NUMERACY INFLUENCES PHYSICIANS' RISK COMMUNICATION ABOUT CANCER SCREENING

Purpose: Many patients have low numeracy, which impedes their understanding of important information about health (e.g., benefits and harms of screening). We investigated whether physicians adapt their risk communication to accommodate the needs of patients with low numeracy, and how physicians’ own numeracy influences their understanding and communication of screening statistics.

Method(s): UK family physicians (N=151) read a description of a patient seeking advice regarding screening for a hypothetical cancer X. In the description, we manipulated the numeracy of the patient (low vs. high vs. unspecified), the effectiveness of the screening for reducing mortality (effective vs. ineffective), and the presence of a clinical guideline recommending screening (present vs. absent). We measured physicians’ risk communication, recommendation to the patient, understanding of screening statistics, and numeracy. 

Result(s): Consistent with best practices, family physicians generally preferred to use visual aids rather than numbers when communicating information to a patient with low (vs. high) numeracy. However, 20% of physicians recommended a screening that was not effective and 44% offered incomplete risk information. Nevertheless, physicians with high (vs. low) numeracy offered more meaningful risk communication: they were more likely to mention mortality rates, OR=8.55 [95% CI 1.77, 41.41], and harms from overdiagnosis, OR=8.82 [1.34, 60.25]. Physicians with high numeracy were also more likely to understand that increased survival rates do not imply screening effectiveness, OR=6.05 [1.27, 28.72].

Conclusion(s): Screening patients for numeracy may help physicians tailor risk communication to patient needs and abilities. However, many well-intentioned physicians have low numeracy and are prone to communicating incomplete information to their patients. Although less numerate physicians know how to make risks easier to understand for patients, they themselves are likely to misunderstand risks and can unintentionally mislead patients. High-quality risk communication and shared decision making can depend critically on factors that can improve the risk literacy of physicians (e.g., numeracy, visual aids).