Impact of a combined community and primary care prevention strategy on all-cause and cardiovascular mortality: a cohort analysis based on 1 million person-years of follow-up in Västerbotten County, Sweden, during 1990-2006

Abstract

Objective: To evaluate the impact of the Västerbotten Intervention Programme (VIP) by comparing all eligible individuals (target group impact) according to the intention-to-treat principle and VIP participants with the general Swedish population.

Design: Dynamic cohort study.

Setting/participants: All individuals aged 40, 50 or 60 years, residing in Västerbotten County, Sweden, between 1990 and 2006 (N=101,918) were followed from their first opportunity to participate in the VIP until age 75, study end point or prior death.

Intervention: The VIP is a systematic, long-term, county-wide cardiovascular disease (CVD) intervention that is performed within the primary healthcare setting and combines individual and population approaches. The core component is a health dialogue based on a physical examination and a comprehensive questionnaire at the ages of 40, 50 and 60 years.

Primary outcomes: All-cause and CVD mortality.

Results: For the target group, there were 5646 deaths observed over 1,054,607 person-years. Compared to Sweden at large, the standardised all-cause mortality ratio was 90.6% (95% CI 88.2% to 93.0%): for women 87.9% (95% CI 84.1% to 91.7%) and for men 92.2% (95% CI 89.2% to 95.3%). For CVD, the ratio was 95.0% (95% CI 90.7% to 99.4%): for women 90.4% (95% CI 82.6% to 98.7%) and for men 96.8% (95% CI 91.7 to 102.0). For participants, subject to further impact as well as selection, when compared to Sweden at large, the standardised all-cause mortality ratio was 66.3% (95% CI 63.7% to 69.0%), whereas the CVD ratio was 68.9% (95% CI 64.2% to 73.9%). For the target group as well as for the participants, standardised mortality ratios for all-cause mortality were reduced within all educational strata.

Conclusions: The study suggests that the VIP model of CVD prevention is able to impact on all-cause and cardiovascular mortality when evaluated according to the intention-to-treat principle.

Keywords: Epidemiology; PRIMARY CARE; PUBLIC HEALTH.