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Interviewer effects on self-reported substance use among homeless persons.

This study examines respondent editing of survey responses to questions regarding substance use. Previous research has identified several types of interviewer effects that may be associated with respondent editing, including direct and social distance effects. Little is known, however, regarding how these potential effects may influence self-reported substance use behavior. Data analyzed for this study were collected as part of a survey of substance use among homeless persons conducted in Cook County, Illinois. A total of 481 respondents were sampled at random in emergency and transitional shelters, soup kitchens, drop-in centers, and single room occupancy (SRO) hotels. Overall, a direct, gender-based effect was observed, with homeless respondents of both genders more willing to reveal substance use behaviors to male interviewers. Some race- and age-related direct effects were also identified, with White and older interviewers obtaining more reports of substance use. These findings yield important evidence regarding respondent editing of self-reported substance use and have implications for the common practice of demographically matching interviewers and respondents.

Adolescent↗
PubMed1993

Effects of adjacent surfaces of different shapes on regurgitant jet sizes: an in vitro study using color Doppler imaging and laser-illuminated dye visualization.

OBJECTIVES: The present study was designed to estimate the influence of different-shaped adjacent surfaces on regurgitant jets as assessed by color Doppler imaging and laser-illuminated dye optical visualization. BACKGROUND: Because color Doppler techniques provide real-time two-dimensional imaging of flow, the evaluation of valvular regurgitation by analysis of variance-encoded regurgitant jets by this method has been widely used in clinical studies. However, recent studies have demonstrated that color Doppler jet sizes are affected not only by several hemodynamic factors and instrument settings but also by the interaction between jets and adjacent wall surfaces. In clinical conditions, jets may interact with adjacent walls of variable shapes that might have different effects on the jet size. METHODS: An in vitro model was constructed consisting of a rigid, optically clear receiving chamber that had no outlet resistance and had a pulsatile pump ejecting through 1.5, 2.3 and 3.1 mm2 inflow orifices into the chamber. The surfaces were flat or smoothly and equally curved, convex and concave aluminum positioned at 0, 2 and 4 mm from and to the side of the inflow orifices. The pump was run with stroke volumes from 0.5 to 3.0 ml and with a pulse frequency of 70 beats/min. The echocardiographic and laser beams were aimed at the inflow orifice imaging jets perpendicular to the surfaces (vertical view) through the central plane of the jet flows. Maximal jet areas were measured by both color Doppler techniques and laser-illuminated dye visualization. RESULTS: Color Doppler study showed fair correlation between the jet areas and the stroke volumes (r = 0.83 to 0.99), but the jet sizes under different surface conditions were variable. All the surface jet areas at a jet-surface distance of 0 and 2 mm were smaller than free jet areas at the same stroke volume for both flat and convex surfaces (p < 0.001). Flow constraint by the concave surface resulted in the smallest jet areas (p < 0.001). The color Doppler jet areas on the curved surfaces were significantly smaller than the laser-illuminated dye visualization jet areas (p < 0.01 to 0.0001). However, at intermediate jet-surface distances (4 mm and sometimes 2 mm with higher velocity flows), jet interaction with the flat and especially with the convex surface resulted in larger jets. This effect was most pronounced on dye fluorescence studies because flow around these jets consisted mainly of low velocity vortical events with only partial surface adherence and these low velocity swirling flows were not well imaged by color Doppler technique. CONCLUSIONS: Our study suggests that the different-shaped adjacent surfaces with different degrees of flow alterations resulted in variable decreases in jet size and that color Doppler imaging could not encode and image the angled and low velocity swirling events well when jets flowed along the curved surfaces. These effects need to be taken into account when interpreting color Doppler images.

Analysis of Variance↗
PubMed1990

Sensitivity of effect variables in rheumatoid arthritis: a meta-analysis of 130 placebo controlled NSAID trials.

In a meta-analysis of placebo controlled NSAID trials, the sensitivity of the effect variables was calculated as the correlation coefficient and as the difference between drug and placebo, divided by the placebo group standard deviation. The patient's global evaluation was the most sensitive variable overall. Pain was more sensitive than Ritchie's index. Several variables may be omitted from clinical trials, especially if two active drugs are being compared. For example, the best maximum estimate for the difference in ESR between NSAIDs and placebo was 1.0 mm/hr (95% confidence interval -1.5 to 3.4 mm/hr), and for joint size 0.44% (-1.0 to 1.9%), corresponding to a quarter of a millimeter for each of the 10 joints usually measured. It is suggested to record only the patient's global evaluation, pain, and morning stiffness.

Anthropometry↗
PubMed1992

Cholesterol and coronary artery disease: age as an effect modifier.

An elevation of serum cholesterol has been one of the more frequently cited risk factors for coronary heart disease, found in both case-control and cohort studies. As a result, this country has undertaken massive screening of adults older than 20 years of age in an attempt to identify those persons with cholesterol levels greater than 200 mg/dl, and follow up with an active approach for intervention. The suggested cutpoints for borderline (200-240 mg/dl), and definite (> or = 240 mg/dl) hypercholesterolemia have been applied to all age groups despite suggestions of a diminution of risk conferred by cholesterol in the elderly. This study of 2544 white men undergoing coronary angiography shows that for all men, aged 25-84 years, plasma cholesterol levels were associated with an increase in coronary artery occlusion (rs = 0.15, p < 0.01). However, when stratified by age, this association held only for the younger men, the association diminishing to near zero in the oldest age group. The negative interaction between cholesterol levels and age in predicting coronary artery disease proved highly significant (p < 0.001) in multivariable linear regression analysis, suggesting that cholesterol levels are much less predictive of coronary artery disease in the elderly as compared to the young. These results point to the need for a more finely tuned set of criteria for the evaluation of hypercholesterolemia, one that takes into account the age of the screenee.

Adult↗
PubMed1993

Change in self-reported functioning in older persons entering a residential care facility.

We evaluated the responsiveness of measures of function in admissions to a long-term care facility. Between baseline and follow-up assessment, one-fifth or more of the subjects either worsened or improved in most aspects of reported function. We compared two measures of self-reported function (COOP charts and a short-form survey). Convergent validity was observed for changes in pain, social health, and mental health (r = 0.39-0.74), but not for physical functioning. Although the short-form physical function measure discriminated worsening on several performance-based external criteria of physical functioning (area under ROC curves up to 0.82), the COOP and other measures of physical functioning were less likely to do so. All physical function measures were less responsive for detecting improvement. Clinicians and investigators intending to monitor change in function must consider the responsiveness of their measures.

Activities of Daily Living↗
PubMed1993

Interviewer versus self-administered questionnaires in developing a disease-specific, health-related quality of life instrument for asthma.

We wished to determine the extent to which respondents provided the same answers to a health-related quality of life (HRQL) questionnaire in self- and interviewer-administered forms. One hundred and fifty patients with asthma who were symptomatic or required treatment at least once a week, and had airway hyperresponsiveness to methacholine aerosol (PC20 < 8.0 mg/ml) participated. Patients completed a 152-item HRQL questionnaire in both interviewer and self-administered forms, separated by a 2-week interval, the order determined by random allocation. The percentage of items endorsed by the self-administered approach was significantly higher than that of the interviewer-administered approach overall (46.9 vs 35.8%) (p < 0.0001). The difference was consistent across all six domains; the absolute difference in the proportion of items endorsed varied from 8.9 to 12.3%. The intraclass correlations for the proportion of subjects endorsing an item was 0.84. Self- and interviewer-administered questionnaires yield very similar results in discriminating between subjects, but the self-administered version shows systematically greater HRQL impairment.

Adult↗
PubMed1996

The evaluation of changes in functional health status in patients with abdominal complaints.

Measuring functional status changes in various patient subgroups is important in stratifying risk, assessing disease severity, and predicting and defining clinically relevant outcomes. Data from a multi-centered study of 980 primary care patients presenting with nonspecific abdominal complaints were studied to demonstrate the importance of such an assessment procedure. Patients were prospectively followed for 6 months. Five diagnostic categories based on illness duration and seriousness were derived from the clinical course of these patients. The functional status of each patient was determined at baseline, 1 month, and 6 months using the Sickness Impact Profile (SIP). Intraclass correlation coefficients accounted for two aspects of the reliability of the SIP regarding the measurement of change over time: differences between patients which are stable over time (reproducibility) and different effects of treatment between subsets (responsiveness). A priori formulated expectations about the degree of health status change in patient subgroups were evaluated with the help of effect-size calculations. Patient impairment only partially depended on the final diagnosis and was also influenced by the presence of co-morbidity, psycho-social determinants, and other complaints. The health status change in the patient subgroups agreed with a priori formulated expectations. Standardized effect-size calculations revealed that the degree of change over time in SIP scores was in accordance with these expectations. We conclude: (a) the SIP appeared to be a reliable clinimetric instrument in detecting change over time resulting from different clinical courses, (b) clinical studies that use clinimetric instruments to assess the effects of clinical interventions must adequately control for the influence of baseline "functional status" as well as traditional demographic features such as gender and age, and (c) evaluating a priori formulated clinical expectations concerning functional change with statistics such as intraclass correlation and effect sizes can lead to a clearer understanding of the clinical relevance of statistically significant changes.

Abdominal Pain↗
PubMed1997

Effect of cognitive-behavioural training on job-finding among long-term unemployed people.

BACKGROUND: The principles of cognitive-behavioural therapy (CBT) have been applied successfully through individual psychotherapy to several psychiatric disorders. We adapted these principles to create a group--training programme for a non-psychiatric group-long-term (> 12 months) unemployed people. The aim was to investigate the effects of the programme on measures of mental health, job-seeking, and job-finding. METHODS: 289 volunteers (of standard occupational classification professional groups) were randomly assigned to a CBT or control programme, matched for all variables other than specific content, that emphasised social support. 244 (134 CBT, 110 control) people started the programmes and 199 (109 CBT, 90 control) completed the whole 7 weeks of weekly 3 h sessions (including three CBT, seven control participants who withdrew because they obtained employment or full-time training). Questionnaires completed before training, on completion, and 3-4 months later (follow-up data available for 94 CBT, 89 control) assessed mental health, job-seeking activities, and success in job-finding. Analyses were based on those who completed the programmes. Participants were not aware that two interventions were being used. Investigators were aware of group allocation, but were accompanied in all programmes by co-trainers who were non-investigators. FINDINGS: Before training, 80 (59%) CBT-group participants and 59 (54%) controls scored 5 or more on the general health questionnaire (GHQ; taken to define psychiatric caseness). After training, 29 (21%) and 25 (23%), respectively, scored 5 or more (p < 0.001 for both decreases). Improvements in mean scores with training on the GHQ (between-group difference 3.91, p = 0.05) and in other measures of mental health were significantly greater in the CBT group than in the control group. There were no significant differences between the groups in job-seeking activity during or after training, but significantly more of the CBT group than of the control group had been successful in finding full-time work (38 [34%] vs 13 [13%], p < 0.001), by 4 months after completion of training. INTERPRETATION: These results suggest that group CBT training can improve mental health and produce tangible benefits in job-finding. Application of CBT among the unemployed is likely to benefit both individuals and society in general.

Adult↗
PubMed1995

Hawthorne effect: implications for prehospital research.

STUDY OBJECTIVE: The phenomenon of altered behavior or performance resulting from awareness of being a part of an experimental study has been termed the "Hawthorne effect." Prehospital studies generally involve paramedics or are designed to use data collected by paramedics. Our objective was to determine whether paramedic performance, as measured by frequency of documentation, can be modified by (1) written notification of the importance of documentation, (2) written notification of a research project involving paramedic documentation, or (3) written notification of a quality-improvement audit of paramedic documentation. DESIGN: Prospective, sequential intervention study with five study phases. SETTING: Urban, all-advanced life support public utility model emergency medical services system with 55,000 emergency calls per year. PARTICIPANTS: One hundred forty-five paramedics who completed all ambulance run reports from August 1992 to May 1993. RESULTS: A total of 30,828 run reports was entered into the study. Baseline undocumented parameters ranged from 3.7% to 6.5%. Compared with baseline, a memo to heighten awareness (phase 2) did not alter documentation (P > or = .08). A medication study memo (phase 3) improved medication documentation (P = .0005) and allergies documentation (P = .037). A quality-improvement audit memo (phase 4) improved documentation of all parameters (P < or = .001). CONCLUSION: The Hawthorne effect occurs in prehospital research. It does not require direct observation, nor does it require direct feedback. However, it may require a perceived demand for performance. The Hawthorne effect must be considered in the design of prehospital studies and interpretation of data collected by paramedics.

Data Collection↗
PubMed1995

Defibrillation by basic emergency medical technicians: effect on survival.

Several studies have examined the effect of early defibrillation by basic EMTs on patient survival. Although the studies have a common theme of early basic EMT defibrillation, they are diverse in locations, devices, control groups, caregivers, and protocols. They provide a confusing array of information that is difficult to review, synthesize, and interpret. Metaanalysis allows data pooling of these primary studies to combine results and statistically compare the observed variation in study outcomes. The purpose of this metaanalysis was to examine the published studies of early basic EMT defibrillation to learn whether this treatment has an effect on survival of out-of-hospital cardiac arrest. Analysis of the 10 studies that met inclusion criteria showed that despite variations in design, the overall effect size for all the studies was .092, indicating a 9.2% increase in survival over what would have been expected had the EMT-Ds not intervened.

Effect Modifier, Epidemiologic↗
PubMed1997

Fitting a routine health-care activity into a randomized trial: an experiment possible without informed consent?

Due to possible methodological and practical problems, many researchers refrain from using a randomized controlled trial design to evaluate procedures already embedded in routine health care. We performed a randomized controlled trial on the effects of routine individual feedback on test ordering behavior of family physicians. The trial started after 4 years of feedback and lasted for 2.5 years. With some adaptations a randomized trial proved to be possible. In evaluating health-care procedures that cannot be blinded in a traditional way, asking full and study-specific informed consent may conflict with the validity of the design. In such studies, an alternative procedure is to be considered. Our trial, with doctors as study subjects, was held on an already accepted routine procedure (feedback). This made it possible to refrain from obtaining study-specific informed consent. Consequently, a Hawthorne effect and contamination of the trial arms through information leakage could be avoided. Justification and general criteria for not obtaining full and study-specific informed consent are worked out. In health-care research on the performance of doctors or on interventions into the quality of care, obtaining a general informed consent in advance is an acceptable alternative approach.

Diagnostic Tests, Routine↗
PubMed1997

Use of goal attainment scaling in measuring clinically important change in cognitive rehabilitation patients.

Measuring the effectiveness of cognitive rehabilitation programs poses both conceptual and practical challenges. We compared several standardized outcome measures with goal attainment scaling (GAS) to assess their sensitivity to changes in health status in patients undergoing cognitive rehabilitation. GAS is a measurement approach that accommodates multiple individual patient goals, and has a scoring system which allows for comparisons between patients. Forty-four patients were evaluated. GAS yielded a mean 4.4 goals per patient. The mean gain in the GAS score was compared with the change in the Rappaport Disability Rating Scale, the Kohlman Evaluation of Daily Living Skills, the Milwaukee Evaluation of Daily Living, the Klein-Bell elimination scale and mobility scale, the Instrumental Activities of Daily Living Scale, and the Spitzer Quality of Life Index. Using a relative efficiency statistic, GAS proved more responsive than any other measure. The effect size statistic also demonstrated greater responsiveness to change with GAS compared with standard measures. GAS shows promise as a responsive measure in cognitive rehabilitation. This study replicates a similar study of GAS in frail elderly patients, suggesting that individualized measures may have broad merit in evaluating rehabilitation programs.

Activities of Daily Living↗
PubMed1997

Assessing the responsiveness of a functional status measure: the Sickness Impact Profile versus the SIP68.

In this study, the Sickness Impact Profile (SIP) and the SIP68 are studied for their ability to detect changes in health-related behavioral status. Methodological approaches toward responsiveness are invented and discussed. Next, literature findings on the responsiveness of the SIP are presented and judged for their validity. The SIP appeared to be able to demonstrate changes in the expected direction and in accordance with changes detected by other instruments. Using data from seven different longitudinal projects in populations with different diagnoses, the responsiveness of both the SIP136 and the SIP68 are subsequently studied and compared. In all populations, changes in functional status were indicated by both instruments. In terms of effect sizes, the SIP136 and the SIP68 do not differ significantly in their responsiveness. Moreover, changes detected by both SIPs appear to be valid representations of changes in health-related functional status.

Activities of Daily Living↗
PubMed1997

Interaction fallacy.

We define interaction fallacy as the situation in which heterogeneity of odds ratios suggests an interaction that does actually not exist among the corresponding risk ratios. We provide a hypothetical example of interaction fallacy between the presence of the germ-line BRCA1 mutation, age at first live birth, and breast cancer risk based on data from the literature. More generally, we present a set of hypothetical conditions under which interaction fallacy may occur.

Adult↗
PubMed1997

Employment status and high blood pressure in women: variations by time and by sociodemographic characteristics.

PURPOSE: The association between employment status and high blood pressure in women was examined at two time periods to determine if associations between employment status and high blood pressure varied by time period or by age, race, education, marital status, or parental status. METHODS: Women participants from the National Health Examination Survey (1960) and the Second National Health and Nutrition Survey (1976-1980) between the ages of 25 and 64 and currently employed or keeping house were included. Logistic regression analysis was used to examine the cross-sectional association between employment status and high blood pressure in each survey, taking into account potential effect modifiers and covariates. RESULTS: In 1960 employment was associated with a slight, but not statistically significant, elevation in odds of high blood pressure. In 1976-1980, it was associated with a modest but significant reduction in odds of high blood pressure. Variations in associations occurred by marital status (protective associations were limited to unmarried women) and race (associations were of stronger magnitude among African-American women). CONCLUSIONS: The employment status-high blood pressure relationship shifted across surveys. Changes in the composition of the employed and nonemployed groups account for at least part of the varying relationships.

Adult↗
PubMed1992

Memory improvements and pharmacological treatment: a method to distinguish direct effects on memory from secondary effects due to attention improvement.

Chronic cerebrovascular disturbances of the aged are characterized by a decline of attention. When these patients undergo pharmacological treatment, it is very difficult to distinguish between a direct benefit and/or a secondary effect on memory resulting from attention improvement. In our study we have proposed and evaluated a new method for identifying the different components of therapeutic efficacy on memory and attention in chronic cerebrovascular patients. This method is based on the use of the Randt Memory Test, traditional scores of memory efficiency (Acquisition, Recall, and a combined index), and the RMT three-factor scores derived from a structural model of memory functioning. The three scores have been called Encoding and Organization, Cognitive Efficiency, and Attention Efficiency. Participants were 96 selected chronic cerebrovascular patients treated in a double-blind study for 12 weeks with dihydroergocristine versus placebo. While changes in both acquisition and recall scores were related to the treatment, only changes of the Encoding and Organization factor scores were systematically related to therapy. Changes in Attention Efficiency were positively related to therapy only in proportion to the degree of cerebrovascular impairment.

Attention↗