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S H Shapiro

Publications and source records attributed to S H Shapiro.

At least 19 recordsLinked to original sources
PubMed2000

Reporting the study populations of clinical trials. Clear transmission or static on the line?

In contrast to attempts that have been made to measure the clarity of reporting of the methods of clinical trials in journal articles, we report here an attempt to measure the accuracy of methods reporting. We focus in this article on eligibility criteria as a test case for the reporting of clinical trial methods. We examined the reporting of eligibility criteria in the protocol, methods paper (if applicable), journal article, and Clinical Alert for articles appearing in print between January 1988 and September 1994 for which a Clinical Alert had been issued. Eligibility criteria were further classified into five categories in order to examine the content of information loss, if any. On average, 82% of protocol eligibility criteria were reported in methods papers. Journal articles and Clinical Alerts fared somewhat worse: 63% of criteria were reported in journal articles, 19% in Clinical Alerts. In all three categories of medical communication, the reporting of criteria that defined the study disease tended to be complete; reporting of criteria relating to trial precision, patient safety, legal and ethical concerns, and administrative considerations, was not complete. We found that criteria for clinical trial eligibility are frequently under-reported in medical communications. Moreover, some of the criteria omitted are of considerable clinical importance. We suggest that in the design phase of clinical trials, proposed eligibility criteria be scrutinized closely. Those criteria that survive this scrutiny and that have clinical import must be reported upon fully and accurately when communicating trial results.

Clinical Trials as Topic↗
PubMed2000

Determinants of patients' treatment preferences in a clinical trial.

Several researchers have suggested that patients' preferences for a particular form of treatment should be taken into account in clinical trials. Preferences may influence the outcome of treatment, especially in trials when patients cannot be blinded to the type of treatment received and the outcome is based on patients' evaluations of therapy. Participants in this study were 136 edentulous patients who took part in a randomised controlled clinical trial comparing two types of treatments for edentulism: conventional dentures and implant-supported prostheses. Prior to receiving treatment, subjects were required to complete a questionnaire regarding their satisfaction with their present prostheses. In addition, they were asked to indicate which treatment they would prefer if given a choice. The objective of this study was to determine whether there are important differences among study participants between patients who have a treatment preference and those who do not. The effects of satisfaction with pre-treatment prostheses, age, gender and level of education on preferences were examined. Level of satisfaction with the original dentures and level of education were significant predictors of preference. Compared to subjects who rated their satisfaction with their current condition as 'low', the odds ratios associated with having a preference for implant treatment were 0.31 (95% CI: 0.09 to 0.96) for subjects who rated their prostheses in the 'medium' range and 0.11 (95% CI: 0.03 to 0.41) for those who rated in the 'high' range. In addition, subjects with high levels of education were significantly less likely to have a preference for either conventional or implant treatments (OR = 0.18, 95% CI: 0.02 to 0.77 and OR = 0.20, 95% CI: 0.05 to 0.76, respectively) compared to those with low education. Neither age nor gender was a significant predictor of preference. We suggest that study designs which incorporate patients' preferences must take into account possible differences between preference groups that might confound the relationship between preference and the outcome of interest.

Adult↗
PubMed1999

Comparing participants and nonparticipants in a smoking cessation trial: selection factors associated with general practitioner recruitment activity.

We studied the relationship between smokers' sociodemographic characteristics, their smoking habit, health status, and the probability of their having been approached for recruitment in the smoking cessation trial performed in Turin, Italy, with the aim of gathering information on the role of selection criteria adopted by general practitioners (GPs) in offering anti-smoking counseling. The 965 smokers who were offered participation in the trial were matched to a sample of eligible smokers (n = 277), selected from the rosters of the 42 GPs collaborating in the trial, who had not been invited to participate. The probability of being offered enrollment, estimated through a multiple conditional logistic regression model, assuming the GP as the matching variable, was significantly increased for intermediate (10-19 cigarettes per day: odds ratio [OR] = 4.13; 95% confidence interval [CI]: 2.63-6.47) and heavy (20 cigarettes per day or more: OR = 10.12; 95% CI: 6.51-15.75) smokers, for smokers diagnosed with chronic cardiovascular (OR = 2.06; 95% CI: 1.19-3.58), or respiratory (OR = 2.50; 95% CI: 1.40-4.48) diseases, and for smokers mentioning an intermediate number (2-4) of past quit attempts (OR = 3.70; 95% CI: 2.18-6.28). General Practitioners focused their recruitment activity on higer-risk smokers or smokers who had tried to quit, to offer more clues for intervention. Assessing the potential public health benefit of preventive interventions requires a more systematic evaluation of the generalizability of the reported findings.

Adult↗
PubMed1996

Analysing non-compliance in clinical trials: ethical imperative or mission impossible?

Assuming that a drug is active and different from placebo, a patient's gain or loss is likely to depend on how much of the drug is taken and when. The present paper motivates the ethical imperative of statistical compliance analysis by considering important clinical questions, the advent of more precise compliance measuring instruments and new statistical efforts towards well understood analyses that seek to preserve scientific integrity. An extension of Efron and Feldman's approach is developed which exploits the randomization assumption in combination with structural models. It also generates more promising designs and alternative statistical approaches.

Data Interpretation, Statistical↗
PubMed1996

Nutritional status and mortality in chronic obstructive pulmonary disease.

The role of nutritional status in the prognosis of subjects with severe chronic obstructive pulmonary disease was studied in a cohort of Canadian men and women followed for 3 to 5 yr. A total of 348 subjects who were recruited for a study of negative pressure ventilation were evaluated for lung function and body weight, and a subset who entered hospital for the study (n=184) had baseline measures of diffusing capacity, maximal inspiratory and expiratory mouth pressure (PImax and PEmax), and blood gases. Predictors of survival were analyzed using Cox regression models. In the total cohort, low body mass index (BMI) and use of home oxygen were independently associated with reduced survival. In the hospitalized group, predictors of respiratory mortality were elevated PaCO2 and low BMI, PImax, and diffusing capacity. PaO2 (measured on oxygen therapy), FEV1, PEmax, age, smoking behavior, and gender were not associated with survival. The predictors of total mortality were similar, except that BMI was no longer significant. In conclusion, low body weight, a potentially modifiable factor, was associated with respiratory mortality, but whether it has a casual effect or is a marker of declining health can only be resolved through an intervention trial.

Adult↗
PubMed1992

Effect of negative pressure ventilation in severe chronic obstructive pulmonary disease.

The hypothesis that patients with chronic obstructive pulmonary disease (COPD) have chronic inspiratory muscle fatigue was tested in an effectiveness trial in which negative pressure ventilation (NPV) was used to produce inspiratory muscle rest. In a double-blind study 184 patients with severe COPD were randomly allocated active or sham NPV treatment for a 12-week period of home use. The distance walked in a 6 min walk test was the primary outcome variable. Secondary outcome measures were cycle exercise endurance time, severity of dyspnoea, quality of life, arterial blood gas tensions, and respiratory muscle strength. The percentage reduction in amplitude of the diaphragmatic electromyographic signal multiplied by hours of NPV was used to reflect the dose of NPV so we could examine dose-response relations. Analysis was based on intention to treat. We found no evidence of a clinically or statistically significant difference in any outcome measure between active and sham groups. No dose-response relation was observed. Moreover, the intervention was poorly accepted despite substantial clinical support. We conclude that NPV as used in this study is difficult to apply and ineffective when used with the aim of resting the respiratory muscles in patients with stable COPD.

Aged↗
PubMed1991

A randomized trial of smoking cessation interventions in general practice in Italy.

The purpose of this study was to examine the effectiveness of different practice-based approaches to assist patients of primary care physicians to quit smoking and sustain cessation. Forty-four nonsmoking general practitioners volunteered for the study. After a period of training, they randomized 923 smoking clients, unselected for motivation toward quitting, to four different intervention groups: (i) minimal intervention, consisting of one single counselling session and a brief handout on quitting techniques; (ii) repeated counselling including reinforcing sessions at Months 1, 3, 6, and 9; (iii) repeated counselling and use of nicotine gum; and (iv) repeated counselling and spirometry. Biochemically validated smoking status was assessed at six and 12 months after recruitment. The proportion of verified quitters at 12 months was 4.8 percent among subjects randomized to the minimal intervention group, compared to 5.5 percent, 7.5 percent, and 6.5 percent among those randomized to the three repeated-counselling groups. In no treatment group was the outcome significantly different from that for one-time counselling at the (P less than 0.05) level. Lack of power, contamination, and low attendance at reinforcing sessions should be taken into account in interpreting the results.

Adult↗
PubMed1991

A randomized clinical trial of negative pressure ventilation in severe chronic obstructive pulmonary disease: design and methods.

This report documents the design and methods of a randomized clinical trial designed to test the effectiveness of home negative pressure ventilation in patients with severe chronic obstructive pulmonary disease. Active negative pressure ventilation was compared with a sham version of the treatment after a pre-trial assessment had indicated the feasibility of the latter. Over 1200 patients in the metropolitan Montreal area were screened. Of these, 348 patients were recruited to enter a 4-week stabilization period, and 184 were subsequently randomized to receive either active or sham negative pressure ventilation. A 5-day in-hospital period was used to train patients in ventilator use and obtain baseline measures of exercise capacity, lung function, respiratory symptoms, and quality of life. Home ventilation treatment took place during a following 12-week period. Respirator use was recorded both from patient logs and from concealed meters installed in the units. Patients received four home visits by physiotherapists during the 12-week period and returned for follow-up to the hospital 4 and 12 weeks post-discharge for reassessment.

Aged↗
PubMed1990

Examining outcome measures in a clinical study of stroke.

We investigated the relation between outcome and sample size for six selected stroke outcome measures to assist investigators in selecting end points for stroke studies. Data from a clinical trial of 167 stroke patients assessed shortly after admission to the hospital and 5 weeks later provided information on clinical, motor, and functional outcomes measured using a neurologic status scale, a stroke severity scale, the Fugl-Meyer Scale, the Barthel Index, and the activities of daily living and cognition subscales of the Level of Rehabilitation Scale. Data were examined using Pearson correlation coefficients and power analyses. All measures were significantly correlated. There was also substantial congruency between the subscales of a measure and its total score. The measures had variable efficiencies; the Barthel Index was the most efficient and therefore required the fewest subjects to identify a significant effect. These data suggest that careful consideration must be given to the choice of stroke outcome measures in terms of their numbers, interrelationships, and statistical properties, as these factors have important implications for the design, analysis, and conduct of clinical stroke studies.

Cerebrovascular Disorders↗
PubMed1989

Effect of nutritional status on exercise performance in patients with chronic obstructive pulmonary disease.

The purpose of our study was to examine the nutritional status of patients with severe chronic obstructive pulmonary disease (COPD) (mean predicted FEV1, 30 +/- 11%) and to explore its relationship to functional capacity. Functional capacity was evaluated by measuring peak oxygen consumption (VO2max) using an incremental cycle ergometry test, a 6-min walk test, self-perceived level of dyspnea, and quality of life. The percentage ideal body weight (%IBW) was less than 90% in 33 of 135 subjects. Triceps skinfold thickness was less than 60% of normal in 19 of 33 of these subjects. Total lymphocyte count was not different between groups, whereas hemoglobin (14.9 versus 15.9 g/dl) and albumin (4.0 versus 4.1 g/dl) were marginally reduced in underweight subjects. Dyspnea and overall quality of life were unaffected by nutritional status. Maximal inspiratory (Pimax) and expiratory mouth pressures (PEmax) were weakly associated with %IBW (R2 = 0.04; p = 01 and R2 = 0.15; p less than 0.01, respectively). The %IBW was a predictor of VO2max (percent predicted) after controlling for FEV1 in regression analysis (partial R2 = 0.08; p less than 0.001). Despite the association of weight status with VO2max, the 6-min walk was not influenced by %IBW. The perceived intensity of exercise as judged by the Borg score was far greater with the bicycle exercise that with the 6-min walk (mean score, 10.6 +/- 1.2 versus 4.6 +/- 1.9). This was supported by the difference in heart rate after these two tests.(ABSTRACT TRUNCATED AT 250 WORDS)

Body Weight↗
PubMed1986

Long-term adult use of ambulatory services provided by physicians in a Canadian medical care plan.

Utilization of physician services by initial subscribers to a Canadian consumer-sponsored medical care plan was examined for the period 1965-1979. After stratification by sex and age, 1,046 individuals aged 18-44 years were sampled and their records abstracted to yield the annual number of in-plan physician visits. The most frequently attending 10% of patients generated almost 30% of all visits. Moreover, those who initially made most frequent use of physician services persisted in doing so over the 15-year period. Utilization patterns differed between the sexes. Women, with a median of 40 visits, made more frequent use of services than men, with a median of 27 visits. Among men, the group that was oldest at enrollment utilized services more heavily than their younger counterparts, and this increased relative utilization became more pronounced with time. Corresponding effects were not seen in women, even after adjustment for prenatal visits. Adjustment for prenatal visits also had only a minimal effect on the frequency and duration of nonattendance. Ascertainment of out-of-plan utilization indicated that for the most recent year of follow-up, 20% of the patients made at least one out-of-plan visit. Although this had little effect on patients' relative utilization status, it had a substantial effect on the identification of nonattenders.

Adolescent↗
PubMed1985

Concentric membranous bodies in hepatocytes from a patient with systemic lupus erythematosus.

Concentric membranous bodies (CMB) are described in the cytoplasm of hepatocytes in a liver biopsy from a patient with systemic lupus erythematosus (SLE). Histologically, the biopsy showed binucleated hepatocytes and rosette formation with lymphocytic infiltrates in portal fields. Hepatocyte cytoplasm showed focal fatty metamorphosis, focal staining for RNA with azure B at pH 4.0 (which was perchloric acid labile), diffuse alloxan-Schiff staining for protein, and PAS-positive, diastase-sensitive glycogen. By electron microscopy one to three CMB were present in 10-15% of hepatocytes. CMB appeared as concentric, "fingerprint" or parallel arrays of particle-studded, membranous profiles. Other membranous configurations included mazelike forms. The space of Disse was dilated. Bile ductular changes included basement membrane thickening and redoubling and luminal bulging of ductular epithelium devoid of microvilli. CMB have been rarely reported in human hepatoma and have not heretofore been observed in non-neoplastic human liver. Their appearance in hepatocytes in a patient with SLE may reflect an increase in protein synthesis during regeneration.

Adult↗
PubMed1984

Scientific challenges in the application of randomized trials.

In recent years, scientific challenges in the application of randomized trials have become more apparent, especially with the extension of such trials to the assessment of nondrug treatments, such as health education, psychotherapy, and health care provision. Six issues (individual v group randomization, blinding and unblinding, the effect of trial participation on outcome, selective subject participation, treatment compliance, and standardized v individualized treatment) are discussed in terms of their impact on internal validity, generalizability (external validity), and clinical relevance. Specific design strategies may be necessary to enhance these methodological and clinical desiderata. Attention to these challenges should lead to improvements in future randomized trials.

Attitude↗