Table 4.

Standardized mortality ratio by injury severity

Severity	No. of Studies	Participants	SMR	95% CI	I² (%)	τ²	Prediction Interval	Q (df), p-value (subgroup test)
Severe (GCS 3–8)	7	32,156	4.51	3.89–5.23	38.2	0.062	3.10–6.57
Moderate (GCS 9–12)	4	18,442	2.84	2.31–3.49	29.1	0.045	1.95–4.14
Mild (GCS 13–15)	3	21,387	1.67	1.28–2.18	18.4	0.029	1.02–2.74	Q = 24.8 (2), p < 0.001
Alternative (AIS/ISS)	5	33,964	3.27	2.78–3.84	44.7	0.071	2.17–4.92