Is a Family History of Cardiovascular Disease Valuable?
Abstract & Commentary
By Michael H. Crawford, MD, Editor
Source: Qureshi N, et al. Effect of adding systematic family history inquiry to cardiovascular disease risk assessment in primary care: A matched-pair, cluster randomized trial. Ann Intern Med 2012;156:253-262.
Although a routine part of a complete medical history, the value of systematically collecting family history has not been shown in controlled trials. Thus, these investigators from the United Kingdom sought to determine the feasibility of collecting a detailed family history and whether this information would identify more high-risk individuals for cardiovascular (CV) disease. Matched Family Practice pairs were randomly assigned to the family history intervention or usual care. Both groups received standard CV risk assessment. The intervention group family history was collected by a self-administered questionnaire. The primary outcome measure was the number of subjects classified as high risk for CV disease based on the two approaches (10-year risk > 20%). Also, anxiety levels were assessed by a standard questionnaire.
A total of 748 subjects from 24 family practices with no history of CV disease participated. The family history questionnaire was completed by 98% of the subjects. The increase in high-risk patients was 41% in the questionnaire group vs 6% in the usual care group where family history was obtained from the medical records. Anxiety levels were not increased by this intervention. The authors concluded that systematically obtaining family history identifies more subjects with high CV risk who may benefit from more aggressive preventive interventions.
This study objectively confirms the value of family history in CV disease prevention. A preliminary survey by the investigators demonstrated that often family history was not recorded in the medical record. One reason for this is the limited time available during the health visit. This was overcome in the intervention group by having the subjects fill out a questionnaire before the visit, which was feasible 98% of the time in this study population. The risk profile of the control group was obtained from the Framingham score, which does not incorporate family history but is widely used in the United Kingdom and the United States.
One of the strengths of the study was the pairing of practices involved with the same patient population, which eliminates ethnic or cultural differences in the groups that were compared. However, a weakness of the study is that few ethnic minorities or low education level subjects were included. Also, there were not a lot of smokers in the subjects studied. However, among the usual care group no one quit smoking, but 6 (20%) smoked less at 6 months of follow-up. Among the intervention group, 10 quit and 8 reduced their smoking (62%). Aspirin use increased among the intervention group as compared to the control group (48 vs 31% increase), but increases in statin use were the same. The patients reclassified as high risk in the intervention group were in the moderate-risk group before (Framingham risk 10-20% over 10 years). In the United Kingdom, aspirin use is not recommended for such patients. Unfortunately, there are no outcome data in this study. Clearly, employing a more robust analysis of family history is feasible in some primary care practices, but whether this influences therapy and prevents CV events remains to be proven.