The 5-item Manage Disease in General Scale of the Chronic Disease Self-Efficacy Scales is a validated measure of the confidence a person has in managing their own health and health care and is closely related to patient activation. The items were adapted to be specific to diabetes rather than a generic condition or illness. Each item uses a 10-point Likert-type scale of response options ranging from 1 (not at all confident) to 10 (totally confident). Responses result in total raw scores ranging from 1 to 10. The score for the scale is the mean of the items. Higher scores indicate greater confidence in managing diabetes in general.

The Problem Areas in Diabetes Scale (PAID-5) is a valid measure of diabetes distress. The PAID-5 contains 5 items which have a five-point response option (0-4 representing 'Not a problem' through to 'Serious problem'). Total scores on the PAID-5 can range from 0 to 20, with higher scores suggesting greater diabetes-related emotional distress care (e.g., Diabetes Eye Exams) will be administered to all study participants.

The System Usability Scale (SUS) is a valid measure of usability and assesses user's perceptions of ease of use, likability of the interface, and overall satisfaction. Each question on the 10-item questionnaire is scored on a 5-point Likert scale [0 (Strongly disagree) to 4 (strongly agree)] and the sum is totaled (0-40). The total sum is then multiplied by 2.5 to convert the original scores to a range of 0 (worst) to 100 (best). Based on prior research, a score above 68 would be above average and a score of 85 or above suggests excellent usability. The SUS has been used in several studies of patient facing health information technology (the article describing its psychometric properties has been cited over 500 times) and has excellent internal consistency reliability (Cronbach's alpha of 0.91).

Participants' most recent hemoglobin A1C will be abstracted from participants' electronic medical record.

The addition of: (a) antihyperglycemic medications and (b) antihypertensive medications will be assessed by EHR abstraction.

The Perceived Diabetes Self-Management Scale (PDSMS) is a valid measure of diabetes self-efficacy (i.e., how confident they feel about their ability to carry out multiple self management tasks). The uni-dimensional, 8-item scale is scored on a five-point Likert scale. The total PDSMS score can range from 8 to 40, with higher scores indicating more confidence in self-managing one's diabetes.

The number of patient reports of diabetes eye exams received outside the Vanderbilt University Medical Center health system submitted via the study intervention.

Total of all reporting groups

The eHealth Literacy Scale (eHEALS) was used to assess eHealth literacy. The eHEALS is an 8-item survey that uses a 5-point Likert scale, where 1 is "strongly disagree" and 5 is "strongly agree". The eHEALS is scored on a scale of 8-40, with higher scores indicating greater eHealth literacy.

Patients have access to an existing patient web portal (My Health at Vanderbilt) embedded with the Diabetes Care Gaps Patient Portal Intervention.

Diabetes Care Gaps Patient Portal Intervention: The Diabetes Care Gaps Patient Portal Intervention is embedded within an existing patient web portal (My Health at Vanderbilt). The intervention (a) notifies patients when selected, clinically meaningful, evidence-based diabetes preventative care (e.g., annual urine microalbumin) are due and (b) allows patients to initiate orders for the care.

The number of patient-initiated orders via the study intervention for evidence-based diabetes monitoring and preventative services (e.g., A1c).

This analysis is limited to the intervention arm only because only patients in the intervention arm were able to initiate orders via the study intervention.

Unique study specific items (four items) to assess participant's understanding of measures of diabetes monitoring and preventative care (e.g., Diabetes Eye Exams) will be administered to all study participants. Each multiple-choice item has only one correct answer and the overall measure is scored as the percent of the items answered correctly.

Number analyzed varies because not all participants answered all items at each timepoint.

The 5-item Manage Disease in General Scale of the Chronic Disease Self-Efficacy Scales is a validated measure of the confidence a person has in managing their own health and health care and is closely related to patient activation. The items were adapted to be specific to diabetes rather than a generic condition or illness. Each item uses a 10-point Likert-type scale of response options ranging from 1 (not at all confident) to 10 (totally confident). Responses result in total raw scores ranging from 1 to 10. The score for the scale is the mean of the items. Higher scores indicate greater confidence in managing diabetes in general.

Number analyzed varies because not all participants answered all items at each timepoint.

The Problem Areas in Diabetes Scale (PAID-5) is a valid measure of diabetes distress. The PAID-5 contains 5 items which have a five-point response option (0-4 representing 'Not a problem' through to 'Serious problem'). Total scores on the PAID-5 can range from 0 to 20, with higher scores suggesting greater diabetes-related emotional distress care (e.g., Diabetes Eye Exams) will be administered to all study participants.

Number analyzed varies because not all participants answered all items at each timepoint.

The System Usability Scale (SUS) is a valid measure of usability and assesses user's perceptions of ease of use, likability of the interface, and overall satisfaction. Each question on the 10-item questionnaire is scored on a 5-point Likert scale [0 (Strongly disagree) to 4 (strongly agree)] and the sum is totaled (0-40). The total sum is then multiplied by 2.5 to convert the original scores to a range of 0 (worst) to 100 (best). Based on prior research, a score above 68 would be above average and a score of 85 or above suggests excellent usability. The SUS has been used in several studies of patient facing health information technology (the article describing its psychometric properties has been cited over 500 times) and has excellent internal consistency reliability (Cronbach's alpha of 0.91).

Number analyzed varies because not all participants answered all items at each timepoint.

Participants' most recent hemoglobin A1C will be abstracted from participants' electronic medical record.

Number analyzed differs because not all patients had a qualifying A1c value in the EHR for the timepoint.

The addition of: (a) antihyperglycemic medications and (b) antihypertensive medications will be assessed by EHR abstraction.

The Perceived Diabetes Self-Management Scale (PDSMS) is a valid measure of diabetes self-efficacy (i.e., how confident they feel about their ability to carry out multiple self management tasks). The uni-dimensional, 8-item scale is scored on a five-point Likert scale. The total PDSMS score can range from 8 to 40, with higher scores indicating more confidence in self-managing one's diabetes.

Number analyzed varies because not all participants answered all items at each timepoint.

The number of patient reports of diabetes eye exams received outside the Vanderbilt University Medical Center health system submitted via the study intervention.

This analysis is limited to the intervention arm only because only patients in the intervention arm were able to report diabetes eye exams received outside the Vanderbilt University Medical Center health system using the study intervention.

Patients have access to an existing patient web portal (My Health at Vanderbilt) embedded with the Diabetes Care Gaps Patient Portal Intervention.

Diabetes Care Gaps Patient Portal Intervention: The Diabetes Care Gaps Patient Portal Intervention is embedded within an existing patient web portal (My Health at Vanderbilt). The intervention (a) notifies patients when selected, clinically meaningful, evidence-based diabetes preventative care (e.g., annual urine microalbumin) are due and (b) allows patients to initiate orders for the care.

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