Effectiveness of NSW health get healthy telephone coaching in adults screened from general practices

Background: The effectiveness of the NSW Health “Get Healthy Information and Coaching Service®”(Get Healthy) to facilitate weight loss on a population scale has been documented, but this was based on self-reported measures. Our study aims to test the effectiveness of the Get Healthy Service on objectively measured weight, BMI, waist circumference, and changes in other health behaviours, including nutrition, physical activity and alcohol intake. Methods: Men and women aged 40–70 years (n = 154) with pre-diabetes (5.7% < HbA1c < 6.5%) were referred from GP Practices to the Get Healthy Service, NSW Health. A subset (n = 98) participated in the “Zinc In Preventing the Progression of pre-Diabetes” (ZIPPeD) trial (ACTRN12618001120268). Results: The self-reported outcomes showed a statistically significant improvement from baseline to 12 months in weight (mean 2.7 kg loss, p < 0.001), BMI (mean 1 unit reduction, p < 0.001), and waist circumference (mean 4.3 cm reduction, p < 0.001). However, in the objectively measured outcomes from ZIPPeD, the differences were more modest, with point estimates of 0.8 kg mean weight loss (p = 0.1), 0.4 unit reduction in BMI (p = 0.03), and 1.8 cm reduction in waist circumference (p = 0.04). Bland-Altman plots indicated that discrepancies were due to a small number of participants who dramatically underestimated their weight or BMI. There were minimal changes in nutrition, physical activity, and alcohol. Conclusions: The potential benefits of Get Healthy should be interpreted with caution as we have shown significant differences between self-reported and objectively measured values. More valid and objective evidence is needed to determine the program’s effectiveness and cost-effectiveness.