Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “instrumental variable”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 901 records · Page 50Linked to original sources
PubMed1988

A neurosciences internship and graduate nurse role conception.

Registered nurse (RN) turnover is a severe problem many hospitals face in today's health care climate. A study was conducted of a graduate nurse (GN) neurosciences internship established in a large metropolitan teaching hospital located in southwestern Tennessee to determine the internship's effect upon role conception of GNs. Thirty-two GNs enrolled in the internship comprised the experimental group, and 22 GNs in traditional orientation were the control group. Data collection instruments consisted of Corwin's Role Conception tool and a demographic questionnaire designed to examine variables that could influence professional role conception. Both instruments were completed at the beginning of employment, and Corwin's Role Conception repeated after completion of the first six months of practice. At this time audiotaped interviews were conducted by a nurse counselor to collect qualitative data from ten randomly selected informants from each group. Results revealed no significant differences in the two groups regarding changes in role conception as measured by Corwin's instrument. Audiotaped interviews brought to light many concerns of new GNs with regard to inadequate staffing, the charge nurse role, coping with the stress of the professional nurse role and new attitudes toward the field of the neurosciences. Implications for nurse administrators include the need to: be aware of the stresses to which new GNs are exposed; examine traditional practices such as the charge nurse role and staffing patterns; determine whether nursing internships, such as the neurosciences internship can improve the attitudes of GNs toward their specialty.

Adult↗
PubMedDate not supplied

[Critical review of measures of quality of life in schizophrenia].

UNLABELLED: In order to provide clinicians, researchers, program evaluators and administrators with current information on the assessment of humanistic outcomes of services for schizophrenic patients, a literature review is performed in which references to quality of life (QOL) assessment were made in the context of schizophrenia. Measures are summarized according to purpose, content, psychometric properties. Fifteen QOL instruments are summarized and reflect considerable variability on the relevant criteria: 11 are developed for persons with severe and persistent mental illnesses and used among populations including a major part of schizophrenic patients; 3 are specific QOL measures for schizophrenic patients; 1 is a generic QOL instrument used among psychotic patients. Given that none of these QOL measures has been widely used or accepted as a standard, the choice of a measure must rest on the investigator's particular purpose and needs. CONCLUSION: There is a clear need for a QOL instrument that is specific for schizophrenia, given its high prevalence and chronic nature. The lack of information related to responsiveness of these scales stresses the problems of their inclusion in clinical trials. Scales that have been used in studies of schizophrenia were nearly all developed in the United States and the relevance of their content must be questioned. Rather than relying on the literature or experts to determine those needs that are important to patients with schizophrenia, the content of the instrument should be derived from qualitative interviews with patients who are at different stages of their illness. Moreover, the questionnaire should be self-administered.

Humans↗
PubMed1987

Severity of illness, quality of care, and physician practice as determinants of hospital resource consumption.

Health care providers continue the debate over why it costs more to care for patients than the DRG reimbursement rate allows. This study examines severity of illness (measured by the AS-SCORE rating), quality of care (measured by the Adverse Patient Occurrences Inventory), and physician practice patterns as sources of variability in hospital resource use by patients in two DRGs. Both instruments independently account for some of the intra-DRG variability in length of stay and total charges. The study indicates that there is a positive relationship between severity of illness and decreased quality of care and that physician practice does not affect variation in resource use when cardiovascular complications, severity of illness, and quality of care are controlled.

Adult↗
PubMed2003

Fast drug stability determination by LC variable-parameter kinetic experiments.

Variable-parameter kinetic experiments were carried out using HPLC as analytical instrument. The hydrolysis of aspirin was followed both at variable-temperature and at variable-pH conditions. The peak areas relative to salicylic acid were processed by direct fit to a mathematical model and/or by differential method obtaining, by single experiments, the values of the apparent rate constant in the whole range of temperature and pH studied. The results, although the discontinuity of this kind of analysis, are in agreement with those obtained by constant-parameter kinetics but saving experimental time.

Aspirin↗
PubMed2005

Patient-assessed health in ankylosing spondylitis: a structured review.

OBJECTIVE: To review evidence relating to the measurement properties for all disease-specific, multi-item, patient-assessed health instruments in patients with ankylosing spondylitis (AS). METHODS: Systematic literature searches were made to identify instruments, using predefined criteria relating to reliability, validity, responsiveness and precision. RESULTS: Twelve AS-specific and three arthritis-specific instruments met the inclusion criteria. Three AS-specific instruments that measure health-related quality of life (HRQL) were reviewed. The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), the Bath Ankylosing Spondylitis Functional Index (BASFI) and the Dougados Functional Index (DFI) had the greatest amount of evidence for reliability, validity and responsiveness across a range of settings. Four instruments lacked evidence for test-retest or internal consistency reliability. Most were assessed for validity through comparisons with other instruments, global judgements of health, mobility or clinical and sociodemographic variables. Most were assessed for responsiveness through mean score changes. Three instruments lacked evidence of responsiveness. CONCLUSION: This review provides a contribution to AS assessment. AS-specific multi-item measures specific to the assessment of pain, stiffness, fatigue and global health were not identified; where assessed, these domains were largely measured with single-item visual analogue scales. Single items may provide a limited reflection of these important domains. The BASFI and DFI remain the instruments of choice for functional assessment. HRQL is recommended as a core assessment domain. Further concurrent evaluation is recommended.

Health Status Indicators↗
PubMed2004

Use of patient and hospital variables in interpreting patient satisfaction data for performance improvement purposes.

Satisfaction scores of 349 patients being discharged from a state psychiatric hospital were examined in relation to available norms for the instrument used and selected patient and hospital variables. Mean item scores fell within the less-than-satisfied category on both total and factor scores. Regression analyses indicated minimal effects of patient attributes. Two hospital factors (restraint rate on patient's unit and accessibility of psychosocial groups) significantly predicted satisfaction, with the former having an unexpected positive relationship to satisfaction. Clinicians were able to use the survey data to improve care, but patients' tendency toward undifferentiated positive or negative responding hindered the prioritizing of change efforts.

Adult↗
PubMed1993

"The Göteborg Quality of Life Instrument"--a psychometric evaluation of assessments of symptoms and well-being among women in a general population.

OBJECTIVE: To examine with psychometric analysis techniques the potential for constructing valid composite variables of "The Göteborg Quality of Life Instruments". DESIGN: Prospective population study of women in 1974-75 and in 1980-81. SETTING: City of Göteborg, Sweden. PARTICIPANTS: Representative samples of the general population of women in five age strata between 44 and 66 years of age in 1974-75, followed 1980-81 including new cohorts of women aged 26 and 38. 1302 women were examined in 1974-75 and 1408 in 1980-81. MAIN OUTCOME MEASURE: "The Göteborg Quality of Life instrument", constructed in the early 1970s to measure symptoms and well-being in a population study of men. RESULTS: Four multi-item scales were identified with satisfactory reliability and validity, i.e., they met defined criteria of multi-item scales and benefit from higher reliability than single questions. The psychological symptom scale comprised all ten questions intended to reflect depression and tension, while the physical symptom scale included all six pain questions, the general symptoms dizziness, breathlessness, and nausea, and general fatigue that belonged to both symptom scales. The social well-being scale comprises all well-being questions believed to reflect the broad concept of life satisfaction. The physical-mental wellbeing scale reflected satisfaction with both general and mental health. Several symptom and well-being questions were clearly outside the main clusters and should be treated as single items. CONCLUSIONS: Use of a few, distinct scales instead of a number of single questions should increase statistical power because the number of comparisons is greatly reduced and problems of chance findings are thus minimized.

Adult↗
PubMed2005

A psychometric evaluation of the Smoking Consequences Questionnaire-Adult in smokers with psychiatric conditions.

Rates of smoking among individuals with psychiatric conditions are much greater than those seen in the general population, yet little is known about the psychometric properties of commonly used instruments that assess smoking-related variables among smokers with psychiatric conditions. The present study examined the factor structure and psychometric characteristics of the Smoking Consequences Questionnaire-Adult (SCQ-A; Copeland, Brandon, & Quinn, 1995, Psychological Assessment, 7, 484-494) among smokers with psychiatric conditions. A confirmatory factor analysis of the instrument indicated that the factor structure derived by the instrument's authors provided an adequate fit to the data. In addition, many of the 10 subscales of the SCQ-A demonstrated adequate internal consistency as assessed by Cronbach's alpha as well as adequate test-retest reliability over the course of 1 week. Based on the data derived from this sample, the SCQ-A has adequate psychometric properties for applications involving smokers with psychiatric conditions.

Adult↗
PubMed1990

Psychosocial correlates of hemoglobin Alc in young adults with type I diabetes.

To determine whether psychosocial variables are related to long-term glycemic control; trait anxiety, depression, loneliness and life stress were assessed in 48 Type I diabetic patients. Hemoglobin A1c (HbA1c), an indicator of long-term glycemic utilization, was assayed from blood samples drawn shortly before the self-report instruments were administered. Of the psychosocial variables, anxiety was significantly related to current values of HbA1c. The association between anxiety and current HbA1c remained after statistically controlling for potentially confounding variables, including the previous value of HbA1c. Despite the stability of HbA1c values over time, anxiety scores were not significantly correlated with follow-up HbA1c. The implications of the significant relationships between psychological constructs and glycemic control are discussed.

Adolescent↗
PubMed2003

Prevalence of anxiety and depression among medical students of private university.

OBJECTIVE: To assess anxiety and depression levels among medical students of a private university by using a self-administered anxiety and depression questionnaire. METHODOLOGY: A cross sectional study was done on the students of Ziauddin Medical University, who had spent more than six months in the medical school. A self-administered questionnaire was given to the students, present in the class and willing to participate in the study. During the survey students of 5th year were not available. The instrument used to asses the anxiety and depression levels was the, Aga Khan University Anxiety and Depression Scale (AKUADS). Additional questions regarding socioeconomic variables were also included in the survey instrument, such as student's birth order, monthly income, number of siblings, and monthly expenditure on education. Data analysis was done on Epi info version 6. RESULTS: There were 252 students in 4th year MBBS to 1st year MBBS. Of these 189 were present during the survey. Using anxiety and depression scale it was found out that 113 (60%) students had anxiety and depression. Prevalence of anxiety and depression in students of 4th year, 3rd year, 2nd year and 1st year was 49%, 47%, 73% and 66% respectively. It was significantly higher in 1st year and 2nd year, as compared to 3rd and 4th year (p < 0.05). It was seen that birth order, monthly income, number of siblings and monthly expenditure on education did not affect the prevalence of anxiety and depression. CONCLUSION: This study suggests that medical students experience anxiety and depression, the finding is consistent with other western studies, however there is no local data available to support our findings. The study finding highlights the need of psychiatric counseling and support services available to vulnerable students. These findings should be further explored in longitudinal studies to identify the stressors leading to these outcomes and appropriate interventions.

Adult↗
PubMedDate not supplied

Effect of role clarity and empathy on support role performance and anxiety.

The purpose of this study was to examine wives' anxiety in response to their husbands' first myocardial infarction from the perspective of perceptions and interpretations of their support roles, their husbands' experience, their abilities to act supportively, and how these and other factors contributed to their degree of anxiety. Major study variables were: role clarity (measured by an instrument developed for the study), empathy (measured by the Barrett-Lennard [1978] Relationship Inventory), support role performance (measured by an instrument developed for the study), and anxiety (measured by the State-Trait Anxiety Inventory Form A [Spielberger, Gorsuch, & Lushene, 1970]). Four exogenous variables, husband's condition, previous experience in the support role, self-esteem, and trait anxiety, were used to test alternate hypotheses. Subjects were 82 wives of men admitted to three cardiac care units. Data were collected prior to the husband's hospital discharge and at 3 weeks postdischarge. Data were analyzed with path analysis procedures. Study findings supported two hypotheses, that support role performance has a direct negative effect on anxiety and trait anxiety has a direct positive effect on anxiety. Descriptive data obtained during the postdischarge interview provided documentation of uncertainty as another source of anxiety.

Adult↗
PubMed1979

An evaluation of the mini-Wright peak flow meter.

The mini-Wright peak flow meter (MPFM) has been evaluated, and the results obtained from it show a strong positive correlation (r=0.970) with the Wright's peak flow meter (PFM). MPFM measurements, however, were biased to be about 38 1/min higher than PFM measurements (95% confidence limits 31.01/min to 45.01/min). Between instrument variation was found (F--ratio 3.67 with 9 and 81 degrees of freedom: P less than 0.001). In practice this did not appreciably affect individual measurements greatly as 95% confidence limits on any individual measurements were increased from +/-24 1/min to +/-27 1/min. There was no significant day-to-day variability in measurements obtained with individual instruments. The MPFM is a pocket-sized, simple, cheap, and robust instrument for following changes in ventilatory function. In clinical trails and surveys, however, both the bias in favour of the MPFM compared to the PFM and inter-machine variation must be taken into account. As the manufacturers have altered the scale to remove the bias since this study was performed, it will be important to know whether the original or the modified meter is being used in future studies.

Evaluation Studies as Topic↗
PubMed2004

Forecasting recidivism in mentally ill offenders released from prison.

Little research has focused on assessing the risk of mentally ill offenders (MIOs) released from state prisons. Here we report findings for 333 mentally ill offenders released from Washington State prisons. Logistic regression identified sets of variables that forecasted felony and violent reconviction as accurately as state-of-the-art risk assessment instruments. Sums of simple recoded versions of these variables predicted reoffense as well as complex logistic regression equations. Five of these 9 variables were found to be relative protective factors. Findings are discussed in terms of the value of stock correctional variables in forecasting risk, the need to base actuarial risk assessments on local data, the importance of protective factors in assessing MIO risk, and the need for dynamic, situational, and clinical variables that can further sharpen predictive accuracy of emergent risk in the community.

Adult↗
PubMed2004

Step width variability, but not step length variability or step time variability, discriminates gait of healthy young and older adults during treadmill locomotion.

The variability of spatial and temporal step kinematics have separately been shown to prospectively predict falls by older adults. However, the published literature has not addressed the relative importance of the information related to locomotion control contributed by variability of spatial variables, temporal variables, or both. We conducted a post hoc analysis to determine the extent to which the variability of spatial and temporal step kinematics are independent descriptors of locomotion control in healthy young and older adults. A second purpose of the analysis was to establish the extent to which treadmill walking mimics overground walking using a benchmark for step kinematics. Eighteen young adults and 12 older adults walked at a self-selected velocity on an instrumented treadmill from which step length variability, step width variability and step time variability were computed. Stepwise discriminant analysis correctly classified group membership of 70 percent of the 30 subjects (i.e., young or older adult) using only step width variability (p=0.037, Wilk's lamda=0.854). Step width variability was 70+/-57 percent larger than step length variability (p<0.001). This relationship was similar to that of the benchmark established for overground locomotion. The results suggest that for healthy younger and older adults step width variability is a more meaningful descriptor of locomotion control than step length variability and step time variability. Given the potential clinical impact, further systematic study and improvement of the methods and technology for acquiring step kinematic data are warranted.

Adult↗
PubMedDate not supplied

Stress in adult students with schizophrenia in a supported education program.

The successful integration of former psychiatric inpatients into the community requires innovative programs of psychosocial rehabilitation, including supported education. This article examines psychological distress as an outcome variable, and social support and coping strategies as mediating variables among 70 service-user students (SUS) with schizophrenia and a comparison group of 55 adult students (AS) with no psychiatric diagnosis. Both groups were participants in a supported education program. The study variables were assessed by standardized research instruments: the Talbieh Brief Distress Inventory (TBDI), the Multidimensional Scale of Perceived Social Support (MSPSS), and the Coping Inventory for Stressful Situations (CISS). Univariate and multivariate analyses were used. Compared with the control subjects, SUS reported higher emotional distress and the utilization of emotion-oriented coping strategies, and a lesser availability of social support from family and friends. These variables explained 46.3%, 24.5%, and 22.5%, respectively, of the total variance in psychological distress scores. The findings provide the basis for interventions geared to reduce distress and, as a result, to enable students with severe mental illness to fully utilize the supported education program.

Adaptation, Psychological↗
PubMed2001

The design and assessment of questionnaires in clinical research.

Questionnaires are one of the most commonly used tools for data collection in clinical research. Despite its simplicity and convenience of use, the design of questionnaire instruments that accurately measure health status and their determinants is nevertheless a difficult and challenging task.We review the two most important issues which are reliability and validity. Reliability can be defined as the degree to which a measure gives 'consistent' or 'reproducible' values when applied in different situations. Validity refers to the extent in which the true value of a variable is correctly measured by the instrument. For different types of questionnaire measurement instruments, specific issues of content, construct and criterion validity should be appropriately addressed. Accuracy in questionnaire-based measurement in clinical studies is achieved by paying attention to the relevant specific issues of reliability and validity during development and testing of such questionnaires.

Reproducibility of Results↗
PubMed1998

Comparison between two devices for measuring hip joint motions.

OBJECTIVE: To compare the reliability of measurements of hip motions obtained with two instruments, an electronic inclinometer and a two-arm goniometer, and to investigate whether the two instruments, and different body positions, produce the same measurement data. METHODS: Maximal active and passive hip movements were measured simultaneously with both instruments, in nine subjects during 10 consecutive measurements at short intervals. RESULTS: Intra-observer variability was lower with the inclinometer in measurements of passive hip rotations. The two instruments showed equal intra-observer variability for hip movements in general. The inclinometer showed lower inter-observer variability in the measurements of active internal rotation. More rotational movement was measured with the two-arm goniometer; more extension and flexion with the inclinometer. Also, more rotational movement was found in the prone position compared to sitting and supine positions. CONCLUSIONS: The inclinometer is more reliable in measurements of hip rotation. For hip movements in general the two-arm goniometer is just as accurate when used by only one observer. The two instruments, and some positions, are not interchangeable during consecutive measurements.

Adult↗
PubMedDate not supplied

[Prevalence and factors associated with suicidal thinking among university students].

OBJECTIVES: To quantify the prevalence of suicidal ideation in a population of university students, to characterize groups in connection with ideation and suicidal behavior, and to determine the variables associated with suicidal ideation and suicide attempts. METHODS: Observational, analytic and cross-sectional study of a probabilistic sample of the population studied. An instrument for measuring suicide risk and associated variables was applied to this sample. RESULTS: The prevalence of the current suicidal ideation was 3.6%, and 18% in the last year. Both suicidal ideation and history of suicide attempts were higher among female students. Rape history, being alone more than eight hours a day, and female gender were the factors more strongly related to suicidal ideation. A relationship suicidal ideation and awareness of the suicide of others was not found in this sample. CONCLUSION: A history of rape, remaining alone for more than eight hours during the day, and being a woman should alert the clinician about the possibility of suicidal ideation. It is recommended to explore and assess suicidal ideation in all people with these factors.

Adolescent↗