Table 2

Data collection measures

Primary outcome measuresGlycosylated haemoglobin A1cBlood specimen will be obtained at screening, 3, 6, 9, 12, and 18 months
Utilisation and costPreviously validated questions on resource utilisation will be administered. The questionnaires capture information on hospitalisations, physician/professional visits and medications
Secondary outcome measuresBlood pressureBlood pressure will be obtained at screening, 3, 6, 9, 12, and 18 months. Blood pressure readings will be obtained using automated BP monitors (OMRON IntelliSense HEM-907XL). The device will be programmed to take 3 readings at 2 min intervals and give an average of the 3 BP readings
LDL cholesterolLow-density lipoprotein (LDL) cholesterol will be obtained at the screening, 3, 6, 9, 12, and 18 months. About 10 cc of blood will be drawn by trained phlebotomists and sent to the laboratory for LDL cholesterol
Quality of lifeThe 12-item Short Form Survey (SF-12) is a valid and reliable instrument to measure functional status and reproduces 90% of the variance in PCS-36 and MCS-36 scores27
Behavioural skillsBehavioural skills will be assessed with the Summary of Diabetes Self-Care Activities (SDSCA), a brief, validated questionnaire of diabetes self-care28
Medication adherenceMedication adherence will be measured with the 6-item validated self-report Brooks Medication Adherence Scale (BMAS).29 Each of 6 items measures a specific medication-taking behaviour29
Delay discountingDelay discounting will be measured using the 10-item self-report Quick Delay Questionnaire (QDQ) developed to test two factors: (1) delay discounting and (2) delay aversion. Test–retest for the two factors are r=0.80 for delay discounting and r=0.81 for delay aversion. Internal consistency is satisfactory for both factors (delay discounting—α=0.68; delay aversion—α=0.77)30
CovariatesPatient demographicsDemographics will be measured using validated items from the Behavioral Risk Factor Surveillance System31
Social supportThe Medical Outcomes Study (MOS) Social Support Survey will be used to measure social support32
DepressionThe PHQ-9 will be used to measure depression. The PHQ-9 is a brief questionnaire that scores each of the 9 DSM-IV criteria for depression as “0” (not at all) to “3” (nearly every day). PHQ-9 score ≥10 have a sensitivity of 88% and a specificity of 88% for major depression33
Medical comorbidityMedical comorbidity will be assessed using previously validated questions regarding chronic disease from the Behavioral Risk Factor Surveillance System31
Health literacyThis will be assessed by the three-item CHEW34