Screening for diabetes: sensitivity and positive predictive value of risk factor total

Area of Science:

• Endocrinology
• Preventive Medicine
• Public Health

Background:

• Diabetes mellitus screening is recommended for individuals aged 45 and older, or younger if risk factors are present.
• Risk factor assessment is a common method for identifying individuals who may have or be at risk for diabetes.

Purpose of the Study:

• To evaluate the sensitivity and positive predictive value (PPV) of a total risk factor count for identifying individuals with diabetes and prediabetes.
• To determine the effectiveness of risk factor screening in detecting glucose metabolism abnormalities.

Main Methods:

• A health fair in Greensburg, PA, served as the study setting.
• Six hundred sixty-one Caucasian participants aged 19-100 were interviewed to identify risk factors.
• Fasting plasma glucose levels were measured to diagnose diabetes and prediabetes.

Main Results:

• Screening with one or more risk factors detected 100% of individuals with diabetes and prediabetes.
• Sensitivity decreased to 91.2% when screening for two or more risk factors.
• The positive predictive value of the risk factor total was poor; 80% of those with four risk factors were not diabetic.
• The risk factor total effectively predicted impaired glucose metabolism, with a near-linear increase in prediction as the total risk factors increased.
• Among participants with normal glucose levels, mean glucose increased with a higher total risk factor count.

Conclusions:

• While using one or more risk factors as a screening algorithm demonstrates 100% sensitivity for detecting diabetes, its positive predictive value is low.
• The same screening algorithm effectively identifies individuals at risk for diabetes, suggesting utility for early intervention and education.
• Risk factor assessment is valuable for identifying individuals with impaired glucose metabolism, even if not all individuals with multiple risk factors have diabetes.