Table 1.
Overall characteristics by subphenotype.
| Features | Subphenotype 1 (n=4417) | Subphenotype 2 (n=9165) | Subphenotype 3 (n=9580) | Subphenotype 4 (n=3866) | Total (n=27,028) | P value | ||
| Beneficiary-level demographics | ||||||||
| Sex, n (%) | ||||||||
| Male | 2080 (47.1) | 5577 (60.9) | 6057 (63.2) | 2483 (64.2) | 16,197 (59.9) | <.001 | ||
| Female | 2337 (52.9) | 3588 (39.1) | 3523 (36.8) | 1383 (35.8) | 10,831 (40.1) | |||
| Age category (years), n (%) | ||||||||
| 65–74 | 2310 (52.3) | 4414 (48.2) | 4810 (50.2) | 2173 (56.2) | 13,707 (50.7) | <.001 | ||
| 75–84 | 1344 (30.4) | 3169 (34.5) | 3321 (34.7) | 1331 (34.4) | 9165 (33.9) | |||
| ≥85 | 763 (17.3) | 1582 (17.3) | 1449 (15.1) | 362 (9.4) | 4156 (15.4) | |||
| Race, n (%) | ||||||||
| Black | 2631 (59.6) | 448 (4.9) | 504 (5.3) | 472 (12.2) | 4055 (15) | <.001 | ||
| White | 1327 (30) | 8234 (89.8) | 8729 (91.1) | 3117 (80.6) | 21,407 (79.2) | |||
| Other | 459 (10.4) | 483 (5.3) | 347 (3.6) | 277 (7.2) | 1566 (5.8) | |||
| Elixhauser Comorbidity Index, median (IQR) | 14.000 (4.000–23.000) | 13.000 (4.000–23.000) | 14.000 (4.000–24.000) | 14.000 (4.000–24.000) | 13.000 (4.000–23.000) | <.001 | ||
| Beneficiary-level hospital procedures and dispositions | ||||||||
| Cardiac catheterization at index hospitalization, n (%) | 843 (19.1) | 1767 (19.3) | 2937 (30.7) | 1342 (34.7) | 6889 (25.5) | <.001 | ||
| Implantable cardioverter defibrillator placement at index hospitalization, n (%) | 351 (7.9) | 653 (7.1) | 1192 (12.4) | 347 (9) | 2543 (9.4) | <.001 | ||
| Interhospital transfer at index hospitalization, n (%) | 107 (2.4) | 6 (0.1) | 11 (0.1) | 3849 (99.6) | 3973 (14.7) | <.001 | ||
| From skilled nursing facility prior to index OHCAa hospitalization, n (%) | 559 (12.7) | 531 (5.8) | 828 (8.6) | 226 (5.8) | 2144 (7.9) | <.001 | ||
| Inpatient hospital stay prior to index OHCA, n (%) | 114 (2.6) | 120 (1.3) | 285 (3) | 155 (4) | 674 (2.5) | <.001 | ||
| Discharged to skilled nursing facility after index OHCA, n (%) | 879 (19.9) | 981 (10.7) | 1594 (16.6) | 1412 (36.5) | 4866 (18) | <.001 | ||
| Total hospital length of stay in days, median (IQR) | 5.000 (1.000–12.000) | 5.000 (1.000–12.000) | 5.000 (1.000–12.000) | 5.000 (1.000–12.000) | 5.000 (1.000–12.000) | <.001 | ||
| Total number of interhospital transfers mean (SD) | 0.024 (0.156) | 0.001 (0.026) | 0.001 (0.034) | 1.135 (0.362) | 0.167 (0.424) | <.001 | ||
| Travel distance to index OHCA hospital from residence (kilometers), n (%) | ||||||||
| <8.0 | 2566 (58.1) | 6049 (66) | 73 (0.8) | 1510 (39.1) | 10,198 (37.7) | <.001 | ||
| 8.0-16.1 | 1182 (26.8) | 2639 (28.8) | 1328 (13.9) | 851 (22) | 6000 (22.2) | <.001 | ||
| >16.1 | 669 (15.1) | 477 (5.2) | 8179 (85.4) | 1505 (38.9) | 10,830 (40.1) | <.001 | ||
| Hospital-level characteristics, n (%) | ||||||||
| Minor academic teaching | 1406 (31.8) | 471 (5.1) | 1541 (16.1) | 431 (11.1) | 3849 (14.2) | <.001 | ||
| Major academic teaching | 3011 (68.2) | 8694 (94.9) | 8039 (83.9) | 3435 (88.9) | 23,179 (85.8) | <.001 | ||
| Total number of bedsb, median (IQR) | 7.000 (5.000–8.000) | 5.000 (4.000–6.000) | 6.000 (4.000–8.000) | 5.000 (4.000–7.000) | 5.000 (4.000–7.000) | <.001 | ||
| Area-level social determinants of health | ||||||||
| Household income (US $) at zip code level, median (IQR) | $36,462 ($29,648-$45,309) | $54,375 ($44,320-$72,394) | $50,818 ($41,825.50-$63,549.25) | $51,659.50 ($41,295-$67,081) | $49,720.50 ($39,893.25-$64,233.25) | <.001 | ||
| Percentage unemployed at zip code level, median (IQR) | 8.4 (6.8–10.4) | 5 (3.9–6.2) | 5.15 (4–6.6) | 5.5 (4.2–7.1) | 5.5 (4.2–7.2) | <.001 | ||
| Percentage below poverty level at zip code level, median (IQR) | 22.1 (16.5–29) | 8.4 (4.9–12.8) | 9.2 (5.5–14) | 9.8 (5.7–15.7) | 10.4 (6–16.4) | <.001 | ||
| Percentage high school education or higher at zip code level, median (IQR) | 79 (72.3–84) | 90.5 (85.9–93.9) | 88.5 (83.2–92.6) | 88.4 (81.8–92.9) | 88 (81.6–92.6) | <.001 | ||
| Percentage bachelor’s degree or higher at zip code level, median (IQR) | 16.9 (11.6–24.6) | 28.3 (19.2–43) | 21 (14.7–31.3) | 24.2 (16.3–36.4) | 22.8 (15.5–34.7) | <.001 | ||
| Percentage who drive alone at zip code level, median (IQR) | 72.9 (58.5–79) | 81 (76.8–84.3) | 82.3 (78.5–85.6) | 80.6 (75.8–84.4) | 80.6 (75.4–84.4) | <.001 | ||
| NCHSc large metropolitan urban classification, n (%) | 3223 (73) | 4776 (52.1) | 3373 (35.2) | 2095 (54.2) | 13,467 (49.8) | <.001 | ||
| NCHS small/mid metropolitan classification, n (%) | 1028 (23.2) | 2599 (28.4) | 3561 (37.2) | 1143 (29.6) | 8331 (30.8) | <.001 | ||
| NCHS nonmetropolitan classification, n (%) | 166 (3.8) | 1790 (19.5) | 2646 (27.6) | 628 (16.2) | 5230 (19.4) | <.001 | ||
| Outcomes | ||||||||
| 1-year mortality | 2375 (53.8) | 4577 (49.9) | 4032 (42.1) | 1207 (31.2) | 12,191 (45.1) | <.001 | ||
aOHCA: out-of-hospital cardiac arrest.
bNumber of beds: 1=6-24 beds, 2=25-49 beds, 3=50-99 beds, 4=100-199 beds, 5=200-299 beds, 6=300-399 beds, 7=400-499 beds, 8=500 or more beds.
cNCHS: National Center for Health Statistics.