Table 3 Data collection instruments

Process and behavioral measures

Information

This will be measured by the 24-item Diabetes Knowledge Questionnaire (DKQ) [17].

Knowledge about diabetes

Previously validated items from the Diabetes Study of Northern California (DISTANCE) survey [18] will be used to capture knowledge about diabetes.

Diabetes education

Three previously validated items from the Behavioral Risk Factor Surveillance System (BRFSS) [19] will be used to capture the patients’ confidence in diabetes self-management.

Motivation

This will be measured by the eight-item Diabetes Empowerment Scale-Short Form (DES-SF) [20].

Self-efficacy

This will be measured by the Perceived Diabetes Self-Management Scale (PDSMS) [21].

Behavioral skills

This will be assessed with the Summary of Diabetes Self-Care Activities (SDSCA) scale [22].

Medication adherence

This will be measured with the new eight-item self-report Morisky Medication Adherence Scale (MMAS) [23].

Diabetes fatalism

This will be measured with the 12-item Diabetes Fatalism Scales (DFS) [24], a valid and reliable measure of diabetes fatalism that is associated with self-care problems, poor glycemic control, and decreased quality of life.

Covariates

Demographics

Previously validated items from the 2002 National Health Interview Survey [25] will be used to capture age, gender, race/ethnicity, marital status, household income, and health insurance.

Social support

The Medical Outcomes Study (MOS) Social Support Survey [26] will be used to measure social support.

Health literacy

The abbreviated version of the Test of Functional Health Literacy in Adults (S-TOFHLA) [27] is designed to rapidly screen patients for potential health literacy problems.

Depression

The Patient Health Questionnaire-9 (PHQ-9) is a brief questionnaire that scores each of the nine Diagnostic and Statistical Manual of Mental Disorders (4th revision) criteria for depression [28].

Diabetes distress

The Diabetes Distress Scale (DDS) is a two-item scale that measures patient concerns about disease management, support, and emotional burden [29].

Delayed discounting

The Quick Delay Questionnaire (QDQ) Discounting Module is a 10-item survey used to help researchers understand how the amount of monetary gain and timing are associated with treatment adherence and clinical outcomes among individuals with type 2 diabetes [30].

Medical comorbidity

The patient's history of medical comorbidity will be documented using chronic health conditions (previously validated items from the BRFSS) [31].