Table 1. Characteristics of Total HA Recipients by Surgical Approach Before and After Matchinga.
| No. (%) of patients | SDMb | No. (%) of patients | SDMb | |||
|---|---|---|---|---|---|---|
| Before matching | After matching | |||||
| Anterior approach | Lateral or posterior approach | Anterior approach | Lateral or posterior approach | |||
| No. of patients | 2995 | Lateral, 21 248 Posterior, 5855 |
2993 | Lateral, 2326; Posterior, 667 |
||
| No. of surgeons | 134 | 297 | 133 | 263 | ||
| Demographics | ||||||
| Age, mean (SD), y | 65.3 (11.4) | 67.2 (10.6) | 0.17 | 65.3 (11.4) | 65.3 (11.1) | 0 |
| Men | 1494 (49.9) | 12 525 (46.2) | 0.07 | 1493 (49.9) | 1469 (49.1) | 0.02 |
| Women | 1501 (50.1) | 14 578 (53.8) | 0.07 | 1500 (50.1) | 1524 (50.9) | 0.02 |
| Rural residence | 548 (18.3) | 4237 (15.6) | 0.07 | 548 (18.3) | 482 (16.1) | 0.06 |
| Income quintile | ||||||
| Lowest | 440 (14.7) | 4464 (16.5) | 0.05 | 440 (14.7) | 433 (14.5) | 0.01 |
| 2 | 533 (17.8) | 5248 (19.4) | 0.04 | 533 (17.8) | 530 (17.7) | 0 |
| 3 | 604 (20.2) | 5235 (19.3) | 0.02 | 604 (20.2) | 620 (20.7) | 0.01 |
| 4 | 612 (20.4) | 5586 (20.6) | 0 | 612 (20.4) | 613 (20.5) | 0 |
| Highest | 804 (26.8) | 6540 (24.1) | 0.06 | 804 (26.9) | 797 (26.6) | 0.01 |
| Comorbidities | ||||||
| Hypertension | 1600 (53.4) | 17 039 (62.9) | 0.19 | 1599 (53.4) | 1597 (53.4) | 0 |
| Diabetes | 425 (14.2) | 5381 (19.9) | 0.15 | 425 (14.2) | 430 (14.4) | 0 |
| COPD | 449 (15.0) | 4892 (18.0) | 0.08 | 449 (15.0) | 430 (14.4) | 0.02 |
| Smoking cessation counseling | 190 (6.3) | 1691 (6.2) | 0 | 190 (6.3) | 164 (5.5) | 0.04 |
| BMI >40 | 143 (4.8) | 2069 (7.6) | 0.12 | 143 (4.8) | 166 (5.5) | 0.03 |
| Frail | 147 (4.9) | 1737 (6.4) | 0.06 | 147 (4.9) | 141 (4.7) | 0.01 |
| Congestive heart failure | 109 (3.6) | 1275 (4.7) | 0.05 | 109 (3.6) | 119 (4.0) | 0.02 |
| Coronary artery disease | 85 (2.8) | 934 (3.4) | 0.03 | 85 (2.8) | 85 (2.8) | 0 |
| Asthma | 75 (2.5) | 875 (3.2) | 0.04 | 73 (2.4) | 81 (2.7) | 0.02 |
| Charlson scorec | ||||||
| 0 | 2547 (85.0) | 21 124 (77.9) | 0.18 | 2546 (85.1) | 2543 (85.0) | 0 |
| 1 | 259 (8.6) | 3585 (13.2) | 0.15 | 259 (8.7) | 249 (8.3) | 0.01 |
| 2 | 123 (4.1) | 1569 (5.8) | 0.08 | 122 (4.1) | 121 (4.0) | 0 |
| ≥3 | 66 (2.2) | 825 (3.0) | 0.05 | 66 (2.2) | 80 (2.7) | 0.03 |
| Fiscal year of procedure | ||||||
| 2015 | 767 (25.6) | 8665 (32.0) | 0.14 | 766 (25.6) | 822 (27.5) | 0.04 |
| 2016 | 938 (31.3) | 9205 (34.0) | 0.06 | 937 (31.3) | 968 (32.3) | 0.02 |
| 2017 | 1290 (43.1) | 9233 (34.1) | 0.19 | 1290 (43.1) | 1203 (40.2) | 0.06 |
| Procedure volume, median (IQR)d | ||||||
| Hospital | 433 (191-651) | 349 (234-533) | 0.12 | 433 (191-651) | 385 (262-611) | 0.03 |
| Surgeon | 111 (69-172) | 77 (50-119) | 0.55 | 111 (69-172) | 118 (71-161) | 0 |
Abbreviations: BMI, body mass index, calculated as weight in kilograms divided by height in meters squared; COPD, chronic obstructive pulmonary disease; IQR, interquartile range; SDM, standardized difference of the mean.
Greedy matching occurred 1:1 on the logit of a propensity score with a caliper of 0.2 SD.
SDMs of 0.1 or more represent meaningful differences in covariates between groups before and after matching.
Deyo-Charlson score is a measure of patient comorbidity (prior to their hip replacement) and ranges from 0 (lowest complication risk) to 3 or more (highest complication risk). Patients may also be classified as having no prior hospital admissions.
Number of hip arthroplasty procedures performed in the 365 days prior to the date of surgery.