Table 1 Study instruments

Background and Clinical Details

Background and clinical details

N/A

10 items assessing background characteristics;

13 items assessing clinical characteristics.

Comorbidity

Charlson Comorbidity Index (CCI) [45]

Valid in predicting risk of death from comorbid disease [45].

Combines age and number of pre-determined, serious comorbidities into a single index. All participants in this study started with a minimum score of 2 for CKD.

CKD Knowledge

Kidney Knowledge Survey (KiKS) [38]

Adequate internal consistency (Kuder-Richardson-20 = .7) [38]; investigates knowledge of important CKD topics such as function, treatment, and BP targets.

α = .7 and .8 in current study.

28 multiple-choice items; Maximum score = 28.

Understanding of Physical Activity Guidelines

Four items from Active Australia Survey (AAS) [40]

Assesses understanding of/agreement with physical activity guidelines. Overall instrument has good-excellent reliability (Spearman’s Rho 0.5–0.8) [44], and items used showed high reliability in this study (α = .9).

4 Likert Scale items (1 = Strongly Disagree – 5 = Strongly Agree); Maximum score = 20.

Self-Efficacy to Manage Chronic Disease

Self-Efficacy for Managing Chronic Disease (SEMCD-6) [36]

High internal consistency (α = .9), scales upon which instrument is based sensitive to change in disease-related self-efficacy in response to intervention [36].

α = .9 and .9 in current study.

6 items scored 1–10. Overall scale score = mean of items 1–10.

Depression, Anxiety, and Stress

Depression Anxiety Stress Scales (DASS-21) [39]

Distinguishes well between psychological disorders and has good-excellent internal consistency (α = .9) [73].

α = .8 - > .9 in current study.

21 Likert Scale items (0 = Never – 3 = Almost Always). Three subscales and overall scale. Scores reported are for 21-item version and must be doubled to be compared to 42-item version scores or cut-offs.

CKD Self-Management Behaviour

Chronic Kidney Disease Self-Management Instrument – Australian Version (Aus.CKD-SM) [37]

Adequate internal consistency (α = .7–.85) [37].

α = .6–.9 in current study.

17 Likert Scale items (1 = Never – 4 = Always). Four subscales and overall scale.

Physical Activity

Human Activity Profile (HAP) [42]

Used extensively in chronic disease research [74]; adequate test-retest reliability (α = .8), content validity [42].

α = .8-. > 9 in current study.

94 items rated “still doing”, “stopped doing” and “never did”. Maximum activity score, adjusted activity score, and four research subscales.

Alcohol Use

Alcohol Use Disorders Identification Test-Consumption Questions (AUDIT-C) [44]

Effective in detection of heavy drinking and alcohol abuse or dependence [44].

α = .7 in current study.

Three multiple-choice questions with five response options scored 0–4; Maximum score 12; clinical cut-off of 3 for women and 4 for men.

Fruit and Vegetable Consumption

Two questions about fruit and vegetable consumption yesterday

Directly assesses consumption of fruit and vegetable on previous day.

Two questions assessing serves of fruit and vegetables eaten on previous day, added together for total.

Communication with Healthcare Providers

Two items from the Partners in Health Scale (PiH) [43]

Overall scale has demonstrated construct and face validity and internal consistency (α = .9) and inter-rater reliability [43].

α = .6 and .8 in current study.

Two Likert Scale items (0 = Never – 8 = Always). Maximum score = 16.

Health-Related Quality of Life

Short Form Health Survey-12-Item Australian v2; (SF-12) [75]

Conceptually and empirically validated [76]; adequate test-retest reliability (α = .8–.9).

12 Likert Scale items (scales vary from 3- to 5-point). Eight subscales contribute to two overall composite scores.