| Risk tool | No of studies | n | Risk of bias | Inconsistency | Indirectness | Imprecision | Observed/Expected ratio (median, range) | Quality |
|---|---|---|---|---|---|---|---|---|
| Mortality | ||||||||
| POSSUM | 10 | 5252 | Serious risk of bias | Serious inconsistency | No serious indirectness | not estimable |
0.86 (0–1.73) | Very low |
| P-POSSUM | 10 | 8029 | Serious risk of bias | Serious inconsistency | No serious indirectness | not estimable |
1.03 (0.56–15.87) | Very low |
| NSQIP | 4 | 2634 | Serious risk of bias | Serious inconsistency | No serious indirectness | not estimable |
1.23 (0.64–1.28) | Very low |
| E-PASS | 1 | 100 | Serious risk of bias | No serious inconsistency | No serious indirectness | not estimable | 1 | Low |
| ASA | 1 | 1186 | Serious risk of bias | No serious inconsistency | No serious indirectness | not estimable | 1.08 | Low |
| SRS | 1 | 949 | Serious risk of bias | No serious inconsistency | No serious indirectness | not estimable | 0.81 | Low |
| Morbidity (composite outcome) | ||||||||
| POSSUM | 9 | 3356 | Serious risk of bias | Serious inconsistency | No serious indirectness | not estimable |
1 (0.8–1.44) | Very low |
| NSQIP | 5 | 3510 | Serious risk of bias | Serious inconsistency | No serious indirectness | not estimable |
1.06 (0.76–1.84) | Very low |
Risk of bias was assessed using the PROBAST checklist. Downgraded by 1 increment if the majority of the evidence was at high risk of bias, and downgraded by 2 increments if the majority of the evidence was at very high risk of bias
Inconsistency was assessed by visual inspection of a plotted summary where reported.
The judgement of precision was not possible in the absence of the confidence region of the O/E ratio, summary ratios were downgraded due to this limitation.
From: Evidence review for preoperative risk stratification tools
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