Table 1.
Patient characteristics in the Get With The Guideline – Stroke after post-stratification weights using raking or Bayesian approach
| 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) | |||
*Characteristic used to anchor post-stratification weights
GWTG Get With The Guidelines, UW unweighted, W weighted, TIA transient ischemic attack, CAD coronary artery disease, HbA1C hemoglobin A1C, EMS emergency medical services