Search PubMed⌕ Search

Biomedical subjects

A R Feinstein

Publications and source records attributed to A R Feinstein.

At least 181 records · Page 10Linked to original sources
PubMed1985

The role of susceptibility bias in epidemiologic research.

Because prognostic adjustment in epidemiologic studies of disease etiology has usually been limited to matchings or stratifications based on demographic characteristics, clinical sources of susceptibility bias have received little attention. This may have led to an incorrect association in two prominent epidemiologic relationships: that between clear-cell vaginal carcinoma and the use of diethylstilbestrol to treat women with bleeding or previous pregnancy loss; and that in the conflicting results of the studies linking sex steroids to the risk of birth defects. The recognition and management of susceptibility bias requires attention to the patients' clinical status at the time of exposure to the alleged causative agent, and also requires collecting and analyzing clinical data excluded or ignored in most epidemiologic studies. To avoid susceptibility bias, data about bleeding, threatened abortion, and other clinical reasons for prescribing therapy are needed for the appropriate matchings or stratifications.

Abnormalities, Drug-Induced↗
PubMed1985

Exclusion bias and the false relationship of reserpine and breast cancer.

Although reserpine has an important role in treating patients with hypertension, its appeal was sharply reduced a decade ago when an alleged relationship to breast cancer was reported in case-control studies. Since the relationship was not confirmed in subsequent research and analyses, the original association is now regarded as erroneous. Since patients with cardiovascular disease were rejected as possible controls in the original reserpine-breast cancer case-control study, we suspected that the false association may have been produced by a phenomenon called exclusion bias. This bias can arise in case-control studies if patients with a particularly high (or low) rate of prior exposure to the alleged etiologic agent are excluded from the selection of either cases or controls, but not from both. To test that suspicion, we recapitulated the original study, in another medical setting. The cases were 257 women with breast cancer; and the controls were 257 hospitalized women matched according to date of admission, age, and race. The overall data showed no association between reserpine and breast cancer (odds ratio [OR] = 1.1), but when we excluded 101 women with cardiovascular disease from the control group, the OR rose to 2.5. The results suggest that exclusion bias played an important role in creating the false association between reserpine and breast cancer.

Aged↗
PubMed1984

Case-control research. Temporal precedence and other problems of the exposure-disease relationship.

We assessed the principle of temporal precedence in recent case-control studies demonstrating the alleged associations between tampon use and toxic shock syndrome and between aspirin use and Reye's syndrome. For both relationships, we considered four components of the exposure-disease association, including: (1) establishing that the agent preceded the disease, (2) selecting an index time, (3) defining criteria for classifying a patient as "exposed," and (4) avoiding the bias that occurs when use of the etiologic agent was influenced by an early manifestation of the disease. The problems can be minimized by interviewing patients early during the course of their illness and by improving strategies for data analysis.

Adult↗
PubMed1984

Diagnostic bias and toxic shock syndrome.

Diagnostic bias could have occurred in the tampon/toxic shock syndrome association if the original diagnostic judgments by physicians or the subsequent diagnostic selections by investigators were influenced by knowledge of the patient's gender, menstrual history, or catamenial product. To determine whether such diagnostic bias can occur, a set of descriptive vignettes was prepared for six cases (Series X) having diverse resemblances to toxic shock syndrome or Kawasaki's disease. For each vignette in Series X, a paired case in a complementary Series Y was described in identical text except for different information about gender, menstrual history, or tampon use. Either Series X or Series Y was sent to a randomly selected sample of internists, family practitioners, and infectious disease subspecialists. The physicians were asked to provide a diagnosis for each case, using their own nomenclature or choosing from a list of 22 diagnostic possibilities. Six weeks later, respondents were asked to provide diagnoses for the complementary series of cases. Regardless of medical specialty or type of series received first, the 368 responding physicians were more likely to diagnose toxic shock for menstruating tampon-users or menstruating women than for non-menstruating women or men. In the most striking difference, toxic shock was diagnosed in 85 percent of instances when the case was described in a menstruating tampon-user, but in 23 percent of instances when the same case was described in a man (odds ratio = 18.8). Since the current epidemiologic data may be seriously distorted by diagnostic bias, the results indicate the need for scientifically valid investigations of the toxic shock syndrome/tampon relationship.

Adolescent↗
PubMed1984

The measurement of dyspnea. Contents, interobserver agreement, and physiologic correlates of two new clinical indexes.

To improve the clinical measurement of dyspnea, we developed a baseline dyspnea index that rated the severity of dyspnea at a single state and a transition dyspnea index that denoted changes from that baseline. The scores in both indexes depend on ratings for three different categories: functional impairment; magnitude of task, and magnitude of effort. At the baseline state, dyspnea was rated in five grades from 0 (severe) to 4 (unimpaired) for each category. The ratings for each of the three categories were added to form a baseline focal score (range, 0 to 12). At the transition period, changes in dyspnea were rated by seven grades, ranging from -3 (major deterioration), to +3 (major improvement). The ratings for each of the three categories were added to form a transition focal score (range, -9 to +9). In 38 patients tested with respiratory disease, interobserver agreement was highly satisfactory for both indexes. The baseline focal score had the highest correlation (r = 0.60; P less than 0.001) with the 12-minute walking distance (12 MW), while significant, but lower, correlations existed for lung function. For the transition focal score, there was a significant correlation only with the 12 MW (r = 0.33; p = 0.04). These results indicate that dyspnea can receive a direct clinical rating that provides important information not disclosed by customary physiologic tests.

Aged↗
PubMed1984

Comorbid and clinical determinants of prognosis in endometrial cancer.

In cancers of the lung, larynx, rectum, and breast, the patients' initial clinical manifestations and comorbid diseases have shown important prognostic distinctions that are not evident in the customary systems of anatomic staging. This study was done to see whether the same phenomena occurred for cancer of the endometrium. In 142 consecutive cases of endometrial carcinoma, strikingly high five-year survival rates were found in women who had no symptoms attributable to the cancer or whose only symptoms might have been caused either by concomitant uterine or cervical disease or by replacement estrogen therapy. A distinct decline in survival was associated with systemic symptoms and with major comorbid ailments. Estimation of prognosis and evaluation of therapy can be improved with a new composite staging system, formed by combining the new clinical categories and the standard morphologic stages of the International Federation of Gynecology and Obstetrics (FIGO) system.

Adenocarcinoma↗
PubMed1984

Rate of disease progression in breast cancer: a clinical estimate of prognosis within nodal and anatomic stages.

From data obtained in the patient's history, the clinical rate of progression of disease in breast cancer patients can be estimated as slow, intermediate, or rapid. The strata defined by these rates had previously been shown to create prognostic gradients within groups of patients similar in anatomic stage or nodal status. In a second, validating cohort of 465 women with primary breast cancer, the strata delineating rate of disease progression were shown to have a cogent prognostic impact when the proportional hazards model was used to control simultaneously for nodal and anatomic status. In addition, the distinctions persisted when different types of treatment were taken into account. These findings from a multivariate analysis employing the Cox method confirmed the importance of clinical rate of disease progression in estimating prognosis of breast cancer.

Adenocarcinoma↗
PubMed1983

The BCG controversy. A methodological and statistical reappraisal.

Because of the conflicting results of eight major controlled trials, BCG vaccination against tuberculosis remains controversial despite more than 50 years of use. Suspecting a methodological source for the controversy, we reviewed the scientific and statistical quality of each trial. The analysis showed that (1) although biased allocation of the vaccine appeared an unlikely explanation for the disparate results, adequate demonstration of unbiased detection of tuberculosis was available only for the three trials reporting 75% or greater protective efficacy; and (2) in most trials reporting low efficacy, the results had wide confidence intervals that could not exclude high efficacy, but the trials reporting high efficacy all had narrow confidence intervals that excluded low efficacy. Because the trials with the best methodological quality and greatest statistical precision reported high efficacy, the evidence suggests that BCG can confer a high degree of protection against tuberculosis and that bias or inadequate statistical power may have contributed to the conflicting data.

BCG Vaccine↗
PubMed1983

Rapid growth rate: a method of identifying node-negative breast cancer patients with a high risk of recurrence.

Among node-negative patients with localized breast cancer (TNM stages T1-3 N0-1 M0), the rate of disease progression, classified with a clinical method of assessment, was rapid in 12%. Prognosis was substantially worse in the rapid groups than in patients classified as slow or intermediate. For instance, the 10 yr disease free survival rate was 55 and 50% in the rapid groups compared with 71% in the intermediate and 82% in the slow groups. Additionally, among those who did develop recurrent disease, the disease-free interval was shortest in the most rapid group (10 months) and longest in the slow group (50 months). The distinctive prognostic gradients formed by the growth-rate strata persisted when differences in symptomatic state, histologic type, tumor size, menstrual status, age, and treatment were taken into account through the Cox proportional hazards model. The node-negative patients who were identified as rapid have had a high risk of recurrence, while those with slow growth rates had an excellent prognosis. The index could improve therapeutic efficacy in this subset of patients by identifying high risk patients in whom adjuvant therapies may do more good than harm.

Breast Neoplasms↗