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

Abstract

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

Research design and methods: 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.

Results: 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).

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