Table 1 Outcome measures

Diabetes Distress Scale (DDS)

Diabetes Distress Scale is a 17-item questionnaire that assesses distress associated with diabetes. It is divided into four subscales: emotional burden, physician-related distress, regimen-related distress, and interpersonal distress. The items are scored on a 6-point Likert scale ranging from 1 (no problem) to 6 (serious problem). Higher scores indicate greater distress. It has good internal consistency with a Cronbach’s alpha of 0.88–0.93 [10].

Patient Activation Measure (PAM)

The PAM is a 13-item questionnaire that measures patients’ knowledge, skill, and confidence in managing their health. Items are scored on a 4-point Likert scale ranging from 1 (strongly disagree) to 4 (strongly agree). The total score is converted to an activation score ranging from 0 to 100, with higher scores indicating greater activation. The PAM has a Cronbach’s alpha of 0.87 [13].

Short Form (SF-12)

The SF-12 is a 12-item generic health-related quality of life measure, derived from the longer SF-36 questionnaire. It consists of two summary scores: the Physical Component Summary (PCS) and the Mental Component Summary (MCS). Scores range from 0 to 100, with higher scores indicating better health. The SF-12 has demonstrated good internal consistency with a Cronbach’s alpha of 0.81 for PCS and 0.76 for MCS [19].

Summary of Diabetes Self-Care Activities Measure (SDSCA)

The MDI is a 12-item self-report questionnaire that measures symptoms of major depression. The questionnaire covers the ten ICD-10 and DSM-IV diagnostic criteria for depression. This MDI is scored on a 6-point Likert scale ranging from 0 (not at all) to 5 (all the time). Total scores range from 0 to 50, with higher scores indicating greater depressive symptoms. The MDI has demonstrated good internal consistency with a Cronbach’s alpha of 0.89 [15].

Major Depression Inventory (MDI)

The MDI is a 12-item self-report questionnaire that measures symptoms of major depression. The questionnaire covers the ten ICD-10 and DSM-IV diagnostic criteria for depression. Items are scored on a 6-point Likert scale ranging from 0 (not at all) to 5 (all the time). Total scores range from 0 to 50, with higher scores indicating greater depressive symptoms. The MDI has demonstrated good internal consistency with a Cronbach’s alpha of 0.89 [20].

2 single-item measures of psychosocial stress

These two single-item measures assess perceived stress and coping resources. The first item measures the level of perceived stress on a scale from 1 (not stressed) to 10 (extremely stressed). The second item measures the perceived ability to cope with stress on a scale from 1 (not able to cope) to 10 (very able to cope). Although single-item measures may have lower reliability than multi-item measures, it has been used in several research settings to assess psychosocial stress [16].

Connor-Davidson Resilience Scale (CD-RISC-10)

The CD-RISC-10 is a shorter, 10-item version of the original 25-item Connor-Davidson Resilience Scale that measures resilience, or the ability to cope with adversity. Items are scored on a 5-point Likert scale ranging from 0 (not true at all) to 4 (true nearly all the time). Total scores range from 0 to 40, with higher scores indicating greater resilience. The CD-RISC-10 has demonstrated good internal consistency with a Cronbach’s alpha of 0.85 [17, 21]

Lubben Social Network Scale-6 (LSNS-6)

The LSNS-6 is a shorter, 6-item version of the original 10-item Lubben Social Network Scale that assesses social network size and social support. It consists of two subscales: family and friends. Items are scored on a 6- point scale ranging from 0 (none) to 5 (nine or more). Total scores range from 0 to 30, with higher scores indicating larger social networks and greater support. The LSNS-6 has good internal consistency with a Cronbach’s alpha of 0.80 for the family subscale and 0.83 for the friend’s subscale [18].

Pittsburgh Sleep Quality Index (PSQI)

The PSQI is a 19-item self-report questionnaire that assesses sleep quality and disturbances over the past month. It consists of seven component scores: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction. Component scores range from 0 to 3, and the total score ranges from 0 to 21, with higher scores indicating poorer sleep quality. A total score greater than five suggests significant sleep disturbances. The PSQI has demonstrated good internal consistency with a Cronbach’s alpha of 0.83 [22].