A framework for health numeracy: how patients use quantitative skills in health care

1. Improving Care and Promoting Health in Populations: Standards of Care in Diabetes-2024

The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a interprofessional expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at https://professional.diabetes.org/SOC.

Factors associated with parental COVID-19 vaccine attitudes and intentions among a national sample of United States adults ages 18-45

PURPOSE

This study explored factors associated with parents' attitudes and intentions to seek information about the COVID-19 vaccine for their children (ages 0-18) and intentions to vaccinate their age-eligible children.

DESIGN AND METHODS

As part of an anonymous online cross-sectional survey, parents' vaccine attitudes, COVID-19 vaccine intentions for their children, health literacy, health numeracy, and sociodemographic variables were assessed. Multivariable ordered logistic regression models identified factors associated with parents' COVID-19 vaccine intentions for their children.

RESULTS

Parents/guardians (n = 963) were mostly White (82.3%), insured (88.0%), and college graduates (57.3%). Men reported higher intentions than women to seek information about the COVID-19 vaccine for their children (p = 0.003) and higher intentions to vaccinate their children (p = 0.049). Parental characteristics associated with increased intentions to have their children vaccinated included higher educational attainment (p < 0.001), more positive general vaccine attitudes (p < 0.001), preference for health information in a language other than English (p = 0.006), higher income (p = 0.048), having health insurance (p = 0.05), health literacy (p = 0.024), and health numeracy (p = 0.049).

CONCLUSIONS

Multiple sociodemographic characteristics including male gender, higher health literacy and numeracy, and language preference are noteworthy factors associated with parental COVID-19 vaccine intentions that could inform the planning and implementation of educational interventions.

PRACTICE IMPLICATIONS

Nurses are important sources of trusted information and play an important role in parent/family health education and in understanding myriad factors that may improve attitudes and enhance readiness toward vaccine uptake. Our findings emphasize the potential value of examining tailored/targeted COVID-19 vaccine education according to key influencing factors.

1. Improving Care and Promoting Health in Populations: Standards of Care in Diabetes-2023

The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Statistical Literacy in the Orthopaedic Trauma Population

OBJECTIVE

To evaluate the baseline level and demographic predictors of statistical literacy in orthopaedic patients who sustained traumatic injuries.

DESIGN

Prospective observational.

SETTING

Level 1 trauma center.

PATIENTS

One hundred ninety-eight patients presenting to the orthopaedic trauma clinic.

INTERVENTION

Berlin Numeracy Test (BNT) and General Health Numeracy Test-6 (GHNT-6).

RESULTS

When assessed using the BNT, 67% of patients had results that placed them into the lowest quartile of objective numeracy skills. Only 3.5% of patients had results that scored in the top quartile. Our multivariate ordinal regression model demonstrated lower education level ( P = 0.01), and older age ( P = 0.03) were significant predictors of poor performance on the BNT. The mean score on the GHNT-6 was 36% (SD 30%).

CONCLUSIONS

In a cohort of traumatically injured patients, poor statistical literacy was common, occurring in more than two-thirds of patient surveyed. Older age and lower levels of education were predictive of poor BNT performance and should be considered when discussing surgical options, associated risks, and likelihood of potential complications.

1. Improving Care and Promoting Health in Populations: Standards of Medical Care in Diabetes-2022

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (https://doi.org/10.2337/dc22-SPPC), are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction (https://doi.org/10.2337/dc22-SINT). Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

The communication of uncertainty in health: A scoping review

OBJECTIVE

To conduct a scoping review of existing studies that examine communication strategies that address uncertainty in health and categorize them using the taxonomy of uncertainty.

METHODS

Relevant articles retrieved from ten databases were categorized according to the dimensions of the taxonomy of uncertainty, and study characteristics were extracted from each article.

RESULTS

All articles (n = 63) explored uncertainty in the context of probabilistic risk and related to scientific issues (n = 63; 100%). The majority focused on complexity (n = 24; 38.1%) and uncertainty experienced by patients (n = 52; 82.5%). Most utilized quantitative methods (n = 46; 73.0%), hypothetical scenarios (n = 49; 77.8%), and focused on cancer (n = 20; 31.7%). Theory guided messages and study design in fewer than half (n = 27; 42.9%).

CONCLUSIONS

Heterogeneity in terminology used to refer to different types of uncertainties preclude a unified research agenda on uncertainty communication. Research predominately focuses on probability as the source of uncertainty, uncertainties related to scientific issues, and uncertainty experienced by patients.

PRACTICE IMPLICATIONS

Additional efforts are needed to understand providers' experience of uncertainty, and to identify strategies to address ambiguity. Future studies should use consistent terminology to allow for coherence and advancement of uncertainty communication scholarship. Continued efforts to refine the existing taxonomy should be undertaken.

Impact of numeracy preferences on information needs for genome sequencing results

OBJECTIVE

This study investigated how self-reported numeracy ability and preferences predict preferences for the amount and types of information provided about genome sequencing results among 1080 women diagnosed with breast cancer at age 40 or younger.

METHODS

Participants reported their level of interest in 14 topics related to genome sequencing results on a survey. We calculated a Participant Information Needs (PIN) value based on the number of topics for which a participant wanted "a lot" of information. Numeracy was assessed using the Subjective Numeracy Scale. Analyses examined associations between the numeracy ability and preferences subscales, information needs for individual content topics, and PIN.

RESULTS

Higher preference for numeric data was correlated with increased PIN (β = 0.60, p < 0.01), while numeric ability was not correlated (β=0.16, p = 0.22). Family composition and knowledge about sequencing benefits were also significant covariates. Patients most preferred information on topics related to disease risk and health implications.

CONCLUSION

There may be utility in separating numeracy ability and preferences into two components in future research in order to investigate how numeracy impacts the return of genetic testing results.

PRACTICE IMPLICATIONS

These data suggest that numeracy preferences may be important to inform strategies for the return of genetic results.

Framing the Clinical Encounter: Shared Decision-Making, Mammography Screening, and Decision Satisfaction

The study examines whether physicians' framing of clinical interactions is related to patient shared decision-making (SDM) satisfaction when using a clinical decision support tool (CDST) concerning mammographic screening. To answer this question, we combined (a) system log data from a CDST, (b) content coding of the physicians' message framing while using the CDST, and (c) a post-visit patient survey to assess SDM satisfaction concerning screening mammography. Results suggest that two types of message frames - consequence frames and numerical frames - moderated the relationship of the CDST on SDM satisfaction. When the CDST displayed low risk of breast cancer for a patient, physicians were able to improve the cognitive aspects of SDM satisfaction by framing the consequences of mammography screening in positive terms. However, when the physician delivered the numerical information in relative, rather than absolute terms, the patient's SDM satisfaction was reduced. Our study advances previous message framing effect research in health communication from experimental settings to clinical encounters. It also discusses the importance of delivering risk-congruent frames in clinical settings.

Improving Communication in Breast Cancer Treatment Consultation: Use of a Computer Test of Health Numeracy

Background: Communication of statistics and probability is challenging in the cancer care setting. The objectives of this study are to evaluate a novel approach to cancer communication through the use of a computer assessment of patient health numeracy. Methods: We conducted a pilot study of the Computer Adapted Test of Numeracy Understanding in Medicine Instrument (CAT-NUMi) before the cancer treatment consultation for women with stage 0-3 breast cancer. Patient outcomes included the interpersonal processes of care (IPC) and the decisional conflict scale. We evaluated clinician use of numeric information in the cancer consultation and assessed feasibility outcomes from the clinician and patient perspective. Results: Patient participants (n = 50) had a median (interquartile range) age of 51 years (46-61), 70% were English speaking, and 30% Spanish speaking. Decisional conflict was low with a mean (standard deviation [SD]) decisional conflict score of 17.4 (12.3). The lack of clarity score (range 1-5) on the IPC was low (mean, SD),1.70 (0.71), indicating clear communication. Clinicians more often used percentages in communicating prognosis among those with higher numeracy scores (median, range): high (2, 0-8), medium (1, 0-7), and low (0, 0-8); p = 0.04. The patient experience of taking the CAT-NUMi was rated as very good or excellent by 65%, fair by 33%, and poor by 2% of patients. Conclusion: Screening for health numeracy with a short computer-based test may be a feasible strategy to optimize clear communication in the cancer treatment consultation. Further studies are needed to evaluate this strategy across cancer treatment clinical settings and populations.

The Influence of Health Numeracy and Health Warning Label Type on Smoking Myths and Quit-Related Reactions

INTRODUCTION

Health numeracy helps individuals understand risk information, but limited data exist concerning numeracy's role in reactions to varying types of health warning labels (HWLs) for cigarettes.

METHODS

A nationally representative online panel of adult current smokers received two exposures (1 week apart) to nine HWLs with either text-only or pictorial images with identical mandated text. Following the second exposure, participants (n = 594) rated their beliefs in smoking myths (eg, health-promoting behaviors can undo the risks of smoking) and how much the warnings made them want to quit smoking. Generalized estimating equation regression examined the relation of objective health numeracy and its interaction with HWL type to smoking-myth beliefs and quit-related reactions.

RESULTS

Health numeracy was not significantly associated with smoking-myth beliefs; the interaction with HWL type was also nonsignificant. Adult smokers with lower health numeracy had higher quit-related reactions than those with higher numeracy following exposure to HWLs. The type of HWL significantly modified numeracy's associations with quit-related reactions; no significant association existed between text-only HWLs and quit-related reactions, whereas among those who viewed the pictorial warnings, lower numeracy was associated with greater quit-related reactions (β = -.23; p < .001).

CONCLUSIONS

Lower as compared to higher health numeracy was significantly associated with higher quit-related reactions to HWLs and especially with pictorial HWLs. Health numeracy and HWL type were not associated with the endorsement of smoking myths. The role of health numeracy in effectively communicating risks to smokers warrants thoughtful consideration in the development of tobacco HWLs.

IMPLICATIONS

Health numeracy plays an important role in an individual's ability to understand and respond to health risks. Smokers with lower health numeracy had greater quit-related reactions to pictorial health warnings than those who viewed text-only warning labels. Development and testing of health warning labels should consider health numeracy to most effectively communicate risk to US smokers.

Preferences of Patients and Pharmacists with Regard to the Management of Drug-Drug Interactions: A Choice-Based Conjoint Analysis

Introduction

The management of drug–drug interactions (DDIs) is a complex process in which risk–benefit assessments should be combined with the patient’s perspective.

Objective

The aim of this study was to determine patients’ and pharmacists’ preferences regarding DDI management.

Methods

We conducted a choice-based conjoint survey about a fictitious DDI concerning the combination of a cardiovascular drug and an antibiotic for pneumonia. Patients and pharmacists had to choose 12 times between two management options. The options were described by five attributes, including risk, benefit and practical consequences. Each attribute could have two different levels, which were varied over the choice tasks. Latent class analysis was used to identify potential classes of respondents with distinct patterns of similar preferences.

Results

In total, 298 patients and 178 pharmacists completed the questionnaire. The latent class model for both patients and pharmacists resulted in three classes. For patients, in one class the most importance was attached to avoiding switch of medication (class probability 20%), in a second class to fewer adverse events (41%), and in a third class to blood sampling (39%). For pharmacists, again one class attached the highest importance to avoiding switch of medication (31%). The other classes gave priority to curing pneumonia (31%) and avoiding blood sampling (38%).

Conclusion

The results showed diverging preferences regarding DDI management among both patients and pharmacists. Different groups attached different value to risk and benefit versus practical considerations. Awareness of existing variability in preferences among and between pharmacists and patients is a step towards shared decision making in DDI management.

Electronic supplementary material

The online version of this article (doi:10.1007/s40264-017-0601-7) contains supplementary material, which is available to authorized users.

Enhanced self-monitoring blood glucose in non-insulin-requiring Type 2 diabetes: A qualitative study in primary care

AIMS AND OBJECTIVES

To contribute to both theoretical and practical understanding of the role of self-monitoring blood glucose for self-management by describing the experience of people with non-insulin-requiring Type 2 diabetes in an enhanced structured self-monitoring blood glucose intervention.

BACKGROUND

The complex context of self-monitoring blood glucose in Type 2 diabetes requires a deeper understanding of the clients' illness experience with structured self-monitoring of blood glucose. Clients' numeracy skills contribute to their response to blood glucose readings. Nurses' use of motivational interviewing to increase clients' regulatory self-efficacy is important to the theoretical perspective of the study.

DESIGN

A qualitative descriptive study.

METHODS

A purposive sample of eleven adults recently (<2 years) diagnosed with non-insulin-requiring Type 2 diabetes who had experienced a structured self-monitoring blood glucose intervention participated in this study. Audio recordings of semi-structured interviews and photographs of logbooks were analysed for themes using constant comparison and member checking.

RESULTS

The illness experience states of Type 2 diabetes include 'Diagnosis,' 'Behavior change,' and 'Routine checking.' People check blood glucose to confirm their Type 2 diabetes diagnosis, to console their diabetes-related fears, to create personal explanations of health behaviour's impact on blood glucose, to activate behaviour change and to congratulate their diabetes self-management efforts.

CONCLUSIONS

These findings support the Transtheoretical model's stages of change and change processes. Blood glucose checking strengthens the relationships between theoretical concepts found in Diabetes Self-management Education-Support including the following: engagement, information sharing and behavioural support.

RELEVANCE TO CLINICAL PRACTICE

Tailoring diabetes care specifically to clients' stage of their illness experience with use of self-monitoring blood glucose contributes to engagement in self-management. Motivational interviewing and collaborative decision-making using blood glucose checking increase regulatory self-efficacy for people living with non-insulin-requiring Type 2 diabetes.

Unpacking decision difficulty: Testing action dynamics in Intertemporal, gamble, and consumer choices

The study examined the two-factor structure of decision difficulty proposed by Cheng and González-Vallejo (2017) in new domains, and the role of numeracy in relation to these factors. Using the measurement methodology of 'mouse' (cursor) movements, participants' temporal and spatial measures were recorded when making decisions in the domains of intertemporal, gamble, and consumer choices. Task manipulations designed to affect difficulty included the sign of the payoffs (gains vs. losses), the similarity of the attribute values being compared, and attribute importance. A psychometric analysis of the measures revealed three orthogonal components, two of which, conflict and wavering, described decision difficulty. The conflict component was most affected by changes in the sign of the payoffs of intertemporal and gamble choices, with greater means observed in the loss than in the gain context. By contrast, the wavering component was most affected by changes of the similarity between the options' attributes, with greater means when the options were more similar. The study also found that choosing the long-term advantageous options in an intertemporal choice task; choosing the riskier gain and safer loss in a gamble choice task; and choosing the more expensive/better-quality hotel in a consumer choice task demonstrated greater conflict and/or wavering. The study further found that numeracy, or the degree to which individuals are able to use and interpret numbers, was negatively related to the conflict component. Taken together, the study demonstrated that decision difficulty varied with contextual changes, and action-dynamic measures reflected different facets of decision difficulty.

Let's talk numbers: a qualitative study of community-dwelling US adults to understand the role of numeracy in the management of heart failure

OBJECTIVE

To examine the perspectives of adults with heart failure (HF) about numerical concepts integral to HF self-care.

SETTING

This qualitative study took place at an urban academic primary care practice.

PARTICIPANTS

Thirty men and women aged 47-89 years with a history of HF were recruited to participate. Eligibility criteria included: a history of HF (≥1 year), seen at the clinic within the last year, and a HF hospitalisation within the last 6 months. Non-English speakers and those with severe cognitive impairment were excluded.

METHODS

In-depth semistructured interviews were conducted. Participants were interviewed about numeracy across three domains of HF self-care: (1) monitoring weight,(2) maintaining a diet low in salt and (3) monitoring blood pressure. Interviews were audio-taped, transcribed verbatim and analysed using grounded theory and word cloud techniques.

RESULTS

Five key themes reflecting participants' attitudes towards numerical concepts pertaining to weight, diet and blood pressure were identified: (1) Communication between healthcare providers and patients is a complex, multistage process; (2) Patients possess a wide range of knowledge and understanding; (3) Social and caregiver support is critical for the application of numerical concepts; (4) Prior health experiences shape outlook towards numerical concepts and instructions and (5) Fear serves as a barrier and a facilitator to carrying out HF self-care tasks that involve numbers. The findings informed a theoretical framework of health numeracy in HF.

CONCLUSION

Effective communication of numerical concepts which pertain to HF self-care is highly variable. Many patients with HF lack basic understanding and numeracy skills required for adequate self-care. As such, patients rely on caregivers who may lack HF training. HF-specific training of caregivers and research that seeks to elucidate the intricacies of the patient-caregiver relationship in the context of health numeracy and HF self-care are warranted.

Numeracy and Understanding of Quantitative Aspects of Predictive Models: A Pilot Study

BACKGROUND

The assessment of user preferences for performance characteristics of patient-oriented clinical prediction models is lacking. It is unknown if complex statistical aspects of prediction models are readily understandable by a general audience.

OBJECTIVE

A pilot study was conducted among nonclinical audiences to determine the feasibility of interpreting statistical concepts that describe the performance of prediction models.

METHODS

We conducted a cross-sectional electronic survey using the Amazon Mechanical Turk platform. The survey instrument included educational modules about predictive models, sensitivity, specificity, and confidence intervals (CIs). Follow-up questions tested participants' abilities to interpret these characteristics with both verbatim and gist knowledge. Objective and subjective numeracy were assessed using previously validated instruments. We also tested understanding of these concepts when embedded in a sample discrete choice experiment task to establish feasibility for future elicitation of preferences using a discrete choice experiment design. Multivariable linear regression was used to identify factors associated with correct interpretation of statistical concepts.

RESULTS

Among 534 respondents who answered all nine questions, the mean correct responses was 95.9% (95% CI, 93.8-97.4) for sensitivity, 93.1% (95% CI, 90.5-95.0) for specificity, and 86.6% (95% CI, 83.3-89.3) for CIs. Verbatim interpretation was high for all concepts, but significantly higher than gist only for CIs (p < 0.001). Scores on each discrete choice experiment tasks were slightly lower in each category. Both objective and subjective numeracy were positively associated with an increased proportion of correct responses (p < 0.001).

CONCLUSION

These results suggest that a nonclinical audience can interpret quantitative performance measures of predictive models with very high accuracy. Future development of patient-facing clinical prediction models can feasibly incorporate patient preferences for model features into their development.

Alignment of Patient Health Numeracy with Asthma Care Instructions in the Patient Portal

Background

After Visit Summary (AVS) instructions provided through the patient portal of the electronic medical record can support asthma self-management if patients have the skills to interpret and apply the health information provided. Print literacy demands of patient materials are often higher than the reading ability of patients. However, less is known regarding the numeric demand of patient education materials and how well it aligns with patient health numeracy.

Objectives

This study (1) developed measures of numeric demand for use in the AVS, (2) described the health numeracy demand of AVS instructions for asthma care, and (3) evaluated the association between numeracy demand of materials and patient health numeracy.

Methods

We reviewed personalized AVS instructions for an index visit from 74 adults with moderate or severe asthma recruited from clinics serving low-income urban communities. Using measures of numeric complexity and density developed for this study, numeracy demand of the AVS was compared to the numeracy skills of patients using the validated Asthma Numeracy Questionnaire.

Key Results

The numeric complexity and density scales demonstrated content and face validity. The median (range) of the numeric complexity score for AVS instructions was 2.5 (0-46), and density of numeric information was 8% (0%-33%). The median (range) of the Asthma Numeracy Questionnaire was 2 (0-4). There was no association between patient asthma-related health numeracy and the complexity (p = .29) or density (p = .81) of numeric information.

Conclusions

Patient instructions regarding medications and self-management often include numeric information. Lack of alignment of the numeracy demand of materials with health numeracy skill may be a barrier to communication, particularly among patients of lower health numeracy. [Health Literacy Research and Practice. 2017;1(1):e1-e10.].

Plain Language Summary

This study developed a way to measure the frequency and complexity of numeric information in instructions given to patients with asthma. No association was found between the difficulty of numeric information provided and the numeracy level of patients. This poses a potential barrier to communication, especially for patients with low health numeracy.

Tailoring Educational and Behavioral Interventions to Level of Health Literacy: A Systematic Review

Background: The relative value of universal compared to contingent approaches to communication and behavioral interventions for persons of low health literacy remains unknown. Objective: To examine the effectiveness of interventions that are tailored to individual health literacy level compared to nontailored interventions on health-related outcomes. Design: Systematic review. Data Sources: PubMed and Embase databases. Eligibility Criteria: Studies were eligible if they were in English, used an experimental or observational design, included an intervention that was tailored based on the individual's level of education, health literacy or health numeracy, and had a comparator group in which the intervention was not tailored to individual characteristics. Review Methods: Databases were searched from inception to January 2016, and the retrieved reference lists hand searched. Abstracts that met PICOS criteria underwent dual review for data extraction to assess study details and study quality. A qualitative synthesis was conducted. Results: Of 2,323 unique citations, 458 underwent full review, and 9 met criteria for the systematic review. Five studies were positive and rated as good quality, 3 were negative with 2 of those of good quality, and 1 had mixed results (fair quality). Positive studies were conducted in the clinical domains of hypertension, diabetes, and depression with interventions including educational materials, disease management sessions, literacy training, and physician notification of limited health literacy among patients. Negative studies were conducted in the clinical domains of heart disease, glaucoma, and nutrition with interventions including medication reconciliation and educational materials. Conclusions: Tailoring communication and behavioral interventions to the individual level of health literacy may be an effective strategy to improve knowledge and indicators of disease control in selected clinical settings.

Sex Differences in Human and Animal Toxicology

Sex, the states of being female or male, potentially interacts with all xenobiotic exposures, both inadvertent and deliberate, and influences their toxicokinetics (TK), toxicodynamics, and outcomes. Sex differences occur in behavior, exposure, anatomy, physiology, biochemistry, and genetics, accounting for female-male differences in responses to environmental chemicals, diet, and pharmaceuticals, including adverse drug reactions (ADRs). Often viewed as an annoying confounder, researchers have studied only one sex, adjusted for sex, or ignored it. Occupational epidemiology, the basis for understanding many toxic effects in humans, usually excluded women. Likewise, Food and Drug Administration rules excluded women of childbearing age from drug studies for many years. Aside from sex-specific organs, sex differences and sex × age interactions occur for a wide range of disease states as well as hormone-influenced conditions and drug distribution. Women have more ADRs than men; the classic sex hormone paradigm (gonadectomy and replacement) reveals significant interaction of sex and TK including absorption, distribution, metabolisms, and elimination. Studies should be designed to detect sex differences, describe the mechanisms, and interpret these in a broad social, clinical, and evolutionary context with phenomena that do not differ. Sex matters, but how much of a difference is needed to matter remains challenging.

Development and Validation of the Spanish Numeracy Understanding in Medicine Instrument

BACKGROUND

The Spanish-speaking population in the U.S. is large and growing and is known to have lower health literacy than the English-speaking population. Less is known about the health numeracy of this population due to a lack of health numeracy measures in Spanish.

OBJECTIVE

we aimed to develop and validate a short and easy to use measure of health numeracy for Spanish-speaking adults: the Spanish Numeracy Understanding in Medicine Instrument (Spanish-NUMi).

DESIGN

Items were generated based on qualitative studies in English- and Spanish-speaking adults and translated into Spanish using a group translation and consensus process. Candidate items for the Spanish NUMi were selected from an eight-item validated English Short NUMi. Differential Item Functioning (DIF) was conducted to evaluate equivalence between English and Spanish items. Cronbach's alpha was computed as a measure of reliability and a Pearson's correlation was used to evaluate the association between test scores and the Spanish Test of Functional Health Literacy (S-TOFHLA) and education level.

PARTICIPANTS

Two-hundred and thirty-two Spanish-speaking Chicago residents were included in the study.

KEY RESULTS

The study population was diverse in age, gender, and level of education and 70 % reported Mexico as their country of origin. Two items of the English eight-item Short NUMi demonstrated DIF and were dropped. The resulting six-item test had a Cronbach's alpha of 0.72, a range of difficulty using classical test statistics (percent correct: 0.48 to 0.86), and adequate discrimination (item-total score correlation: 0.34-0.49). Scores were positively correlated with print literacy as measured by the S- TOFHLA (r = 0.67; p < 0.001) and varied as predicted across grade level; mean scores for up to eighth grade, ninth through twelfth grade, and some college experience or more, respectively, were 2.48 (SD ± 1.64), 4.15 (SD ± 1.45), and 4.82 (SD ± 0.37).

CONCLUSIONS

The Spanish NUMi is a reliable and valid measure of important numerical concepts used in communicating health information.

Perceptions of oocyte banking from women intending to circumvent age-related fertility decline

INTRODUCTION

Women can now opt to bank their oocytes with the intention of increasing their chances of achieving a pregnancy after their fertility has declined. This exploratory study aimed to gain insight into how women, considering oocyte banking to circumvent age-related fertility decline, perceive this intervention.

MATERIAL AND METHODS

We conducted a qualitative study in a Dutch university medical center and held in-depth interviews with women on the waiting list for oocyte banking. We recorded the interviews, transcribed them verbatim and used thematic analysis.

RESULTS

All women were financially independent and lived in single-person urban households. They opted for oocyte banking because they wished to share parenthood with a future partner rather than becoming a single parent. This strong desire was key in their interpretation of all aspects of the intervention. Women set aside information about the limited success rates and potential risks, as they were optimistic about their own prognosis, thought that the chances for success were equally likely as the chances it would fail, and because of "anticipatory regret". They perceived oocyte banking as a "helping hand" to achieve shared parenthood. Although women found the costs of the intervention high, they were willing to invest their money to increase their chances for shared parenthood.

CONCLUSIONS

Oocyte banking allows women to circumvent age-related fertility decline. The prospect of potential shared parenthood overrules the perceived health risks and burden. Health professionals should take this into account when informing potential users of oocyte banking.

Public engagement with scientific evidence in health: A qualitative study among primary-care patients in an urban population

The purpose of this study is to explore the experience and perspective of patients regarding scientific evidence in health and the degree that this information impacts health behavior and medical decision making. A focus group study was conducted. Participants were recruited from an urban primary-care practice. The focus group discussions were audio-recorded, transcribed verbatim, and coded by two independent investigators. Emergent themes were identified. Participants (n = 30) ranged in age from 30 to 79 years, 60% were female, 77% were black, and 50% had at least some college experience. Three thematic areas informed a wide range in level of interest regarding scientific study design and result information: (1) scientific literacy, (2) medical decision making style, and (3) impact of culture and community on decision making. Our findings indicate that communication strategies that incorporate key elements of scientific study design, methods, and results will most effectively translate findings from comparative effectiveness research to patient-informed decision making regarding evidence-based health interventions.

Empirical relationships between numeracy and treatment decision making: A scoping review of the literature

OBJECTIVES

To determine what is known from the existing literature about empirical relationships between numeracy and the three stages of the treatment decision making process (information exchange, deliberation, and deciding on the treatment to implement). We also examined if, and how, numeracy was mentioned in relation to health literacy.

METHODS

A search of four databases returned 2772 records. After de-duplication and three levels of relevance screening, 38 primary studies were included in this review.

RESULTS

Relationships between numeracy and the information exchange stage have received greater attention than relationships between numeracy and the deliberation and deciding on the treatment to implement stages. The lack of overlap in the empirical relationships examined in studies, the measure(s) of numeracy used, and the characteristics of study populations, made findings difficult to compare. Multiple knowledge gaps and measurement-related problems were identified. Numeracy and health literacy have largely been treated as separate concepts.

CONCLUSION

More research is needed to better understand the importance of numeracy and health literacy to treatment decision making.

PRACTICE IMPLICATIONS

Decision aids designed for patients with different levels of health literacy may not meet the needs of patients with different levels of numeracy. The numeracy skills of health professionals require attention.

Subjective Quality Information: Effects of Patient Experience Outcomes and Display Formats on Evaluation and Choice Intentions

This study analyzes the impact of subjective quality information in the form of aggregate patient experience outcomes on respondent evaluation and intended choice of hospitals. We compared clinical performance-based quality measures (i.e., wound infection rates) with participant evaluations and choice intentions when they were additionally provided with subjective quality information (i.e., patient experience outcomes in different display formats). Results suggest that patient experience outcomes significantly affected the evaluations and choice intentions. Additionally, we found significant effects of subjective information display formats. Limitations, directions for future research, and implications for publishing subjective quality information in health care markets are discussed.

Validation of a Short, 3-Item Version of the Subjective Numeracy Scale

BACKGROUND AND OBJECTIVE

Efficiency in scale design reduces respondent burden. A brief but reliable measure of numeracy may provide a useful research tool eligible for integration into large epidemiological studies or clinical trials. Our goal was to validate a 3-item version of the Subjective Numeracy Scale (SNS-3).

DESIGN AND SETTING

We examined 7 separate cross-sectional data sets: patients in the emergency department (n = 208), clinic (n = 205), and hospital (n = 460; n = 2053) and patients with chronic kidney disease (n = 147), with diabetes (n = 318), and on hemodialysis (n = 143).

MEASUREMENTS

Internal reliability of the SNS-3 was assessed with Cronbach's α. Criterion validity was determined by nonparametric correlations of the SNS-3 with SNS-8 and other measures of numeracy; construct validity was determined by correlations with measures of health literacy and education.

RESULTS

The SNS-3 had good internal reliability (median Cronbach's α = 0.78) and correlated highly with the full SNS (median ρ = 0.91). The SNS-3 was significantly correlated with other measures of numeracy (e.g., median ρ = 0.57 with the Wide Range Achievement Test 4), health literacy (e.g., median ρ = 0.35 with the Shortened Test of Functional Health Literacy in Adults), and education (median ρ = 0.41), providing good evidence of criterion and construct validity.

CONCLUSION

The SNS-3 is sufficiently reliable and valid to be used as a measure of subjective numeracy.

Improving bone mineral density reporting to patients with an illustration of personal fracture risk

Background

To determine patients’ preferences for, and understanding of, FRAX® fracture risk conveyed through illustrations.

Methods

Drawing on examples from published studies, four illustrations of fracture risk were designed and tested for patient preference, ease of understanding, and perceived risk. We enrolled a convenience sample of adults aged 50 and older at two medical clinics located in the Midwestern and Southern United States. In-person structured interviews were conducted to elicit patient ranking of preference, ease of understanding, and perceived risk for each illustration.

Results

Most subjects (n = 142) were female (64%), Caucasian (76%) and college educated (78%). Of the four risk depictions, a plurality of participants (37%) listed a bar graph as most preferred. Subjects felt this illustration used the stoplight color system to display risk levels well and was the most “clear,” “clean,” and “easy to read”. The majority of subjects (52%) rated the pictogram as the most difficult to understand as this format does not allow people to quickly ascertain their individual risk category.

Conclusions

Communicating risk to patients with illustrations can be done effectively with clearly designed illustrations responsive to patient preference.

Trial Registration

ClinicalTrials.gov Identifier: NCT01507662

Doctors and numbers: an assessment of the critical risk interpretation test

BACKGROUND

Risk interpretation affects decision making. Yet, there is no valid assessment of how clinicians interpret the risk data that they commonly encounter.

OBJECTIVE

To establish the reliability and validity of a 20-item test of clinicians' risk interpretation.

METHODS

The Critical Risk Interpretation Test (CRIT) measures clinicians' abilities to 1) modify the interpretation based on meaningful differences in the outcome (e.g., disease specific v. all-cause mortality) and time period (e.g., lifetime v. 10-year mortality), 2) maintain a stable interpretation for different risk framings (e.g., relative v. absolute risk), and 3) correctly interpret how diagnostic testing modifies risk. There were 658 clinicians and medical trainees who participated: 116 nurse practitioners (NPs) at a national conference, 273 medical students at 1 institution, 148 residents in internal medicine at 2 institutions, and 121 internists at 1 institution. Participants completed a self-administered paper test during educational conferences. Seventeen evidence-based medicine experts took the test online and formally assessed content validity. Eighteen second-year medical students were recruited to take the test and a retest 3 weeks later to explore test-retest correlation.

RESULTS

Expert review supported test clarity and content validity. Factor analysis supported that the CRIT identifies at least 3 separable areas of clinician knowledge. Test-retest correlation was fair (intraclass correlation coefficient = 0.65; standard error = 0.15). Scores on our test correlated with other tests of related abilities. Mean test scores varied among groups, with differences in prior evidence-based medicine training and experience (93 for NPs, 101 for medical students, 101 for residents, 103 for academic internists, and 110 for physician experts; P < 0.001).

CONCLUSIONS

Our results provide supporting evidence for the reliability and validity of the CRIT as an index of critical risk interpretation abilities, which is acceptable and feasible to administer in an educational setting.

Health numeracy: perspectives about using numbers in health management from African American patients receiving dialysis

Health numeracy is linked to important clinical outcomes. Kidney disease management relies heavily on patient numeracy skills across the continuum of kidney disease care. Little data are available eliciting stakeholder perspectives from patients receiving dialysis about the construct of health numeracy. Using focus groups, we asked patients receiving hemodialysis open-ended questions to identify facilitators and barriers to their understanding, interpretation, and application of numeric information in kidney care. Transcripts were analyzed using content analysis. Twelve patients participated with a mean (standard deviation) age of 56 (12) years. All were African American, 50% were women, and 83% had an annual income <$20,000/year. Although patients felt numbers were critical to every aspect in life, they noted several barriers to understanding, interpreting and applying quantitative information specifically to manage their health. Low patient self-efficacy related to health numeracy and limited patient-provider communication about quantitatively based feedback, were emphasized as key barriers. Through focus groups of key patient stakeholders we identified important modifiable barriers to effective kidney care. Additional research is needed to develop tools that support numeracy-sensitive education and communication interventions in dialysis.

Subjective numeracy and preference to stay with the status quo

BACKGROUND

Preference for the status quo, or clinical inertia, is a barrier to implementing treat-to-target protocols in patients with chronic diseases such as rheumatoid arthritis (RA). The objectives of this study were to examine the influence of subjective numeracy on RA-patient preference for the status quo and to determine whether age modifies this relationship.

METHODS

RA patients participated in a single face-to-face interview. Numeracy was measured using the Subjective Numeracy Scale. Treatment preference was measured using Adaptive Conjoint Analysis.

RESULTS

Of 205 eligible subjects, 156 agreed to participate. Higher subjective numeracy was associated with lower preference for the status quo in a regression model including race, employment, and use of biologics (adjusted odds ratio [95% confidence interval] = 0.71 [0.52-0.95], P = 0.02). Higher subjective numeracy was protective against status quo preferences among subjects younger than 65 years (adjusted odds ratio [95% confidence interval] = 0.64 (0.43-0.94), P = 0.02) but not among older subjects.

CONCLUSIONS

Subjective numeracy is independently associated with younger, but not older, RA patients' preferences for the status quo. Our results add to the literature demonstrating age and numeracy differences in treatment preferences and medical decision-making processes.

Patient perceptions of osteoporosis treatment thresholds

OBJECTIVE

Many older patients express concerns about medication risks, and have higher risk thresholds than physicians for cardiovascular preventive medications. We hypothesized that patients have relatively high risk thresholds for fracture preventive medications.

METHODS

Women ≥ 60 years old were recruited from 3 primary care internal medicine clinics in Wisconsin. Participants were provided information regarding fracture risks and treatment risks and benefits, followed by a series of vignettes depicting a 70-year-old woman at baseline fracture risks between 5-50%. Fracture risks were shown graphically and treatment side effects were provided for each vignette, and participants were asked to respond regarding whether they would accept treatment. The association of vignette treatment acceptance with participant beliefs regarding medication risks was examined in analyses adjusted for perceived risk of medications, patient numeracy, and prior respondent experience with osteoporosis.

RESULTS

The mean age of women in the cohort was 69.4 years (SD 7.29). Ninety-one percent were non-Hispanic whites, 34% reported a history of fracture, and 20.3% a history of osteoporosis. Subjects varied substantially in their responses to vignettes, but only 51% reported they would accept prescription osteoporosis treatment at the threshold currently recommended by national physician treatment guidelines, and fewer would accept treatment at lower risks. Belief that medications are generally not worth their risks was associated with lower acceptance of treatment at all levels of fracture risk.

CONCLUSION

There is substantial variability in preferences for postmenopausal osteoporosis treatment. Presentation of individualized fracture risks as recommended by current guidelines has potential to allow better targeting to higher-risk patients, but further work is needed regarding how to present this information and counsel patients.

Development and validation of the numeracy understanding in Medicine Instrument short form

Health numeracy can be defined as the ability to understand and use numeric information and quantitative concepts in the context of health. The authors previously reported the development of the Numeracy Understanding in Medicine Instrument (NUMi), a 20-item test developed using item response theory. The authors now report the development and validation of a short form of the NUMi. Item statistics were used to identify a subset of 8 items representing a range of difficulty and content areas. Internal reliability was evaluated with Cronbach's alpha. Divergent and convergent validity was assessed by comparing scores of the S-NUMI with existing measures of education, print and numeric health literacy, mathematic achievement, cognitive reasoning, and the original NUMi. The 8-item scale had adequate reliability (α=.72) and was strongly correlated to the 20-item NUMi (α=.92). S-NUMi scores were strongly correlated with the Lipkus Expanded Health Numeracy Scale (α=.62), the Wide Range of Achievement Test-Mathematics (α=.72), and the Wonderlic Cognitive Ability Test (α=.76). Moderate correlation was found with education level (α=.58) and print literacy as measured by the Test of Functional Health Literacy in Adults (α=.49). Results show that the short form of the NUMi is a reliable and valid measure of health numeracy feasible for use in clinical and research settings.

Developing a bone mineral density test result letter to send to patients: a mixed-methods study

PURPOSE

To use a mixed-methods approach to develop a letter that can be used to notify patients of their bone mineral density (BMD) results by mail that may activate patients in their bone-related health care.

PATIENTS AND METHODS

A multidisciplinary team developed three versions of a letter for reporting BMD results to patients. Trained interviewers presented these letters in a random order to a convenience sample of adults, aged 50 years and older, at two different health care systems. We conducted structured interviews to examine the respondents' preferences and comprehension among the various letters.

RESULTS

A total of 142 participants completed the interview. A majority of the participants were female (64.1%) and white (76.1%). A plurality of the participants identified a specific version of the three letters as both their preferred version (45.2%; P<0.001) and as the easiest to understand (44.6%; P<0.01). A majority of participants preferred that the letters include specific next steps for improving their bone health.

CONCLUSION

Using a mixed-methods approach, we were able to develop and optimize a printed letter for communicating a complex test result (BMD) to patients. Our results may offer guidance to clinicians, administrators, and researchers who are looking for guidance on how to communicate complex health information to patients in writing.

Media, messages, and medication: strategies to reconcile what patients hear, what they want, and what they need from medications

Background

Over the past 30 years, patients’ options for accessing information about prescription drugs have expanded dramatically. In this narrative review, we address four questions: (1) What information sources are patients exposed to, and are they paying attention? (2) Is the information they hear credible and accurate? (3) When patients ask for a prescription, what do they really want and need? Finally, (4) How can physicians reconcile what patients hear, want, and need?

Analysis

A critical synthesis of the literature is reported. Observations indicate that the public is generally aware of and attends to a growing body of health information resources, including traditional news media, advertising, and social networking. However, lay audiences often have no reliable way to assess the accuracy of health information found in the media, on the Internet, or in direct-to-consumer advertising. This inability to assess the information can lead to decision paralysis, with patients questioning what is known, what is knowable, and what their physicians know. Many patients have specific expectations for the care they wish to receive and have little difficulty making those expectations known. However, there are hazards in assuming that patients’ expressed desires are direct reflections of their underlying wants or needs. In trying to reconcile patients’ wants and needs for information about prescription medicines, a combination of policy and clinical initiatives may offer greater promise than either approach alone.

Conclusions

Patients are bombarded by information about medicines. The problem is not a lack of information; rather, it is knowing what information to trust. Making sure patients get the medications they need and are prepared to take them safely requires a combination of policy and clinical interventions.

Playing the numbers: how hepatitis C patients create meaning and make healthcare decisions from medical test results

In this article we describe how patients assign meanings to medical test results and use these meanings to justify their actions. Evidence is presented from lay interpretations of medical tests for monitoring hepatitis C viral infection (HCV) to show how numeracy becomes embodied in the absence of physical symptoms. Illness narratives from 307 individuals infected with HCV were collected from the internet and analysed qualitatively. As part of standard medical care, chronically infected HCV patients are required to have periodic blood tests for laboratory testing. The lab results are presented numerically and compared with established physiological standards. HCV patients' knowledge and interpretations of test results have important consequences for their health behaviour and their medical decisions. In their stories, the patients described their decisions to begin, delay or stop treatment and developed strategies to alter their diet, exercise and use alternative therapies according to changes in their test result. The perceived meanings of test results are powerful signifiers that are capable of altering the course of HCV patients' illness, lives and stories. An interpretive model of health numeracy has the advantage of promoting understanding between patients and healthcare providers over a model that views innumeracy as a skill deficit.

The numeracy understanding in medicine instrument: a measure of health numeracy developed using item response theory

BACKGROUND

Health numeracy can be defined as the ability to understand and apply information conveyed with numbers, tables and graphs, probabilities, and statistics to effectively communicate with health care providers, take care of one's health, and participate in medical decisions.

OBJECTIVE

To develop the Numeracy Understanding in Medicine Instrument (NUMi) using item response theory scaling methods.

DESIGN

A 20-item test was formed drawing from an item bank of numeracy questions. Items were calibrated using responses from 1000 participants and a 2-parameter item response theory model. Construct validity was assessed by comparing scores on the NUMi to established measures of print and numeric health literacy, mathematic achievement, and cognitive aptitude.

PARTICIPANTS

Community and clinical populations in the Milwaukee and Chicago metropolitan areas.

RESULTS

Twenty-nine percent of the 1000 respondents were Hispanic, 24% were non-Hispanic white, and 42% were non-Hispanic black. Forty-one percent had no more than a high school education. The mean score on the NUMi was 13.2 (s = 4.6) with a Cronbach α of 0.86. Difficulty and discrimination item response theory parameters of the 20 items ranged from -1.70 to 1.45 and 0.39 to 1.98, respectively. Performance on the NUMi was strongly correlated with the Wide Range Achievement Test-Arithmetic (0.73, P < 0.001), the Lipkus Expanded Numeracy Scale (0.69, P < 0.001), the Medical Data Interpretation Test (0.75, P < 0.001), and the Wonderlic Cognitive Ability Test (0.82, P < 0.001). Performance was moderately correlated to the Short Test of Functional Health Literacy (0.43, P < 0.001).

LIMITATIONS

The NUMi was found to be most discriminating among respondents with a lower-than-average level of health numeracy.

CONCLUSIONS

The NUMi can be applied in research and clinical settings as a robust measure of the health numeracy construct.

Impact of literacy and numeracy on motivation for behavior change after diabetes genetic risk testing

BACKGROUND

Type 2 diabetes genetic risk testing might motivate at-risk patients to adopt diabetes prevention behaviors. However, the influence of literacy and numeracy on patient response to diabetes genetic risk is unknown.

OBJECTIVE

The authors investigated the association of health literacy, genetic literacy, and health numeracy with patient responses to diabetes genetic risk.

DESIGN

and Measurements Overweight patients at high phenotypic risk for type 2 diabetes were recruited for a clinical trial of diabetes genetic risk testing. At baseline, participants predicted how their motivation for lifestyle modification to prevent diabetes might change in response to hypothetical scenarios of receiving "high" and "low" genetic risk results. Responses were analyzed according to participants' health literacy, genetic literacy, and health numeracy.

RESULTS

Two-thirds (67%) of participants (n = 175) reported very high motivation to prevent diabetes. Despite high health literacy (92% at high school level), many participants had limited health numeracy (30%) and genetic literacy (38%). Almost all (98%) reported that high-risk genetic results would increase their motivation for lifestyle modification. In contrast, response to low-risk genetic results varied. Higher levels of health literacy (P = 0.04), genetic literacy (P = 0.02), and health numeracy (P = 0.02) were associated with an anticipated decrease in motivation for lifestyle modification in response to low-risk results.

CONCLUSIONS

While patients reported that high-risk genetic results would motivate them to adopt healthy lifestyle changes, response to low-risk results varied by patient numeracy and literacy. However, anticipated responses may not correlate with true behavior change. If future research justifies the clinical use of genetic testing to motivate behavior change, it may be important to assess how patient characteristics modify that motivational effect.

Health numeracy and understanding of risk among older American Indians and Alaska Natives

American Indian and Alaska Native people suffer extreme health disparities and remain underrepresented in health research. This population needs adequate numeracy skills to make informed decisions about health care and research participation, yet little is known about their numeracy skills. Participants were 91 American Indian and Alaska Native elders who completed an anonymous survey that measured numeracy and the correlation between framing of risk and comprehension of risk. The authors measured numeracy by a previously developed 3-item scale that assessed basic probability skills and the ability to manipulate percentages and proportions. Risk comprehension was measured by 3 items on treatment benefits, which were variously framed in terms of relative risk reduction, absolute risk reduction, and number needed to treat. Framing in terms of relative risk was associated with higher odds of correct interpretation compared to absolute risk (OR=1.8, 95% CI=1.2-2.9) and number needed to treat (OR=2.0, 95% CI=1.2-3.5). This association persisted after adjusting for covariates, including baseline numeracy skills. Our results underscore the need for clinicians to consider how health information is framed and to check carefully for understanding when communicating risk information to patients.

Adherence and oral agents with older patients

OBJECTIVE

Oral antineoplastic agents offer multiple advantages in cancer therapies. Thus, understanding issues of adherence to these agents for older adults becomes critical to successful comprehensive care of the older cancer patient.

DATA SOURCES

This analysis of adherence to oral agents among older cancer patients draws on interdisciplinary geriatric and oncologic research reports and clinical reviews.

CONCLUSION

Older adults are at increased risk for poor adherence to oral agents. Barriers to adherence are diverse. Problems emerge from age-related physical changes, comorbid conditions, polypharmacy, and drug interactions. Psychosocial barriers include limited insurance coverage and transportation problems to social isolation and inadequate social support.

IMPLICATION FOR NURSING PRACTICE

Nurses should lead interdisciplinary, individualized plans of care to mitigate barriers and support adherence to cancer therapy.

The meaning of numbers in health: exploring health numeracy in a Mexican-American population

BACKGROUND

Health numeracy can be defined as the ability to use numeric information in the context of health. The interpretation and application of numbers in health may vary across cultural groups.

OBJECTIVE

To explore the construct of health numeracy among persons who identify as Mexican American.

DESIGN

Qualitative focus group study. Groups were stratified by preferred language and level of education. Audio-recordings were transcribed and Spanish groups (n = 3) translated to English. An analysis was conducted using principles of grounded theory.

PARTICIPANTS

A purposeful sample of participants from clinical and community sites in the Milwaukee and Chicago metropolitan areas.

MAIN MEASURES

A theoretical framework of health numeracy was developed based upon categories and major themes that emerged from the analysis.

KEY RESULTS

Six focus groups were conducted with 50 participants. Initial agreement in coding was 59-67% with 100% reached after reconciliation by the coding team. Three major themes emerged: 1) numeracy skills are applied to a broad range of communication and decision making tasks in health, 2) affective and cognitive responses to numeric information influence use of numbers in the health setting, and 3) there exists a strong desire to understand the meaning behind numbers used in health. The findings informed a theoretical framework of health numeracy.

CONCLUSIONS

Numbers are important across a range of skills and applications in health in a sample of an urban Mexican-American population. This study expands previous work that strives to understand the application of numeric skills to medical decision making and health behaviors.

How numeracy influences risk comprehension and medical decision making

We review the growing literature on health numeracy, the ability to understand and use numerical information, and its relation to cognition, health behaviors, and medical outcomes. Despite the surfeit of health information from commercial and noncommercial sources, national and international surveys show that many people lack basic numerical skills that are essential to maintain their health and make informed medical decisions. Low numeracy distorts perceptions of risks and benefits of screening, reduces medication compliance, impedes access to treatments, impairs risk communication (limiting prevention efforts among the most vulnerable), and, based on the scant research conducted on outcomes, appears to adversely affect medical outcomes. Low numeracy is also associated with greater susceptibility to extraneous factors (i.e., factors that do not change the objective numerical information). That is, low numeracy increases susceptibility to effects of mood or how information is presented (e.g., as frequencies vs. percentages) and to biases in judgment and decision making (e.g., framing and ratio bias effects). Much of this research is not grounded in empirically supported theories of numeracy or mathematical cognition, which are crucial for designing evidence-based policies and interventions that are effective in reducing risk and improving medical decision making. To address this gap, we outline four theoretical approaches (psychophysical, computational, standard dual-process, and fuzzy trace theory), review their implications for numeracy, and point to avenues for future research.

Evaluating existing measures of health numeracy using item response theory

OBJECTIVE

To evaluate existing measures of health numeracy using item response theory (IRT).

METHODS

A cross-sectional study was conducted. Participants completed assessments of health numeracy measures including the Lipkus expanded health numeracy scale (Lipkus), and the Medical Data Interpretation Test (MDIT). The Lipkus and MDIT were scaled with IRT utilizing the two-parameter logistic model.

RESULTS

Three-hundred and fifty-nine (359) participants were surveyed. Classical test theory parameters and IRT scaling parameters of the numeracy measures found most items to be at least moderately discriminating. Modified versions of the Lipkus and MDIT were scaled after eliminating items with low discrimination, high difficulty parameters, and poor model fit. The modified versions demonstrated a good range of discrimination and difficulty as indicated by the test information functions.

CONCLUSION

An IRT analysis of the Lipkus and MDIT indicate that both health numeracy scales discriminate well across a range of ability.

PRACTICE IMPLICATIONS

Health numeracy skills are needed in order for patients to successfully participate in their medical care. The accurate assessment of health numeracy may help health care providers to tailor patient education interventions to the patient's level of understanding and ability. Item response theory scaling methods can be used to evaluate the discrimination and difficulty of individual items as well as the overall assessment.

Linking numeracy and asthma-related quality of life

OBJECTIVE

To examine the correlation of numerical skills used in patients' self-management of asthma with asthma-related quality of life (AQOL).

METHODS

Adults with moderate-severe asthma completed the Asthma Numeracy Questionnaire (ANQ), assessments of reading comprehension and self-efficacy, and the mini-Asthma Quality of Life Questionnaire (miniAQLQ). The numeracy-AQOL relationship was evaluated in the context of potential confounders (demographic variables) and mediators (e.g. income and self-efficacy), using tests of correlation then multivariable models to assess for confounders and mediators.

RESULTS

80 adults with moderate or severe asthma were evaluated. Mean ANQ score was 2.3+/-1.2 (range 0-4). ANQ was correlated with miniAQLQ (rho=0.24, p=0.03). This association was sustained (rho=0.27, p=0.02) when controlling for potential confounders significantly associated with AQOL (age, Latino ethnicity). The ANQ-miniAQLQ association was mediated by household income; the correlation was reduced by 81% when adjusting for income (rho=0.05, p=0.65). In contrast, self-efficacy less strongly mediated this association; the correlation was reduced by 26% when controlled for self-efficacy (rho=0.20, p=0.08).

CONCLUSION

Numerical skills needed for asthma self-management influence AQOL primarily through their impact on income and, to a lesser extent, on self-efficacy.

PRACTICE IMPLICATIONS

Adults with asthma will benefit from self-management instructions employing the simplest mathematical constructs whose understanding is confirmed by clinicians.

Interventions to Improve Care for Patients with Limited Health Literacy

OBJECTIVE: To propose a framework and describe best practices for improving care for patients with limited health literacy (LHL). METHODS: Review of the literature. RESULTS: Approximately half of the U.S. adult population has LHL. Because LHL is associated with poor health outcomes and contributes to health disparities, the adoption of evidence-based best practices is imperative. Feasible interventions at the clinician-patient level (eg, patient-centered communication, clear communication techniques, teach-to-goal methods, and reinforcement), at the system-patient level (eg, clear health education materials, visual aids, clear medication labeling, self-management support programs, and shame-free clinical environments), and at the community-patient level (eg, adult education referrals, lay health educators, and harnessing the mass media) can improve health outcomes for patients with LHL. CONCLUSION: Because LHL is prevalent, and because the recommended communication strategies can benefit patients of all literacy levels, clinicians, health system planners, and health policy leaders should promote the uptake of these strategies into routine care.