Table 4.
Meta-analysis of unadjusted and age- and sex-adjusted hazard ratios for the association between ASA classes and 1-year mortality
| ASA I as reference | ASA II | Unadjusted HR (CI) ASA III |
ASA IV | ASA II | Adjusted HR (CI) ASA III |
ASA IV |
|---|---|---|---|---|---|---|
| Registries | ||||||
| Australia | 4.5 (2.5–8.2) | 17 (9.0–30) | 69 (38–129) | 2.7 (1.4–4.9) | 6.9 (3.8–13) | 22 (12–41) |
| Finland | 3.3 (1.0–11) | 16 (5.0–50) | 69 (21–229) | 2.0 (0.6–6.4) | 6.8 (2.1–22) | 24 (7.0–84) |
| Kaiser Permanente | 1.5 (0.5–4.7) | 5.3 (1.7–17) | 19 (6.0–64) | 1.0 (0.3–3.2) | 2.7 (0.9–8.4) | 7 (2.0–25) |
| Netherlands | 2.2 (1.7–2.8) | 8.8 (6.9–11) | 32 (21–50) | 1.4 (1.1–1.8) | 4.2 (3.2–5.4) | 14 (9.0–22) |
| New Zealand | 3.6 (1.8–7.1) | 18 (9.0–34) | 97 (47–204) | 2.3 (1.2–4.5) | 8.0 (4.0–16) | 34 (16–74) |
| Norway | 3.1 (1.3–7.1) | 21 (10–48) | 120 (47–309) | 1.7 (0.7–3.9) | 7.7 (3.3–18) | 34 (13–91) |
| Sweden | 4.4 (2.9–6.6) | 16 (10–24) | 54 (30–95) | 3.0 (2.0–4.6) | 8.6 (5.6–13) | 28 (16–50) |
| Pooled HR | 3.2 (2.3–4.3) | 14 (10–19) | 59 (38–93) | 2.0 (1.4–2.7) | 6.1 (4.4–8.5) | 22 (15–32) |
| P-value a | < 0.001 | < 0.001 | < 0.001 | < 0.001 | < 0.001 | < 0.001 |
| Heterogeneity | ||||||
| Q Cochran | 11 | 14 | 14 | 12 | 13 | 10 |
| Cochran test (p) | 0.06 | 0.03 | 0.03 | 0.06 | 0.05 | 0.11 |
| I2 (%) | 50 | 57 | 58 | 51 | 53 | 42 |
a p-value for testing the null hypothesis that the pooled HR equals 1.