XLSTAT: Life Table Analysis in Excel

 

Dataset for Example

The attached data have been obtained in [Lee E.T. (1992). Statistical Methods for Survival Data Analysis, Second Edition, John Wiley & Sons, New York] and represent the evolution of the number of patients with angina pectoris, during a 15 year period (Jan 1,1927 - Dec 31,1941).

Survival time is measured as years from the time of diagnosis. The counts correspond to events (number of patients who died during a time interval) and to withdrawals (number of patients lost to follow up).

Our goal is to determine to display the life table, analyze the median residual lifetime (or median survival time), and plot the non-parametric estimate of the survival distribution function.

 

Setting Up

• Open XLSTAT.

• Click on the Life Sciences/ Survival analysis menu and select the Life table analysis feature.

• Once the Life table analysis box opens.

In the General tab:

• Select the Time data (interval end times).

• Check the Weighted data option.

• Select "Died" for the Event indicator field.

• Select "Censored" for the Censored indicator field.

In the Charts tab:

• Activate the charts you wish to display, and choose the symbol you want to use to represent Censored data.

• Click on the OK button to launch the computations.

• The results are displayed on a new Excel sheet.

 

Interpreting the Results

The first table summarizes the data. The "Actuarial table" follows, showing life table results, including key indicators like the median survival time.

The third table highlights the median survival time and its standard deviation. It shows that the median residual lifetime for angina pectoris is 5.3 years—meaning 50 out of 100 patients are expected to die within 5.3 years of diagnosis.

Last, we can visualize several curves, including the survival distribution function (SDF, or survivor function), and the -Log(SDF) curve. From the latter, we see that the function is close to an exponential model.