Table 1 Study outcomes

 Distress

Patient Health Questionnaire Anxiety and Depression Scale (PHQ-ADS) [45]

Composite measure of depression and anxiety.

0–48, higher scores indicate more symptoms of depression and anxiety, cut off: 0–9 minimal, 10–19 mild, 20–29 moderate, 30–48 severe.

X

X

X

 Personalized outcome assessment

Patient Priority and Progress Questionnaire (PPPQ) [46]

Patient priorities and personal meaningful changes over time. Measured by 1 item on priorities and 8 items on functioning using 5-point Likert scales for the baseline measurement and 7-point Likert scales for the follow-up measurement. Based on the follow-up measurement, a progress score is calculated on the selected priority.

−3–3, progress score, higher scores indicate subjective improvement on the selected priority as compared to the baseline measurement.

X

X

X

 Domains of functioning

RAND Short Form-36 Health Status Inventory (RAND SF-36) [47]

Health-related quality of life, including physical and mental component scores. Measured by 36 items using several Likert scales and yes/no questions.

T-scores, M=50±10 in the general population.

X

X

X

Dialysis Symptom Index (DSI) [48]

Physical and emotional symptom burden in dialysis patients. 30 items regarding the presence of symptoms, when present symptom severity is assessed by 5-point Likert scales.

30 yes/no questions, if “yes” 1=not at all, 5=very much. Minimum score is 0 when none of the symptoms are reported. Maximum score is 150 when all 30 symptoms are reported and rated as “bothers very much” (Likert scale score 5).

X

X

X

Subjective experience of fatigue subscale, Checklist Individual Strength (CIS) [49]

Fatigue. Measured by 8 items using 7-point Likert scales.

8–56, higher scores indicate more fatigue.

X

X

X

Itch subscale of the Impact of Chronic Skin Disease on Daily Life (ISDL) [50]

Itch. Measured by 4 items including 3 items using 4-point Likert scales and 1 VAS (0 = no itch, 10 = worst itch ever).

4–16, the 11-point VAS will be transformed into a 4-point Likert scale to assess the total score. Higher scores indicate more itch.

X

X

X

Inventory for Social Resilience (ISR) [51]

Social functioning. Measured by the subscales perceived support (5 items), actual support (3 items), and mutual visits (2 items) using 4-point Likert scales.

5–20, perceived support.

2–13, actual support.

2–8, mutual visits.

Higher scores indicate better social functioning.

X

X

X

Lifestyle behavior

Lifestyle behavior. Measured by 5 items using 4-point Likert scales, 2 yes/no questions, and 2 open questions to report height and weight.

7–48, total score of the 5 4-point Likert scale items and the 2 yes/no questions (2 yes/no questions are transformed to 4-point Likert scales). Higher scores indicate better lifestyle behaviors.

BMI will be calculated using the patients’ height and weight, ≤18.5 underweight, 18.5–24.9 healthy weight, 25.0–29.9 overweight,

≥30.0 obese.

X

X

X

 Psychological parameters

Self-Efficacy for Managing Chronic Disease 6-ltem Scale (SEMCD-6) [52]

Self-efficacy. Measured by 6 items using 10-point Likert scales.

6–60, higher scores indicate better self-efficacy.

X

X

X

Partners in Health Scale (PiH) [53]

Chronic condition self-management knowledge and behaviors, version adjusted to chronic kidney disease. Measured by 13 items using 9-point Likert scales.

0–104, higher scores indicate better self-management.

X

X

X

Illness Cognition Questionnaire (ICQ) [54]

Illness cognitions. Measured by the subscales helplessness (6 items), acceptance (6 items), and perceived benefits (6 items) using 4-point Likert scales.

1–24, helplessness.

1–24, acceptance.

1–24, perceived benefits.

Higher scores indicate higher levels of the illness cognitions.

X

X

X

Life Orientation Test – Revised (LOT-R) [55]

Optimism. Measured by 3 items on optimism, 3 items on pessimism, and 4 filler items using 5-point Likert scales.

0–12, 3-item optimism subscale, higher scores indicate more optimism.

0–12, 3-item pessimism subscale, higher scores indicate more pessimism.

0–24, total score 6 items, higher scores indicate more optimism.

X

X

X

Eysenck Personality Questionnaire – Revised Short Scale (EPQ-RSS) [56], Dutch version [57]

Extraversion. Measured by 12 yes/no questions.

Neuroticism. Measured by 12 yes/no questions.

0–12, extraversion, higher scores indicate more extraversion.

0–12, neuroticism, higher scores indicate more neuroticism.

X

X

X

Internet-specific Therapeutic Relationship Questionnaire (ITRQ) [58]

Therapeutic relationship. Measured by 8 items using 10-point Likert scales.

8–80, higher scores indicate a better therapeutic relationship.

X

Intervention group only

 Cost-effectiveness

Five-level EQ-5D (EQ-5D-5L) [59]

Health-related quality of life for economic evaluations. Measured by 5 items using 5-point Likert scales and 1 visual analog scale indicating an overall health score.

5-point Likert scales, 1=no problems, 5=unable to/extreme problems.

Visual analog scale, 0=worst health you can imagine, 100=the best health you can imagine. Dutch tariff [60].

X

X

X

iMTA Productivity Cost Questionnaire (iPCQ) [61]

Productivity losses. Measured by 12 items using open and yes/no questions and a 10-point Likert scale.

NA

X

X

X

iMTA Medical Consumption Questionnaire (iMCQ) [62]

Medical costs. Measured by 31 items using open and yes/no questions. Depending on the answers, not all items will be presented.

NA

X

X

X

ICEpop CAPability measure for Adults (ICECAP-A) [63]

Capability wellbeing. Measured by 5 items using 4-point Likert scales.

5–20, higher scores indicate full capability.

X

X

X

 Use of ICBT intervention

Contact with e-Coach

Content, frequency, and duration of contact with the e-coach

Log data e-Coach

X

Intervention group only

Evaluation of the intervention

Evaluation of the intervention. Measured by 23 items using several Likert scales and open questions.

NA

X

Intervention group only