Equivalency between the shock index and subtracting the systolic blood pressure from the heart rate: an observational cohort study

Table 2 SI and SI derived by sSI (HR-SBP) equivalence tests

	N	Mean difference (90% CI)
Age, years
15–64	2420	0.009 (0.008 to 0.011)*
≥ 65	3009	0.000 (− 0.001 to 0.002)*
Sex
Female	2677	0.003 (0.001 to 0.004)*
Male	2752	0.005 (0.004 to 0.007)*
Pre-existing condition
Trauma	1653	0.000 (−0.002 to 0.002)*
Pregnancy	91	0.008 (0.004 to 0.012)*
Acute myocardial infarction	97	0.016 (0.006 to 0.026)*
Sepsis	65	−0.022 (− 0.038 to − 0.006)*
Chronic respiratory disease	114	−0.003 (− 0.011 to 0.005)*
Intracranial disease	643	−0.005 (− 0.008 to − 0.002)*
Systolic blood pressure
Hypotension (< 90 mmHg)	129	0.008 (−0.014 to 0.031)*
Normotension (90–139 mmHg)	2467	0.030 (0.029 to 0.031)*
Hypertension (140–179 mmHg)	2282	−0.007 (− 0.009 to − 0.006)*
Severe hypertension (≥180 mmHg)	551	−0.064 (− 0.066 to − 0.061)
Total	5429	0.004 (0.003 to 0.005)*

SI Shock index, sSI Simple shock index, HR Heart rate, SBP Systolic blood pressure, CI Confidence interval. Equivalence margin is 0.052. SI derived by sSI was calculated according to the following estimation equation: sSI = 258.55 log SI.
*Significant results based on the 90% CI values

ISSN: 1471-227X