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Biomedical subjects

H G Welch

Publications and source records attributed to H G Welch.

At least 127 records · Page 7Linked to original sources
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A new scale for assessing perceptions of chance: a validation study.

BACKGROUND: Clinicians and researchers often wish to know how patients perceive the likelihoods of health risks. Little work has been done to develop and validate scales and formats to measure perceptions of event probabilities, particularly low probabilities (i.e., <1%). OBJECTIVE: To compare a new visual analog scale with three benchmarks in terms of validity and reliability. DESIGN: Survey with retest after approximately two weeks. Respondents estimated the probabilities of six events with the new scale, which featured a "magnifying glass" to represent probabilities between 0 and 1% on a logarithmic scale. Participants estimated the same probabilities on three benchmarks: two linear visual analog scales (one labeled with words, one with numbers) and a "1 in x" scale. SUBJECTS: 100 veterans and family members and 107 university faculty and students. MEASURES: For each scale, the authors assessed: 1) validity-the correlation between participants' direct rankings (i.e., numbering them from 1 to 6) and scale-derived rankings of the relative probabilities of six events; 2) test-retest reliability-the correlation of responses from test to retest two weeks later; 3) usability (missing/ incorrect responses, participant evaluation). RESULTS: Both the magnifier and the two linear scales outperformed the "1 in x" scale on all criteria. The magnifier scale performed about as well as the two linear visual analog scales for validity (correlation between direct and scale-derived rankings = 0.72), reliability (test-retest correlation = 0.55), and usability (2% missing or incorrect responses, 65% rated it easy to use). 62% felt the magnifier scale was a "very good or good" indicator of their feelings about chance. The magnifier scale facilitated expression of low-probability judgments. For example, the estimated chance of parenting sextuplets was orders of magnitude lower on the magnifier scale (median perceived chance 10(-5)) than on its linear counterpart (10(-2)). Participants' assessments of high-probability events (e.g., chance of catching a cold in the next year) were not affected by the presence of the magnifier. CONCLUSIONS: The "1 in x" scale performs poorly and is very difficult for people to use. The magnifier scale and the linear number scale are similar in validity, reliability, and usability. However, only the magnifier scale makes it possible to elicit perceptions in the low-probability range (<1%).

Adult↗
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Women's views on breast cancer risk and screening mammography: a qualitative interview study.

BACKGROUND: To promote informed decision making about mammography, clinicians are urged to present women with complete, relevant information about breast cancer and screening. Understanding women's current beliefs may help guide such efforts by uncovering misunderstandings, conceptual gaps, and areas of concern. OBJECTIVE: The authors sought to learn how women view breast cancer, their personal risk of breast cancer, and how screening mammography affects that risk. METHODS: Forty-one open-ended semistructured telephone interviews with women selected from a national database by quota sampling to ensure a wide range in demographics of the participants. RESULTS: Almost all respondents viewed breast cancer as a uniformly progressive disease that begins in a silent curable form (typically found by mammograms) and, unless treated early, invariably grows, spreads, and kills. Some women felt that any abnormality found must be treated, even if it was not malignant. None had heard of potentially nonprogressive cancers, and when informed, most felt that the uncertain prognosis of such lesions reinforced the need to find and treat disease as soon as possible. Women expressed a wide range of views about their personal risk of breast cancer. Although some saw breast cancer as a central threat to their health, many others cited heart disease, other cancers, violence, and trauma as greater concerns. Most recognized the importance of "uncontrollable" factors for breast cancer such as age, sex, family history, and genetics. However, other "controllable" factors with little or no demonstrated link to breast cancer (e.g., smoking, diet, toxic exposures, "bad attitudes") were given equal or greater prominence, suggesting that many women feel considerable personal responsibility for their level of breast cancer risk. Similarly, although women recognized that mammography was not perfect, almost all believed that failure to have mammograms put one at risk for premature and preventable death. When asked how mammography worked, almost all repeated the message that "early detection saves lives," suggesting that advanced cancer (and perhaps most cancer deaths) reflected a failure of early detection. The belief in the benefit of early detection was so strong that some women advocated scaring other women into getting mammograms because it is "better to be safe than sorry." CONCLUSIONS: Women view breast cancer as a uniformly progressive disease rarely curable unless caught early. The exaggerated importance many attribute to a variety of controllable factors in modifying personal risk and the "danger" seen in failing to have mammograms may lead women diagnosed with breast cancer to blame themselves.

Adult↗
PubMedDate not supplied

Determining transition probabilities from mortality rates and autopsy findings.

The Markov process is a useful tool for modeling the natural history of disease, which is becoming increasingly important as new diagnostic tests increase the detectability of early-stage disease. The accuracy of a Markov model, however, depends on the accuracy of the estimates for the transition probabilities between different stages of disease. Because these estimates are usually based on "expert opinion" or small cohort studies, they are subject to imprecision and bias. The authors describe an alternative method of estimating transition probabilities from the stage distribution of disease observed at the time of death and age-specific mortality rates from other causes. In addition, they prove that the transition probabilities are unique given certain assumptions about how they change with age. Finally, they illustrate the method using population-based data for prostate cancer.

Adult↗
PubMedDate not supplied

Women's perceptions of breast cancer risk: how you ask matters.

BACKGROUND: Some studies suggest that women dramatically overestimate the risk of having breast cancer while others conclude that they underestimate it. To understand better how women perceive the chance of getting breast cancer, the authors asked women to estimate the risk in several ways. Each woman's answer was related to her actual risk. METHODS: Women were randomly selected from a registry of female veterans in New England. A mailed questionnaire asked each woman to estimate her ten-year risk of dying from breast cancer as a number out of 1,000 ("___ in 1,000" perceived risk) and whether this risk was higher than, the same as, or lower than that of an average woman her age (comparative perceived risk). The woman was also asked to compare her risk of dying from breast cancer with her risk of dying from heart disease. Risk-factor data were collected so that each woman's actual risk of breast cancer death could be estimated (actual risk). RESULTS: 201 women had complete data. The median age of the respondents was 62 years (range 27-80), and 98% were high school graduates. Most women (98%) overestimated the "___ in 1,000" risk of breast cancer death-half by eightfold or more (interquartile range, 4-36-fold overestimates). In contrast, only 10% of these women thought that they were at higher risk than an average woman their age. Most correctly thought that their risk of dying from breast cancer was lower than their risk of dying from heart disease. The women's "____in 1,000" perceived risks of breast cancer death were unrelated to their actual risks and had no significant agreement with an external bench-mark of importantly "high risk" (i.e., met risk criteria for the Tamoxifen primary prevention trial). In contrast, the women's comparative perceptions of being at low, average or high risk were related to actual risks and significantly agreed with the "high risk" benchmark. Most women not at importantly "high risk" correctly classified themselves; however, almost two thirds of "high risk" women misclassified themselves as "average or lower than average risk." CONCLUSIONS: The method used to elicit perceptions of risk matters. These women's responses to the comparative questions showed that they "knew more" about their actual risks than their open-ended numeric responses suggested.

Adult↗
PubMedDate not supplied

When should this patient be seen again?

CONTEXT: The decision about when to ask a patient to return to the clinic for his or her next visit is common to all outpatient encounters in longitudinal care. It directly affects provider workloads and has a potentially great impact on health care costs and outcomes. GENERAL QUESTION: What are the effects of lengthening or shortening revisit intervals (the recommended period between one visit and the next) on health status and health care costs? SPECIFIC RESEARCH CHALLENGE: How can we change the average revisit interval while preserving provider input for individual patients? PROPOSED APPROACH: Patients could be randomly assigned to either short or long revisit intervals. So that provider input would be preserved, providers would select from among three discrete categories of revisit intervals: near-term (1 to 2 months); intermediate-term (2 to 4 months); and long-term (4 to 8 months). On the basis of randomization, patients would receive appointments at either the lower or the upper bound of the category selected. POTENTIAL DIFFICULTIES: Because blinding would be almost impossible, providers might "game" randomization at subsequent visits. ALTERNATE APPROACHES: A comparison of shorter and longer revisit intervals might be achieved with less direct approaches. In one such approach, patients would be randomly assigned to 1) having an appointment made immediately after the initial visit or 2) calling back for an appointment according to the interval recommended by the provider. In another approach, patient panel size would be held constant and providers would be randomly assigned to either an increased or a reduced number of clinic sessions.

Continuity of Patient Care↗
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Preparing manuscripts for submission to medical journals: the paper trail.

CONTEXT: Preparing a manuscript for publication in a medical journal is hard work. OBJECTIVE: To make it easier to prepare a readable manuscript. APPROACH: Start early--A substantial portion of the manuscript can be written before the project is completed. Even though you will revise it later, starting early will help document the methods and guide the analysis. Focus on high-visibility components--Pay attention to what readers are most likely to look at: the title, abstract, tables, and figures. Strive to develop a set of tables and figures that convey not only the major results but also the basic methods. Develop a systematic approach to the body of the paper--A standard framework can make it easier to write the introduction, methods, results, and discussion. An obvious organization with frequent subheadings and consistent labels makes the paper easier to read. Finish strong--Improve the paper by sharing it with others and by learning how to elicit and receive their feedback. Take the time to incorporate useful feedback by revising frequently.

Data Display↗
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Risky business.

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Communication↗
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Telephone care as an adjunct to routine medical follow-up. A negative randomized trial.

CONTEXT: In 1992, a randomized trial at one outpatient clinic demonstrated that making telephone appointments part of routine medical follow-up could save money and reduce hospitalization. OBJECTIVE: To ascertain the effects of telephone care in other clinics. DESIGN: Consenting patients of 20 physicians were randomly assigned to receive telephone care or usual care. SETTING: Veterans Affairs General Medical Clinics in Denver, Colorado, and Sioux Falls, South Dakota. PATIENTS: 512 predominately male elderly veterans (mean age, 68 years) who had a broad range of chronic medical conditions. INTERVENTION: At the intake clinic visit, the recommended revisit interval (e.g., return in 3 months) for telephone care patients was doubled (e.g., return in 6 months) and three intervening telephone appointments were scheduled. Three telephone appointments were also scheduled at all subsequent clinic visits. MAIN OUTCOME MEASURES: Utilization of services and self-reported health status. RESULTS: More than 2000 calls were made during the 2-year study period. Although the revisit interval was longer for telephone care patients after the intake visit (as was expected), it was the same for both telephone care and usual care patients after all subsequent visits, despite the scheduling of three telephone appointments for telephone care patients. The intervention had no effect on self-reported health status, hospital admission, or number of deaths. The intervention also had no effect on the total number of clinic visits, outpatient laboratory tests, or radiologic tests. Telephone care patients had fewer unscheduled visits than did usual care patients (2.0 vs. 2.8 visits/patient; P = 0.01). CONCLUSION: Telephone care had little effect in this study. Instead of providing a way to maintain contact with patients without requiring them to appear in clinic frequently, telephone appointments became simply an additional service.

Aged↗
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Number fifteen.

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Ambulatory Care↗