Screening for diabetes in an outpatient clinic population.

BACKGROUND

Opportunistic disease screening is the routine, asymptomatic disease screening of patients at the time of a physician encounter for other reasons. While the prevalence of unrecognized diabetes in community populations is well known, the prevalence in clinical populations is unknown.

OBJECTIVE

To describe the prevalence, predictors, and clinical severity of unrecognized diabetes among outpatients at a major medical center.

DESIGN AND SETTING

A cross-sectional observational study at the Durham Veterans Affairs Medical Center.

SUBJECTS

Outpatients without recognized diabetes (N=1,253).

METHODS

We screened patients for diabetes by using an initial random Hemoglobin A1c (HbA1c) measurement, and then obtaining follow-up fasting plasma glucose (FPG) for all subjects with HbA1c > or =6.0%. A case of unrecognized diabetes was defined as either HbA1c > or =7.0% or FPG > or =7 mmol/L (126 mg/dL). Height and weight were obtained for all subjects. We also obtained resting blood pressure, fasting lipids, and urine protein in subjects with HbA1c > or =6.0%.

RESULTS

The prevalence of unrecognized diabetes was 4.5% (95% confidence interval [CI], 3.4 to 5.7). Factors associated with unrecognized diabetes were the diagnosis of hypertension (adjusted odds ratio [OR], 2.5; P=.004), weight >120% of ideal (adjusted OR, 2.2; P=.02), and history of a parent or sibling with diabetes (adjusted OR, 1.7; P=.06). Having a primary care provider did not raise or lower the risk for unrecognized diabetes (P=.73). Based on the new diagnosis, most patients (61%) found to have diabetes required a change in treatment either of their blood sugar or comorbid hypertension or hyperlipidemia in order to achieve targets recommended in published treatment guidelines. Patients reporting a primary care provider were no less likely to require a change in treatment (P=.20).

CONCLUSIONS

If diabetes screening is an effective intervention, opportunistic screening for diabetes may be the preferred method for screening, because there is substantial potential for case-finding in a medical center outpatient setting. A majority of patients with diabetes diagnosed at opportunistic screening will require a change in treatment of blood sugar, blood pressure, or lipids to receive optimal care.