Assessing completeness of cancer family history in EHRs using genetically defined kinships: A cross-sectional study.

Purpose: Family history (FHx) is the most widely available tool for reducing mortality and morbidity caused by heritable diseases. However, FHx may be inadequately documented. Our objective was to assess the rate at which cancers in patient relatives are documented as FHx in electronic health records (EHRs). Methods: Our primary analysis included 903 Healthy Nevada Project participants who had cancer-diagnosed patient relatives removed by ≤2 degrees in a kinship analysis. The rate of successful EHR documentation of relatives' cancer type was quantified using generalized estimating equations. Results: The population-average rate of cancer FHx documentation in the EHR was 45.2% (95% confidence interval [CI]: 42.0%-48.4%). The odds ratio (OR) for successful documentation was 0.39 (95% CI: 0.24-0.64) for patients >69 years old versus patients <30 years old. Additionally, FHx documentation increased with years since a relative's cancer diagnosis, with an OR of 2.19 (95% CI: 1.57-3.06) for patients with ≥10 years since their relative's diagnosis versus <5 years. Compared with females, males were less likely to document female-specific cancers (OR 0.31 [95% CI: 0.19-0.49]) but more likely to document male-specific cancers (OR 2.42 [95% CI: 1.16-5.04]). In a secondary analysis of 83 patients with variants in Conclusion: More than half of cancers affecting patient relatives were not documented as FHx in patient EHRs. This suggests that familial risk is underestimated, likely resulting in missed opportunities to reduce cancer mortality and morbidity.