Community-based screening for cardiovascular disease and diabetes using HbA1c

Persons from inner-city immigrant and mixed-ethnic communities are known to be at high risk for cardiovascular disease and diabetes. Such communities may also be underserved for preventive medical care. The authors hypothesized that hemoglobin A1c (HbA1c) could be used as a screening test for a community-based program to detect new cases of diabetes and persons at risk for diabetes and cardiovascular disease.

Screenings took place in churches, group homes, shelters, community centers, and street corners of the Bronx. Screening data included history of diabetes, age, ethnicity, body mass index, blood pressure, lipid panel, random glucose, and HbA1c. Data were analyzed for number of cases of new diabetes (HbA1c > or =7%), for patients at risk for diabetes (HbA1c 6%-6.99%), and for associations between HbA1c and other variables. The effect of location of screening and self-reported ethnicity on outcome variables was also analyzed.

Seven hundred four persons were screened in 25 different sessions. HbA1c and lipid profile were obtained on 539 persons, which formed the cohort for analysis. Mean HbA1c for the cohort was 6.00%. Thirty-two percent of the cohort had HbA1c of more than 6%, and 11.4% had HbA1c of more than 7%. Excluding known diabetics (13% of cohort), 24% had HbA1c of more than 6%, and 3.4% had HbA1c of more than 7%. HbA1c was significantly correlated with total cholesterol, triglycerides, low-density lipoprotein, systolic blood pressure, body mass index, and age; in all cases, correlation coefficients were higher with HbA1c than with random glucose. In addition, significantly higher cardiovascular disease risk factors were found in persons with HbA1c of more than 6%; 6% may be a threshold value for the metabolic syndrome. Mean HbA1c was higher in persons from the South Bronx (which has a higher poverty rate) than the North Bronx (6.08% v 5.74%, p=0.013). There were no statistically significant differences between self-reported ethnic groupings.

There was a high prevalence of undiagnosed diabetes, and of patients at risk for diabetes, in this community setting. Community-based screening can be used as a method for identifying high percentages of patients at risk for diabetes or with undiagnosed diabetes in an inner city, immigrant, mixed-ethnic population.