Table 2 Characteristics of studies included in this review

Claassen et al [59]

Netherlands

2012

To examine differences in self-reported perceived risk, causal attributions of IHD^a, perceived efficacy of preventive behaviour and adoption of preventive behaviour between people with and without a known genetic predisposition of IHD.

Hypotheses: Those with a known genetic predisposition to IHD compared to those without will:

-Have higher perceptions of IHD risk.

-Attribute IHD more strongly to genetics and less to an unhealthy lifestyle.

-Have more confidence in the efficacy of medication, and less confidence in efficacy of a healthy lifestyle to reduce IHD risk.

-No hypotheses for the adoption of preventive behaviour.

100 participants:

n = 51 individuals with a GP^b to IHD, who had a recent diagnosis of familial hypercholesterolemia through DNA testing in a national family cascade screening program in the Netherlands. 15 had one FDR^d, and 28 had two or more FDRs.

n = 49 individuals with NGP^c but still at risk for IHD. These participants were from a larger interventional study. 16 had one FDR and 12 had 2 or more FDRs.

Age (mean (SD))-

GP n = 54 (13).

NGP n = 55(8).

Sex-

GP-female n = 27 male n = 24.

NGP-

female n = 23.

male n = 26.

Education-

GP- low n = 19, medium n = 15, high n = 16.

NGP- low n = 23, medium n = 14, high n = 10.

Design- Cross-sectional postal survey that measured self-reported cholesterol levels, blood pressure, number of FDRs with IHD, perceived risk (susceptibility and comparative risk within the next 10 years), causal attributions of IHD (genetic e.g. hereditary/ predisposition and lifestyle e.g. unhealthy diet/lack of exercise/smoking), perceived efficacy of preventive behaviours (medication use for those who were prescribed medication, dietary behaviour, exercise and smoking cessation) and reported preventive behaviour (medication adherence, diet, exercise and smoking).

Setting- Netherlands.

Intervention- The study directly compared two different populations who experienced different types of risk assessments (genetic and cholesterol).

Predictive test(s)- DNA test (for those in the genetic predisposition condition) and blood test to measure cholesterol levels.

Perceived comparative risk, genetic attributions to developing IHD and perceived efficacy of taking medication was significantly higher in those who had a genetic compared to a cholesterol test (28% higher for perceived comparative risk (p = 0.003), 11% higher for genetic attributions (p = 0.02) and 16% higher for perceived efficacy of taking medication (p = 0.001)).No differences between groups in terms of perceived susceptibility of IHD, lifestyle attributions for developing IHD, perceived efficacy of a healthy lifestyle or preventive behaviour.

Those with a higher number of FDRs with IHD reported higher perceived susceptibility to IHD (p = 0.04), stronger genetic attributions (p = 0.03), increased confidence in the efficacy of medication (p = 0.04) and reported engaging in physical activity and a healthy diet more often than those with a lower number of FDRs (p = 0.005).

Medication adherence was high for those who took a genetic or cholesterol test (96 and 97%, respectively), and did not differ based on family history.

The number of participants who reported not smoking was high for those who took a genetic or cholesterol test (88 and 82%, respectively), and did not differ based on family history.

Imes et al [60]

USA

2016

To examine the effect of a pilot intervention for young adults with a family history of IHD on IHD knowledge, perceived IHD risk, and intention to engage in IHD risk reducing behaviours.

Hypothesis: Perceived IHD risk, IHD knowledge and IHD risk reducing behaviours will increase from baseline to post-intervention.

n = 15 undergraduate and postgraduate students.

1 participant had an FDR with IHD, and 12 had at least one SDR^e with IHD.

Age (mean (SD)) 20.8 (2.2).

Sex-

Female n = 13.

Male n = 2.

Ethnicity-

Caucasian n = 10.

Asian n = 2.

Asian and Native Hawaiian n = 1

Hispanic or Latino n = 2.

Black n = 0.

Design-Experimental pre-post test pilot study.

A self-report questionnaire measured IHD knowledge, perceived IHD risk and intention to engage in IHD risk reducing behaviours (diet and physical activity) at baseline and 2 weeks post-intervention.

Setting- Pacific Northwest University, Washington, USA.

Intervention- IHD risk assessment incorporating information on family history (three-generation pedigree), a blood test to assess lipid levels, and a brief educational counselling intervention on increasing physical activity and dietary behaviours.

Predictive test- Blood test to assess lipid levels associated with elevated IHD risk (LDL-C, HDL-C and triglyceride levels).

Participants’ IHD knowledge significantly increased post-intervention compared to baseline (95% CI of the difference 0.80–9.01, p = 0.02).

Participants’ perceived risk of IHD was significantly higher post-intervention compared to baseline (Z = 1.97 (95% CI 0.02–1.98), p = 0.048). However, when adjusting for multiple comparisons (perceived lifetime risk, perceived susceptibility, and perceived lifetime risk after receiving family history information only) this effect was no longer significant.

Participants expressed a higher intention to engage in exercise after receiving the intervention compared to baseline (Z = 2.09 (95% CI 0.36–1.28), p = 0.036), with a medium effect size (d = 0.58). However, after adjustment for multiple comparisons (engagement in exercise, diet, health-promoting lifestyles (total score for exercise and diet), and likelihood to engage in a health-promoting lifestyle after receiving family history information only, p ≤ 0.0125) this effect was no longer statistically significant. Participants’ intention to adopt a healthy diet did not differ from baseline to post-intervention (Z = 1.85 (95% CI − 0.04-0.53), p = 0.064).

Those with a higher number of first- and second-degree relatives with IHD had significantly higher risk perceptions of IHD (p = 0.014), and a significantly higher intention to exercise after receiving the intervention than those with a lower number of first- and second-degree relatives (p = 0.035). This result was not found for diet.

Middlemass et al¹ [56]

UK

2014

To explore how patients who had a recent IHD assessment perceive additional information from genetic testing for IHD, and perceptions of whether this additional genetic information influenced their behaviour.

n = 29 individuals from primary care practices who were part of a larger ongoing study and who had received a conventional IHD risk assessment within 18 months prior to this study and had agreed to have a genetic test.

17 had either an FDR or SDR with IHD.

Age (median (IQR))-

59 (53.5–62).

Sex-

Female n = 8.

Male n = 21.

Ethnicity-

Caucasian n = 28.

Asian n = 0.

Mediterranean n = 1.

Black n = 0.

Education-

No formal qualifications n = 6.

GCSE n = 2.

Vocational qualification n = 3.

A-level n = 2.

First degree n = 10.

Other n = 5.

Missing n = 1

Design- Qualitative interview study. Interviews were conducted 4 months after receiving risk results (conventional, genetic and overall risk, communicated by letter).

Participants were asked about their conventional risk assessment, experience of the genetic test, their interpretations of the genetic and conventional risk results, and whether the results had influenced any change in their behaviours.

Setting- 12 primary care practices from both urban and rural settings in Nottinghamshire, UK.

Intervention- There was no intervention for this study, as all participants had a genetic (and conventional) test.

Predictive test- Saliva sample which involved an IHD panel of nine risk alleles to produce a combined risk profile score.

For the conventional IHD risk assessment conducted previously, a blood sample was taken to measure cholesterol levels.

Family history was cited as the primary motivation for having a genetic test, so they can clarify their family history further and are able to discuss their results with their children.

Testing was seen as beneficial as it could motivate behaviour change, particularly in those with high genetic and conventional risk results. However, for some individuals identified as at high risk from a conventional IHD risk assessment, an average genetic risk score provided false reassurance that they did not have to modify their lifestyle to reduce their risk.

Genetic testing was cited as being more appropriate for a younger age group as prevention is more likely to lead to health benefits.

Stocks et al [61]

Australia

2015

Primary aim: To determine whether the provision of advice promoting IHD risk assessment to FDRs of patients with premature IHD (PIHD) would increase the proportion of relatives who

undertake IHD risk assessment.

Secondary aim: To ascertain absolute IHD risk of relatives in the intervention group.

n = 97 FDRs (siblings and children) of patients hospitalised with PIHD in tertiary care cardiovascular wards in South Australia.

n = 55 were in the intervention group for this study.

n = 42 were in the control group.

Age-

18 and over.

Sex-

Female n = 59.

Male n = 38.

Design- Prospective randomised- controlled trial.

Patients were randomly allocated to provide an information pack (either intervention or control) to their FDRs either in the hospital or via post.

Evidence that relatives had an IHD risk assessment was provided by GPs through a postcard returned to the University, detailing relatives’ risk results. FDRs were also

phoned 6 months after providing consent to ascertain whether they had attended their GP for a IHD risk assessment within those 6 months, whether any IHD risk factors were identified and whether any lifestyle changes had been made.

Setting- Tertiary care cardiovascular wards at Royal Adelaide Hospital, Flinders Medical Centre and Flinders Private Hospital, Australia.

Intervention- Written advice/ recommendation to attend their GP for a risk assessment.

Predictive test-Blood test to measure total cholesterol: HDL ratio.

52% of all FDRs attended their GP for an IHD risk assessment within 6 months of the trial, 75% from the intervention group and 21% from the control group (difference (in proportions) 53% (95% CI 36–71%).

More FDRs from the control group compared to the intervention group did not see their GP at all during the 6-month follow-up (41% vs 15%, respectively).

A small number of FDRs from the control and intervention groups attended the GP for a risk assessment after 6 months (17 and 2%, respectively).

The majority of FDRs from the intervention group who attended their GP had low IHD risk (66%). All FDRs who had moderate to very high IHD risk (34%) were siblings.

Saukko et al¹ [62]

UK

2012

To explore how individuals who are at high risk of heart disease configure risk information provided by an IHD risk assessment, and how their understanding of their risk may shape their preventive behaviours.

n = 30 participants who were taking part in a trial assessing the utility of family history in an IHD risk assessment. 20 participants from the current study were in the intervention group in the trial, and 10 were in the control group. Maximum variation sampling was conducted in the current study based on sex, socioeconomic status, and family history.

11 participants in the intervention group had a family history of IHD. The degree of family history was not disclosed. Family history was not assessed in the control group.

Age (range)-

30–49 n = 2.

50–59 n = 11.

60–65 n = 17.

Sex-

Female n = 10.

Male n = 20.

Employment-

Managerial and professional n = 10.

Intermediate n = 5.

Manual and unemployed n = 15.

Design- Qualitative interview study, nested within a trial. Participants took part in interviews at 2 weeks and 6 months after receiving risk results. These interviews asked participants what they thought about being classed as at high risk of IHD, their thoughts about the risk assessment, what interaction they’d had with their clinicians about their risk, and what they’d done with the information.

Setting- 24 general practices in diverse socioeconomic areas in the East Midlands and Southwest of the UK.

Intervention-The current study was not an interventional study, but for the nested trial participants were invited to discuss their risk, lifestyle and medications with their clinicians. The intervention arm of the trial had their family history of IHD formally assessed (self-report).

Predictive test-Blood test to measure cholesterol (conducted as part of the trial).

Initially, most participants were shocked to be identified at high risk of IHD and planned some preventive actions to reduce their risk. At the 6 month follow up, 23 participants reported engaging in health behaviours; 13 reported taking statins only, five reported taking part in lifestyle behaviours (diet and physical activity) and five reported taking statins and engaging in lifestyle behaviours.

Seven reported not engaging in any health behaviours, which was often due to overwhelming personal and social circumstances. Participants in this group often had a lower socioeconomic status than those who engaged in risk-reducing behaviours and had poor communication with their clinicians.

No substantial difference was found in these results between those in the intervention and control groups of the nested trial, or those with and without a family history.

Sanderson and Michie [58]

UK

2007

To investigate the impact of IHD risk test type (genetic high risk, genetic low risk and oxidative high risk) on intention to quit smoking.

To examine whether the impact of test type is the same for individuals with a family history compared to without.

Hypotheses: -Smokers in the genetic high-risk group would have lower outcome expectations about quitting smoking, and lower perceived control over quitting than the oxidative high-risk group.

-Outcome expectations and perceived control would partly mediate the effect of test type on intention to quit smoking.

n = 261 smokers overall:

n = 75 were undergraduate students from a UK university.

n = 161 were undergraduate students’ family/friends or staff from a UK university.

n = 25 were recruited through Quitline- a telephone quit-smoking service.

All participants smoked seven or more cigarettes per week.

58 had a family history of IHD. The degree of history was not disclosed.

Age (mean (SD))-

Genetic high risk- 34 (12).

Genetic low risk- 30 (12).

Oxidative high risk- 30(10).

Sex-

Female n = 116.

Male n = 145.

Ethnicity-

Caucasian n = 217.

Non-Caucasian n = 44.

Education-

GCSE n = 49.

A-level n = 88.

Bachelor’s degree n = 89.

Higher degree n = 34.

Design-Randomised controlled trial. Self-reported family history was measured at baseline, intention to quit smoking was measured at baseline and post-intervention. Self-reported attitudes towards quitting smoking, outcome expectations, perceived control over quitting, and perceived social pressure was

measured post-intervention using a questionnaire.

Setting- UK.

Intervention- Hypothetical predictive test result from one of three types of predictive test: high genetic risk vs low genetic risk vs high oxidative stress risk.

Predictive test- Hypothetical genetic or oxidative stress test, described as a blood test that tests for different genes (genetic risk) or enzymes and antioxidants (oxidative stress) associated with IHD risk.

Those who received a high genetic risk result had significantly higher outcome expectations (p < 0.001), more positive attitudes towards quitting smoking (p = 0.039) and had a higher intention to quit smoking than those who received a high oxidative risk result (p = 0.009). No significant difference was found for perceived control or social pressure.

The genetic high-risk group also had significantly higher outcome expectations (p = 0.003), greater perceived control over quitting smoking (p = 0.012) and a stronger intention to quit (p < 0.001) than those who received a genetic low risk result. No significant difference was found for perceived attitudes towards quitting or perceived social pressure.

30.3% of the effect of risk results on intention to quit smoking was mediated by stronger beliefs that quitting smoking would reduce risk of IHD (outcome expectations) (p = 0.011).

When examining the interaction between family history and risk results, the effect of a high genetic risk result on outcome expectations was greatest amongst smokers with no family history of heart disease. (p = 0.04). The interaction between family history and risk results was not significant for attitudes towards quitting (p = 0.61), perceived control over quitting (p = 0.27), perceived social pressure (p = 0.58) or intention to quit (p = 0.34).

Sanderson et al [57]

UK

2004

To examine interest in genetic testing for IHD and cancer, and the influence of factors such as family history, age, sex, education, and ethnicity on interest.

Hypotheses:

-The same factors that predict interest in genetic testing for cancer (previously, younger adults, women and those with a higher level of education) will predict interest in genetic testing for IHD.

-People will be more interested in genetic testing for IHD than for cancer.

n = 1960 respondents from a stratified random probability sample as part of the Office for National Statistics Omnibus survey.

830 respondents had at least one FDR or SDR with IHD.

Age (mean (SD))-47(18.2).

Sex-

Female n = 999.

Male n = 961.

Education-

No formal qualifications n = 629.

GCSEs n = 524.

A-levels n = 559.

Degree n = 247.

Ethnicity-

Caucasian n = 1843.

Non-Caucasian n = 112.

Design- Cross-sectional survey study. The survey questions were delivered by researchers through telephone calls to participants.

Participants were asked if they would take a genetic test for IHD (and cancer) in the next 6 months. They were also asked about their age, sex, ethnicity, education, and family history.

Setting- UK.

Predictive test- Hypothetical genetic test.

Respondents were significantly more likely to be interested in taking a predictive test for IHD (mean 2.95 (95% CI of the difference 2.91:3.01)) than for cancer (mean 2.83 (95% CI 2.78:2.88), p < 0.001).

42% of participants would definitely take a predictive test for IHD and 28% would probably take a test.

Men were significantly more likely to say they would take a predictive test for IHD than women (OR 0.79 (0.65:0.97)), respectively, p < 0.05). Middle-aged respondents (46–60 years) were more interested in predictive testing for IHD than those aged 16–30 years (OR 1.99 (1.45:2.75), p < 0.001). Those aged 31–45 years (OR 1.43 (1.08:1.90)) and > 75 years (OR 0.61 (0.39:0.94)) were also more interested in testing than those aged 16–30 years, p < 0.05). Compared to those with a university degree, those with school-based qualifications such as GCSEs (OR 1.90 (1.35:2.66)) and A-levels (OR 1.99 (1.43:2.79)) had a higher interest in testing, p < 0.001. No significant difference in interest in testing for IHD was found for ethnicity (p = 0.16).

Participants who had at least one FDR or SDR with IHD had a significantly higher interest in predictive testing compared to those who did not have a family history (OR 1.36 (1.09:1.66), p < 0.01). Those who did not know their family history showed no greater interest in testing than those who did not have a family history of IHD (OR 1.20 (0.59 to 2.43)).