Knapp, P., Gardner, P. H., Raynor, D. K., Woolf, E., & McMillan, B. (2010). Perceived risk of tamoxifen side effects: a study of the use of absolute frequencies or frequency bands, with or without verbal descriptors. Patient education and counseling, 79(2), 267-271.

Knapp, P.; Gardner, P.; Raynor, D.; Woolf, E.; McMillan, B.

2010

Knapp, P., Gardner, P. H., Raynor, D. K., Woolf, E., & McMillan, B. (2010). Perceived risk of tamoxifen side effects: a study of the use of absolute frequencies or frequency bands, with or without verbal descriptors. Patient education and counseling, 79(2), 267-271.

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To investigate the effectiveness of presenting medicine side effect risk information in different forms, including that proposed by UK guidelines.134 Cancer Research UK (CRUK) website users were recruited via a ‘pop-up’. Using a 2 x 2 factorial design, participants were randomly allocated to one of four conditions and asked to: imagine they had to take tamoxifen, estimate the risks of 4 side effects, and indicate a presentation mode preference. Those presented with absolute frequencies demonstrated greater accuracy in estimating 2 of 4 side effects, and of any side effect occurring, than those presented with frequency bands. Those presented with combined descriptors were more accurate at estimating the risk of pulmonary embolism than those presented with numeric descriptors only. Absolute frequencies outperform frequency bands when presenting side effect risk information. However, presenting such exact frequencies for every side effect may be much less digestible than all side effects listed under 5 frequency bands. Combined numerical and verbal descriptors may be better than numeric only descriptors when describing infrequent side effects. Information about side effects should be presented in ways that patients prefer, and which result in most accurate risk estimates.

Participants generally over-estimated the risk of side effects irrespective of the manner of presentation. Participants may not have completely trusted the information supplied in the scenario, or personal experiences of cancer treatment may have influenced their judgment. In 4 of 6 side effect estimates, those in the frequency format condition were significantly more accurate at estimating risk than were participants receiving frequency band information. When comparing those who received information in numeric format only with those who received it in combined format, only one statistically significant difference existed. Participants presented with absolute frequency information were generally more accurate than participants presented with frequency bands.

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