Question 1

What is target trial emulation?

Accepted Answer

Target trial emulation is a framework for analyzing observational data as though it were a randomized trial. You specify the trial you would have run — eligibility, treatment strategies, assignment, follow-up, outcome, and analysis plan — and then emulate each component in the observational data, which makes the assumptions explicit and exposes design errors such as immortal time bias.

Question 2

How closely do emulations reproduce their target trials?

Accepted Answer

Across 279 benchmarked comparisons, the pooled hazard ratio of emulation to trial estimate is 1.02 (95% credible interval 0.96 to 1.07): no systematic bias on average. Agreement in individual comparisons is much looser — the emulation confidence interval contains the trial estimate in 53% of comparisons, and the prediction interval for a new comparison spans 0.68 to 1.52.

Question 3

Why are some comparisons excluded from the pooled analysis?

Accepted Answer

Every extracted comparison is shown, but only those whose randomized benchmark could be verified against the trial’s primary report enter the pooled models. Comparisons are held back when the benchmark is unverifiable, when the emulation and trial report incompatible effect scales, or when the reference trial had not reported before the emulation was published. Each excluded comparison states its reason.

Question 4

Is XeraTTE open access?

Accepted Answer

Yes. Every study, comparison and analysis result is browsable and downloadable as CSV or JSON with no registration, and the API is public.

Study	Outcome & target trial	Trial vs emulation	Agreement
Admon 2019 Intensive care	Lowest oxygen saturation % vs PreVent·MD·Efficacy	3.901.40–6.40 1.80-1.00–4.60	not pooled
Admon 2019 Intensive care	Lowest oxygen saturation <80% vs PreVent·RR·Efficacy	0.480.30–0.77 0.600.38–0.93	not pooled
Admon 2019 Intensive care	Lowest oxygen saturation <90% vs PreVent·RR·Efficacy	0.740.60–1.00 0.890.70–1.20	not pooled
Admon 2019 Intensive care	Lowest oxygen saturation <70% vs PreVent·RR·Efficacy	0.410.20–0.90 0.630.30–1.30	not pooled
Admon 2019 Intensive care	Decrease in oxygen saturation % vs PreVent·MD·Efficacy	-4.50-6.80–-2.20 -1.90-4.50–0.80	not pooled
Admon 2019 Intensive care	Operator-reported aspiration vs PreVent·RR·Safety	0.640.20–1.90 3.000.40–10.80	not pooled
Admon 2019 Intensive care	Cardiac arrest 1 h after intubation vs PreVent·RR·Safety	0.760.20–3.40 2.000.40–10.80	not pooled
Admon 2019 Intensive care	Ventilator-free days vs PreVent·MD·Efficacy	0.60-1.70–2.90 -0.50-3.00–1.90	not pooled
Admon 2019 Intensive care	ICU-free days vs PreVent·MD·Efficacy	0.80-1.30–2.90 0.10-2.20–2.40	not pooled
Admon 2019 Intensive care	Died before hospital discharge vs PreVent·RR·Efficacy	1.000.80–1.30 1.000.80–1.30	not pooled
Petito 2020 Oncology	Overall survival vs QUASAR·HR·Efficacy	1.020.70–1.48 1.010.97–1.05	not pooled
Kirchgesner 2021 Gastroenterology	Treatment failure, 26 weeks vs SONIC·RR·Efficacy	0.780.62–0.97 0.710.62–0.82	not pooled
Kirchgesner 2021 Gastroenterology	Treatment failure, 16 weeks vs UC SUCCESS·RR·Efficacy	0.770.62–0.96 0.730.60–0.90	not pooled
Matthews 2021 Cardiology	Composite of death from any cause, MI, or major bleeding events by 180 days vs VALIDATE-SWEDEHEART·RR·Efficacy	0.960.83–1.10 0.930.77–1.12	not pooled
Matthews 2021 Cardiology	Death by 180 days vs VALIDATE-SWEDEHEART·RR·Efficacy	1.050.78–1.41 1.210.88–1.68	not pooled
Matthews 2021 Cardiology	MI by 180 days vs VALIDATE-SWEDEHEART·RR·Efficacy	0.840.60–1.19 1.080.76–1.54	not pooled
Matthews 2021 Cardiology	Major bleeding by 180 days vs VALIDATE-SWEDEHEART·RR·Safety	1.000.84–1.19 0.690.50–0.95	not pooled
Yiu 2021 Immunology	PASI ≤ 2 after 12 months vs CLEAR·RR·Efficacy	1.241.11–1.37 1.281.06–1.55	not pooled
Yiu 2021 Immunology	PASI 90 (≥ 90% improvement in PASI) vs CLEAR·RR·Efficacy	1.241.11–1.37 1.271.04–1.56	not pooled
Jang 2022 Oncology	Acute renal failure vs ASPIRE·RR·Safety	1.190.70–2.00 1.300.53–3.16	not pooled
Jang 2022 Oncology	Heart failure vs ASPIRE·RR·Safety	1.590.83–3.02 1.450.61–3.48	not pooled
Jang 2022 Oncology	Ischemic heart disease vs ASPIRE·RR·Safety	1.280.68–2.42 1.000.34–2.92	not pooled
Jang 2022 Oncology	Cough vs ASPIRE·RR·Safety	1.941.37–2.72 1.040.45–2.45	not pooled
Jang 2022 Oncology	Dyspnea vs ASPIRE·RR·Safety	1.380.94–2.00 2.271.24–4.16	not pooled
Jang 2022 Oncology	Hypokalemia vs ASPIRE·RR·Safety	2.461.69–3.57 1.910.62–5.87	not pooled