Background: Navajo community members face high rates of diabetes mellitus and other chronic diseases. The Navajo Community Health Representative Outreach Program collaborated with healthcare providers and academic partners to implement structured and coordinated outreach to patients living with diabetes. The intervention, called Community Outreach and Patient Empowerment or COPE, provides home-based health coaching and community-clinic linkages to promote self-management and engagement in healthcare services among patients living with diabetes. The purpose of this study was to evaluate how outreach by Navajo Community Health Representatives ("COPE Program") affected utilization of health care services among patients living with diabetes. Methods: De-identified data from 2010 to 2014 were abstracted from electronic health records at participating health facilities. In this observational cohort study, 173 cases were matched to 2880 controls. Healthcare utilization was measured as the number of times per quarter services were accessed by the patient. Changes in utilization over 4 years were modeled using a difference-indifferences approach, comparing the trajectory of COPE patients' utilization before versus after enrollment with that of the control group. The model was estimated using generalized linear mixed models for count outcomes, controlling for clustering at the patient level and the service unit level. Results: COPE enrollees showed a 2.5% per patient per quarter (pppq) greater increase in total utilization (p = 0.001) of healthcare services than non-COPE enrollees; a 3.2% greater increase in primary care visits (p = 0.024); a 6.3% greater increase in utilization of counseling and behavioral health services (p = 0.013); and a 9.0% greater increase in pharmacy visits (p < 0.001). We found no statistically significant differences in utilization trends of inpatient, emergency room, specialty outpatient, dental, laboratory, radiology, or community encounter services among COPE participants versus control.