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PubMed1991

Prognostic modeling of clinical outcomes: an illustration with data from patients with membranous nephropathy.

Probabilities that a patient will occupy any of five clinically defined compartments at different future times are generated and graphed by a personal computer. The probabilities are functions of a patient's relevant baseline characteristics (treated or control group), clinical status, and follow-up time at which the prognosis is made. The illustrative prognostic model is based on a reanalysis of detailed individual records for 81 patients with idiopathic membranous nephropathy (42 treated with methylprednisolone and chlorambucil; 39 controls) in a randomized clinical trial. The compartments to and from which patients may pass are identified as (1) complete remission, (2) partial remission, (3) the nephrotic syndrome, (4) renal failure, and (5) death. Estimated risk functions for transitions between compartments involve baseline treatment, and intermediate and temporal variables, together with their relevant interactions. The model illustrates how, despite the overall advantage of treated over control patients, the comparative prognoses can change greatly and can even sometimes be reversed, depending on a variety of follow-up experiences.

Computer Simulation↗
PubMed1991

Methodological issues in the study of confidentiality: a reinterpretation of findings.

Investigations of confidentiality management have been constrained by an inability to obtain direct measures of clinicians' behaviors when deciding whether to breach or safeguard a confidence. Some researchers have used responses to hypothetical case vignettes to derive approximations of how clinicians manage confidences entrusted to them by their patients. However, these studies have focused primarily on total confidentiality scores, without exploring the possibility that subsets of clinical cases might elicit different confidentiality decisions. In this investigation, reanalysis of responses to case vignettes obtained from 436 psychologists, psychiatrists, and internists revealed that on the issue of confidentiality management, these health care providers discriminate among cases involving: Premeditated harm to others, socially irresponsible acts with possible dire consequences to self or others, and minor theft. Of these three categories of cases, those involving social irresponsibility elicited the greatest disagreement among the clinician groups studied.

Confidentiality↗
PubMed1991

Oral contraceptives and breast cancer. Cause and effect?

Case-control studies dealing with breast cancer and oral contraceptives (OCs) were reviewed against a background of currently accepted rules for conducting and interpreting epidemiologic research. There is a strong consensus that OCs have not increased the risk of breast cancer in women over age 45, even when they have been used for long periods. The controversy is confined to studies of cancer diagnosed in young women. Although an effect of duration of OC use has been observed in some studies, there is neither a latency period nor an effect from recent or current use. There is no obvious relationship to the type of pill and no consistent effect of the dose of estrogen. The effect, if it exists at all, is not confined to any specific subgroup; it has not been related to age at starting OCs. It has been observed in only a few studies, some of which were subsequently discounted. Others have shown no effect or have suggested a reduced risk of breast cancer with increasing duration of use. None of the studies purporting to show an effect of OCs have controlled for the potential confounding effects of duration of lactation, induced abortion, recent pregnancy or a history of diseases that are associated both with reduced use of OCs and reduced risk of breast cancer. Most have inappropriately controlled for benign breast disease. There is an urgent need for a reanalysis of existing studies to take these factors into account. The lack of consistency and the potential for bias and confounding argue strongly against concluding, at this time, that there is a causal relationship between OCs and breast cancer.

Abortion, Spontaneous↗
PubMed1991

Pelvic inflammatory disease.

Two studies compared and showed equal efficacy of the two intravenous treatment regimens recommended by the Centers for Disease Control: cefoxitin plus doxycycline and aminoglycoside plus clindamycin. The increased risk of pelvic inflammatory disease (PID) among users of an intrauterine device was confirmed in a reanalysis of the Oxford Family Planning Study. However, a prospective study showed that prophylactic, single-dose oral doxycycline significantly reduced the risk of post-insertion gonococcal, but not chlamydial, PID. According to Canadian investigators, laparoscopy is not very specific for PID diagnosis when tubal and endometrial histopathology is used as the gold standard. Two studies showed that vaginal douching is significantly associated with PID and with ectopic pregnancy. The risk of PID increased with frequency of douching. Data from the Women's Health Study suggest increased risk of PID among cigarette smokers. However, the risk of PID was unrelated to the number of cigarettes smoked.

Anti-Bacterial Agents↗
PubMed1991

Hypertensives' pressor response to norepinephrine. Analysis by infusion rate and plasma levels.

After 5 days of a 10 mEq sodium diet or 4 days of a 200 mEq sodium diet, 15 hypertensives and 11 normotensive control subjects received pressor doses of intravenous norepinephrine (NE). Analysis of pressor responses to the rate of NE infusion showed that the high salt diet sensitized subjects so that they needed less NE to raise systolic blood pressure (SBP) 20 mm Hg (P = .005). There was a complex interaction of salt intake, black race, and hypertension on NE pressor sensitivity (P = .03). Hypertensives attained lower plasma NE levels during the stepwise NE infusion, so we reanalyzed NE sensitivity in terms of the changes in plasma NE levels. This analysis also showed that during the high salt diet, subjects initiated a pressor response at lower plasma NE levels (P = .017) and raised SBP 20 mm Hg at lower NE levels (P = .007). The reanalysis showed that hypertensives initiated a pressor response at lower plasma NE levels (P = .03) and raised SBP 20 mm Hg at lower NE levels (P = .002). Plasma NE levels should provide a better guide to the concentration of NE at cardiovascular receptors than the rate of NE infusion. Analysis of pressor responses to plasma NE levels demonstrated that the hypertensives had an exaggerated pressor response to NE.

Black People↗
PubMed1991

Advanced prostatic carcinoma. Early versus late endocrine therapy.

Since the landmark observations of Huggins and Hodges in 1941, androgen deprivation has been the mainstay of treatment for advanced-stage prostate cancer. Although early, poorly controlled studies suggested enhanced survival with hormonal therapy, this view fell into disfavor as a result of the observations of the first and second VACURG studies. Recently, there has been a proliferation of experimental and clinical data supporting early androgen deprivation, including a reanalysis of the VACURG data, which suggests a survival advantage for younger patients with stage D disease and high-grade tumors who undergo androgen-ablative therapy at the time of diagnosis. The risk-benefit analysis presented in this review is strongly supportive of early hormonal therapy. Finally, long-term survival of patients with metastatic prostate cancer will require the development of novel treatment strategies effective against androgen-resistant tumor cells and their use in concert with early androgen deprivation.

Androgen Antagonists↗
PubMed1990

[Coping with illness as conforming to technological rules: an analysis of coping behavior of schizophrenic patients].

Coping can be conceptualized in terms of conformity with certain rules describing the relation between appraisals (here: control-ability and variability of stressors) and coping behaviour (here: problem-oriented, non-problem-oriented). The goal of the study is to examine the relevance of this approach for the analysis of schizophrenic patients' coping with their disease. This was done with the help of a reanalysis of data from a previous study. Subjects were 40 patients, which could be grouped in three clusters: high symptom strain, low symptom strain, specific strain (prodromal). Results showed that patients with low strain had a higher level of rule-conformity. Also, subjects with high rule conformity had a higher level of well-being, better prognosis and a higher level of professional education.

Adaptation, Psychological↗
PubMed1990

[Efficacy of influenza vaccination--the detection of a seeming efficacy].

In Japan, influenza vaccination has been offered to schoolchildren as a collective preventive program with parents given the right to participate or not participate in this program since 1987. Literature on the efficacy of influenza vaccination including the research report by the Ministry of Health and Welfare (1987) which proposed the continuation of the collective immunization program were examined. In almost all of the papers supportive of vaccination, approaches by which the final conclusions of the efficacy of vaccination were obtained have been found to be scientifically marginal in design and analysis. In order to further investigate these problems, a reanalysis of the data from recent studies by Satomi and Mori (1989) was conducted. A significant efficacy of the influenza vaccination could not be detected from this analysis, strongly suggesting that what appeared to be an efficacy in many papers may have been produced as a result of the confounding by the "healthiness" of the study population.

Binomial Distribution↗
PubMed1978

World Health Organization studies of prostaglandins versus saline as abortifacients. A reappraisal.

The World Health Organization (WHO) Task Force on the Use of Prostaglandins for the Regulation of Fertility has sponsored a series of randomized clinical trials and case-series investigations to assess the effectiveness and safety of prostaglandins as abortifacients. Our reanalysis of the WHO studies found the prostaglandins to be faster and more hazardour than hypertonic saline as intraamniotic abortifacients. Moreover, studies by the Center for Disease Control imply that dilatation and evacuation (D&E) may be more effective, safe, convenient, and inexpensive than prostaglandins for abortions after 12 weeks' gestation, especially in the 13- to 16-week interval. For gestations of greater than or equal to 17 weeks, the occurrence of live births in prostaglandin-induced abortions has produced serious legal and ethical problems in the United States. Until the effectiveness and safety of other prostaglandins regimen approach that of D&E, we feel that D&E should be the index of comparison against which newer methods of inducing abortion are tested.

Abortion, Induced↗
PubMed1990

How common is postpartum thyroiditis? A methodologic overview of the literature.

The incidence of postpartum thyroiditis (PPT) in the general population has been reported to range from 1.9% to 16.7%, depending on the study. To determine whether bias may have played a role in the generation of these widely varying estimates, a set of methodologic criteria were applied to the published original research dealing with the epidemiology of PPT. The articles that passed these methodologic filters reported a narrow range of incidences of PPT, varying between 3.7% and 5.9%. Reanalysis of these articles confirmed that thyrotoxicosis occurred more frequently in the first 3 months post partum than did hypothyroidism, and that a positive antimicrosomal antibody titer was strongly associated with postpartum thyroid dysfunction (odds ratio, 86.6; 95% confidence interval, 45.9 to 163.2). This article suggests that PPT is a common condition that occurs in the postpartum period. The best estimate of the incidence of PPT in an unselected cohort of postpartum women is 4.9%.

Autoantibodies↗
PubMed1990

[Kaposi's sarcoma. Development in Norway during the period 1957-86].

The article analyzes the incidence of Sarcoma Kaposi in Norway during the period 1957-86 (30 years). A clear increase is found for both sexes, particularly over the last 15 years. Whether this is due to changes in diagnostics, classification etc. can best be decided by histopathological reanalysis of the material and a representative sample of known differential diagnoses. There was also a marked increase among males under 50 years of age, mainly related to known AIDS or HIV infection. Among females under the age of 50, no association to HIV is reported. This may be due to under-reporting, or may be because the increase among females under 50 years of age is not related to HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Joint estimation of recombination fractions and interference coefficients in multilocus linkage analysis.

Estimation of recombination fractions and interference coefficients is of importance in multilocus linkage analysis. With the development of molecular genetic technologies such as RFLP, multilocus data are readily available to researchers. Several methods have been developed to analyze such data, and each performs well under restrictive conditions. The present paper proposes a method based on a multiplicative model and maximum-likelihood estimation of recombination fractions and interference coefficients. The estimators are consistent regardless of the model assumptions and are efficient if the model is a good approximation. The estimators are tractable even when there are incomplete observations. Furthermore, the interference between nonadjacent chromosomal regions or those among three chromosomal regions can be modeled and tested by a simple Z-test. The proposed method was applied to linkage analysis of four-locus data obtained from Drosophila and that of seven-locus data obtained again from Drosophila. Reanalysis of the first example revealed that there is interference between chromosomal regions 2 and 3. Analysis of the second example suggested that there is triple interference as well as pairwise interference between nonadjacent chromosomal regions; the genetic interpretation of these findings remains to be developed.

Genetic Linkage↗
PubMed1989

Serodiagnosis of ovine paratuberculosis, using lipoarabinomannan in an enzyme-linked immunosorbent assay.

The use of lipoarabinomannan (LAM; obtained from Mycobacterium paratuberculosis) in and ELISA (LAM-ELISA) to test 75 sheep sera from a paratuberculosis-infected flock resulted in an approximate threefold increase in sensitivity (from 23.5% to 70.6%), compared with the use of Annau's polysaccharide in a complement fixation test (P-CFT). Even after manipulation of the LAM-ELISA cut-off value to produce a specificity of 100% to match that of the P-CFT, the sensitivity still was approximately twofold greater than that of the P-CFT. Anti-bovine monoclonal antiglobulin-enzyme conjugates matched commercially available anti-ovine polyclonal antiglobulin-enzyme conjugates with respect to sensitivity and specificity. False-positive results were found to be less frequent after combining 2 serodiagnostic tests, LAM-ELISA and D antigenagar gel immunodiffusion, resulting in an increase in specificity from 88.1% to 95.2%. The repeatability of true seropositive and seronegative results was found to be 89.5% and 91.1%, respectively, for sera obtained less than or equal to 1 month prior to slaughter and 91.7% and 95.5%, respectively, for reanalysis of sera obtained at the time of slaughter.

Animals↗
PubMed1989

Investigating drug plasma levels and clinical response using random regression models.

The reanalysis of the Riesby dataset using a random regression model indicates a significant effect of DMI plasma measurements on HAM-D scores across the four timepoints of the study. This effect is especially strong when the HAM-D change from baseline score is used in place of the actual HAM-D score at the four timepoints. A significant effect of IMI was not found for either the actual HAM-D score or the HAM-D change from baseline score. An endogenous effect was marginally significant when the actual HAM-D score was used; however, this effect was not observed when the HAM-D change score was used as the dependent measure. There also was evidence of a marginally significant effect due to autocorrelation of the residuals, indicating that the residuals at a given timepoint were related to the residuals from previous timepoints according to a first-order autoregressive process. In contrast, when the repeated measures MANOVA was used to analyze these data, a significant effect of DMI was not observed, since subjects without complete data at all timepoints had to be dropped from the analysis. In longitudinal psychiatric studies where missing data are the rule (rather than the exception), the random regression approach provides an attractive alternative to the traditional methods of analyzing longitudinal data.

Humans↗
PubMed1989

The effect of death certification practice on recorded national asthma mortality rates.

There is a wide variation in the mortality from asthma between the countries of the European Community. Studies using a standard case history of a typical asthmatic to assess death certification practice have suggested that this variation is not related to the ways that doctors fill out death certificates. Reanalysis of the data from one of these studies suggests, however, that the way doctors certify more ambivalent case histories may explain much more of the variation. Repetition of this study in a small group of French and English doctors with a special interest in asthma came to the same conclusion, suggesting that these differences are due to both a genuine difference in nosology between the countries as well as to the quality of death certification.

Adolescent↗
PubMed1989

Spurious hyperphosphatemia in patients with dysglobulinemia.

Following the introduction of the ASTRA automated chemical analyzer to the Brooklyn VA Hospital, we identified 14 patients with normal renal function and marked hyperphosphatemia (9.1 +/- 3.1 mg/dl). Reanalysis of these samples by standard SMA-II autoanalyzer demonstrated normal phosphate concentration (3.5 +/- 0.7 mg/dl). All patients had a dysglobulinemic syndrome and further examination indicated that ASTRA reagents produced significant optical turbidity in these sera. We conclude that chemical analysis of inorganic phosphorus by methods which do not deproteinate sera prior to colorimetric analysis are subject to nephelometry in the presence of dysglobulinemic samples and may result in spurious hyperphosphatemia.

Aged↗
PubMed1989

Passage and rumination of inert particles varying in size and specific gravity as determined from analysis of faecal appearance using multicompartment models.

Plastic particles of defined length (2, 5 mm) and specific gravity (sp.gr. 1.10, 1.34, 1.77) were administered just before feeding into the reticulo-rumen of four cattle and four swamp buffaloes given a diet predominantly of rice straw ad lib. Simultaneously, doses of ground rice straw marked with Cr and Yb were likewise given. Plastic particles were recovered from faeces for 12 d after dosing, and divided into non-ruminated (NR) and ruminated (R) particles. Excretion data of plastic particles were interpreted using a four-pool model incorporating passage of NR (kp) and R from the reticulo-rumen, post-ruminal passage, rate of chewing (kr) and two lag times. An inverse relationship was found between kr and sp.gr. The kr was higher for 5 mm than that for 2 mm particles. In contrast, kp was greatest for particles of sp.gr. 1.34, with higher kp for 2 mm than for 5 mm particles. Rates of passage and rumination (kp, kr) were higher for buffaloes than for cattle. Rumination time was related to kr, most highly (r2 0.96) with kr of 2 mm, 1.10 sp.gr. particles. Fragmentation of 5 mm particles by rumination tended to increase the rate of passage from the rumen. Ruminal passage rates of Yb and Cr markers were poorly correlated with each other and with kp of any of the plastic markers. Reanalysis of published data from plastic particle studies supported the relationships between sp.gr., size, kp and kr.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1989

Analysis of the DS86 atomic bomb radiation dosimetry methods using data on severe epilation.

This report presents a reanalysis of the Hiroshima and Nagasaki data on severe epilation as an acute radiation effect using both the new DS86 and the old T65D dosimetries. The focus of the report is on several aspects of the data which have previously been examined by Jablon et al (ABCC TR 12-70, 1970) and Gilbert and Ohara [Radiat. Res. 100, 124-138 (1984)]. The report examines the uniformity of epilation response across shielding category, across sex and age, and in terms of interactions between city, sex, age, and shielding category; it also investigates the apparent relative biological effectiveness (RBE) of neutrons in the DS86 dose compared with the T65D dose, using both within- and between-city information. In addition the report discusses evidence for nonlinearity in epilation response. The epilation response function exhibits nonlinearity in terms of both a marked increase in slope at about 0.75 Gy, and then, beginning at about 2.5 Gy, a leveling off and eventual decrease in response. The principal conclusions of the report are as follows. The use of the DS86 dosimetry rather than T65D increases the apparent RBE of neutrons compared with gamma dose from approximately 5 to 10. At these values of RBE the slope of the dose response, in a middle range from 0.75-2.5 Gy, is about 165% greater using DS86 than T65D. With respect to the interactions of sex, city, and shielding method, the size and significance of virtually all nonuniformities in epilation response seem using T65D are also evident with DS86. Additionally it seems difficult to find any evidence that DS86 is an improved predictor of epilation response over T65D. Finally, the fact that the nonlinearity in dose response and apparent actual downturn in epilation occurrence rate at the high end of dose is more striking with DS86 than with T65D is found to be due primarily to the common practice of truncating all T65D doses to 600 rad.

Adult↗