Table 2.
Comparisons of parameters of control and intervention groups 1 week prior to operation, perioperatively and 6 weeks postoperatively. Difference between the 2 groups is calculated between means when presented, otherwise between proportions (shown in parentheses) and is presented with 95% confidence interval. Values are count (%) unless otherwise specified
| Patient characteristics 1 week prior to operation | Intervention group (n = 746) | Missing | Control group (n = 738) | Missing | Difference [CI] |
|---|---|---|---|---|---|
| Age a | 67.9 (9.7) | 66.7 (8.8) | 1.2 [0.3 to 2.2] | ||
| Female sex | 414 (55) | 421 (57) | –1.6 [–6.6 to 3.5] | ||
| BMI a | 31.0 (5.4) | 30.6 (5.2) | 1 (0.1) | 0.4 [–0.2 to 0.9] | |
| < 18.5 | 1 (0.1) | 1 (0.1) | 0.0[–0.6 to 0.6] | ||
| 18.5–24.9 | 102 (14) | 94 (13) | 0.9 [–2.5 to 4.4] | ||
| 25–29.9 | 231 (31) | 258 (35) | –4.0 [–8.8 to 0.7] | ||
| 30–34.9 | 241 (32) | 238 (32) | 0.0 [–4.7 to 4.8] | ||
| 35–39.9 | 126 (17) | 108 (15) | 2.2 [–1.5 to 5.9] | ||
| 40–44.9 | 39 (5.2) | 33 (4.5) | 0.8 [–1.5 to 3.0] | ||
| 45–49.9 | 6 (0.8) | 5 (0.7) | 0.1 [–0.9 to 1.1] | ||
| ≥ 50 | 0 (0) | 0 (0) | 0.0 [–0.5 to 0.5] | ||
| Patient comorbidities | |||||
| Smoking | 28 (3.8) | 10 (1.3) | 54 (7.3) | 11 (1.5) | –3.6 [–6.1 to –1.3] |
| Hypertension | 465 (62) | 401 (54) | 8.0 [3.0 to 13.0] | ||
| Ischemic heart disease | 120 (16) | 80 (11) | 5.2 [1.8 to 8.7] | ||
| Arrythmias | 122 (16) | 105 (14) | 2.1 [–1.5 to 5.8] | ||
| Anticoagulation | 113 (15) | 78 (11) | 4.6 [1.2 to 8.0] | ||
| Congestive heart failure | 30 (4.0) | 13 (1.8) | 2.3 [0.5 to 4.1] | ||
| Lung disease | 133 (18) | 131 (18) | 0.1 [–3.8 to 4.0] | ||
| Pulmonary embolism | 26 (3.5) | 7 (0.9) | 2.5 [1.1 to 4.2] | ||
| Deep vein thrombosis | 27 (3.6) | 10 (1.4) | 2.3 [0.7 to 4.0] | ||
| Diabetes | 93 (13) | 65 (8.8) | 3.7 [0.5 to 6.8] | ||
| Renal insufficiency | 82 (11) | 45 (6.1) | 4.9 [2.1 to 7.8] | ||
| Transient ischemic attack | 42 (5.6) | 48 (6.5) | –0.9 [–3.3 to 1.6] | ||
| CNS bleeding | 4 (0.5) | 5 (0.7) | –0.1 [–1.1 to 0.8] | ||
| Inflammatory arthritis | 51 (6.8) | 50 (6.8) | 0.1 [–2.5 to 2.7] | ||
| Depression | 78 (11) | 73 (9.9) | 0.6 [–2.5 to 3.7] | ||
| Anxiety | 62 (8.3) | 43 (5.8) | 2.5 [–0.1 to 5.1] | ||
| Cancer | 94 (13) | 78 (11) | 2.0 [–1.2 to 5.3] | ||
| Type of operation | |||||
| Knee replacement | 480 (64) | 476 (65) | –0.2 [–5.0 to 4.7] | ||
| Hip replacement | 266 (36) | 262 (36) | 0.2 [–4.7 to 5.0] | ||
| Type of anesthesia | |||||
| Spinal | 691 (93) | 659 (89) | 3.3 [0.4 to 6.3] | ||
| General | 55 (7.4) | 79 (11) | –3.3 [–6.3 to –0.4] | ||
| ASA classification | |||||
| Class 1 | 41 (5.5) | 44 (6.0) | –0.5 [–2.9 to 1.9] | ||
| Class 2 | 469 (63) | 528 (72) | –8.7 [–13.4 to –3.9] | ||
| Class 3 | 236 (32) | 164 (22) | 9.4 [4.9 to 13.9] | ||
| Class 4 | 0 (0) | 2 (0.3) | –0.3 [–1.0 to 0.3] | ||
| ASA ≥ 3 | 236 (32) | 166 (23) | 9.1 [4.6 to 13.6] | ||
| Hemoglobin, g/L a | |||||
| Preoperative a | 140.9 (12.6) | 141.3 (13.4) | 2 (0.3) | –0.4 [–1.8 to 0.9] | |
| Postoperative a | 112.9 (12.7) | 4 (0.5) | 115.9 (12.8) | 34 (4.6) | –3.0 [–4.4 to –1.7] |
| Postoperative drop a | 28.0 (8.4) | 4 (0.5) | 25.8 (10.9) | 34 (4.6) | 2.2 [1.2 to 3.2] |
| Anemia preoperative | 44 (5.9) | 0 (0) | 56 (7.6) | 2 (0.3) | –1.7 [–4.3 to 0.9] |
| Mild | 38 (5.1) | 47 (6.3) | –1.3 [–3.7 to 1.1] | ||
| Moderate | 6 (0.8) | 8 (1.1) | –0.3 [–1.4 to 0.8] | ||
| Severe | 1 (0.1) | –0.1 [–0.8 to 0.4] | |||
| Creatinine, µmol/L a | |||||
| Preoperative | 83.9 (47.7) | 78.5 (22.6) | 2 (0.3) | 5.4 [2.5 to 10.7] | |
| Postoperative | 85.7 (56.0) | 5 (0.7) | 81.4 (29.3) | 34 (4.6) | 4.3 [0.6 to 10.3] |
| Glucose, mmol/L a | |||||
| Preoperative | 6.4 (1.5) | 1 (0.1) | 6.1 (1.5) | 13 (1.8) | 0.3 [0.1 to 0.4] |
| Postoperative | 6.5 (1.2) | 12 (1.6) | 6.8 (1.3) | 38 (5.1) | –0.3 [–0.4 to –0.2] |
| HbA1c, mmol/L a | |||||
| Preoperative | 37.8 (7.3) | 7 (0.9) | 38.1 (7.6) | 17 (2.3) | –0.2 [–1.0 to 0.5] |
| HbA1c for non-DM patients | 7 (1.1) | ||||
| 42–47 mmol/mol | 49 (6.6) | 52 (7.0) | –0.3 [–3.3 to 2.6] | ||
| > 47 mmol/mol | 8 (1.1) | 13 (1.8) | –0.7 [–2.2 to 0.7] | ||
| Albumin, g/L a | 43.4 (2.7) | 10 (1.3) | 44.2 (2.7) | 12 (1.6) | –0.7 [–1.0 to –0.5] |
| Albumin < 35 g/L | 1 (0.1) | 10 (1.3) | 1 (0.1) | 12 (1.6) | 0.0 [–0.6 to 0.6] |
| Lymphocytes < 1.5x10⁹/L | 79 (11) | 1 (0.1) | 129 (18) | 2 (0.3) | –6.9 [–10.5 to –3.4] |
| Vitamin D, nmol/L (SD) a,b | 84.7 (34.5) | 5 (0.7) | 79.6 (33.9) | 16 (2.2) | 5.1 [1.6 to 8.7] |
| Vitamin D < 50 nmol/L c | 16 (2.1) | 20 (2.7) | 121 (16) | 16 (2.2) | –14.6 [–17.6 to –11.7] |
| Peri- and postoperative differences | |||||
| Blood transfusion | 35 (4.7) | 19 (2.6) | 2.1 [0.2 to 4.1] | ||
| Length of stay (days) a | 1.9 (3.2) | 1.7 (1.7) | 0.1 [–0.1 to 0.5] | ||
| Postoperative medical complications ≤ 6 weeks from operation | |||||
| Myocardial infarction | 2 (0.3) | ||||
| Heart failure | 6 (0.8) | 3 (0.4) | 0.4 [–0.5 to 1.4] | ||
| Pneumonia | 3 (0.4) | 7 (0.9) | –0.5 [–1.6 to 0.4] | ||
| Transient ischemic attack | 3 (0.4) | 7 (0.9) | –0.5 [–1.6 to 0.4] | ||
| Pulmonary embolism | 5 (0.7) | 3 (0.4) | 0.3 [–0.6 to 1.2] | ||
| Deep vein thrombosis | 3 (0.4) | 3 (0.4) | 0.0 [–0.8 to 0.8] | ||
| Renal insufficiency | 24 (3.2) | 11 (1.5) | 1.7 [0.2 to 3.4] | ||
| Death | 0 (0.0) | 0 (0.0) | 0.0 [–0.5 to 0.5] |
a
Values are mean (SD)
b
Vitamin D results for the intervention group are based on blood tests taken on decision for operation.
c
Results for number of patients with vitamin D < 50 nmol/L 1 week prior to operation in the intervention group are based on repeated blood tests of those 91 patients who had < 50 nmol/L on decision for operation.