Validity of the primary care diagnosis of diabetes in veterans in the southeastern United States

Aims: To determine the validity of diagnosis of diabetes in primary care.

Methods: Patients with initial primary care diagnosis (ICD-9 code 250.xx) were compared to matched controls (without code or diabetes drugs), and patients meeting VA Diabetes Epidemiology Cohort (DEpiC) criteria (any 250.xx twice, or diabetes drug) in "diagnostic accuracy" (whether hyperglycemia preceded diagnosis) and "predictive accuracy" (whether diabetes drug or A1c ≥ 6.5% followed diagnosis).

Results: Only 1.8% of primary care diagnoses met ADA criteria, while nonstandard non-fasting morning glucose ≥ 126 mg/dl or A1c ≥ 6.5% were utilized in 51.5%; broad "diagnostic accuracy" criteria were met in 53% of 2980 primary care vs. 2% of 13,397 control (p<0.001), and 60% of 2456 DEpiC patients (p<0.001). "Predictive accuracy" was 88% in primary care diagnosis vs. 12% control (p<0.001) and 93% DEpiC patients (p=0.08), but was higher if ADA criteria were met. Delay from hyperglycemia to diagnosis averaged 12.5 months in primary care vs. 20.1 months in DEpiC patients (p<0.001).

Conclusions: While generally not based on ADA criteria, the primary care diagnosis of diabetes is valid, and identifies patients earlier than detection by DEpiC criteria. Either primary care diagnosis or DEpiC criteria could be used to trigger electronic reminders aimed to facilitate management.