Sudden Death Associated with Treatment for Hypertension| Original Article | Zipped SPSS Save File | FrankHarrell's Critique of the Article

Analyze the MRC dataset. The SPSS save file can easily be imported into R using the Hmisc spss.get function. The goal of the analysis is to assess whether there is an increase in sudden death associated with one of the treatments. Note that this study was published in BMJ in 1992 and now a Vanderbilt investigator has added a new variable (sudden death). Please note that this is real patient data that we must keep confidential.

As part of your analysis please do the following:
  1. Read the BMJ paper
  2. Use a simple command to change the names of the variables to lower case and another command to change underscores in the names to periods. The latter may be handled by modifying the following code: gsub('_','.',variablenames). Note: as of 22Dec04 spss.get does this automatically.
  3. Test whether there is an increase in sudden death associated with one of the treatments.
  4. Use survival methods to assess factors associated with time to sudden death (dl.death and sdeath). Consider treatment (tmtnew), gender, age, and other baseline factors such as EKG results (e.g., bl.ecgm3). Also, assess baseline heart rate, baseline cholesterol, and smoking status.
  5. Are there important interactions, such as sex-treatment, or treatment with baseline factors?
  6. Determine whether the statistical methods in the BMJ paper were appropriate.
  7. What conclusions would you make regarding these results? Are there subgroups that might be at increased risk or questions that might require another trial?

The important variables are:
sdeath Was this a sudden death? 0=no, 1=yes
tmtnew Treatment group 1=Diuretic (moduretic), 2=B-blocker (tenormin), 3=Placebo
dl.death years to death, end of study, or lost to followup
age age in years
sex gender of the patient 0=women, 1=men
dl.mi Years to MI/end of followup
bl baseline
bl.smoke baseline smoking 0=no, 1=yes
bl.ecgm3 vertricular hypertroyphy on ecg 0=no, 2=yes
bl.ecgm4 ST depression on ecg
bl.chol baseline cholesterol baseline heart rate

Variable and value labels are included in the data file, so you can ignore some of the numeric codes listed above.
Note: The ID for accessing the article and the dataset is articles. Please contact FrankHarrell for the password.
Topic revision: r3 - 24 Dec 2004, FrankHarrell

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