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. Author manuscript; available in PMC: 2021 Sep 20.
Published in final edited form as: J Bone Joint Surg Am. 2020 Dec 16;102(24):2157–2165. doi: 10.2106/JBJS.20.00203

Table 5.

Unplanned readmissions over 90-days episode of care by arthroplasty type

Characteristic Knee Arthroplasty Hip Arthroplasty
N (%) Readmission (95% CI) N (%) Readmission (95% CI)
Overall 351,183 6.3% (6.2, 6.4) 164,508 7.0% (6.9, 7.1)
Sex
 Male 127,799 (36.4%) 6.8% (6.7, 6.9) 63,860 (38.8%) 6.9% (6.7, 7.1)
 Female 223,384 (63.6%) 6.1% (6.0, 6.2) 100,648 (61.2%) 7.1% (6.9, 7.3)
Age, years
 65–69 112,283 (32.0%) 4.7% (4.6, 4.9) 49,056 (29.8%) 5.1% (4.9, 5.3)
 70–74 103,095 (29.4%) 5.6% (5.5, 5.7) 45,391 (27.6%) 6.0% (5.8, 6.2)
 75–79 76,664 (21.8%) 7.2% (7.0, 7.3) 34,933 (21.2%) 7.7% (7.4, 8.0)
 80–84 42,401 (12.1%) 8.8% (8.6, 9.1) 23,032 (14.0%) 9.4% (9.1, 9.8)
 ≥85 16,740 (4.8%) 11.3% (10.8, 11.8) 12,096 (7.4%) 12.1% (11.5, 12.7)
Race/Ethnicity
 Non-Hispanic White 310,029 (88.3%) 6.2% (6.2, 6.3) 150,707 (91.6%) 7.0% (6.9, 7.2)
 Non-Hispanic Black 17,576 (5.0%) 8.1% (7.7, 8.5) 7,232 (4.4%) 8.1% (7.5, 8.7)
 Hispanic 13,360 (3.8%) 6.4% (6.0, 6.8) 3,044 (1.9%) 6.4% (5.5, 7.2)
 Other 10,218 (2.9%) 5.7% (5.2, 6.1) 3,525 (2.1%) 4.9% (4.2, 5.7)
Disability entitlement a
 No 320,125 (91.2%) 6.0% (5.9, 6.1) 152,317 (92.6%) 6.7% (6.5, 6.8)
 Yes 31,058 (8.8%) 9.5% (9.1, 9.8) 12,191 (7.4%) 11.3% (10.8, 11.9)
Dual eligibility b
 No 324,423 (92.4%) 6.0% (6.0, 6.1) 155,315 (94.4%) 6.8% (6.6, 6.9)
 Yes 26,760 (7.6%) 9.8% (9.4, 10.2) 9,193 (5.6%) 11.2% (10.6, 11.9)
Prior hospitalization
 0 323,093 (92.0%) 6.0% (5.9, 6.1) 150,112 (91.2%) 6.6% (6.5, 6.7)
 1 25,581 (7.3%) 9.5% (9.1, 9.8) 12,651 (7.7%) 10.1% (9.6, 10.7)
 2 2,124 (0.6%) 16.3% (14.8, 17.9) 1,439 (0.9%) 18.7% (16.7, 20.7)
 3+ 385 (0.1%) 29.9% (25.3, 34.4) 306 (0.2%) 30.1% (24.9, 35.2)
Hospital LOS, days c
 <4 296,634 (84.5%) 5.6% (5.5, 5.7) 139,849 (85.0%) 6.2% (6.1, 6.3)
 4–7 51,597 (14.7%) 9.7% (9.5, 10.0) 23,138 (14.1%) 10.9% (10.5, 11.3)
 8+ 2,952 (0.8%) 21.0% (19.5, 22.5) 1,521 (0.9%) 21.7% (19.6, 23.8)
ICU/CCU d
 No 336,649 (95.9%) 6.2% (6.1, 6.2) 156,869 (95.4%) 6.8% (6.7, 6.9)
 Yes 14,534 (4.1%) 10.0% (9.5, 10.4) 7,639 (4.6%) 11.9% (11.2, 12.6)
Diabetes Status
 None 270,889 (77.1%) 5.8% (5.7, 5.9) 136,621 (83.0%) 6.6% (6.4, 6.7)
 Controlled – Uncomplicated 72,137 (20.5%) 7.6% (7.4, 7.8) 25,244 (15.3%) 8.8% (8.5, 9.2)
 Controlled – Complicated 5,031 (1.4%) 11.5% (10.6, 12.4) 1,712 (1.0%) 14.7% (13.0, 16.4)
 Uncontrolled 3,126 (0.9%) 10.6% (9.5, 11.7) 931 (0.6%) 12.0% (9.9, 14.1)

Abbreviations: LOS = length of stay, ICU/CCU = intensive care unit/coronary care unit

a

“Disability” original reason for receiving Medicare.

b

Eligible for Medicare and Medicaid.

c

LOS for hospitalization during joint arthroplasty procedure

d

Admitted to ICU or CCU during hospitalization for joint arthroplasty procedure.