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Biomedical subjects

H G Welch

Publications and source records attributed to H G Welch.

At least 37 records · Page 2Linked to original sources
PubMed1998

Preferences for chemotherapy in patients with advanced non-small cell lung cancer: descriptive study based on scripted interviews.

OBJECTIVE: To determine how patients with lung cancer value the trade off between the survival benefit of chemotherapy and its toxicities. DESIGN: Scripted interviews that included three hypothetical scenarios. Each scenario described the same patient with metastatic non-small cell lung cancer with an expected survival of 4 months without treatment. Subjects were asked to indicate the minimum survival benefit required to accept the side effects of chemotherapy in the first two scenarios (mild toxicity and severe toxicity). In the third scenario, subjects were asked to choose between chemotherapy and supportive care when the benefit of chemotherapy was either to prolong life by 3 months or to palliate symptoms. SUBJECTS: 81 patients previously treated with cis-platinum based chemotherapy for advanced non-small cell lung cancer. MAIN OUTCOME MEASURE: Survival threshold for accepting chemotherapy. RESULTS: The minimum survival threshold for accepting the toxicity of chemotherapy varied widely in patients. Several patients would accept chemotherapy for a survival benefit of 1 week, while others would not choose chemotherapy even for a survival benefit of 24 months. The median survival threshold for accepting chemotherapy was 4.5 months for mild toxicity and 9 months for severe toxicity. When given the choice between supportive care and chemotherapy only 18 (22%) patients chose chemotherapy for a survival benefit of 3 months; 55 (68%) patients chose chemotherapy if it substantially reduced symptoms without prolonging life. CONCLUSIONS: Patients' willingness to accept chemotherapy for the treatment of metastatic lung cancer varies widely. Many would not choose chemotherapy for its likely survival benefit of 3 months but would if it improved quality of life. The conflict between these patients' preferences and the care they previously received has several explanations, one being that some patients had not received the treatment they would have chosen had they been fully informed.

Adult↗
PubMed1998

Diagnostic testing following screening mammography in the elderly.

BACKGROUND: To provide some sense of the general frequency and timing of diagnostic testing following screening mammography in the United States, we investigated the experience of women screened in the Medicare population. METHODS: By use of Medicare's National Claims History System, we identified a cohort (n=23172) of women 65 years old or older screened during the period from January 1, 1995, through April 30, 1995, and tracked each woman over the subsequent 8 months for the performance of additional breast imaging and biopsy procedures. Using two claims-based definitions for newly detected breast cancer, we also estimated the positive predictive value of screening mammography. RESULTS: For every 1000 women aged 65-69 years who underwent screening, 85 (95% confidence interval [CI]=79-91) had follow-up testing in the subsequent 8 months; 76 (95% CI=71-82) had additional breast imaging, and 23 (95% CI=20-26) had biopsy procedures. Corresponding numbers for women aged 70 years or more were similar. Some women underwent repeated examinations; 13% of those receiving diagnostic mammograms had more than one; 11% of those undergoing biopsy procedures had more than one. About half of the women who underwent a biopsy had the procedure more than 3 weeks after the imaging test upon which the decision to perform a biopsy was presumably made. The estimated positive predictive value of an abnormal screening mammogram (defined as a mammogram that engendered additional testing) was 0.08 (95% CI=0.06-0.10) for women aged 65-69 years and 0.14 (95% CI=0.12-0.16) for women aged 70 years or more. CONCLUSION: Additional testing is a frequent consequence of screening mammography and may require a considerable period of time to come to closure. The need for additional testing, however, is weakly predictive of cancer.

Aged↗
PubMed1998

Probabilities for singleton and multiple pregnancies after in vitro fertilization.

OBJECTIVE: To help physicians provide risk estimates for specific pregnancy outcomes. DESIGN: Computation of exact binomial probabilities for singleton and multiple pregnancies as a function of two inputs: the number of embryos transferred and the implantation rate. Inputs were varied over the range of values reported in the literature. MAIN OUTCOME MEASURE(S): Probabilities for a singleton pregnancy (none), a multiple pregnancy (Pmult), and no pregnancy (Pnone) after one IVF cycle. RESULT(S): Given a 30% implantation rate and three embryos transferred, Pone=.44, Pmult=.22, and Pnone=.34. Although further increasing the number of embryos transferred increases the chance of pregnancy, it also raises the probability of a multiple pregnancy and lowers the chance of a singleton pregnancy. Although varying the implantation rate changes the specific probability estimates, the same trade-off persists. CONCLUSION(S): Those who consider an IVF "success" to be a singleton pregnancy should be attentive to the number of embryos transferred. Infertility therapy may be one area in medicine where more is not necessarily better.

Adult↗
PubMed1998

The effectiveness of cost-effectiveness analysis in containing costs.

OBJECTIVE: Although cost-effectiveness analyses (CEAs) have been advocated as a tool to critically appraise the value of health expenditures, it has been widely hoped that they might also help contain health care costs. To determine how often they discourage additional expenditures, we reviewed the conclusions of recently published CEAs. DATA SOURCES: A search of the Abridged Index Medicus (a subset of MEDLINE designed to afford rapid access to the literature of "immediate interest" to the practicing physician) between 1990 and 1996. STUDY SELECTION: We only included articles that reported an explicit cost-effectiveness (CE) ratio (a cost for some given health effect) in the abstract. DATA ABSTRACTION: From each abstract, we collected the value for the incremental CE ratio and the measure of health effect (life-years, quality-adjusted life-years [QALYs], other). We then categorized the authors' conclusion into one of three categories: supports strategy requiring additional expenditure, no firm conclusion, and supports low-cost alternative. Finally, we obtained the article and collected information on funding source. DATA SYNTHESIS: Among the 109 eligible articles, the authors' conclusion supported strategies requiring additional expenditure in 58 (53%) and supported the low-cost alternative in 28 (26%). We then focused on the 65 articles reporting either life-years or QALYs. Cost-effectiveness ratios ranged from $400 to $166,000 (per life-year or QALY) in the 39 articles (60%) in which authors supported additional expenditure, and ranged from $61,500 to $11,600,000 in the 13 articles (20%) in which authors supported the low-cost alternative. Despite identifying similar CE ratios, authors arrived at different conclusions in the overlapping range ($61,500 to $166,000). Of the 10 articles acknowledging industry funding, 9 supported a strategy requiring additional expenditure (p = .01 as compared with those without such funding). CONCLUSIONS: Authors of CEAs are more likely to support strategies requiring additional expenditure than the low-cost alternative. There is no obvious consensus about how small the CE ratio should be to warrant additional expenditure. Finally, concerns about funding source seem to be warranted.

Cost Control↗
PubMed1997

The role of numeracy in understanding the benefit of screening mammography.

BACKGROUND: Quantitative information about risks and benefits may be meaningful only to patients who have some facility with basic probability and numerical concepts, a construct called numeracy. OBJECTIVE: To assess the relation between numeracy and the ability to make use of typical risk reduction expressions about the benefit of screening mammography. DESIGN: Randomized, cross-sectional survey. SETTING: A simple random sample of 500 female veterans drawn from a New England registry. INTERVENTION: One of four questionnaires, which differed only in how the same information on average risk reduction with mammography was presented. MEASUREMENTS: Numeracy was scored as the total number of correct responses to three simple tasks. Participants estimated their risk for death from breast cancer with and without mammography. Accuracy was judged as each woman's ability to adjust her perceived risk in accordance with the risk reduction data presented. RESULTS: 61% of eligible women completed the questionnaire. The median age of these women was 68 years (range, 27 to 88 years), and 96% were high school graduates. Both accuracy in applying risk reduction information and numeracy were poor (one third of respondents thought that 1000 flips of a fair coin would result in < 300 heads). Accuracy was strongly related to numeracy: The accuracy rate was 5.8% (95% CI, 0.8% to 10.7%) for a numeracy score of 0, 8.9% (CI, 2.5% to 15.3%) for a score of 1, 23.7% (CI, 13.9% to 33.5%) for a score of 2, and 40% (CI, 25.1% to 54.9%) for a score of 3. CONCLUSIONS: Regardless of how information was presented, numeracy was strongly related to accurately gauging the benefit of mammography. More effective formats are needed to communicate quantitative information about risks and benefits.

Adult↗
PubMed1997

Using autopsy series to estimate the disease "reservoir" for ductal carcinoma in situ of the breast: how much more breast cancer can we find?

PURPOSE: To determine how many cases of breast cancer might be found if women not known to have the disease were thoroughly examined (the disease "reservoir"). DATA SOURCES: MEDLINE search from 1966 to the present. STUDY SELECTION: Hospital-based and forensic autopsy series examining women not known to have had breast cancer during life. DATA EXTRACTION: Observed prevalence of occult invasive breast cancer or ductal carcinoma in situ (DCIS) in which the number of women who were given a diagnosis was the numerator and the number of women examined was the denominator. For each autopsy series, we attempted to ascertain the level of scrutiny (sampling method, number of slides examined) given to the pathologic specimens. DATA SYNTHESIS: Among seven autopsy series of women not known to have had breast cancer during life, the median prevalence of invasive breast cancer was 1.3% (range, 0% to 1.8%) and the median prevalence of DCIS was 8.9% (range, 0% to 14.7%). Prevalences were higher among women likely to have been screened (that is, women 40 to 70 years of age). The mean number of slides examined per breast ranged from 9 to 275; series that reported higher levels of scrutiny tended to discover more cases of cancer. CONCLUSIONS: A substantial reservoir of DCIS is undetected during life. How hard pathologists look for the disease and, perhaps, their threshold for making the diagnosis are potentially important factors in determining how many cases of DCIS are diagnosed. The latter has important implications for what it means to have the disease.

Adult↗
PubMed1997

Test performance in systemic sclerosis: anti-centromere and anti-Scl-70 antibodies.

PURPOSE: To determine the sensitivity and specificity of anti-centromere (ACA) and anti-Scl-70 antibodies in systemic sclerosis (SSc). METHODS: Four-hundred ninety-seven English language articles published from 1966 to 1994 were identified by structured MEDLINE search. Articles in which either ACA or anti-Scl-70 antibodies were measured in both SSc patients and a non-SSc control group were reviewed and rated using a previously published diagnostic testing scale. Reported sensitivity and specificity from each study was converted into a 2 x 2 table, and combined across studies to calculate summary rates for each antibody. Author's clinical classification criteria for SSc served as the gold standard for disease diagnosis. RESULTS: In 30 articles that fulfilled inclusion criteria, ACA were found in 441 of 1,379 SSc patients (sensitivity 32%, range 17% to 56%). This increased to 57% (332 of 585) in patients with the limited cutaneous, or CREST, subset of SSc (IcSSc). Anti-Scl-70 antibodies were found in 366 of 1,074 SSc patients (sensitivity 34%, range 3% to 75%), and this increased slightly to 40% in patients with the diffuse cutaneous form of SSc (dcSSc). Both antibodies were measured in 670 patients, and either test was positive in 58% (range 29% to 86%), but in only 3 patients were both antibodies present. The specificity of each antibody was high, but varied by control group. ACA were present in 5% and anti-Scl-70 antibodies were present in 2% of patients with other connective tissue diseases, but fewer than 1% of disease free controls had either antibody present. CONCLUSIONS: As individual diagnostic tests in SSc, both ACA and anti-Scl-70 antibodies are highly specific. Each performs somewhat better as discriminators of clinical subsets for patients in whom a diagnosis of SSc has already been established. Clinicians can rely on a positive test result as being specific in the detection of disease, but 40% of SSc patients are likely to have neither antibody present, and a negative result does not exclude the diagnosis. Measurement of these antibodies should be considered secondary to the clinical features when making a diagnosis of SSc.

Antibodies, Antinuclear↗
PubMed1997

Is language a barrier to the use of preventive services?

OBJECTIVE: To isolate the effect of spoken language from financial barriers to care, we examined the relation of language to use of preventive services in a system with universal access. DESIGN: Cross-sectional survey. SETTING: Household population of women living in Ontario, Canada, in 1990. PARTICIPANTS: Subjects were 22,448 women completing the 1990 Ontario Health Survey, a population-based random sample of households. MEASUREMENTS AND MAIN RESULTS: We defined language as the language spoken in the home and assessed self-reported receipt of breast examination, mammogram and Pap testing. We used logistic regression to calculate odds ratios for each service adjusting for potential sources of confounding: socio-economic characteristics, contact with the health care system, and measures reflecting culture. Ten percent of the women spoke a non-English language at home (4% French, 6% other). After adjustment, compared with English speakers, French-speaking women were significantly less likely to receive breast exams or mammography, and other language speakers were less likely to receive Pap testing. CONCLUSIONS: Women whose main spoken language was not English were less likely to receive important preventive services. Improving communication with patients with limited English may enhance participation in screening programs.

Adolescent↗
PubMed1997

Physician relations in Canada: shooting inward as the circle closes.

As economic disputes between physicians become more frequent, discussions between physicians are becoming increasingly important. Those seeking insight into how physician organizations might mediate these disputes may be able to learn from others who have had negotiating responsibilities for over a quarter of a century--the provincial medical associations in Canada. In this article we examine the structure, process, and outcomes of negotiations between physicians, with a focus on responses to new physician expenditure caps in Ontario, Alberta, and British Columbia. Early negotiations between physicians over changes in relative fees favored general practitioners because they were the dominant voting block within the associations. Despite fewer gains in the fee arena, specialists were willing to remain in the associations because all physicians generally enjoyed similar income growth. Under new physician expenditure caps, however, physicians have been unable to resolve conflicts over how to allocate income limits across specialties. Negotiations between physicians face expanding economic issues and diverging interests as expenditure caps force physicians to concentrate on total costs.

Alberta↗
PubMed1997

Screening for disease.

Screening for disease has become a major activity over the last few decades, and the potential for future growth is almost boundless. However, the necessity for and effectiveness of screening has often been overstated with misused survival statistics. Nevertheless, screening with certain radiologic tests may provide modest benefits at acceptable costs under certain conditions. The challenge for the future is to better identify the tests, populations, and other conditions under which screening is appropriate. Various quantitative techniques for eliciting patient preferences [76] and analyzing benefits, harms, and costs over time [77-80] may help us meet this challenge.

Diagnostic Imaging↗
PubMed1997

A reader's guide to surgical decision analysis.

BACKGROUND: Studies using decision analysis appear increasingly often in the surgical literature. Because readers and reviewers may be unfamiliar with decision analysis, we review the technique and provide guidance on its interpretation. STUDY DESIGN: Review article. RESULTS: Decision analysis is a systematic approach to structuring a decision, collecting relevant information about the probability and relative value of outcomes, and making quantitative recommendations. Decision analysis includes the following basic components: (1) the decision model, (2) the probabilities of clinical outcomes in the model, (3) the utilities of clinical outcomes, and (4) the analysis and interpretation. To critically interpret the results of a decision analysis, readers must consider the validity of each component. The model should include all relevant clinical strategies and all important clinical outcomes. Probability estimates, whether derived from published studies or based on "clinical consensus," should be in general agreement with the reader's clinical experience. Utilities (values assigned to outcomes) are often expressed in terms of quality-adjusted life expectancy. Methods used to estimate life expectancy and to adjust for quality of life must be scrutinized carefully. Within the analysis, readers should consider the effect of varying uncertain variables in the model (sensitivity analysis) and, thus, the stability of the results. Finally, readers must assess whether the magnitude of expected benefit from the favored clinical strategy is clinically important. CONCLUSIONS: As decision analysis becomes more frequently used to influence clinical policy in surgery, surgeons must learn to examine the technique more critically.

Decision Support Techniques↗
PubMed1996

Assessing competing risks in treating the elderly.

For elderly patients, risks associated with a newly diagnosed disease may be less than competing risks of death and disability from other causes. Treatment benefits should be viewed in the context of normal life expectancy and quality of life.

Age Factors↗
PubMed1996

The use of Medicare home health care services.

BACKGROUND: Medicare's home health care program, consisting primarily of home visits by nurses and health aides, was conceived as a means to facilitate hospital discharge. Because home health care is now one of the fastest-growing categories of Medicare expenditures, we analyzed Medicare claims data to determine current patterns of use. METHODS: We used 1993 data from Medicare's National Claims History File to examine the temporal relation between home visits and hospital discharge, as well as the number of months Medicare enrollees received home health care. To determine whether home visits replaced hospital services, we calculated population-based utilization rates, adjusted for age and sex, for enrollees living in the 310 U.S. metropolitan statistical areas and determined whether the areas with higher rates of home health care also had lower admission rates or shorter lengths of stay. Finally, we compared the geographic variation in use of home health care with that of other Medicare services. RESULTS: Roughly 3 million Medicare enrollees received over 160 million home health care visits in 1993. Seventy-eight percent of the visits either occurred more than a month after hospital discharge (35 percent) or were not associated with any inpatient care during the previous six months (43%). Home health care often represented a long-term intervention: 61 percent of the visits were to enrollees who received home health care for six months or more. We could find no evidence that home health care was substituted for hospital care; the metropolitan statistical areas with higher rates of home health care did not have fewer hospital admissions or shorter lengths of stay. There was more geographic variation in the use of home health care than in the use of other major categories of Medicare services (e.g., hospital admissions and physicians' services). Five states (all in the South) had more than 9000 visits per 1000 enrollees, and 14 states had fewer than 3000 visits per 1000 enrollees. CONCLUSIONS: Home health care visits are used primarily to provide long-term care. There is no evidence that services provided at home replace hospital services, and the dramatic geographic variation in home visits suggests a lack of consensus about their appropriate use.

Home Care Services↗