Effect of adding systematic family history enquiry to cardiovascular disease risk assessment in primary care: a matched-pair, cluster randomized trial.

Background: Evidence of the value of systematically collecting family history in primary care is limited.

Objective: To evaluate the feasibility of systematically collecting family history of coronary heart disease in primary care and the effect of incorporating these data into cardiovascular risk assessment.

Design: Pragmatic, matched-pair, cluster randomized, controlled trial. (International Standardized Randomized Controlled Trial Number Register: ISRCTN 17943542).

Setting: 24 family practices in the United Kingdom.

Participants: 748 persons aged 30 to 65 years with no previously diagnosed cardiovascular risk, seen between July 2007 and March 2009.

Intervention: Participants in control practices had the usual Framingham-based cardiovascular risk assessment with and without use of existing family history information in their medical records. Participants in intervention practices also completed a questionnaire to systematically collect their family history. All participants were informed of their risk status. Participants with high cardiovascular risk were invited for a consultation.

Measurements: The primary outcome was the proportion of participants with high cardiovascular risk (10-year risk ≥ 20%). Other measures included questionnaire completion rate and anxiety score.

Results: 98% of participants completed the family history questionnaire. The mean increase in proportion of participants classified as having high cardiovascular risk was 4.8 percentage points in the intervention practices, compared with 0.3 percentage point in control practices when family history from patient records was incorporated. The 4.5-percentage point difference between groups (95% CI, 1.7 to 7.2 percentage points) remained significant after adjustment for participant and practice characteristics (P = 0.007). Anxiety scores were similar between groups.

Limitations: Relatively few participants were from ethnic minority or less-educated groups. The potential to explore behavioral change and clinical outcomes was limited. Many data were missing for anxiety scores.

Conclusion: Systematically collecting family history increases the proportion of persons identified as having high cardiovascular risk for further targeted prevention and seems to have little or no effect on anxiety.

Primary Funding Source: Genetics Health Services Research program of the United Kingdom Department of Health.