Table 1 Secondary outcomes: definitions and measurement techniques
Outcome | Definition and measurement | Timepoint measured | |||
|---|---|---|---|---|---|
Baseline | Post-intervention | 1-year follow-up | |||
1 | Postprandial glucose dysfunction | Mean reduction in two-hour postprandial (PP) blood glucose on a 75 gram oral glucose tolerance test (OGTT) | ✓ | ✓ | |
2 | Insulin resistance | Decrease in insulin resistance as measured by Homeostasis Model Assessment (HOMA) on insulin and glucose values on a 75 gram OGTT | ✓ | ✓ | |
3 | Diet adherence | Two-point improvement in overall MedDietScore - a composite diet index based on the traditional Mediterranean dietary pattern | ✓ | ✓ | ✓ |
4 | Weight and shape | a. Mean weight reduction (kilograms) in individuals with a Body Mass Index (BMI) of >30 kg/m2 at baseline; and | ✓ | ✓ | ✓ |
b. Mean reduction in waist circumference in individuals with a measurement of >88 cm at baseline | |||||
5 | Physical activity and fitness | a. Proportions meeting physical activity target of at least 30 minutes of moderate intensity aerobic activity on at least five days of the week; and | ✓ | ✓ | ✓ |
b. Change in functional capacity on an objective physical fitness test (Chester Step Test or six-minute walk test), estimated in metabolic equivalents (METs) or time on test | |||||
6 | Lipid profile | a. Proportions achieving a lipid target profile of the following values: total cholesterol <4.5 mmol/l, LDL cholesterol <2.5 mmol/l, triglycerides <1.69 mmol/l, HDL cholesterol >1.29 mmol/l; and | ✓ | ✓ | ✓ |
b. Mean reduction in total and LDL cholesterol | |||||
7 | Psychological evaluation (including: positive mental health; general health; quality of life; perceived social support; motivation to change; diabetes-related self-efficacy; depression, anxiety and stress) | a. Positive mental health: four-items from RAND SF-36 questionnaire addressing affective aspects of well-being and five-items from the Mental Health Index-5 (MHI-5) in the RAND SF-36 questionnaire on the occurrence and extent of non-specific psychological distress | ✓ | ✓ | |
b. General health: Stand-alone measure of self-rated health included in the Irish Survey of Lifestyle, Attitudes and Nutrition (SLÁN), 2007 (originally from The Healthy Days Measures (HRQOL-4)) | |||||
c. Quality of life: Single-item assessment included in SLÁN 2007 (originally from the World Health Organization’s Quality of Life Survey (WHO-QOL Group, 1998)) | |||||
d. Perceived social support: Multidimensional Scale of Perceived Social Support from family, friends, and a significant other (Zimet, Dahlem, Zimet and Farley, 1988) | |||||
e. Motivation to change: Moore et al.’s (2011) scale developed for Australian randomised controlled trial on a lifestyle intervention programme to prevent type 2 diabetes (based on Prochaska et al.’s (1992) identification of various stages in relation to maintaining a healthier lifestyle) | |||||
f. Diabetes-related self-efficacy: 18-item assessment of confidence to engage in exercise and healthy eating under different ‘barrier’ conditions (Moore et al., 2011) | |||||
g. Depression, anxiety and stress: 21-item Depression, Anxiety and Stress Scale (DASS-21) | |||||