VIP, recruitment base

In the Västerbotten intervention programme (VIP), all inhabitants in the county of Västerbotten aged 40, 50, or 60 years were invited to a health examination with CVD risk factor screening followed by a motivational interview aimed to promote lifestyle adjustments and pharmacological preventive treatment according to clinical guidelines [13]. Participation rates during the inclusion period April 2013–May 2016 were 59–69%, corresponding to 6500–7000 participants yearly. Only a small social selection bias has been previously reported [14].

Participants VIPVIZA

Participants, who fulfilled the inclusion criteria, were invited to join the VIPVIZA trial after the VIP motivational interview. The inclusion criteria for VIPVIZA were as follows:

1.

60 years of age

2.

50 years of age with at least one of the following risk factors: diabetes, smoking, hypertension, LDL-cholesterol > 4.5 mmol/L, abdominal obesity or first degree relative with CVD history before 60 years of age

3.

40 years old with first-degree relative with CVD history before 60 years of age

Of the VIP-population, 61% were eligible for VIPVIZA, and in this study, only 50 and 60 years old were included.

In the VIPVIZA baseline assessment, asymptomatic atherosclerotic disease was identified by carotid ultrasound examination, measuring carotid intima media thickness (cIMT) as well as the presence of carotid plaque. Before the ultrasound examination, participants were randomised 1:1 to the intervention or control group, but the randomization was concealed to participants and the ultrasound operator. Details about the VIPVIZA procedures have been previously published [8, 10, 12].

Study population

Of the 4177 invited individuals, 3532 were enrolled in VIPVIZA. Five hundred forty-six of those met the criteria “active statin treatment during the last 270 days before baseline examination”. Thirty-four participants were excluded; see Table 1 for participant characteristics and Fig. 1 for flow chart. The VIPVIZA participants in the present study, those on statins prior to baseline, generally had higher cholesterol levels and more risk factors than the excluded participants. As all 512 participants in the final analysis were on statin treatment, adherence analyses could be performed without time lag to initiation.

Table 1 Background characteristics of study population by sex and groupFig. 1

Flowchart illustrating exclusion and group eligible for analysis

Intervention

The results from the ultrasound baseline examination were used to compile the VIPVIZA pictorial risk information consisting of a graphical representation of atherosclerosis. A red circle represented presence and a green circle represented non-presence of plaque. A coloured gauge represented the vascular age based on measurement of carotid intima-media thickness versus actual (chronological) age. Vascular age was estimated in relation to subjects with the same sex and age in a reference population [8]. The gauge ranged from green to yellow, orange, and red, where the green sector corresponded to a vascular age at least − 10 years compared to chronological age and red corresponded to at least +10 years.

The intervention procedure consisted of three parts:

1.

Mailing the result of the carotid ultrasound as a pictorial presentation within 2 weeks after examination, to participants and their respective physician in primary care. Written information was included to participants about the dynamic nature of atherosclerosis and opportunities to modify the progress through lifestyle change and pharmacological treatment [15 Supplementary material].

2.

A follow-up phone call to the participant, in the intervention group, was made 2–4 weeks later by a research nurse, to reassure or answer questions as needed as well as a dialogue concerning measures for CVD prevention. To the family physician, information about the current guideline-based clinical significance of carotid ultrasound results was enclosed to all reports.

3.

The pictorial information was repeated to the participant after 6 months.

The control group and their family physician did not receive this intervention at baseline. Details on the cognitive and emotional response to the VIPVIZA intervention has been previously published [15, 16].

Both the intervention and control groups underwent risk factor measurements and questionnaires at the 1-year follow-up. At the 1-year follow-up, the same CVD risk factors were measured as at baseline (blood pressure, lipids, fasting glucose, BMI) and with the same methodology as at baseline. Also, the identical questionnaire regarding smoking habits, physical activity, and alcohol use was answered. The results were fed back with a structured written form to participants in both the intervention—and the control groups and to their primary care physicians. This also included structured recommendations for follow-up, lifestyle modification, and, if needed according to guidelines, contact with the physician for further evaluation. The research team was not involved in preventive measures at the health care centres. The general practitioners acted according to their own judgements and existing guidelines for prevention [9]. At the 3-year follow-up, the same risk factor measurements, questionnaires, and an ultrasound examination were repeated. This time, the intervention was given to both groups and their physicians, due to ethical reasons. Further details about VIPVIZA procedures, inclusion, and exclusion criteria have previously been published [8].