The accuracy of surrogate decision makers: informed consent in hypothetical acute stroke scenarios

BMC Emergency Medicine

Table 2 Agreement between patients and surrogates for hypothetical stroke scenarios

Scenario 1: TPA vs. no treatment				Scenario 2: TPA vs. clot removal procedure				Scenario 3: TPA vs. standard RCT				Scenario 4: TPA vs. adaptive RCT
	Patients				Patients				Patients				Patients
Proxies	Would you want TPA?	Yes	No	Proxies	Would you want the procedure?	Yes	No	Proxies	Would you want the trial?	Yes	No	Proxies	Would you want the trial?	Yes	No
	Yes	95.5% (n = 191)	2% (n = 4)		Yes	1% (n = 2)	4.5% (n = 9)		Yes	4.5% (n = 9)	9% (n = 18)		Yes	28.5% (n = 57)	21.5% (n = 43)
	No	2% (n = 4)	0.5% (n = 1)		No	8.5% (n = 17)	86% (n = 172)		No	17% (n = 34)	69.5% (n = 139)		No	29.5% (n = 59)	20.5% (n = 41)
		Mean	SD			Mean	SD			Mean	SD			Mean	SD
Patient confidence		8.0	2.1	Patient confidence		8.1	2	Patient confidence		8.0	1.9	Patient confidence		7.8	1.9
Proxy confidence		8.5	1.7	Proxy confidence		8.5	1.9	Proxy confidence		8.4	1.9	Proxy confidence		8.0	1.9
Proxy certainty		8.4	1.9	Proxy certainty		8.0	2.2	Proxy certainty		7.8	2.3	Proxy certainty		7.5	2.1
Cohen’s Kappa statistic		0.18		Cohen’s Kappa statistic		0.07		Cohen’s Kappa statistic		0.11		Cohen’s Kappa statistic		-0.02
AC1 (95% CI)		0.96 (0.93-0.99)		AC1 (95% CI)		0.87 (0.79-0.91)		AC1 (95% CI)		0.63 (0.53-0.74)		AC1 (95% CI)		-0.01 (-0.13 – 0.13)

Overall agreement is observed in the bolded diagonal cells (i.e for scenario 1: 96% of patients and proxies agreed). Counts and proportions listed for all scenarios. Patient and surrogate confidence was measured on a 10 point Likert scale. SD = standard deviation. tPA = tissue plasminogen activator. RCT = Randomized controlled trial. AC1 = Gwet’s agreement coefficient. CI = confidence interval.

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