Question

A) Fifteen patients at risk for diabetes were placed on an investigational drug and followed for 5 years to determine the rate of diabetes development. After the end of the 5 -year study period, 4 patients had developed diabetes. What would be the incidence rate per year for the development of diabetes in this group?

B) Further examination of the data showed that not all patients were actually followed for the entire 5-year period. The actual observation periods are shown in the following table. Show another way to calculate incidence which would provide a better indication of the true rate given the time observed during the study.

Answer 1

The incidence rate per year for the development of diabetes in this group is 5.3%. To calculate a better indication of the true rate, we can use a weighted incidence rate based on the actual observation periods of each patient.

Step-by-step explanation:

The incidence rate per year for the development of diabetes in this group can be calculated by dividing the number of new cases (4) by the total person-years of observation. In this case, the total person-years of observation would be 15 patients x 5 years = 75 person-years. Therefore, the incidence rate per year would be 4/75 = 0.053 or 5.3%.

To calculate a better indication of the true rate given the time observed during the study, we can take into account the actual observation periods for each patient.

For example, if one patient was followed for 2 years and another patient was followed for 4 years, we can assign a weight to each patient based on their observation period.

By summing up the weights, we can calculate the weighted incidence rate which would provide a more accurate reflection of the true rate of diabetes development in this group.

Answer 2

The answer is 76 -25=145