Table:
Baseline characteristics of all patients with invasive β-haemolytic streptococcal infections treated with β-lactam antibiotics
| Unmatched cohort |
Propensity-matched cohort |
|||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Invasive group A β-haemolytic streptococcal infection (n=1079) |
Invasive non-group A/B β-haemolytic streptococcal infection (n=877) |
Invasive group A β-haemolytic streptococcal infection (n=777) |
Invasive non-group A/B β-haemolytic streptococcal infection (n=295) |
|||||||||
| No clindamycin treatment (n=736) | Clindamycin treatment (n=343) | p value | No clindamycin treatment (n=761) | Clindamycin treatment (n=116) | p value | No clindamycin treatment (n=500) | Clindamycin treatment (n=277) | p value | No clindamycin treatment (n=193) | Clindamycin treatment (n=102) | p value | |
| Patient-related | ||||||||||||
| Age, years | 51 (34–67) | 46 (27–62) | 0.0008 | 60 (46–74) | 54 (42–68) | 0.023 | 48 (30–63) | 47 (26–64) | 0.91 | 55 (41–67) | 59 (43–69) | 0.32 |
| Sex | ||||||||||||
| Male | 423 (575%) | 200 (58.3%) | 0.85 | 518 (68.1%) | 65 (56.0%) | 0.014 | 292 (58.4%) | 160 (57.8%) | 0.81 | 124 (64.2%) | 60 (58.8%) | 0.54 |
| Female | 313 (42.5%) | 143 (42.7%) | 0.85 | 243 (32.9%) | 51 (44.0%) | 0.014 | 208 (42.6%) | 117 (42.2%) | 0.81 | 69 (36.8%) | 42 (41.2%) | 0.54 |
| White | 553 (757%) | 233 (67.9%) | 0.016 | 590 (77.5) | 86 (74.1%) | 0.50 | 359 (778) | 183 (66.1%) | 0.31 | 150 (77.7%) | 75 (73.5%) | 0.37 |
| Elixhauser Comorbidity Index* | 2.0 (0.0–3.0) | 2.0 (0.0–3.0) | 0.18 | 3.0 (1.0–4.0) | 2.5 (1.0–4.0) | 0.40 | 2.0 (0.0–3.0) | 1.0 (0.0–3.0) | 0.50 | 2.0 (1.0–4.0) | 3.0 (1.0–4.0) | 0.55 |
| Immunocompromised† | 58 (7.9%) | 27 (7.9%) | 1.00 | 60 (7.9%) | 12 (10.3%) | 0.47 | 39 (78%) | 22 (7.9%) | 0.93 | 13 (6.7%) | 7 (6.9%) | 1.00 |
| Obese (body-mass index >30 kg/m2)‡ | 60 (8.2%) | 32 (9.3%) | 0.60 | 117 (15.4%) | 27 (23.3%) | 0.045 | 41 (8.2%) | 24 (87%) | 0.89 | 45 (23.3%) | 25 (24.5%) | 0.96 |
| Baseline Sequential Organ Failure Assessment score§ | 1.0 (0.0–3.0) | 1.0 (0.0–3.0) | 0.0090 | 1.0 (0.0–3.0) | 1.0 (0.0–2.0) | 0.42 | 1.0 (0.0–3.0) | 1.0 (0.0–3.0) | 0.29 | 1.0 (0.0–3.0) | 1.0 (0.0–2.0) | 0.89 |
| Infection-related | ||||||||||||
| Proven invasive β-haemolytic streptococcal disease | 398 (54.1%) | 191 (55.7%) | 0.67 | 430 (56.5%) | 66 (56.9%) | 1.00 | 282 (56.4%) | 153 (557%) | 1.00 | 106 (54.9%) | 57 (55.9%) | 1.00 |
| Community-onset | 707 (96.1%) | 329 (95.9%) | 1.00 | 704 (92.5%) | 108 (93.1%) | 0.97 | 483 (96.6%) | 267 (96.4%) | 0.84 | 180 (93.3%) | 96 (94.1%) | 0.87 |
| Site | .. | .. | 0.0020 | .. | .. | 0.27 | .. | .. | 0.69 | .. | .. | 0.69 |
| Musculoskeletal, skin, or soft tissue | 275 (37.4%) | 141(41.1%) | .. | 225 (29.6%) | 36 (31.0%) | .. | 202 (40.4%) | 115 (41.5%) | .. | 60 (31.1%) | 32 (31.4%) | .. |
| Respiratory | 82 (11.1%) | 15 (4.4%) | .. | 130 (17.1%) | 17 (14.7%) | .. | 24 (4.8%) | 12 (4.3%) | .. | 33 (17.1%) | 15 (14.7%) | .. |
| Other deep-seated site¶ | 22 (3.0%) | 11 (3.2%) | .. | 28 (37%) | 5 (4.3%) | .. | 17 (3.4%) | 9 (3.2%) | .. | 9 (4.7%) | 5 (4.9%) | .. |
| Primary bacteraemia | 102 (13.9%) | 36 (10.5%) | .. | 102 (13.4%) | 8 (6.9%) | .. | 68 (13.6%) | 32 (11.6%) | .. | 20 (10.4%) | 7 (6.9%) | .. |
| Secondary bacteraemia | 255 (34.6%) | 140 (40.8%) | .. | 276 (36.3%) | 50 (43.1%) | .. | 189 (378%) | 109 (39.4%) | .. | 71 (36.8%) | 43 (42.2%) | .. |
| Necrotising fasciitis | 12 (1.6%) | 41 (12.0%) | <0.0001 | 2 (0.3%) | 5 (4.3%) | 0.0006 | 5 (1.0%) | 5 (1.8%) | 1.00 | 0 | 0 | NA |
| Year | .. | .. | 0.83 | .. | .. | 0.019 | .. | .. | 0.31 | .. | .. | 0.91 |
| 2000–04 | 77 (10.5%) | 32 (9.3%) | .. | 64 (8.4%) | 7 (6.0%) | .. | 48 (9.6%) | 28 (10.1%) | .. | 10 (5.2%) | 17 (6.9%) | .. |
| 2005–09 | 256 (34.8%) | 123 (35.9%) | .. | 283 (372%) | 59 (50.9%) | .. | 173 (34.6%) | 104 (37.5%) | .. | 89 (46.1%) | 48 (47.1%) | .. |
| 2010–15 | 403 (54.8%) | 188 (54.8%) | .. | 414 (54.4%) | 50 (43.1%) | .. | 279 (55.8%) | 145 (527%) | .. | 94 (48.7%) | 47 (46.1%) | .. |
| Treatment-related | ||||||||||||
| Intensive care unit stay | 128 (17.4%) | 95(277%) | 0.0001 | 123 (16.2%) | 26 (22.4%) | 0.12 | 90 (18.0%) | 55 (19.9%) | 1.00 | 36 (18.7%) | 19 (18.6%) | 1.00 |
| Intravenous immunoglobulin | 7 (1%) | 27 (8%) | <00001 | 1 (<1%) | 2 (2%) | 0.06 | 4 (1%) | 4 (1%) | 0.63 | 0 | 0 | NA |
| Vasopressor use|| | 90 (12.2%) | 83 (24.2%) | <00001 | 72 (9.5%) | 11 (9.5%) | 1.00 | 57 (11.4%) | 37 (13.4%) | 1.00 | 14 (73%) | 7 (6.9%) | 1.00 |
| Debridement within 3 days of infection | 137 (18.6%) | 99 (29) | 0.0002 | 103 (13.5%) | 28 (24.1%) | 0.0044 | 106 (21.2%) | 70 (253%) | 0.33 | 38 (19.7%) | 20 (19.6%) | 1.00 |
| β-lactam antibiotic treatment** | ||||||||||||
| Penicillin | 51 (6.9%) | 83 (24.2%) | <0.0001 | 39 (5.1%) | 9 (7.8%) | 0.35 | 38 (7.6%) | 55 (19.9%) | <0.0001 | 9 (4.7%) | 8 (78%) | 0.39 |
| Ampicillin-sulbactam | 111 (15,1%) | 56 (16.3%) | 0.66 | 86 (11.3%) | 20 (17.2%) | 0.23 | 85 (17.0%) | 44 (15.9%) | 0.76 | 24 (12.4%) | 18 (17.6%) | 0.30 |
| Ampicillin | 133 (18.1%) | 69 (20.1%) | 0.47 | 98 (12.9%) | 30 (25.9%) | 0.0004 | 102 (20.4%) | 56 (20.2%) | 1.00 | 28 (14.5%) | 26 (255%) | 0.03 |
| Cefazolin | 168 (22.8%) | 66 (19.2%) | 0.21 | 159 (20.9%) | 21 (18.1%) | 0.57 | 123 (24.6%) | 60 (21.7%) | 0.40 | 43 (22.3%) | 26 (255%) | 0.56 |
| Piperacillin-tazobactam | 221 (30.0%) | 98 (28.6%) | 0.67 | 257 (33.8%) | 39 (33 6%) | 1.00 | 145 (29.0%) | 69 (24.9%) | 0.26 | 68 (357%) | 32 (31.4%) | 0.59 |
| Ceftriaxone | 276 (37.5%) | 140 (40.8%) | 0.33 | 296 (39) | 52 (44.8%) | 0.27 | 179 (35.8%) | 110 (39.7%) | 0.32 | 67 (34.7%) | 46 (45.1%) | 0.11 |
| Center-related | ||||||||||||
| Academic | 486 (660%) | 229 (66.8%) | 0.87 | 508 (66.8%) | 78 (67.2%) | 1.00 | 335 (67.0%) | 182 (65.7%) | 0.76 | 132 (68.4%) | 68 (67%) | 0.69 |
| Urban | 612 (83 2%) | 277 (80.8%) | 0.38 | 613 (80.6%) | 109 (94.0%) | 0.0007 | 420 (84.0%) | 230 (83.0%) | 0.84 | 181 (93.8%) | 95 (93.1%) | 0.72 |
| Geographic region | .. | .. | <0.001 | .. | .. | 0.80 | .. | .. | 0.99 | .. | .. | 0.59 |
| Midwest | 176 (23.9%) | 49 (14.3%) | .. | 180 (237%) | 32 (27.6%) | .. | 81 (16.2%) | 42 (15.2%) | .. | 44 (22.8%) | 28 (275%) | .. |
| Northeast | 244 (33.2%) | 107 (31.2%) | .. | 262 (34.4%) | 39 (31.2%) | .. | 173 (34.6%) | 88 (31.8%) | .. | 68 (357%) | 33 (32.4%) | .. |
| South | 212 (28.8%) | 111 (32.4%) | .. | 200 (26.3%) | 27 (23.3%) | .. | 153 (30.6%) | 90 (32.5%) | .. | 50 (25.9%) | 25 (25) | .. |
| West | 104 (14.1%) | 76 (227%) | .. | 119 (15.6%) | 18 (15.5%) | .. | 93 (18.6%) | 57 (20.6%) | .. | 31 (16.1%) | 16 (15.7%) | .. |
| Bed capacity | .. | .. | 0.71 | .. | .. | 0.13 | .. | .. | 1.00 | .. | .. | 0.89 |
| <200 | 178 (24.2%) | 78 (227%) | .. | 169 (227%) | 27 (23.3%) | .. | 114 (22.8%) | 64 (23.1%) | .. | 44 (22.8%) | 23 (22.5%) | .. |
| 200–500 | 414 (56.2%) | 191 (55 7%) | .. | 433 (56.9%) | 74 (63.8%) | .. | 281 (56.2%) | 156 (56.3%) | .. | 124 (64.2%) | 65 (63.7%) | .. |
| >500 | 144 (19.6%) | 74 (21.6%) | .. | 159 (20.9%) | 15 (12.9%) | .. | 105 (21.0%) | 57 (20.6%) | .. | 25 (13.0%) | 14 (13.7%) | .. |
Data are median (IQR) or n (%). NA=not applicable. ICD-9=International Classification of Diseases version 9.
*
This score was calculated by use of ICD-9-clinical modification codes (appendix pp 6–8) and adapted from the methods used by Quan and colleagues.25
†
Defined by use of ICD-9 codes (see appendix pp 9–10 for the algorithm used).
‡
Defined by use of ICD-9-clinical modification code 278 for obesity.
§
Calculated by use of an electronic health record-based adaption of the original Sequential Organ Failure Assessment (appendix p 14).
¶
Includes mediastinitis, orchitis or epididymitis, parapharyngeal abscess, periapical abscess, peritonsillar abscess, retropharyngeal abscess, abscess of the mediastinum, and abscess of the salivary gland.
||
Refers to norepinephrine, epinephrine, phenylephrine, and dopamine administered within a 24-h period either side of culture sampling.
**
Groups are not mutually exclusive; this variable was not included in the propensity score model.