Screening for Diabetes: Sensitivity and Positive Predictive Value of Risk Factor Total

Abstract

OBJECTIVE: Screening for diabetes is recommended for individuals ≥45 years of age, or earlier if they manifest ≥ one specific risk factors. This study examined the sensitivity and positive predictive value (PPV) of risk factor total for identifying individuals with diabetes and prediabetes.

DESIGN: Subjects were interviewed to assess the presence of risk factors. Fasting plasma glucose levels were obtained.

SETTING: The study occurred at a health fair in Greens-burg, PA.

PATIENTS: Six hundred sixty-one Caucasians between the ages of 19 and 100.

RESULTS: Using the criterion of screening individuals with ≥ one risk factors detected 100% of both diabetics and prediabetics. This dropped to 91.2% when screening individuals with > two factors. The PPV of the risk factor total was poor (80% of individuals with a total of four factors were not diabetic). The ability of the risk factor total to predict individuals with impaired glucose metabolism (prediabetics + diabetics) was considerably better, and increased almost linearly with the risk factor total. Of the subjects with normal glucose values, the mean glucose increased as the risk factor total increased.

CONCLUSION: While the sensitivity of using ≥ one risk factor as an algorithm to screen is 100% for identifying diabetics, the PPV of risk factor analysis for identifying diabetics is poor. The same algorithm works well to identify at-risk individuals, presumably allowing early intervention and education.

ABBREVIATIONS: FPG = fasting plasma glucose; PPV = positive predictive value.