The stiqsp command: A nonparametric approach for the simultaneous analysis of quality-of-life and survival data using the integrated quality survival product

In medical research, particularly in the field of cancer, it is often important to evaluate the impact of treatments and other factors on a composite outcome based on survival and quality-of-life data, such as a Quality Adjusted Life Year (QALY). We present a Stata program, stiqsp, which determines the mean QALY using the Integrated Quality Survival Product. In this nonparametric approach, the survival function is estimated using the Kaplan–Meier method and the quality-of-life function is derived from the mean quality-of-life score at the unique death times. Confidence intervals for the QALY score are determined using the bootstrap method. We illustrate the features of the command with a large dataset of patients with lung cancer.