170 (13.12) 182,170 (13.12) 186,208 (13.41)    
*Hospital ownership      0.0 5.6 5.6
 Government 73,541 (10.12) 165,400 (11.91) 165,400 (11.91) 142,585 (10.27)    
 Private, Non-Profit 579,983 (79.84) 1,034,510 (74.52) 1,034,510 (74.52) 1,063,608 (76.61)    
 Private, Investor-Owned 72,866 (10.03) 188,385 (13.57) 188,385 (13.57) 182,102 (13.12)    
*Rural/teaching status      0.0 16.0 16.0
 Rural 25,374 (3.49) 142,920 (10.29) 142,920 (10.29) 83,637 (6.02)    
 Urban nonteaching 149,164 (20.53) 476,970 (34.36) 476,970 (34.36) 477,741 (34.41)    
 Urban teaching 551,852 (75.97) 768,405 (55.35) 768,405 (55.35) 826,917 (59.56)    
*Bed Size Categories      0.0 7.4 7.4
 Small 92,088 (12.68) 184,630 (13.30) 184,630 (13.30) 159,846 (11.51)    
 Medium 198,454 (27.32) 379,405 (27.33) 379,405 (27.33) 357,012 (25.72)    
 Large 435,848 (60.00) 824,260 (59.37) 824,260 (59.37) 871,437 (62.77)    
Primary Stroke Center 509,534 (70.15) N/A 941,419 (67.81) 953,966 (68.71) 1.9
Comprehensive Stroke Center 110,333 (15.19) N/A 149,156 (10.74) 179,012 (12.89) 6.7
Number of Beds, Median (IQR) 374 (243–581) N/A 302 (195–464) 350 (205–532) 9.8
Annual Volume of IS Admissions, Median (IQR) 243 (166–382) N/A 208 (143–318) 228 (143–361) 8.2
Patient Characteristics
 Age      2.4 1.5 0.8
  Mean (SD) 70.49 (14.57) 70.61 (14.10) 70.47 (20.02) 70.29 (20.11)    
Age category        0.8
  ≤ 60 184,201 (25.36) 339,800 (24.48) 350,934 (25.28) 356,665 (25.69)    
 61–70 160,447 (22.09) 302,770 (21.81) 309,032 (22.26) 309,064 (22.26)    
 71–80 169,763 (23.37) 328,650 (23.67) 327,235 (23.57) 326,584 (23.52)    
  > 80 211,979 (29.18) 417,075 (30.04) 401,094 (28.89) 395,981 (28.52)    
 Female 368,770 (50.77) 714,159 (51.44) 704,825 (50.77) 701,281 (50.51) 1.3 1.9 0.5
*Race/Ethnicity      0.0 4.6 4.6
 White 506,456 (69.72) 925,390 (66.66) 925,390 (66.66) 923,221 (66.50)    
 Black 124,170 (17.09) 217,450 (15.66) 217,450 (15.66) 214,227 (15.43)    
 Hispanic 46,836 (6.45) 98,615 (7.10) 98,615 (7.10) 99,818 (7.19)    
 Asian & Pacific Islander 22,425 (3.09) 34,935 (2.52) 34,935 (2.52) 45,134 (3.25)    
 Other 26,503 (3.65) 111,905 (8.06) 111,905 (8.06) 105,896 (7.63)    
Insurance      13.1 14.3 1.7
 Private/VA/Champus/Other Insurance 140,727 (23.12) 256,085 (19.01) 259,132 (22.47) 268,964 (23.02)    
 Medicaid 39,428 (6.48) 104,045 (7.72) 71,336 (6.19) 73,610 (6.30)    
 Medicare 388,813 (63.88) 917,520 (68.10) 741,833 (64.32) 741,999 (63.51)    
 Self Pay/No Insurance 39,722 (6.53) 69,685 (5.17) 81,042 (7.03) 83,748 (7.17)    
Stroke Admission Year
 2012 220,387 (30.34) 452,240 (32.58) 452,240 (32.58) 452,240 (32.58)    
 2013 242,633 (33.40) 460,400 (33.16) 460,400 (33.16) 460,400 (33.16)    
 2014 263,370 (36.26) 475,655 (34.26) 475,655 (34.26) 475,655 (34.26)    
Medical History
 Atrial Fibrillation/Flutter 172,120 (23.76) 343,981 (24.78) 318,990 (23.05) 320,231 (23.14) 4.0 3.8 0.2
 Previous Stroke/TIA 222,336 (30.99) N/A 429,240 (31.31) 423,422 (30.94) 0.8
 CAD/Prior Myocardial Infarction 176,850 (24.65) 378,739 (27.28) 341,816 (24.93) 339,277 (24.79) 5.4 5.7 0.3
 Diabetes Mellitus 243,745 (33.97) 553,176 (39.85) 473,934 (34.57) 469,364 (34.29) 10.9 11.5 0.6
 Peripheral Vascular Disease 33,481 (4.67) 142,639 (10.27) 64,133 (4.68) 64,556 (4.72) 21.4 21.2 0.2
 Hypertension 548,231 (76.41) 1,149,625 (82.81) 1,049,345 (76.54) 1,043,025 (76.21) 15.6 16.4 0.8
 Smoker 133,412 (18.59) 433,520 (31.23) 258,994 (18.89) 259,894 (18.99) 28.8 28.5 0.3
 Dyslipidemia 325,549 (45.37) 797,295 (57.43) 615,319 (44.88) 613,296 (44.81) 25.3 25.4 0.1
 Heart Failure 66,449 (9.26) 199,810 (14.39) 125,027 (9.12) 126,046 (9.21) 16.4 16.1 0.3
 Prosthetic Heart Valve 9147 (1.27) 20,590 (1.48) 16,757 (1.22) 17,899 (1.31) 2.3 1.5 0.8
 Obesity/Overweight 84,405 (11.76) 151,915 (10.94) 148,136 (10.80) 159,219 (11.63) 0.4 2.2 2.6
 Chronic Renal Insufficiency 40,204 (5.60) 200,960 (14.48) 74,183 (5.41) 74,472 (5.44) 30.6 30.5 0.1
Vital and Laboratory Measurements
 SBP mmHg, Mean (SD) 157.02 (30.09) N/A 157.51 (41.69) 157.35 (41.69) 0.4
 BMI, Median (IQR) 27.2 (23.8–31.6) N/A 27.3 (23.8–31.7) 27.3 (23.8–31.6) 0.0
 HbA1c, % Mean (SD) 6.71 (1.89) N/A 6.77 (2.57) 6.74 (2.6) 1.4
 Blood Glucose mg/dL, Mean (SD) 142.48 (70.78) N/A 143.65 (99.06) 143.42 (99.34) 0.3
 Serum Creatinine mg/dL, Median (IQR) 1 (0.8–1.3) N/A 1 (0.8–1.3) 1 (0.8–1.3) 0.2
Arrival Information
 Arrival Mode: EMS 328,713 (49.63) N/A 615,016 (48.88) 608,291 (48.43) 0.9
Ambulatory Status at Admission      0.7
 Unable to ambulate 140,461 (32.84) N/A 258,705 (31.75) 261,489 (31.79)    
 With assistance from person 117,069 (27.37) N/A 228,196 (28.01) 232,655 (28.28)    
 Able to ambulate independently 170,187 (39.79) N/A 327,796 (40.24) 328,418 (39.93)    
 On-time Arrival (non-holiday weekday 7 am-6 pm) 351,852 (48.44) N/A 680,317 (49.00) 676,280 (48.71) 0.6
Initial NIHSS Score (0–42)      0.5
 Median (IQR) 4 (1–9) N/A 4 (1–9) 4 (1–9)    
 Mean (SD) 6.7 (7.57) N/A 6.63 (10.43) 6.68 (10.41)    
Medications Prior to Admission
 Antiplatelets 315,626 (49.64) N/A 597,965 (49.49) 593,907 (49.15) 0.7
 Anticoagulants 70,885 (15.87) N/A 131,611 (15.49) 132,891 (15.56) 0.2
 Antihypertensives 411,912 (69.26) N/A 778,405 (69.30) 783,141 (69.14) 0.3
 Cholesterol-Reducers 320,192 (44.35) N/A 607,248 (43.98) 600,088 (43.55) 0.9
 Diabetic Medications 156,575 (26.98) N/A 302,257 (27.61) 301,123 (27.37) 0.5
Outcomes
 Length of Stay, (days), Median (IQR) 4 (2–6) 3 (2–6) 4 (2–6) 4 (2–6) 0.8
 Stroke Unit Admission 394,102 (73.18)   710,891 (70.40) 710,406 (69.84) 1.2
Discharge Disposition        0.9
 Home 343,284 (47.26) 679,755 (48.96) 663,414 (47.79) 660,288 (47.56) 2.3 2.7  
 Home Hospice 10,019 (1.38) N/A 19,336 (1.39) 19,701 (1.42)  
 Hospice Facility 22,950 (3.16) N/A 43,410 (3.13) 43,532 (3.14)  
 Acute Care Facility 14,739 (2.03) 40,225 (2.90) 33,304 (2.40) 34,595 (2.49)  
 Other Health Care Facility 297,278 (40.93) 592,875 (42.71) 558,726 (40.25) 558,770 (40.25) 4.9 4.9  
 Left Against Medical Advice 4954 (0.68) 10,720 (0.77) 9644 (0.69) 9459 (0.68)  
 Expired (in-hospital mortality) 32,540 (4.48) 62,430 (4.50) 59,108 (4.26) 60,650 (4.37) 1.2 0.6  
Discharge Disposition - Other Facilities      1.5
 Skilled Nursing Facility 128,134 (43.40) N/A 247,379 (44.57) 243,845 (43.93)    
 Inpatient Rehabilitation Facility 155,283 (52.60) N/A 284,112 (51.19) 286,456 (51.61)    
 Long Term Care Hospital 6322 (2.14) N/A 11,988 (2.16) 12,680 (2.28)    
 Intermediate Care facility 2831 (0.96) N/A 6238 (1.12) 6408 (1.15)    
  1. *Characteristic used to anchor post-stratification weights
  2. GWTG Get With The Guidelines, UW unweighted, W weighted, TIA transient ischemic attack, CAD coronary artery disease, HbA1C hemoglobin A1C, EMS emergency medical services