Study context and design of the VIPVIZA trial
VIPVIZA, conducted in Västerbotten county in northern Sweden, is a pragmatic, open-label, randomized controlled trial with masked evaluators (PROBE) that investigates the impact of pictorial information about subclinical atherosclerosis, added to traditional risk factor-based communication. VIPVIZA is integrated in the Västerbotten Intervention Program (VIP), which offers screening for CVD risk factors and individual health promotion counselling to all inhabitants of the county the year they turn 40, 50, and 60 years (n = 6,500-7,000 per year) (35). Participation rate for VIP during the inclusion period was 68%, and only small social selection bias has been observed (36).
For VIP participants aged 60 years, age alone constitutes inclusion criteria (64% of the VIPVIZA study population), those aged 50 years were included due to at least one conventional CVD risk factor (28%), and those aged 40 years on the bases of history of early CVD among first-grade relatives (8%). Recruitment was done in different parts of the county during three years, aiming to obtain a representative sample that is large enough according to a power-estimation, and facilitated by only one team travelling across the county to perform the ultrasound examinations. In total, 4,177 VIP participants were invited to the VIPVIZA study, and participation rate was 84.6% (n = 3532). Participants were included in the study during April 2013-June 2016, and were consecutively and randomly assigned 1:1 to the intervention (n = 1749) or the control group (n = 1783). For an overview of the study, see Appendix 1.
In the VIP, all participants responded to a questionnaire covering life style, medication, psychosocial situation, and family history of CVD and diabetes. Blood pressure and anthropometric measurements were taken, and blood samples were collected to measure lipids and blood sugar. At the baseline visit in VIPVIZA, participants also responded to several validated questionnaire instruments, e.g. on health literacy, coping, self-efficacy and depression/anxiety. Presence of carotid atherosclerotic plaque and intima media thickness (IMT) was assessed with ultrasound. Examinations were performed by sonographers specially trained in carotid ultrasound techniques with a mobile CardioHealth Station, provided by Panasonic Healthcare Corporation of North America, Newark, NJ, USA. VIPVIZA applies the Mannheim consensus definition of carotid artery plaque. After the baseline visit, the intervention group and their primary care physicians received a letter with the pictorial presentation of the ultrasound result. Also, within 2–4 weeks after they had received the letter, the participants in the intervention group were contacted by a research nurse by telephone for clarifications if needed, any remaining questions and a motivational interview (37) (referred to as the nurse follow-up call). In order to evaluate the effect of the intervention, the control group and their primary care physicians did not receive the result from the baseline ultrasound. After six months, participants in the intervention group once again received the letter with the pictorial presentation of the ultrasound result, including also a reminder of preventive measures. After nine months, and also after 2 and 2.5 years, participants in the intervention group received letters reminding them about the next follow-up visit. These letters contained general information about proceedings in the study and the importance of a healthy lifestyle to prevent progression of atherosclerosis, but no personalized health information was given in the letters. No information letters were sent to the control group.
At 1-year follow up, clinical risk factors were measured again, and all participants and their primary care physician were given the results. Participants also responded to a shorter questionnaire on preventive medication and life style. At 3-year follow-up, the participants were again examined with ultrasound and the full baseline routine of validated psychometric questionnaires, blood samples and measurements of anthropometric data and blood pressure. The intervention group also responded to questions on cognitive and emotional reactions to their first ultrasound result letter, and the nurse follow-up call. These reactions were analysed in the present study. After this visit, all participants received a letter with pictorial presentation of their ultrasound result. The complete study protocol is available at https://clinicaltrials.gov/ct2/show/NCT01849575.
Pictorial risk communication and motivational interview as intervention
IMT was communicated as vascular age. Here the individual’s IMT was compared to that of individuals with the same sex and age in a reference population (29), and depicted as a graphical continuous gauge ranging from green via yellow and orange to red. Green corresponds to the IMT of a person at least ten years younger, and red corresponds to an IMT of a person being at least ten years older than the participant’s actual age. Plaque was presented as a traffic light with a red (plaque identified) or green (no plaque) dot. An illustration of graphical elements in the letter is provided in Fig. 1. Written information was also provided in the same letter, describing atherosclerosis as a dynamic process that can be slowed or even reversed by healthier life style and preventive medication. Within 2–4 weeks after participants in the intervention group had received the letter, they were contacted by a research nurse by telephone for clarifications if needed, any remaining questions and a motivational interview. The latter is a method for collaborative communication aiming to enhance readiness for change, where evoking the client´s own perceptions, values and motivations for change is central (37).
Study Sample
Of the 1749 participants in the intervention group, 1397 participated in the current study since questions regarding the participants’ assessment of and response to the intervention were not included until a few months into the 3-year follow up.
Ethical Considerations
All study participants provided written informed consent when included in the VIPVIZA study. The present study was approved by the Umeå Regional Ethics Board (2011-455-31M and 2012-463-32M).
Material
Participants’ assessment of the intervention
Comprehension of the ultrasound result letter was assessed with the question How would you assess your understanding of the letter? Five response alternatives were given: It was very easy, It was rather easy, It was rather difficult, It was very difficult, and Do not remember/know. Assessment of the contribution of the ultrasound result letter for understanding personal CVD risk was assessed with the question Did the letter contribute to you understanding your risk of cardiovascular disease better than before? (1 missing case, out of 1397). Assessment of the contribution of the nurse phone call for understanding of the ultrasound result letter was assessed with the question Did the follow-up call contribute to understanding the letter? Response alternatives for these two questions were Very much, Rather much, To some extent, Not at all, Do not remember/know (25 missing cases).
Cognitive impact of the intervention
One question assessed risk perception and two questions assessed efficacy beliefs. For each statement, participants were asked to evaluate to what extent the letter and the phone call in combination had contributed: The letter and the phone call in combination have contributed to that: (i) … I better understand my personal risk for cardiovascular disease (43 missing). (ii) … I better understand my possibility to influence my risk (40 missing). (iii) … I better understand how I can influence my risk (44 missing). For each statement, the alternatives were Completely agree, Partly agree, Partly disagree, Completely disagree, and Do not remember/know.
Emotional impact of the ultrasound result letter
The participants were asked about their reactions to the ultrasound result letter with the following statements: I was positively surprised (54 missing); I was relieved/calmed (52 missing); I was worried/afraid (45 missing); and I was shocked (50 missing. The response alternatives were Completely agree, Partly agree, Partly disagree, Completely disagree, and Do not remember/know. For analyses of associations between emotional reactions and lifestyle modification, emotions were assessed as arousal and negative valence (see statistical analysis section).
Lifestyle index
The use of lifestyle indices for assessing and predicting CVD risk has previously been described (38). In VIPVIZA, the lifestyle index is based on the four frequently evaluated health behaviours physical activity, diet, smoking and alcohol consumption. For each behaviour, a score between 1 and 3 is given, where 1 corresponds to the unhealthiest level and 3 to the most health-promoting level. The definition of levels for physical activity, smoking and alcohol consumption was based on commonly used definitions and clinical guidelines. The measure for diet, described below, was included at baseline, but not at the start of the 3-year follow up, resulting in missing values on lifestyle index. In our sample, 886 individuals provided data on change in lifestyle index (511 missing).
Physical activity. Three levels of physical activity were constructed based on assessment of level of physical activity in every-day life and leisure time. These were (1) sedentary, (2) moderate physical activity of < 150minutes/week, and (3) around or above the recommended level of physical activity of at least moderate intensity at least 150 minutes/week.
Diet. Diet was assessed with the Food Frequency Questionnaire (FFQ), (39) from which a Healthy Diet Score (HDS) was calculated, reflecting daily intake of eight categories of food and beverages. HDS has been described elsewhere (40), and change in HDS is associated with change in cardio-metabolic risk factors (41). Fish, fruits, vegetables and whole grains represented favourable food, whereas red or processed meats, desserts and sweets, sugar-sweetened beverages and fried potatoes represented unfavourable food/beverage. For both sexes, intake frequencies were ranked in ascending quartile ranks for favourable foods/beverage groups, and in descending quartile ranks for unfavourable foods/beverage groups. The HDS, ranging from 0 to 24, represents the sum of all quartile ranks where higher rank indicates healthier food and beverage choice. For the Lifestyle index, the three levels of HDS represented (1) the first, (2) second, and (3) third tertile.
Smoking. The three levels were (1) Daily smoker, (2) Occasional smoker, (3) Non-smoker.
Alcohol consumption. In accordance with the cut-off levels for the Alcohol Use Disorders Identification Test (AUDIT)(42), the three levels were (1) not at risk, (2) harmful use, and (3) abuse or dependence of alcohol.
Statistical analysis
Chi-square test was used to study associations between cognitive response and level of education as well as severity of atherosclerosis as presented by the risk message and cognitive/emotional reactions. Lifestyle modification over three years was derived by subtracting the value of lifestyle index at baseline from that at 3-year follow-up. The association between lifestyle modification, on the one hand, and cognitive and emotional response, on the other hand, were studied with analysis of covariance (ANCOVA), in which Lifestyle index at baseline was used as covariate. Among the 886 participants who provided data on change in lifestyle index, 864 provided data on the composite variable for cognitive response, and 859 on the composite variable for emotional response.
For each of the three questions assessing the cognitive impact of the intervention, the response alternative Completely agree corresponded to 5 points, Partly agree to 4 points, Partly disagree to 3 points, Completely disagree to 2 points, and Do not remember/know to 1 point. When combined, a score of 1–4 was categorized as Low cognitive response (n = 317), 4.33–4.66 as Moderate cognitive response (n = 207), and 5 (corresponding to completely agreeing on all three questions) as High cognitive response (n = 340).
For the analyses of emotional reactions, only the statements regarding being positively surprised and relieved/calmed was used. The statements regarding being worried/afraid and shocked were excluded since very few participants reported that they to a large extent experienced these reactions, and because the questions used captured emotions of both positive and negative valence.
When emotional reactions were studied from the perspective of level of negative emotions, participants who replied Do not remember/know were excluded from the analyses, since it is not possible to interpret direction of valence from this statement. For each of the questions, the response alternative Completely agree corresponded to 1 point, Partly agree and Partly disagree to 2 points, and Completely disagree to 3 points. When the questions were combined, a score of 1-1.5 was categorized as Low negative emotion (n = 124), 2-2.5 as Moderate negative emotion (n = 378), and 3 as High negative emotion (n = 218).
When emotional reactions were studied from the perspective of level of arousal, participants who replied Do not remember/know were included in the analyses, since it can be argued that this statement strongly indicates an absence of increased arousal. The response Do not remember/know corresponded to 1 point, Partly agree and Partly disagree to 2 points, and Completely agree and Completely disagree to 3 points. A score of 1-1.5 was categorized as Low arousal (n = 125), 2-2.5 as Moderate arousal (n = 458), and 3 as High arousal (n = 276).
The impact of the combination of cognitive response and emotional arousal on change in lifestyle index was analysed based on the groups formed in each variable respectively. These combinations were low cognition/low arousal (n = 275), low cognition/high arousal (n = 237), high cognition/low arousal (n = 141), and high cognition/high arousal (n = 190).