How Useful Is Family History?
Abstract & Commentary
By Mary Elina Ferris, MD, Clinical Associate Professor, University of Southern California. Dr. Ferris reports no financial relationship to this field of study.
Synopsis: Although current evidence is lacking to define the key elements of a family history in primary care, family history may be useful for motivating positive lifestyle changes, enhancing individual empowerment, or influencing choice of clinical interventions.
Source: Wilson BJ, et al. Family history in risk assessment for common diseases. Ann Intern Med 2009;151:878-885.
Obtaining a patient's family history has become increasingly important in risk assessment for many diseases, and as a determinant for potential genetic testing. However, exactly what constitutes a family history and the accuracy of the information collected has come into question, particularly as new technology is crafted to collect this information in the electronic medical record and to use it for decision analysis. This article summarizes an extensive literature review from the U.S. Agency for Healthcare Research and Quality, which was then utilized by a National Institutes of Health (NIH) State-of-the-Science Conference held in August 2009 to answer these questions.1
All English-language articles published from 1995 through March 2009 that studied systematic family history collection, its connection to disease frequency and preventive interventions, and validation against relatives' true disease status were collected for review. Of 32,444 titles and abstracts screened, 137 publications met the eligibility criteria. The focus was on primary care and common diseases, looking at the usefulness, accuracy, benefits, and risks of the family history on both disease outcomes and risk assessment.
Reviewing 41 studies that utilized family history for risk assessment of common diseases, there were multiple different definitions of what constituted a positive family history, and only a few included age of onset or lineage criteria (e.g., whether first- or second-degree relatives were identified or whether parents were identified). Disease prevalence rates in different populations (1%-21%) and the positive family history (0.3%-60%) varied, making the associations very heterogeneous.
The actual accuracy of the family history provided by patients was addressed in 21 studies, mostly related to cancer. Patients were better at reporting absence of disease in relatives (specificity, 0.91-1.00) than the actual disease (sensitivity, as low as 0.3 for colon cancer, up to 0.9 for breast cancer and cardiovascular disease).
Some articles studied the effect of collecting family history on subsequent personal behaviors, such as measuring whether there was an increase of personal breast exams after obtaining family history of breast or ovarian cancer, but there was limited or insufficient evidence to show statistical differences. Mild adverse effects from collecting family history were found in 3 studies where there was an increase in anxiety scores in the intervention group compared with the control group within 2 weeks, but the scores normalized 3 months later.
Even something so seemingly fundamental to good medical care as the family history can reveal new findings when subjected to an evidence-based analysis. Clearly the extensive pedigrees obtained for genetic medicine are not feasible in the primary care office, so what should we be collecting, and how useful is this information? Based on this review, the NIH Conference concluded that evidence is lacking to define the key elements of a family history in primary care, and acknowledged that inaccuracy is to be expected when so many variables contribute to a relative's memory of disease occurrence.1 Research on whether collecting this information could cause harm was particularly lacking. Family history as a part of medical care was established so long ago that current research analysis may never be feasible, and we will have to settle for uncertainty in its use.
Despite this inaccuracy, the NIH Conference acknowledged that the family history may be useful for other purposes, such as motivating positive lifestyle changes, enhancing individual empowerment, or influencing choice of clinical interventions. There are some diseases where the genetic linkage has evidence-based support (e.g., the BRCA gene), but for many others the association is weaker and the information may be less useful. As with so many uncertainties of the human condition, the family history is another medical piece of information that does not stand alone, but must be used in context with other factors when making decisions about patient care.
1. Berg AO, et al. National Institutes of Health State-of-the-Science Conference Statement: Family history and improving health. Ann Intern Med 2009;151:872-877.