Glycemic Control Associated With Secure Patient-Provider Messaging Within a Shared Electronic Medical Record: A longitudinal analysis

OBJECTIVE: To study differences in glycemic control and HbA(1c) testing associated with use of secure electronic patient-provider messaging. We hypothesized that messaging use would be associated with better glycemic control and a higher rate of adherence to HbA(1c) testing recommendations. RESEARCH DESIGN AND METHODS: Retrospective observational study of secure messaging at Group Health, a large nonprofit health care system. Our analysis included adults with diabetes who had registered for access to a shared electronic medical record (SMR) between 2003 and 2006. We fit log-linear regression models, using generalized estimating equations, to estimate the adjusted rate ratio of meeting three indicators of glycemic control (HbA(1c) <7%, HbA(1c) <8%, and HbA(1c) >9%) and HbA(1c) testing adherence by level of previous messaging use. Multiple imputation and inverse probability weights were used to account for missing data. RESULTS: During the study period, 6,301 adults with diabetes registered for access to the SMR. Of these individuals, 74% used messaging at least once during that time. Frequent use of messaging during the previous calendar quarter was associated with a higher rate of good glycemic control (HbA(1c) <7%: rate ratio, 1.26 [95% CI, 1.15–1.37]) and a higher rate testing adherence (1.20 [1.15–1.25]). CONCLUSIONS: Among SMR users, recent and frequent messaging use was associated with better glycemic control and a higher rate of HbA(1c) testing adherence. These results suggest that secure messaging may facilitate important processes of care and help some patients to achieve or maintain adequate glycemic control.