Population impact of the Swedish Targeted Health Dialogue programme on ischaemic heart disease: an interrupted time-series analysis

Background The Swedish Targeted Health Dialogue (THD) is a widely implemented, individual-focused intervention involving screening and health counselling for mid-life individuals. Previous research has shown somewhat mixed results; therefore, this study aims to provide rigorous evidence on the population-level impact of the THD programme on ischaemic heart disease (IHD) in Sweden. Methods This study used the number of recorded county-specific IHD events and mortality among 40–69-year-olds between 1987 and 2023 in Sweden to estimate the effect of the THD programme. Six out of 21 counties had implemented THD fully during the study period. These six counties were used to evaluate the effect of the programme by estimating the change in IHD incidence trend post implementation compared with controls where the programme was not implemented at that specific time. This intervention effect was estimated using generalised multilevel controlled interrupted time-series models. Results In men, the intervention showed no statistically significant effect on IHD events compared with the controls, with an estimated increased annual rate of 0.1% (95% CI −0.1% to 0.2%). In women, a similar non-significant increase in incidence rate of 0.2% (95% CI −0.1% to 0.5%) per year was observed in the intervention counties. These figures can be contrasted with an annual linear reduction of 3.2% in IHD incidence among men and 1.5% among women. Similar results were attained regarding IHD mortality. Conclusion These findings do not support evidence for any beneficial population effect of the THD programme on future IHD. Hence, revisiting the fundamental concern on the effectiveness of the programme is pertinent.