Rural Residence is Associated with a Delayed Trend Away From Sulfonylurea Use for Treatment Intensification of Type 2 Diabetes

Objective: To examine the intersection between location of residence along the rural-urban continuum (metropolitan/urban/rural) and sulfonylurea dispensation records for the management of type 2 diabetes.
Research Design and Methods: This retrospective cohort study used administrative health records of adult new metformin users between April 2008-March 2019 in Alberta, Canada. Multivariable logistic regression was performed to examine the association between sulfonylurea-based treatment intensification and location of residence.
Results: Treatment was intensified in 66,084 (38%) of 171,759 new metformin users after a mean of 1.5 years. At treatment intensification, mean age was 55 years, 62% were male, and 27% were rural residents. The most common antihyperglycemic drug, given to 30,297 (46%) people for treatment intensification, was a sulfonylurea. At the beginning of our observation period, the proportion of people dispensed a sulfonylurea at first treatment intensification was highest in rural (57%), compared to urban (54%) and metropolitan (52%) areas (p=0.009). Although proportions decreased over time across the province, rural residents continued to have the highest proportion of sulfonylurea users (45%) compared to urban (35%) and metropolitan (37%) (p< 0.001) and the trend away from sulfonylurea use was delayed by ~4 years for rural residents. Adjusting for potential sources of confounding, rural residence was associated with a significantly higher likelihood of using a sulfonylurea compared to metropolitan (aOR:1.34; 95% CI:1.29-1.39).
Conclusions: Variation in sulfonylurea dispensation across the rural-urban continuum provides a basis for continued research in the differences in process of care by location.