Associations of Four Community Factors With Longitudinal Change in Hemoglobin A1c Levels in Patients With Type 2 Diabetes

To evaluate associations of community factors with glycated hemoglobin (HbA_1c).

We identified patients with type 2 diabetes who had an HbA_1c ≥7.5% (58 mmol/mol) and subsequent HbA_1c testing within 90–270 days. We used mixed-effect models to assess whether treatment intensification (TI) and community domains (community socioeconomic deprivation [CSD], food availability, fitness assets, and utilitarian physical activity favorability [quartiled]) were associated with HbA_1c change over 6 and 24 months, controlling for demographics, HbA_1c, BMI, and time with evidence of type 2 diabetes. We evaluated whether community domains modified associations of TI with HbA_1c change using cross product terms.

There were 15,308 patients with 69,818 elevated HbA_1c measures. The average reduction in HbA_1c over 6 months was 0.07% less in townships with a high level of CSD (third quartile versus the first). Reductions were 0.10% greater for HbA_1c in townships with the best food availability (versus worst). HbA_1c reductions were 0.17–0.19% greater in census tracts in the second and third quartiles of utilitarian physical activity favorability versus the first. The association of TI with 6-month HbA_1c change was weaker in townships and boroughs with the worst CSD (versus best) and in boroughs with the best fitness assets (versus worst). The association of TI with 24-month HbA_1c change was weaker in census tracts with the worst CSD (versus third quartile) and strongest in census tracts most favorable for utilitarian physical activity (versus worst).

Community domains were associated with HbA_1c change and blunted TI effectiveness.