Shifts in Safety Lab Grades in Clinical Trials
In clinical trials laboratory values are graded in severity using some system such as the NCI CTCAE grading system for Cancer drug trials. The table below is a typical presentation of data about shifts in safety grades from the baseline to the worst grade while on treatment (this table is created using made-up data which does not bear any resemblance to any real clinical trial). This is how you read the table:
34 patients had a grade 3 anemia at baseline and that improved to a worst grade of 2 in 20 patients and grade 1 in 14 patients.
157 patients were normal on anemia at baseline. 61 stayed normal on treatment, 86 had a worst grade of 1 and 10 had a worst grade of 2.
The Tepee Graphic below the table provides an intuitive visualization of this data. The length of each horizontal line represents the row total – the total number of patients in each baseline anemia grade. The segments of each horizontal line represents the total in this baseline grade who end up in the different worst grades on treatment indicated by the colors in the legend. The number of patients with any combination of baseline grade and worst grade can be read off from the length of the associated segment using the scale provided. The area of the colors are directly proportional to the column totals – the number of patients in each worst grade.
|Shifts in Anemia Grades from Baseline to Worst Grade on Treatment|
|Normal||Grade 1||Grade 2||Grade 3||Row Sum|
|Baseline Grade 3||0||14||20||0||34|
|Baseline Grade 2||14||101||85||10||210|
|Baseline Grade 1||40||162||45||7||254|