Abstract PL01: Screening mammography and overdiagnosis

Cancer screening involves trade-offs. Screening offers the potential benefit of avoiding advanced cancer and subsequent cancer death. It also produces the harms of false alarms, overdiagnosis and unnecessary treatment. Because different individuals value these benefits and harms differently, there is no single calculation to answer the question of what to do.

The trade-off of benefits and harms is present in screening mammography. The reduction in breast cancer mortality identified in the original randomized trials has likely been diminished by subsequent – and substantial – improvements in treatment. The rate of false positives can be high – particularly in the United States. Less familiar is the harm of overdiagnosis: the detection of early cancers that are not destined to ever cause clinicaldisease. Because women given the diagnosis of “cancer” are generally treated, overdiagnosis is rarely directly observed. Instead, inferences about overdiagnosis are based on indirect evidence: long-term follow-up of randomized trials and changes in stage-specific incidence over time. There is no single “right” number to describe the magnitude of either the benefits or harms of screening mammography and there is no single “right” value to assign to the various outcomes. Consequently, screening mammography is a choice – not a public health imperative.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr PL01.

Direct-to-consumer advertisements for prescription drugs: what are Americans being sold?

BACKGROUND

Pharmaceutical companies spent US$1.8 billion on direct-to-consumer advertisements for prescription drugs in 1999. Our aim was to establish what messages are being communicated to the public by these advertisements.

METHODS

We investigated the content of advertisements, which appeared in ten magazines in the USA. We examined seven issues of each of these published between July, 1998, and July, 1999.

FINDINGS

67 advertisements appeared a total of 211 times during our study. Of these, 133 (63%) were for drugs to ameliorate symptoms, 54 (26%) to treat disease, and 23 (11%) to prevent illness. In the 67 unique advertisements, promotional techniques used included emotional appeals (45, 67%) and encouragement of consumers to consider medical causes for their experiences (26, 39%). More advertisements described the benefit of medication with vague, qualitative terms (58, 87%), than with data (9, 13%). However, half the advertisements used data to describe side-effects, typically with lists of side-effects that generally occurred infrequently. None mentioned cost.

INTERPRETATION

Provision of complete information about the benefit of prescription drugs in advertisements would serve the interests of physicians and the public.

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.

US women's attitudes to false-positive mammography results and detection of ductal carcinoma in situ: cross-sectional survey

OBJECTIVE

To determine women's attitudes and knowledge of both false-positive mammography results and the detection of ductal carcinoma in situ after screening mammography.

DESIGN

Cross-sectional survey.

SETTING

United States.

PARTICIPANTS

A total of 479 women aged 18 to 97 years who did not report a history of breast cancer. Main outcome measures Attitudes and knowledge about false-positive results and the detection of ductal carcinoma in situ after screening mammography.

RESULTS

Women were aware that false-positive results do occur. Their median estimate of the false-positive rate for 10 years of annual screening was 20% (25th percentile estimate, 10%; 75th percentile estimate, 45%). The women were highly tolerant of false-positive results: 63% thought that 500 or more false-positives per life saved was reasonable, and 37% would tolerate a rate of 10,000 or more. Women who had had a false-positive result (n = 76) expressed the same high tolerance: 30 (39%) would tolerate 10,000 or more false-positives. In all, 62% of women did not want to take false-positive results into account when deciding about screening. Only 8% of women thought that mammography could harm a woman without breast cancer, and 94% doubted the possibility of nonprogressive breast cancers. Few had heard of ductal carcinoma in situ, a cancer that may not progress, but when informed, 60% of women wanted to take into account the possibility of it being detected when deciding about screening.

CONCLUSIONS

Women are aware of false-positive results and seem to view them as an acceptable consequence of screening mammography. In contrast, most women are unaware that screening can detect cancers that may never progress but think that such information would be relevant. Education should perhaps focus less on false-positive results and more on the less-familiar outcome of the detection of ductal carcinoma in situ.

Risk communication in clinical practice: putting cancer in context

CONTEXT

Clinicians are increasingly urged-even mandated-to help patients make informed medical decisions by paying more attention to risk counseling. For many, the role of risk counseling is new and unfamiliar. This effort is made more difficult given the practical constraints created by 15-minute visits and competing demands (e.g., patient's chief complaint and institutional needs).

OBJECTIVE

We detail a three-part approach for improving risk communication, acknowledging the role of clinicians, patients, and other communicators (i.e., media or public health agencies).

PROPOSED APPROACH

Office-based tools to help clinicians do more. We suggest two ways to help make up-to-date estimates of disease risk and treatment benefit easily available during office visits. We propose the development of a comprehensive population database about disease risk and treatment benefit to be created and maintained by the federal government. Educating patients. We propose "Understanding Numbers in Health" a tutorial that reviews basic concepts of probability and their application to medical studies to help people become better critical readers of health information. Guidance for communicators. Finally, we propose a writer's guide to risk communication: a set of principles to help health communicators present data to the public clearly and objectively.

CONCLUSION

In addition to tools to help clinicians better communicate risk information, serious efforts to improve risk communication must go beyond the clinic. Efforts that help the public to better interpret health risk information and guide communicators to better present such information are a place to start.

A chest wall restrictor to study effects on pulmonary function and exercise. 2. The energetics of restrictive breathing

Chest wall restriction, whether caused by disease or mechanical constraints such as protective outerwear, can cause decrements in pulmonary function and exercise capacity. However, the study of the oxygen cost associated with mechanical chest restriction has so far been purely qualitative. The previous paper in this series described a device to impose external chest wall restriction, its effects on forced spirometric volumes, and its test-retest reliability. The purpose of this experiment was to measure the oxygen cost associated with varied levels of external chest wall restriction. Oxygen uptake and electromyogram (EMG) of the external intercostals were recorded during chest restriction in 10 healthy males. Subjects rested for 9 min before undergoing volitional isocapnic hyperpnea for 6 min. Subjects breathed at minute ventilations (V.I) of 30, 60, and 90 liters/min with chest wall loads of 0, 25, 50 and 75 mm Hg applied. Frequency of breathing was set at 15, 30, and 45 breaths per minute with a constant tidal volume (VT) of 2 liters. Oxygen uptake was measured continuously at rest and throughout the hyperventilation bouts, while controlling V.I and VT. Integrated EMG (IEMG) from the 3rd intercostal space was recorded during each minute of rest and hyperventilation. Two-way ANOVA with repeated measures revealed that chest wall loading and hyperpnea significantly increased V.O2 values (p < 0.01). External intercostal IEMG levels were significantly increased (p < 0.05) at higher restrictive load (50 and 75 mm Hg) and at the highest minute ventilation (90 liters/min). These data suggest that there is a significant and quantifiable increase in the oxygen cost associated with external chest wall restriction which is directly related to the level of chest wall restriction.

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%).

US women's attitudes to false positive mammography results and detection of ductal carcinoma in situ: cross sectional survey

OBJECTIVE

To determine women's attitudes to and knowledge of both false positive mammography results and the detection of ductal carcinoma in situ after screening mammography.

DESIGN

Cross sectional survey.

SETTING

United States.

PARTICIPANTS

479 women aged 18-97 years who did not report a history of breast cancer.

MAIN OUTCOME MEASURES

Attitudes to and knowledge of false positive results and the detection of ductal carcinoma in situ after screening mammography.

RESULTS

Women were aware that false positive results do occur. Their median estimate of the false positive rate for 10 years of annual screening was 20% (25th percentile estimate, 10%; 75th percentile estimate, 45%). The women were highly tolerant of false positives: 63% thought that 500 or more false positives per life saved was reasonable and 37% would tolerate 10 000 or more. Women who had had a false positive result (n=76) expressed the same high tolerance: 39% would tolerate 10 000 or more false positives. 62% of women did not want to take false positive results into account when deciding about screening. Only 8% of women thought that mammography could harm a woman without breast cancer, and 94% doubted the possibility of non-progressive breast cancers. Few had heard about ductal carcinoma in situ, a cancer that may not progress, but when informed, 60% of women wanted to take into account the possibility of it being detected when deciding about screening.

CONCLUSIONS

Women are aware of false positives and seem to view them as an acceptable consequence of screening mammography. In contrast, most women are unaware that screening can detect cancers that may never progress but feel that such information would be relevant. Education should perhaps focus less on false positives and more on the less familiar outcome of detection of ductal carcinoma in situ.

Are increasing 5-year survival rates evidence of success against cancer?

CONTEXT

Increased 5-year survival for cancer patients is generally inferred to mean that cancer treatment has improved and that fewer patients die of cancer. Increased 5-year survival, however, may also reflect changes in diagnosis: finding more people with early-stage cancer, including some who would never have become symptomatic from their cancer.

OBJECTIVE

To determine the relationship over time between 5-year cancer survival and 2 other measures of cancer burden, mortality and incidence.

DESIGN AND SETTING

Using population-based statistics reported by the National Cancer Institute Surveillance, Epidemiology, and End Results Program, we calculated the change in 5-year survival from 1950 to 1995 for the 20 most common solid tumor types. Using the tumor as the unit of analysis, we correlated changes in 5-year survival with changes in mortality and incidence.

MAIN OUTCOME MEASURE

The association between changes in 5-year survival and changes in mortality and incidence measured using simple correlation coefficients (Pearson and Spearman).

RESULTS

From 1950 to 1995, there was an increase in 5-year survival for each of the 20 tumor types. The absolute increase in 5-year survival ranged from 3% (pancreatic cancer) to 50% (prostate cancer). During the same period, mortality rates declined for 12 types of cancer and increased for the remaining 8 types. There was little correlation between the change in 5-year survival for a specific tumor and the change in tumor-related mortality (Pearson r=.00; Spearman r=-.07). On the other hand, the change in 5-year survival was positively correlated with the change in the tumor incidence rate (Pearson r=+. 49; Spearman r=+.37).

CONCLUSION

Although 5-year survival is a valid measure for comparing cancer therapies in a randomized trial, our analysis shows that changes in 5-year survival over time bear little relationship to changes in cancer mortality. Instead, they appear primarily related to changing patterns of diagnosis. JAMA. 2000.

Women's understanding of the mammography screening debate

BACKGROUND

The fractious public debate over mammography screening recommendations for women aged 40 to 49 years has received extensive attention in medical journals and in the press.

OBJECTIVE

To learn how women interpret the mammography screening debate.

METHODS

We mailed a survey to a random sample of American women 18 years and older, oversampling women of screening age (40-70 years). Sixty-six percent of women completed the survey (n = 503).

MAIN OUTCOME MEASURES

The main outcome measures were women's reactions to the debate, their suggestion for the starting age for mammography screening, and their understanding of the source of the debate.

RESULTS

Almost all women (95%) said that they had paid some attention to the recent discussion about mammography screening. Only 24% said the discussion had improved their understanding of mammography, while 50% reported being upset by the public disagreement among screening experts. Women's beliefs about mammography differed from those articulated by experts in the debate. Eighty-three percent believed that mammography had proven benefit for women aged 40 to 49 years, and 38% believed that benefit was proven for women younger than 40 years. Most women suggested that mammography screening should begin before age 40 years, while only 5% suggested a first mammogram should be performed at 50 years or older. In response to an open-ended question about why mammography has been controversial, 15% cited concerns about the potential harms of radiation and another 12% cited questions about efficacy. Nearly half (49%), however, identified costs as the major source of debate (eg, "Health maintenance organizations [HMOs] don't want to pay for mammography").

CONCLUSIONS

Most women paid attention to the recent debate about routine mammography screening for women aged 40 to 49 years, but many believed the debate was about money rather than the question of benefit. Policy makers issuing recommendations about implementation of large-scale mammography screening services need to consider how to effectively disseminate their message.

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.

Teaching evidence-based medicine: caveats and challenges

Evidence-based medicine (EBM) is an important new paradigm of the medical profession. While the quantitative approach of EBM has its place, clinical medicine must take into account many subtleties that EBM fails to consider. In this article, the authors describe three caveats to this quantitative approach: (1) the detection of "maybe disease" (physiologic, anatomic, or histologic abnormalities that may not ever be overtly expressed in the patient's lifetime) inflates apparent diagnostic test performance; (2) probability revision is valuable primarily as an exercise to gain qualitative insights; and (3) patients are likely to be interested more than just central tendencies in making treatment decisions. They then consider some challenging questions facing clinician-educators: how do they prepare students for situations where there is an absence of rigorous evidence? Should they teach students that the burden of proof lies in demonstrating efficacy or in demonstrating ineffectiveness? And what should they tell students about when to seek evidence to aid diagnostic and treatment decisions?

The cost-effectiveness of treating all patients with type 2 diabetes with angiotensin-converting enzyme inhibitors

BACKGROUND

Although guidelines recommend angiotensin-converting enzyme inhibitors for diabetic patients with microalbuminuria, this strategy requires that providers adhere to screening recommendations. In addition, the benefit of angiotensin-converting enzyme inhibitors in normoalbuminuric patients was recently demonstrated.

OBJECTIVE

To evaluate the cost-effectiveness of treating all patients with type 2 diabetes.

DESIGN

Markov model simulating the progression of diabetic nephropathy.

DATA SOURCES

Randomized trials estimating the progression of diabetic nephropathy with and without angiotensin-converting enzyme inhibitors.

TARGET POPULATION

Patients 50 years of age with newly diagnosed type 2 diabetes (fasting plasma glucose level > or = 7.8 mmol/L [140 mg/dL]).

TIME HORIZON

Lifetime.

PERSPECTIVE

Societal.

INTERVENTIONS

Patients received angiotensin-converting enzyme inhibitors, screening for microalbuminuria, or screening for gross proteinuria.

OUTCOME MEASURES

Lifetime cost, quality-adjusted life expectancy, and marginal cost-effectiveness.

RESULTS OF BASE-CASE ANALYSIS

Screening for gross proteinuria had the highest cost and the lowest benefit. Compared with screening for microalbuminuria, treating all patients was more expensive ($15240 and $14940 per patient) but was associated with increased quality-adjusted life expectancy (11.82 and 11.78 quality-adjusted life-years). The marginal cost-effectiveness ratio was $7500 per quality-adjusted life-year gained.

RESULTS OF SENSITIVITY ANALYSIS

Results were sensitive to the cost, effectiveness, and quality of life associated with angiotensin-converting enzyme inhibitor therapy, as well as age at diagnosis. The model was relatively insensitive to adherence with screening and costs of treating end-stage renal disease.

CONCLUSIONS

Treating all middle-aged diabetic patients with angiotensin-converting enzyme inhibitors is a simple strategy that provides additional benefit at modest additional cost. The strategy assumes that patients meet the older diagnostic criteria for diabetes and makes sense only for those who are not bothered by treatment.

Diagnostic testing following fecal occult blood screening in the elderly

BACKGROUND

Screening with a fecal occult blood test (FOBT) has been shown to reduce colorectal cancer mortality in controlled trials. Recently, Medicare approved payment for FOBT screening. We evaluated the pattern of diagnostic testing following the initial FOBT in elderly Medicare beneficiaries. Such follow-up testing would in the long run influence both the cost and the benefit of widespread use of FOBT.

METHODS

Using Medicare's National Claims History System, we identified 24 246 Americans 65 years old or older who received FOBT at physician visits between January 1 and April 30, 1995. Prior to FOBT, these people had no evidence of any conditions for which FOBT might be used diagnostically. We examined relevant diagnostic testing in this cohort during the subsequent 8 months and determined what proportion of those received an evaluation recommended by the American College of Physicians.

RESULTS

For every 1000 Medicare beneficiaries who received FOBT, 93 (95% confidence interval = 89-96 per 1000) had positive findings and relevant testing in the subsequent 8 months. Of these, 34% had the recommended evaluation of either colonoscopy or flexible sigmoidoscopy with an air-contrast barium enema. Another 34% received a partial colonic evaluation with either flexible sigmoidoscopy or a barium enema. The remaining 32% received other gastrointestinal (GI) testing without evaluation of the colonic lumen: computed tomography or magnetic resonance imaging of the abdomen (15%), upper GI series (10%), carcinoembryonic antigen (7%), and upper endoscopy (2%). Restricting the analysis to testing performed within 2 months of the initial FOBT yielded similar results.

CONCLUSION

Following FOBT, many Medicare beneficiaries get further diagnostic testing, but only a small proportion receives the recommended evaluation. With this pattern of practice, population screening is likely to be more costly and less effective than estimated from controlled trials.

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.

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.

The role of patients and providers in the timing of follow-up visits. Telephone Care Study Group

OBJECTIVE

Although the decision about how frequently to see outpatients has a direct impact on a provider's workload and may impact health care costs, revisit intervals have rarely been a topic of investigation. To begin to understand what factors are correlated with this decision, we examined baseline data from a Department of Veterans Affairs (VA) Cooperative Study designed to evaluate telephone care.

DESIGN

Observational study based on extensive patient data collected during enrollment into the randomized trial. Providers were required to recommend a revisit interval (e.g., "return visit in 3 months") for each patient before randomization, under the assumption that the patient would be receiving clinic visits as usual. POPULATION/SETTING: Five hundred seventy-one patients over age 55 cared for by one of the 30 providers working in three VA general medical clinics. Patients for whom immediate follow-up (</=2 weeks) was recommended were excluded.

MEASUREMENTS

Mean revisit interval was adjusted for patient factors using a regression model that accounted for patients being nested within providers and providers being nested within sites. Four patient-level variable blocks (illness burden-patient, travel time, illness burden-physician, and prior utilization) were sequentially entered into a linear model to determine their role in explaining the variance in revisit intervals. Physician identity was also entered after four blocks.

MAIN RESULTS

Recommended revisit intervals ranged from 1 month to over 1 year with the most common recommended intervals being 2, 3, or 6 months. About 10% of the variance in revisit interval was explained by illness measures independent of provider (e.g., general health perception) and travel time. Adding other illness measures (e.g., diagnoses, medications) and prior utilization (e.g., clinic visits) doubled the variance explained (R2 =.21). Finally, the identification of individual provider doubled the explained variance again (R2 =.45). After adjusting for patient factors, the average revisit interval for individual providers ranged from 8 to 26 weeks (8 to 19 weeks when restricted to the 16 staff physicians). There were also substantial differences across the three sites (adjusted means: 14, 17, and 11 weeks).

CONCLUSIONS

Even after adjusting for a detailed array of patient-level data, primary care providers have different practice styles regarding the timing of return visits. These may, in turn, reflect the local "culture" in which they practice. How many patients providers are able to care for may be determined by the providers' inclinations toward the timing of follow-up visits.

Setting the revisit interval in primary care

OBJECTIVE

Although longitudinal care constitutes the bulk of primary care, physicians receive little guidance on the fundamental question of how to time follow-up visits. We sought to identify important predictors of the revisit interval and to describe the variability in how physicians set these intervals when caring for patients with common medical conditions.

DESIGN

Cross-sectional survey of physicians performed at the end of office visits for consecutive patients with hypertension, angina, diabetes, or musculoskeletal pain.

PARTICIPANTS/SETTING

One hundred sixty-four patients under the care of 11 primary care physicians in the Dartmouth Primary Care Cooperative Research Network.

MEASUREMENTS

The main outcome measures were the variability in mean revisit intervals across physicians and the proportion of explained variance by potential determinants of revisit intervals. We assessed the relation between the revisit interval (dependent variable) and three groups of independent variables, patient characteristics (e.g., age, physician perception of patient health), identification of individual physician, and physician characterization of the visit (e. g., routine visit, visit requiring a change in management, or visit occurring on a "hectic" day), using multiple regression that accounted for the natural grouping of patients within physician.

MAIN RESULTS

Revisit intervals ranged from 1 week to over 1 year. The most common intervals were 12 and 16 weeks. Physicians' perception of fair-poor health status and visits involving a change in management were most strongly related to shorter revisit intervals. In multivariate analyses, patient characteristics explained about 18% of the variance in revisit intervals, and adding identification of the individual provider doubled the explained variance to about 40%. Physician characterization of the visit increased explained variance to 57%. The average revisit interval adjusted for patient characteristics for each of the 11 physicians varied from 4 to 20 weeks. Although all physicians lengthened revisit intervals for routine visits and shortened them when changing management, the relative ranking of mean revisit intervals for each physician changed little for different visit characterizations-some physicians were consistently long and others were consistently short.

CONCLUSION

Physicians vary widely in their recommendations for office revisits. Patient factors accounted for only a small part of this variation. Although physicians responded to visits in predictable ways, each physician appeared to have a unique set point for the length of the revisits interval.

Avoiding the unintended consequences of growth in medical care: how might more be worse?

The United States has experienced dramatic growth in both the technical capabilities and share of resources devoted to medical care. While the benefits of more medical care are widely recognized, the possibility that harm may result from growth has received little attention. Because harm from more medical care is unexpected, findings of harm are discounted or ignored. We suggest that such findings may indicate a more general problem and deserve serious consideration. First, we delineate 2 levels of decision making where more medical care may be introduced: (1) decisions about whether or not to use a discrete diagnostic or therapeutic intervention and (2) decisions about whether to add system capacity, eg, the decision to purchase another scanner or employ another physician. Second, we explore how more medical care at either level may lead to harm. More diagnosis creates the potential for labeling and detection of pseudodisease--disease that would never become apparent to patients during their lifetime without testing. More treatment may lead to tampering, interventions to correct random rather than systematic variation, and lower treatment thresholds, where the risks outweigh the potential benefits. Because there are more diagnoses to treat and more treatments to provide, physicians may be more likely to make mistakes and to be distracted from the issues of greatest concern to their patients. Finally, we turn to the fundamental challenge--reducing the risk of harm from more medical care. We identify 4 ways in which inadequate information and improper reasoning may allow harmful practices to be adopted-a constrained model of disease, excessive extrapolation, a missing level of analysis, and the assumption that more is better.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.