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Table 1 Initial patient, procedure, and hospital characteristics

From: A large database study of hospitalization charges and follow-up re-admissions in US lumbar fusion surgeries using a cellular bone allograft (CBA) versus recombinant human bone morphogenetic protein-2 (rhBMP-2)

Characteristic, unit Full cohort Single-level only cohort
Group P value Group P value
V-CBA (n = 6588) rhBMP-2 (n = 9584) V-CBA (n = 5683) rhBMP-2 (n = 8505)
Age in years, mean (std. dev.) [1] 60.86 (13.13) 60.74 (13.46) 0.5604 60.09 (13.31) 60.05 (13.62) 0.8749
Female sex, n (%) [2] 3653 (55.45) 5302 (55.32) 0.8850 2963 (55.08) 4492 (55.20) 0.4381
Race, n (%) [3]
 White 5586 (84.79) 8415 (87.80) < 0.0001* 4568 (84.92) 7121 (87.50) < 0.0001^
 Black 500 (7.59) 521 (5.44) 393 (7.31) 457 (5.62)
 Other/unknown 502 (7.62) 648 (6.76) 418 (7.77) 560 (6.88)
Ethnicity, n (%) [3]
 Hispanic 143 (2.17) 342 (3.57) < 0.0001* 126 (2.34) 298 (3.66) < 0.0001^
 Non-Hispanic 5588 (84.82) 8712 (90.90) 4574 (85.03) 7383 (90.72)
 Unknown 857 (13.01) 530 (5.53) 679 (12.62) 457 (5.62)
Charlson comorbidities, n (%) [2]
 Any malignancy 83 (1.26) 63 (0.66) 0.0001* 77 (1.34) 58 (0.68) < 0.0001^
 Cerebrovascular disease 105 (1.60) 109 (1.14) 0.0141* 99 (1.74) 98 (1.15) 0.0041^
 Congestive heart failure 380 (5.77) 499 (5.21) 0.129 364 (6.41) 472 (5.55) 0.0372^
 Chronic obstructive pulmonary disorder 1403 (21.30) 1878 (19.60) 0.0086* 1310 (23.05) 1694 (19.92) < 0.0001^
 Dementia 113 (1.72) 149 (1.60) 0.447 107 (1.88) 138 (1.62) 0.2712
 Diabetes with chronic complications 494 (7.50) 601 (6.27) 0.0025* 480 (8.45) 505 (5.94) < 0.0001^
 Diabetes without chronic complications 1030 (15.63) 1304 (13.60) 0.0003* 912 (16.05) 1114 (13.10) < 0.0001^
 Hemiplegia or paraplegia 149 (2.26) 94 (0.98) < 0.0001* 139 (2.45) 86 (1.01) < 0.0001^
 HIV/AIDS 4 (0.06) 4 (0.04) 0.7232 0 (0.00) 2 (0.02) 0.6639
 Metastatic solid tumor 54 (0.82) 9 (0.09) < 0.0001* 51 (0.90) 9 (0.11) < 0.0001^
 Myocardial infarction 351 (5.33) 389 (4.06) 0.0002* 336 (5.91) 355 (4.17) < 0.0001^
 Mild liver disease 35 (0.53) 41 (0.43) 0.3513 28 (0.49) 28 (0.33) 0.1660
 Moderate or severe liver disease 9 (0.14) 7 (0.07) 0.2144 9 (0.16) 7 (0.08) 0.2857
 Peptic ulcer disease 39 (0.59) 33 (0.34) 0.0233* 36 (0.63) 30 (0.35) 0.0225^
 Peripheral vascular disease 266 (4.04) 319 (3.33) 0.0184* 247 (4.35) 284 (3.34) 0.0023^
 Renal disease 458 (6.92) 699 (7.29) 0.4196 425 (7.48) 642 (7.54) 0.9025
 Rheumatic disease 376 (5.71) 531 (5.54) 0.6513 359 (6.32) 494 (5.81) 0.2251
Charlson comorbidity index, mean (Std. Dev.) [4] 0.92 (1.39) 0.78 (1.20) < 0.0001* 0.90 (1.38) 0.78 (1.20) < 0.0001^
Health insurance status, n (%) [3]
 Medicare 3276 (49.73) 4669 (48.72) < 0.0001* 2570 (49.78) 3856 (47.38) < 0.0001^
 Medicaid 617 (9.37) 522 (5.45) 526 (9.78) 470 (5.78)
 Private insurance 1416 (21.49) 2509 (26.18) 1172 (21.79) 2202 (27.06)
 Commercial indemnity 727 (11.04) 1107 (11.55) 627 (11.66) 931 (11.44)
 Other/unknown 552 (8.38) 777 (8.11) 484 (9.00) 679 (8.34)
Initial visit admission type, n (%) [3]
 Elective 6035 (91.61) 8742 (91.21) < 0.0001* 4938 (91.80) 7425 (91.24) < 0.0001^
 Emergency 309 (4.69) 231 (2.41) 249 (4.63) 201 (2.47)
 Urgent 124 (1.88) 574 (5.99) 104 (1.93) 480 (5.90)
 Trauma 86 (1.31) 18 (0.19) 67 (1.25) 16 (0.20)
 Other/unknown 34 (0.52) 19 (0.20) 21 (0.39) 16 (0.20)
Initial visit admission source, n (%) [3]
 Transfer from non-healthcare facility 3528 (53.55) 6939 (72.40) < 0.0001* 2902 (54.11) 5849 (71.93) < 0.0001^
 Clinic 2895 (43.94) 2411 (25.16) 2354 (43.87) 2090 (25.70)
 Transfer from different hospital facility 103 (1.56) 168 (1.75) 81 (1.51) 146 (1.80)
 Other/unknown 62 (0.94) 66 (0.69) 27 (0.50) 47 (0.58)
Initial discharge status, n (%) [3]
 Home/home care service/self-care 4056 (61.57) 5623 (58.67) < 0.0001* 3390 (63.02) 4880 (59.97) < 0.0001^
 Home health organization 1158 (17.58) 1919 (20.02) 942 (17.51) 1594 (19.59)
 Transferred to skilled nursing facility 792 (12.02) 1078 (11.25) 598 (11.12) 876 (10.76)
 Nursing, rehabilitation, or hospice facility 477 (7.24) 889 (9.28) 383 (7.12) 732 (8.99)
 Other/unknown 105 (1.59) 75 (0.78) 67 (1.25) 56 (0.69)
Cage insertion, n (%) [2] 4115 (62.46) 5667 (59.13) 0.0010* 3210 (56.48) 4588 (53.94) 0.0007*
Multiple levels treated, n (%) [2] 905 (13.74) 1079 (11.26) < 0.0001*
Hospital size, n (%) [3]
 1 to 299 beds 696 (10.56) 4062 (42.38) < 0.0001* 596 (11.08) 3304 (40.60) < 0.0001^
 300 to 499 beds 2735 (41.51) 2987 (31.17) 2223 (41.33) 2632 (32.34)
 500+ beds 3157 (47.92) 2535 (26.45) 2560 (47.59) 2202 (27.06)
Hospital teaching status, n (%) [3]
 Teaching hospital 4580 (69.52) 5087 (53.08) < 0.0001* 3754 (69.79) 4249 (52.21) < 0.0001^
 Non-teaching hospital 2008 (30.48) 4497 (46.92) 1625 (30.21) 3889 (47.79)
Hospital population served, n (%) [3]
 Rural 563 (8.55) 6 (0.06) < 0.0001* 560 (8.55) 6 (0.07) < 0.0001^
 Urban 6025 (91.45) 9578 (99.94) 4919 (91.45) 8132 (99.93)
Hospital region, n (%) [3]
 Midwest 1031 (15.65) 2639 (27.54) < 0.0001* 872 (16.21) 2280 (28.02) < 0.0001^
 Northeast 967 (14.68) 2413 (25.18) 767 (14.26) 1968 (24.18)
 South 3688 (55.98) 4234 (44.18) 2959 (55.01) 3626 (44.56)
 West 902 (13.69) 298 (3.11) 781 (14.52) 264 (3.24)
  1. Planned analyses were conducted on the full cohort
  2. Ad hoc analyses were conducted on the single-level only cohort, which only included patients who received treatment at a single level of the spine
  3. *Statistically significant in the full cohort. The following confounding variables were used as covariates in the primary multivariate regression models for the full cohort: race, ethnicity, Charlson comorbidity index, health insurance status, initial admission type, initial admission source, initial discharge status, cage insertion, multiple levels treated, hospital size, hospital teaching status, hospital population served, and hospital region
  4. ^Statistically significant in the single-level only cohort. The following confounding variables were used as covariates in the ad hoc multivariate regression models for the single-level only cohort: race, ethnicity, Charlson comorbidity index, health insurance status, initial admission type, initial admission source, initial discharge status, cage insertion, hospital size, hospital teaching status, hospital population served, and hospital region
  5. [1]Two-sided t test
  6. [2]Fisher’s exact test
  7. [3]Chi-square test
  8. [4]Wilcoxon rank-sum test