Effectiveness of the blended-care lifestyle intervention ‘PerfectFit’: a cluster randomised trial in employees at risk for cardiovascular diseases

BACKGROUND: Web-based lifestyle interventions at the workplace have the potential to promote health and work productivity. However, the sustainability of effects is often small, which could be enhanced by adding face-to-face contacts, so-called ‘blended care’. Therefore, this study evaluates the effects of a blended workplace health promotion intervention on health and work outcomes among employees with increased cardiovascular risk. METHODS: In this multicentre cluster-randomised controlled trial (PerfectFit), 491 workers in 18 work units from military, police, and a hospital with increased cardiovascular risk were randomised into two intervention groups. The limited intervention (n = 213; 9 clusters) consisted of a web-based Health Risk Assessment with advice. In the extensive intervention (n = 271; 8 clusters), coaching sessions by occupational health physicians using motivational interviewing were added. One cluster dropped out after randomisation but before any inclusion of subjects. Primary outcome was self-rated health. Secondary outcomes were body weight, body mass index (BMI), work productivity, and health behaviours. Follow-up measurements were collected at 6 and 12 months. Effect sizes were determined in mixed effects models. RESULTS: At 12 months, the extensive intervention was not statistically different from the limited intervention for self-rated health (4.3%; 95%CI -5.3-12.8), BMI (− 0.81; 95%CI -1.87-0.26) and body weight (− 2.16; 95%CI -5.49-1.17). The within-group analysis showed that in the extensive intervention group body weight (− 3.1 kg; 95% CI -2.0 to − 4.3) was statistically significantly reduced, whereas body weight remained stable in the limited intervention group (+ 0.2 kg; 95% CI -1.4 to 1.8). In both randomised groups productivity loss and physical activity increased and excessive alcohol use decreased significantly at 12 months. CONCLUSIONS: There were no effects on self-rated health, body weight, and BMI. However, within the group with web-based tailored Health Risk Assessment including personalized advice body weight reduced significantly. Adding motivational coaching is promising to reduce body weight. TRIAL REGISTRATION: Retrospectively registered at the Netherlands Trial Registry with number NTR4894, at Nov 14 2014. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12889-018-5633-0) contains supplementary material, which is available to authorized users.