The numerical translation of verbal probability expressions by patients and clinicians in the context of peri-operative risk communication

Aids to improve understanding of statistical risk in patients consenting for surgery and interventional procedures: A systematic review

BACKGROUND

Informed consent is an essential process in clinical decision-making, through which healthcare providers educate patients about benefits, risks, and alternatives of a procedure. Statistical risk information is difficult to communicate and the effectiveness of aids aimed at supporting this type of communication is uncertain. This systematic review aims to study the impact of risk communication adjuncts on patients' understanding of statistical risk in surgery and interventional procedures.

METHODS

A systematic search was performed across Medline, Embase, PsycINFO, Scopus, and Web of Science until July 2021 with a repeated search in September 2022. RCTs and observational studies examining risk communication tools (e.g., information leaflets and audio-video) in adult (age >16) patients undergoing a surgical or interventional procedure were included. Primary outcomes included the objective assessment of statistical risk recall. Secondary outcomes included patient attitudes with respect to statistical information. Due to the study heterogeneity, a narrative synthesis was performed.

RESULTS

A total of 4348 articles were identified, and following abstract and full-text screening 14 articles, including 9 RCTs, were included. The total number of adult patients was 1513. The most common risk communication tool used was written information (n = 7). Most RCTs (7/9, 77.8%) showed statistically significant improvements in patient understanding of statistical risk in the intervention group. Quality assessment found some concerns with all RCTs.

CONCLUSION

Risk communication tools appear to improve recall of statistical risk. Additional prospective trials comparing various aids simultaneously are warranted to determine the most effective method of improving understanding.

Association between Risk Communication Format and Perceived Risk of Adverse Events after COVID-19 Vaccination among US Adults

The format used to communicate probability-verbal versus numerical descriptors-can impact risk perceptions and behaviors. This issue is salient for the Coronavirus disease 2019 (COVID-19), where concerns about vaccine-related risks may reduce uptake and verbal descriptors have been widely used by public health, news organizations and on social media, to convey risk. Because the effect of risk-communication format on perceived COVID-19 vaccine-related risks remains unknown, we conducted an online randomized survey among 939 US adults. Participants were given risk information, using verbal or numerical descriptors and were asked to report their perceived risk of experiencing headache, fever, fatigue or myocarditis from COVID-19 vaccine. Associations between risk communication format and perceived risk were assessed using multivariable regression. Compared to numerical estimates, verbal descriptors were associated with higher perceived risk of headache (β = 5.0 percentage points, 95% CI = 2.0-8.1), fever (β = 27 percentage points, 95% CI = 23-30), fatigue (β = 4.9 percentage points, 95% = CI 1.8-8.0) and myocarditis (β = 4.6 percentage points, 95% CI = 2.1-7.2), as well as greater variability in risk perceptions. Social media influence was associated with differences in risk perceptions for myocarditis, but not side effects. Verbal descriptors may lead to greater, more inaccurate and variable vaccine-related risk perceptions compared to numerical descriptors.

Dimensions of uncertainty communication: What is conveyed by verbal terms and numeric ranges

The paper reviews two strands of research on communication of uncertainty that usually have been investigated separately: (1) Probabilities attached to specific outcomes, and (2) Range judgments. Probabilities are sometimes expressed by verbal phrases ("rain is likely") and at other times in a numeric format ("70% chance of rain"), whereas range judgments describe the potential amounts expected ("1-4 mm of rain"). Examination of previous research shows that both descriptions convey, in addition to the strength of expectations, pragmatic information about the communicative situation. For instance, so-called verbal probability expressions (VPE), as likely, unlikely, a chance, or not certain give some, albeit vague, probabilistic information, but carry in addition an implicit message about the sources of uncertainty, the outcome's valence and severity, along with information about the speakers' attitudes and their communicative intentions. VPEs are directional by drawing attention either to an outcome's occurrence ("it is possible") or to its non-occurrence ("it is doubtful"). In this sense they may be more informative than numbers. Uncertainties about outcomes in a distribution (continuous quantities) are alternatively expressed as interval estimates. The width of such intervals can function as a cue to credibility and expertise. Incomplete, one-sided intervals, where only one boundary is stated, imply directionality. "More than 100 people" suggests a crowd, while "less than 200" implies a shortfall. As with VPEs, directionally positive intervals are more frequent, and perhaps more neutral than negative ones. To convey expectancies and uncertainty in a balanced way, communicators may have to alternate between complementary frames.

Effective communication regarding risk of fracture for individuals at risk of fragility fracture: a scoping review

Two scoping reviews were conducted to review recommendations and guidelines for communication regarding general health risk, and to investigate communication strategies regarding risk of fracture. Healthcare professionals are invited to apply these recommendations to optimize a patient-centered approach to reducing risk of fracture.

INTRODUCTION

To conduct a scoping review of the medical literature regarding recommendations and tools for effective communication between healthcare professionals and patients regarding general health risk and risk of fracture.

METHODS

The scoping review was divided into two parts to search for (1) studies presenting recommendations and guidelines for communication regarding general health risk; (2) studies investigating communication regarding risk of fracture for individuals at risk for fractures. Medline was searched in April 2020 to identify relevant studies.

RESULTS

The scoping review included 43 studies on communication with regard to general health risk and 25 studies about communication regarding risk of fracture. Recommendations for effective communication with regard to risk are presented. Communication of numeric data on risk should be adapted to the literacy and numeracy levels of the individual patient. Patient understanding of numerical data can be enhanced with appropriate use of visual aids (e.g., pie charts, icon arrays, bar charts, pictograms). The FRAX® tool is the most recommended and most used tool for assessing risk of fracture. Communication sent as individualized letters to patients following DXA scans has been studied, although patient understanding of their risk of fracture is often reported as low using this technique. Use of visual aids may improve patient understanding.

CONCLUSION

Healthcare professionals are encouraged to apply recommendations presented in this scoping review in their clinical practice. Patient understanding of risk of fracture should be confirmed by making sure that patients feel free to ask questions and express their concerns. This will contribute to an optimal patient-centered approach. Developing online tools to convert the probability of fracture into patient-friendly visual presentations could facilitate communication between healthcare professionals and patients about risk of fracture.

Imprecision and Preferences in Interpretation of Verbal Probabilities in Health: a Systematic Review

INTRODUCTION

Many health providers and communicators who are concerned that patients will not understand numbers instead use verbal probabilities (e.g., terms such as "rare" or "common") to convey the gist of a health message.

OBJECTIVE

To assess patient interpretation of and preferences for verbal probability information in health contexts.

METHODS

We conducted a systematic review of literature published through September 2020. Original studies conducted in English with samples representative of lay populations were included if they assessed health-related information and elicited either (a) numerical estimates of verbal probability terms or (b) preferences for verbal vs. quantitative risk information.

RESULTS

We identified 33 original studies that referenced 145 verbal probability terms, 45 of which were included in at least two studies and 19 in three or more. Numerical interpretations of each verbal term were extremely variable. For example, average interpretations of the term "rare" ranged from 7 to 21%, and for "common," the range was 34 to 71%. In a subset of 9 studies, lay estimates of verbal probability terms were far higher than the standard interpretations established by the European Commission for drug labels. In 10 of 12 samples where preferences were elicited, most participants preferred numerical information, alone or in combination with verbal labels.

CONCLUSION

Numerical interpretation of verbal probabilities is extremely variable and does not correspond well to the numerical probabilities established by expert panels. Most patients appear to prefer quantitative risk information, alone or in combination with verbal labels. Health professionals should be aware that avoiding numeric information to describe risks may not match patient preferences, and that patients interpret verbal risk terms in a highly variable way.