Type of adverse outcome in three periods (1997–1999, 2000–2002 and 2003–2005)*
| Type category | 2000–2002 vs 1997–1999, OR (99% CI) | 2003–2005 vs 1997–1999, OR (99% CI) | Per cent of total number of adverse outcomes |
| Rejection/allergy/other immunological reaction | 1.68 (0.88 to 3.23) | 2.03 (1.09 to 3.76) | 1.3 |
| Bleeding/haematoma | 0.79 (0.60 to 1.05) | 0.90 (0.69 to 1.17) | 7.4 |
| Pressure sore | 0.88 (0.44 to 1.74) | 0.92 (0.48 to 1.77) | 1.1 |
| Fistula | 2.06 (0.93 to 4.55) | 2.41 (1.13 to 5.12) | 1.3 |
| Functional disorder | 0.97 (0.80 to 1.18) | 1.27 (1.06 to 1.52) | 22.9 |
| Ischaemia | 1.15 (0.61 to 2.16) | 1.54 (0.86 to 2.76) | 1.3 |
| Symptoms without diagnosis | 1.52 (1.03 to 2.25) | 2.27 (1.58 to 3.25) | 4.4 |
| Injury by mechanical/physical–chemical cause | 0.97 (0.71 to 1.34) | 1.16 (0.86 to 1.56) | 5.0 |
| Necrosis/Infarction | 1.63 (1.11 to 2.40) | 1.21 (0.82 to 1.79) | 3.8 |
| Inflammation/infection | 1.05 (0.89 to 1.25) | 1.32 (1.13 to 1.54) | 28.7 |
| Psychological disturbance | 2.03 (1.18 to 3.46) | 2.32 (1.39 to 3.89) | 2.2 |
| Procedure with specified unintended substandard outcome | 0.35 (0.14 to 0.86) | 0.48 (0.22 to 1.03) | 0.7 |
| Shock | 0.94 (0.69 to 1.28) | 1.04 (0.77 to 1.40) | 5.1 |
| Thrombosis/embolus | 1.20 (0.78 to 1.85) | 1.30 (0.86 to 1.97) | 2.4 |
| Accumulation/leakage of body fluids | 1.01 (0.75 to 1.36) | 1.26 (0.95 to 1.66) | 6.2 |
| Wound healing | 1.34 (0.93 to 1.95) | 1.38 (0.96 to 1.98) | 3.9 |
| Other/non-specified | 0.71 (0.47 to 1.05) | 0.94 (0.65 to 1.34) | 2.2 |
| All adverse outcomes | 1.03 (0.90 to 1.17) | 1.39 (1.23 to 1.57) | 100 |
↵* The main contributing groups of adverse outcomes are analysed further by localisation (tables 6 and 7).