Question

The following are data from a Primary Care Practice (PCP) who sees 80% people who are on Medicare.

In 2019, the PCP saw 6,000 individuals for 18,322 visits. Since the population the practice sees is over 65, they regularly screen for diabetes every year. Prior to 2019, 10% of the patients had tested positive to diabetes. In 2019, the practice screened people for diabetes and found that 20% screened positive. Of those who screened positive, 80% were confirmed to have diabetes. In addition, 86 people had diabetes but screened negative. Fill in the table with data either given or calculated.

Calculate the following based on the information provided (to 1 decimal place):

	Diabetes	No Diabetes	total
Screen positive
Screen negative
Total

1. Sensitivity

2. Specificity

3. Positive Predictive Value

4. Negative Predictive Value

5. Do you think the screening test performed well? Why or why not?

6. What do you think the Primary Care Practice should do in this situation?

Answer 1

	Diabetes	No Diabetes	Total
Screen Positive	0.8 x 1200 = 960	1200-960 = 240	0.2 x 6000 = 1200
Screeen Negative	86	4800-86 = 4714	6000-1200 = 4800
Total	1046	4954	6000

1. Sensitivity = True Positive/ People with Diabetes = 960/1046 = 0.9177

2. Specificity = True Negative/ People without Diabetes = 4714/4954 = 0.9515

3. Positive Predictive Value =True Positive/ Total Positive tests = 960/ 1200 = 0.8

4. Negative Predictive Value = True Negative/ Total Negative tests = 4717/4800 = 0.9827

(only 4 subparts per question allowed)