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 HbA1c 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 HbA1c 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 (HbA1c <7%, HbA1c <8%, and HbA1c >9%) and HbA1c 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 (HbA1c <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 HbA1c 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.