Interpreting Research Results Research Articles

Prescribers' Knowledge and Skills for Interpreting Research Results: A Systematic Review.

Appropriate medication prescribing may be influenced by a prescriber's ability to understand and interpret medical research. The objective of this review was to synthesize the research related to prescribers' critical appraisal knowledge and skills-defined as the understanding of statistical methods, biases in studies, and relevance and validity of evidence. We searched PubMed and other databases from January 1990 through September 2015. Two reviewers independently screened and selected studies of any design conducted in the United States, the United Kingdom, or Canada that involved prescribers and that objectively measured critical appraisal knowledge, skills, understanding, attitudes, or prescribing behaviors. Data were narratively synthesized. We screened 1204 abstracts, 72 full-text articles, and included 29 studies. Study populations included physicians. Physicians' extant knowledge and skills were in the low to middle of the possible score ranges and demonstrated modest increases in response to interventions. Physicians with formal education in epidemiology, biostatistics, and research demonstrated higher levels of knowledge and skills. In hypothetical scenarios presenting equivalent effect sizes, the use of relative effect measures was associated with greater perceptions of medication effectiveness and intent to prescribe, compared with the use of absolute effect measures. The evidence was limited by convenience samples and study designs that limit internal validity. Critical appraisal knowledge and skills are limited among physicians. The effect measure used can influence perceptions of treatment effectiveness and intent to prescribe. How critical appraisal knowledge and skills fit among the myriad of influences on prescribing behavior is not known.

How do I interpret a p value?

A p-value is a number between 0 and 1 that is extremely useful in interpreting research results. Using comparison of the means of two samples as an example, a p-value <0.05 suggests that there is enough evidence to presume a real difference between groups from which the samples were drawn (that the "null hypothesis" can be rejected). We say that the difference between the means is statistically significant. However, it isn't iron clad proof and there is still a chance that there is really no difference. Furthermore, a statistically significant difference may not be clinically significant if it is not enough to appreciably affect patient outcomes. We describe the theory behind p-values and some common errors in interpretation.

The Danish National Patient Registry: a review of content, data quality, and research potential.

BackgroundThe Danish National Patient Registry (DNPR) is one of the world’s oldest nationwide hospital registries and is used extensively for research. Many studies have validated algorithms for identifying health events in the DNPR, but the reports are fragmented and no overview exists.ObjectivesTo review the content, data quality, and research potential of the DNPR.MethodsWe examined the setting, history, aims, content, and classification systems of the DNPR. We searched PubMed and the Danish Medical Journal to create a bibliography of validation studies. We included also studies that were referenced in retrieved papers or known to us beforehand. Methodological considerations related to DNPR data were reviewed.ResultsDuring 1977–2012, the DNPR registered 8,085,603 persons, accounting for 7,268,857 inpatient, 5,953,405 outpatient, and 5,097,300 emergency department contacts. The DNPR provides nationwide longitudinal registration of detailed administrative and clinical data. It has recorded information on all patients discharged from Danish nonpsychiatric hospitals since 1977 and on psychiatric inpatients and emergency department and outpatient specialty clinic contacts since 1995. For each patient contact, one primary and optional secondary diagnoses are recorded according to the International Classification of Diseases. The DNPR provides a data source to identify diseases, examinations, certain in-hospital medical treatments, and surgical procedures. Long-term temporal trends in hospitalization and treatment rates can be studied. The positive predictive values of diseases and treatments vary widely (<15%–100%). The DNPR data are linkable at the patient level with data from other Danish administrative registries, clinical registries, randomized controlled trials, population surveys, and epidemiologic field studies – enabling researchers to reconstruct individual life and health trajectories for an entire population.ConclusionThe DNPR is a valuable tool for epidemiological research. However, both its strengths and limitations must be considered when interpreting research results, and continuous validation of its clinical data is essential.

Internal validity: A must in research designs

In experimental research, internal validity refers to what extent researchers can conclude that changes in the dependent variable (that is, outcome) are caused by manipulations to the independent variable. This causal inference permits researchers to meaningfully interpret research results. This article discusses internal validity threats in social and educational research using examples from the contemporary literature, and research designs in terms of their ability to control internal validity threats. An Eric and psychINFO search was performed to the current review of internal validity. The review indicated that appropriate research designs that control possible extraneous variables are needed to be able to meaningfully interpret research results in education and social sciences. Although, pretest- posttest experimental-control group design controls most of the internal validity threats, the most appropriate research design would vary based on the research questions or goals. Key words: Internal validity, education, confounding variables, research design.

Perceptions of Men With Moderate to Severe Hemophilia Regarding the Management of Their Chronic Disorder and Utilization of Community-Based Support.

Hemophilia is a genetic bleeding disorder that almost exclusively affects men. There is a nationwide network of nonprofit organizations providing support to men with hemophilia, which are affiliated with localized agencies that serve affected individuals within specific regions of the country. This community-based study was implemented in response to a local Utah agency's concern that men with hemophilia may be disengaged from and underserved by their local support network. The goal of the study was to gain a better understanding of the (a) unique challenges, (b) adaptations, and (c) physical, financial, psychological, and social needs of adult men with moderate to severe hemophilia from the local community. Over a period of 9 months, verbal qualitative interviews were conducted with 10 affected individuals, and written interviews were obtained from 3 additional participants. Using a grounded-theory approach, six themes were identified, based on men's commentary from interviews, across a spectrum of physical, social, communal, personal, medical, and vocational dimensions. Resilience theory, which explores internal resources that assist in coping with adverse situations, was used as a framework for interpreting research results. Findings indicate that men value the array of educational, social, and medical services that are available to them but choose to manage their hemophilia independently from the community and access support according to their individual needs. Understanding this dynamic may be helpful in developing services that are more specifically tailored to the physical and psychosocial needs of adult men with hemophilia and, potentially, men with other chronic health disorders.

Risk of bias in oral and maxillofacial surgery research

Background and objectives: Risk of bias is an important factor in interpreting research results. Therefore, risk of bias of randomized controlled trials (RCTs) in oral and maxillofacial surgery (OMS) over a ten year period was evaluated.

Phenotypic Characterization of the KK/HlJ Inbred Mouse Strain

Detailed histopathological diagnoses of inbred mouse strains are important for interpreting research results and defining novel models of human diseases. The aim of this study was to histologically detect lesions affecting the KK/HlJ inbred strain. Mice were examined at 6, 12, and 20 months of age and near natural death (ie, moribund mice). Histopathological lesions were quantified by percentage of affected mice per age group and sex. Predominant lesions were mineralization, hyperplasia, and fibro-osseous lesions. Mineralization was most frequently found in the connective tissue dermal sheath of vibrissae, the heart, and the lung. Mineralization was also found in many other organs but to a lesser degree. Hyperplasia was found most commonly in the pancreatic islets, and fibro-osseous lesions were observed in several bones. The percentage of lesions increased with age until 20 months. This study shows that KK/HlJ mice demonstrate systemic aberrant mineralization, with greatest frequency in aged mice. The detailed information about histopathological lesions in the inbred strain KK/HlJ can help investigators to choose the right model and correctly interpret the experimental results.

GIS as a Community Engagement Tool: Developing a Plan to Reduce Infant Mortality Risk Factors

This article describes how a community coalition focusing on maternal and child health engages community participation through the use of geographic information systems (GIS) mapping, developing strategies that culminate in the implementation of a service delivery plan to improve birth outcomes. Vital statistics data from 2007 to 2009 was analyzed by zip code in Pinellas County Florida to produce choropleth thematic maps using ArcGIS for 3year rolling average infant deaths and single year percentages for prematurity. The maps were presented at the organization's annual coalition meeting to discuss risk areas, changes over time in the selected indicators and solicit community feedback on how to best target issues addressing infant mortality and prematurity. The maps identified new zip codes of concern for prematurity in addition to known high risk zip codes for both infant mortality and prematurity. The community identified changes in demographic composition and changes in housing patterns, such as new mobile home areas, in the high risk areas. In response, the community assisted the Coalition in developing a holistic plan addressing risk factors affecting birth outcomes by expanding current services, hiring a nutritionist, and contracting a health navigator. When compared to tables and charts, a visual depiction of a neighborhood by recognizable zip codes is a useful tool to help community decision makers better visualize public health concerns and interpret trends based on local knowledge. Public health professionals should use this community knowledge to interpret research results and implement strategies to improve birth outcomes.

The Language of Data

In clinical practice, nurses are expected to understand and implement the science that supports patient care, yet they fall short of goals to implement evidence in practice. One reason is difficulty in interpreting research results. Interpretation requires an ability to read and speak a language that many nurses have never mastered-the language of data. This article presents a skill-based solution for use in nursing professional development to improve nurses' understanding of statistics as a language.

Use and Misuse of Statistical Methods in the Journal of Korean Academy of Nursing Administration

Purpose: To do nursing research effectively requires an understanding of fundamental principles of statistical methods. In this article, some key statistical methods which are commonly used in nursing research are identified and summarized. Methods: Ninety-two original articles from the Journal of Korean Academy of Nursing Administration were reviewed. Statistical methods were classified and summarized for usage in research and occurrence of common errors. Results: Among the original articles reviewed, 58 statistical usages contained errors. Most errors were found in linear regression analysis, Pearson correlation analysis, and chi-square test. From the detection of statistical errors in usage, suggestions for appropriate statistical methods were made. Conclusion: In order to improve validity of original articles in the Journal of Korean Academy of Nursing Administration, clearly stated statistical usage and close editorial attention to statistical methods are needed. Understanding statistical methods is part of the process that researchers must use to determine both quality and usefulness of the research. Research findings will be used to guide nursing practice and reduce uncertainty in decision making. However, to understand how to interpret research results, it is important to be able to understand basic statistical concepts. Researchers should also choose statistical methods that match their purposes.

Genome sequencing and comparison of two nonhuman primate animal models, the cynomolgus and Chinese rhesus macaques

The nonhuman primates most commonly used in medical research are from the genus Macaca. To better understand the genetic differences between these animal models, we present high-quality draft genome sequences from two macaque species, the cynomolgus/crab-eating macaque and the Chinese rhesus macaque. Comparison with the previously sequenced Indian rhesus macaque reveals that all three macaques maintain abundant genetic heterogeneity, including millions of single-nucleotide substitutions and many insertions, deletions and gross chromosomal rearrangements. By assessing genetic regions with reduced variability, we identify genes in each macaque species that may have experienced positive selection. Genetic divergence patterns suggest that the cynomolgus macaque genome has been shaped by introgression after hybridization with the Chinese rhesus macaque. Macaque genes display a high degree of sequence similarity with human disease gene orthologs and drug targets. However, we identify several putatively dysfunctional genetic differences between the three macaque species, which may explain functional differences between them previously observed in clinical studies.

Frontiers in Thyroid Cancer: December 2009

Frontiers in Thyroid Cancer: December 2009

Application of statistical power analysis – How to determine the right sample size in human health, comfort and productivity research

The minimum size of subjects required for the research on human health, thermal comfort and productivity is a frequently asked question. In this paper the idea of power analysis, which helps to determine required sample size as well as to interpret research results, is introduced in order to promote good practice of power analysis in the context of human and building environment relationship research. How to calculate effect size from published article or experimental data is presented with plenty of examples. The effect sizes of several physiological and psychological measurements indicating the effect of indoor environment quality on human health, thermal comfort and productivity are presented, which could be worked as references when researchers planning their own studies. How to determine required sample size when planning a study and how to interpret the research results with power analysis are also illustrated step by step with samples. Finally how to make decisions when evaluating the study results is summarized. It is expected that these examples and the summary could help researchers to better apply power analysis in indoor environment quality (IEQ) studies. Some statistical terms used in this paper, such as power analysis, effect size, and t-test, etc., are explained in detail in the Appendix.

Alternative Medicine Research in Clinical Practice

Little is known about whether federally funded complementary and alternative medicine (CAM) research is translating into clinical practice. We sought to describe the awareness of CAM clinical trials, the ability to interpret research results, the acceptance of research evidence, and the predictors of trial awareness among US clinicians. We conducted a cross-sectional mailed survey of 2400 practicing US acupuncturists, naturopaths, internists, and rheumatologists. A total of 1561 clinicians (65%) responded. Of the respondents, 59% were aware of at least 1 major CAM clinical trial; only 23% were aware of both trials. A minority of acupuncturists (20%), naturopaths (25%), internists (17%), and rheumatologists (33%) were "very confident" in interpreting research results (P < .001). Fewer acupuncturists (17%) and naturopaths (24%) than internists (58%) and rheumatologists (74%) rated the results of randomized controlled trials as "very useful" (P < .001). Twice as many internists (53%) and rheumatologists (64%) rated patient preferences as "least important" compared with acupuncturists (27%) and naturopaths (31%) (P < .001). In multivariate analyses, for clinicians aware of at least 1 trial, male sex (odds ratio [OR], 1.30 [95% confidence interval {CI}, 1.05-1.62]), prior research experience (OR, 1.45 [95% CI, 1.13-1.86]), institutional or academic practice setting (ORs, 1.98 [95% CI, 1.01-3.91], and 1.23 [95% CI, 0.73-2.09], respectively), and rating randomized trials as "very useful" (OR, 1.46 [95% CI, 1.12-1.91]) (P < .001) for clinical decision making were positively associated with CAM trial awareness. Acupuncturists, naturopaths, and internists (ORs, 0.15 [95% CI, 0.10-0.23], 0.15 [95% CI, 0.09-0.24], and 0.18 [95% CI, 0.12-0.28], respectively) were all similarly less aware of CAM trial results compared with rheumatologists. For clinical research in CAM to achieve its social value, concerted efforts must be undertaken to train clinicians and improve the dissemination of research results.

Perfect Study, Poor Evidence: Interpretation of Biases Preceding Study Design

In the interpretation of research evidence, data that have been accumulated in a specific isolated study are typically examined. However, important biases may precede the study design. A study may be misleading, useless, or even harmful, even though it seems to be perfectly designed, conducted, analyzed, and reported. Some biases pertain to setting the wider research agenda and include poor scientific relevance, minimal clinical utility, or failure to consider prior evidence (non-consideration of prior evidence, biased consideration of prior evidence, or consideration of biased prior evidence). Other biases reflect issues in setting the specific research questions: examples include straw man effects, avoidance of head-to-head comparisons, head-to-head comparisons bypassing demonstration of effectiveness, overpowered studies, unilateral aims (focusing on benefits and neglecting harms), and the approach of the industry towards research as bulk advertisement (including ghost management of the literature). The concerted presence of such biases may have a multiplicative, detrimental impact on the scientific literature. These issues should be considered carefully when interpreting research results.

Interpreting research results: Government regulation of anthropogenic noise sources

The Precautionary Principle, which advocates taking anticipatory management action in the absence of complete proof of harm, is embedded in several U.S. environmental laws, including the Marine Mammal Protection Act and the Endangered Species Act. However, in practice it is often ignored. Recent U.S. regulatory actions addressing the following anthropogenic noise sources are evaluated as cases in point: the North Pacific Acoustic Laboratory (NPAL), the U.S.S. Winston S. Churchill ship shock trials, and the Surveillance Towed Array Sensor System (SURTASS) Low Frequency Active (LFA) sonar. The impact of anthropogenic noise on marine mammals is poorly understood. Therefore, establishing adequate mitigation measures for noise sources is difficult. In an effort to increase knowledge and build toward certainty regarding the impacts of anthropogenic noise on the marine environment, recent research on low-frequency noise has focused on behavioral responses of large whales. These studies address limited hypotheses, but their results have been broadly interpreted to justify regulatory decisions. The pursuit of carefully designed research on the impacts of noise on the marine environment and the refinement of noise source mitigation is important, but interpreting research results is subject to political and economic pressures, casting doubt on the research conservation value.

The Prevalence and Impact of ‘Atypical’ Days in 4-day Food Records

Objective To understand how days with atypical food intake affect estimates of usual nutrient intake from 4-day food records. Participants/Setting Secondary analyses of 4-day food records (4DFRs) (n=2,560) collected from 1,090 women, aged 50 to 79 years, who participated in the Women's Trial Feasibility Study in Minority Populations, a randomized dietary intervention trial Design Food records were classified as atypical if participants marked one or more day's food intake as “more than usual” or “less than usual.” Total amounts and nutrient densities (percent of energy or grams per 1,000 kcal) were examined for all macronutrients, fiber, vitamin C, beta carotene, and calcium. Statistical analysis Contingency tables were used to examine associations of demographic characteristics with the likelihood of completing a 4DFR with atypical intake days. Analysis of variance was used to test whether nutrient intake differed among records with and without atypical days. Student t tests were used to identify any differences in total energy and percent energy from fat among typical and atypical intake days. Results Approximately 16% of records included at least 1 atypical day. Reporting less-than-usual intake was associated with younger age, higher income, and higher body mass index. Black women were less likely to report more-than-usual intake than whites and Hispanics. Records with less-than-usual intake had lower intakes of all nutrients analyzed except alcohol; however, there were no differences in nutrient densities. Records with more-than-usual intake had higher intakes of alcohol and all nutrients except beta carotene and vitamin C, with higher nutrient density measures of alcohol and decreased nutrient density measures of protein, vitamin C, and fiber. Conclusions Atypical intake days are common in 4DFRs and they have a large effect on mean total intakes of most nutrients. Applications It is important for researchers to collect information on atypical intake days included in a 4-day food record. Strategies are needed to incorporate information on atypical intake days when analyzing and interpreting research results. J Am Diet Assoc. 2000;100:421-422, 425-427.

Potential role of CCR5 polymorphism in the development of AIDS dementia complex

The chemokine receptor CCR5 and to a lesser extent CCR2b and CCR3 have been shown to serve as coreceptors for HIV-1 entry into macrophages. Individuals that are homozygous for a defective CCR5 allele (ΔCCR5) are highly, but not fully, resistant to infection with HIV-1. Here, we want to emphasize the importance of ΔCCR5 in in vitro as well as in vivo studies. We provide data that suggest that CCR5 polymorphism may affect the onset of AIDS dementia complex in vivo and data that show that HIV-1 replication is influenced by the ΔCCR5 allele in vitro. Knowing the CCR5 genotype of an individual will help to better interpret research results and may even provide new information about mechanisms of disease.

Potential role of CCR5 polymorphism in the development of AIDS dementia complex

The chemokine receptor CCR5 and to a lesser extent CCR2b and CCR3 have been shown to serve as coreceptors for HIV-1 entry into macrophages. Individuals that are homozygous for a defective CCR5 allele (DeltaCCR5) are highly, but not fully, resistant to infection with HIV-1. Here, we want to emphasize the importance of DeltaCCR5 in in vitro as well as in vivo studies. We provide data that suggest that CCR5 polymorphism may affect the onset of AIDS dementia complex in vivo and data that show that HIV-1 replication is influenced by the DeltaCCR5 allele in vitro. Knowing the CCR5 genotype of an individual will help to better interpret research results and may even provide new information about mechanisms of disease.

Is adjuvant tamoxifen used optimally in the treatment of breast cancer? Results of an Italian survey

Background: Institutional and physician-related factors can influence the way in which physicians interpret research results. The aim of this study was to determine what physicians know about, and their opinions of, hormone treatment in breast cancer patients, and the factors comprising their medical decision-making.Materials and methods: A questionnaire was mailed to a random sample of physicians inquiring as to their preferences with respect to adjuvant tamoxifen, and the usual duration of the treatment applied in various clinical scenarios (according to a woman's menopausal status, the oestrogen receptor status and the stage of disease).Results: Of 500 physicians identified, 38% returned the questionnaire. Of the non-responders, a random sample of 60 physicians was interviewed by phone. The total number of available questionnaires was 250 (50%).About 3/4 of the doctors would prescribe tamoxifen in older ER+ women and 30%–40% in post-menopausal ER− patients, but only 2/5 would do so in younger ER+ women.The vast majority of physicians considered five years as standard for ER+ patients. Nevertheless, about 1/4 of the doctors chose a shorter treatment duration for node-negative, pre-menopausal patients. A minority of physicians used tamoxifen for longer than five years. Older clinicians were less likely to prescribe tamoxifen, particularly for low-risk patients.Conclusions: According to the data of the recent EBCTG overview, an additional 20,000 lives could be saved worldwide each year if tamoxifen were given to all early breast cancer patients with hormone-sensitive disease, irrespective of age and disease stage, and for a minimum of five years.Our study, involving a representative sample of physicians practicing in Italy, shows that tamoxifen is not used optimally, with a substantial under-use in younger women and women with node-negative disease.