ClinicalTrialSummary-package {ClinicalTrialSummary}

Summary Measures for Clinical Trials with Survival Outcomes

Description

ClinicalTrialSummary provides estimates of several summary measures of the treatment effect for design and analysis of clinical trials with survival outcomes, introduced in Yang (2018). These estimates are obtained under the short-term and long-term hazard ratio model (Yang and Prentice, 2005) which allows a range of time-varying hazard ratio shapes including crossing hazards situations.

Let hr(x) = \lambda_{t}(x)/\lambda_{c}(x) be the hazard ratio function, where \lambda_{t}(x) and \lambda_{c}(x) are the hazard functions for the treatment group and the control group, respectively. The main function of the package, ypsummary, provides following five summary measures:

• the average hazard ratio (AHR): \int hr(x) dx

• the weighted average hazard ratio (WAHR): \int hr(x) dw(x) where dw(x) = dF_c(x)/F_c(\tau)

• the restricted superiority probability ratio (RSPR): \frac{\int S_c(x) dF_t(x)}{\int St(x) dF_c(x)}

• the restricted mean survival difference (RMSD): \int S_t(x) dx - \int S_c(x) dx

• the ratio of restricted mean times lost (RRMTL): \frac{\tau - \int S_t(x) dx}{\tau - \int S_c(x) dx}

Note that all integrals are taken over (0, \tau) for \tau less than or equal to the maximum follow-up duration of the trial. The asymptotic results for the average hazard ratio and the restricted mean survival difference were established in Yang and Prentice (2011) and Yang (2013), respectively. For other measures, the asymptotic results were established in Yang (2018).

The data used as an example in this package was from Gastrointestinal Tumor Study Group (1982) and the object returned by ypsummary can be formatted to a table using the function summary.

Details

Package:	ClinicalTrialSummary
Type:	Package
Version:	1.0.0
Date:	2018-12-19
License:	GPL (>= 3)

Author(s)

Daewoo Pak and Song Yang

References

Yang, S. (2018). Improving testing and description of treatment effect in clinical trials with survival outcomes. Statistics in medicine.

Yang S, and Ross L. Prentice (2005). Semiparametric analysis of short-term and long-term hazard ratios with two-sample survival data. Biometrika, 92.1:1-17.

Yang S, and Ross L. Prentice (2011). Estimation of the 2-sample hazard ratio function using a semiparametric model. Biostatistics, 12.2:354-368.

Yang S. (2013). Semiparametric inference on the absolute risk reduction and the restricted mean survival difference in clinical trials. Special issue on risk assessment. Lifetime Data analysis, 19:219-241.

Gastrointestinal Tumor Study Group (1982). A comparison of combination chemotherapy and combined modality therapy for locally advanced gastric carcinoma. Cancer.

See Also

ypsummary

Examples

	library(ClinicalTrialSummary)
	data(ggas)
	result <- ypsummary(time=ggas$time, event=ggas$event, group=ggas$group, tau = 8.2)
	print(result)
	summary(result)