Communicating Down syndrome risk according to maternal age: "1-in-X" effect on perceived risk.

OBJECTIVE: The appropriateness of the 1-in-X numerical format to convey quantitative medical probabilities is currently under discussion because of its distortive effect on subjective probability assessment. Previous research, however, always asked participants to imagine a hypothetical scenario. The aim of the present research is to support the existence of the 1-in-X effect in a real setting: when pregnant women have to evaluate their personal risk of Down syndrome according to their maternal age. METHOD: During the first prenatal visit, pregnant women were asked to evaluate their own risk of having a child with Down syndrome according to their age, when such risk was presented either in the 1-in-X or in the N-in-NX format. Then, they were asked to assess their risk of having a child with Down syndrome. RESULTS: Results showed a systematic higher risk assessment when pregnant women were presented with the 1-in-X format (mean = 3.57, standard deviation = 1.4) than with the N-in-NX format (mean = 3.03, standard deviation = 1.4), P = 0.007. Whereas the effect was shown to be not moderated by a differential comprehension of the two numerical formats, women with a low educational level and those who were at their first pregnancy were shown to be significantly more vulnerable. CONCLUSION: The present findings corroborate the existence of the 1-in-X effect in a real-world setting, showing that, in pregnant women, the 1-in-X format actually elicits a higher perceived risk of Down syndrome, compared with the N-in-NX format.

Sociocognitive factors associated with nonadherence to medication after hospital discharge.

Poor adherence to prescribed medication is a well-known problem and continues to be a major challenge in all medical specialties. Unlike previous studies that have mainly focused on nonadherence behaviors in specific diseases, this study sought to examine socio-cognitive factors associated with nonadherence behavior in a sample of a general clinical population. A questionnaire investigating socio-demographic and cognitive factors and a telephone follow-up interview were administered to 84 patients recruited in a General Medicine Unit before their discharge. Half of the participants were informed about that follow-up procedure. One month after hospital discharge, 42% of uninformed patients reported nonadherence behaviors, as against 21% of informed patients. Middle-aged patients and short-term treatments were associated significantly more often with nonadherence. Among cognitive factors, patients' perceived risks and benefits of nonadherence, personal susceptibility to diseases, subjective health value, and reported memory failures were significantly associated with adherence. We conclude that a patient's perception may be more important than medication load, illness severity, and complexity of regimen in influencing medication adherence, and that a telephone call follow-up helps in monitoring medication adherence after hospital discharge.

Using comparison scenarios to improve prenatal risk communication.

UNLABELLED: The present research provides empirical evidence of whether communicating the prenatal risk of chromosomal anomalies using comparison scenarios influences women's ability to distinguish between different risk levels. In 2 experiments, participants read a description of a hypothetical woman who was learning of the risk of chromosomal anomaly as a result of a prenatal screening test. Both experiments used a 3 (risk level) × 3 (scenario) full between-subjects design. In accordance with the experimental condition, participants were presented with a low (e.g., 1 in 5390), a medium (e.g., 1 in 770), or a high risk value (e.g., 1 in 110). Such risk values were presented either on their own or along with additional information illustrating a comparison scenario that provided 2 numerical comparison points. Participants were asked to evaluate the risk of chromosomal anomaly. In Experiment 2, participants' numeracy skills were also assessed. RESULTS: showed that the use of comparison scenarios results in significant differences in perceived risk across risk levels whereas such differences are not significant without the comparison scenario, but such a technique has differential effects according to participants' capacity to deal with numbers. Although the technique is beneficial for high-numerate participants, it has no effect on low-numerate participants.

The 1-in-X effect on the subjective assessment of medical probabilities.

Among numerical formats available to express probability, ratios are extensively used in risk communication, perhaps because of the health professional's intuitive sense of their clarity and simplicity. Moreover, health professionals, in the attempt to make the data more meaningful, tend to prefer proportions with a numerator of 1 and shifting denominators (e.g., 1 in 200) rather than equivalent rates of disease per unit of population exposed to the threat (e.g., 5 in 1000). However, in a series of 7 experiments, it is shown that individual subjective assessments of the same probability presented through proportions rather than rates vary significantly. A 1-in-X format (e.g., 1 in 200) is subjectively perceived as bigger and more alarming than an N-in-X*N format (e.g., 5 in 1000). The 1-in-X effect generalizes to different populations, probabilities, and medical conditions. Further-more, the effect is not attenuated by a communicative intervention (verbal analogy), but it disappears with an icon array visual aid.