| Sarkar et al. 2010 |
Adult diabetics (n=14,102) in the Kaiser Permanente Northern California Diabetes Registry (28% non-Hispanic white, 14% Latino, 21% African American, 21% Asian, and 17% multiracial or other ethnicity) |
Cross-sectional survey and review of electronic records on patient portal use |
About 40% of respondents (n=5,671) registered for the web portal. Those with limited health literacy were less likely to sign on to the web portal [adjusted odds ratio (OR) =1.7, 95% confidence interval (CI) =1.4–1.9] compared with those who did not have a limitation in health literacy |
The study findings may not be generalizable to uninsured patients. |
| Wade-Vuturo et al. 2013 |
54 adult patients with type 2 diabetes seen at a Nashville, TN hospital |
Mixed-methods study that included a cross-sectional patient survey |
Secure messaging between patient and clinician was positively associated with glycemic control (P=0.04) |
Small sample size, uncertain generalizability |
| Shimada et al. 2016 |
Diabetic patients registered for the Veterans Health Administration My HealtheVet patient portal |
5-year retrospective cohort study of the link between use of My HealtheVet for refilling prescription medications, secure messaging, and lab tests used for managing type 2 diabetes |
Patients with elevated hemoglobin A1c (HbA1c) at baseline who used secure messaging were more likely than nonusers to achieve glycemic control (adjusted OR =1.24; 95% CI: 1.14–1.34). Patients with elevated blood pressure at baseline who used web-based refills were more likely than nonusers to achieve blood pressure control (OR=1.08; 95% CI: 1.02–1.14). |
Non-randomized design, uncertain generalizability |
| Harris et al. 2009 |
Group Health Cooperative diabetic patients (n=15,427) aged ≥18 years |
Cross-sectional study. The outcomes were diabetes-related quality-of-care indicators [HbA1c <7%, blood pressure <130/80 mmHg, and low density lipoprotein (LDL) cholesterol <100 mg/dL] |
About 19% of diabetic patients used secure messaging to communicate with their health care providers. Use of secure messaging was positively associated with HbA1c <7% [adjusted relative risk (RR) =1.36; 95% CI 1.16–1.58]. Frequent use of secure messaging was positively associated with increased outpatient visits. |
Nonrandomized design. The study findings may not be generalizable to uninsured patients. |
| Zhou et al. 2010 |
Adult Kaiser Permanente patients (n=35,423) in Southern California with diabetes or hypertension |
Matched-control analysis |
Secure messaging was positively associated with improved HbA1c screening and control (P<0.0001), LDL-C screening and control, retinopathy screening, and nephropathy screening. Secure messaging was also associated with improvement in blood pressure (P<0.001) |
Non-randomized design. The study findings may not be generalizable to uninsured patients |
| Tenforde et al. 2012 |
Adult diabetics followed at the Cleveland Clinic (n=10,746) aged 18–75 years |
Retrospective analysis. The outcome measures were dilated retinal exam, pneumococcal vaccination, test for microalbuminuria, foot exam, smoking cessation, HbA1C, systolic and diastolic blood pressure, LDL cholesterol, and body mass index |
Personal health record users had better diabetes quality measure profiles than non-users. The adjusted OR of HbA1c testing was 2.06 (P<0.01). Among personal health record users, increasing number of login days was not associated with more favorable diabetes quality measures |
Non-randomized design, lack of information about care received outside the Cleveland Clinic health system |
