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PubMed1978

The epidemiology of depressive disorder.

The concept of depression is reviewed. Depression is defined as a syndrome and thus involves particularly subjective decisions by the diagnostician. The conceptual difficulties which arise from this are outlined. The rate of risk is reviewed, using both studies of treated cases and community interview surveys. The study of treated rates tells more of the variables affecting the process of declaration than of depression. It is proposed that case-finding has the prerequisite of precise case-definition with a standardized instrument. Only then can comparability be reached. The effect sociodemographic variables on rates of risk is analysed: it is concluded that they do not account for much of the variance because they are at best gross measures. The role of life events is assessed and it is argued that only by the study of their possible interactions with other factors will an adequate causal explanation of depression be achieved. The usefulness of this as a validation of the concept of depression is emphasized. In this paper we shall firstly look at how concepts of depression affect the process of arriving at a diagnosis and secondly at policies of case finding. We are then in a position to survey critically the findings of epidemiology in the study of depression. Finally, we will review work which throws light on the social causation of depression with the emphasis on recent developments.

Age Factors↗
PubMed1991

[The consistency and validity of a measurement in clinical pediatric research. Its definition, evaluation and interpretation].

In clinical pediatric research as in all research, one of the fundamental characteristics is the measurement of the studied features, either clinical, of laboratory or cabinet. A measurement must have two fundamental characteristics, for it to be considered as scientific: consistency and validity. The first one is centered on the variability of the measurement, which is due to the measuring instrument, to the subject or entity which is measured and to the individual or individuals who carry out the measuring, this is known as intra or interobserver variability, respectively. Validity is the fact of "actually" measuring what we want to measure. Both characteristics of measurement, are often mixed, between them and with other concepts, and this is the reason of not having a clear idea of what is the real meaning. This paper discusses the different terms that have been used for consistency and validity of a measurement. Also it points out how to assess consistency, from the validity, taking into account the measuring scale of the variables and the number of observers. Easy examples are used for the application of different formulas and for the interpretation of the results.

Pediatrics↗
PubMed1999

Financial efficacy of clinical assessment: rational guidelines and issues for future research.

Whereas the financial efficacy of assessment has been well documented in industrial/organizational settings, there is no comparable literature within the field of clinical assessment. This has become a significant issue due to the increasing cost-consciousness of managed health care organizations. A rational means of increasing the financial efficacy of assessment is outlined, which includes the following: (a) focus on domains most relevant to treatment planning and outcome; (b) use formal assessment for risk management; (c) target problems most likely to result in cost savings (i.e., dissociation, somatization, panic); (d) increase the use of computer-assisted assessment; (e) use time-efficient instruments; (f) more closely link assessment, feedback, and therapy; and (g) integrate treatment planning, monitoring progress, and evaluating outcome. Issues and strategies for developing a research program include clearly defining what should be considered a cost, enumerating possible outcome variables, optimal follow-up time frame, selection of instruments, and the function of assessment.

Cost-Benefit Analysis↗
PubMed1984

The relationship of instrument parameters to performance within a survey peer group.

Using simulators of transmission imaging, an interlaboratory survey assessed the discriminatory performance of 86 subscribers, each of whom imaged a liver phantom in anterior and right lateral projections. Analysis was by receiver operating characteristic (ROC) with Az, the area under the ROC curve, used as a measure of accuracy unconfounded by decision bias. Az values were then defined as the dependent variable in a statistical model that related performance to several instrument design and operating parameters. Six of 14 postulated parameters explained approximately half of observed subscriber variability. These were: year of camera manufacture or upgrade, number of photomultiplier tubes, collimator type, total counts collected, use of a Co-57 disk source for imaging the phantom, and computer processing of the image. The findings confirm previous inferences drawn from controlled intralaboratory experimentation, but hitherto unsubstantiated by clinical imaging data.

Humans↗
PubMed2004

Measuring symptom response to pharmacological interventions in patients with COPD: a review of instruments used in clinical trials.

OBJECTIVES: To identify and evaluate the instruments used to measure the effect of pharmacological intervention on symptoms of chronic obstructive pulmonary disease (COPD) in clinical trials. DESIGN: An extensive literature search was conducted for articles published in English in a peer-reviewed journal from 1995 to March 2002 which described a randomised controlled clinical trial measuring symptoms of COPD in response to pharmacological interventions. PATIENTS: Patients with any severity of COPD. INTERVENTIONS: Any pharmacological intervention for treatment of COPD. MEASUREMENTS AND RESULTS: A total of 43 eligible articles were identified. The individual symptoms most frequently measured were dyspnoea/breathlessness, chest tightness or discomfort and exacerbations. There was considerable variability in the methods, terminology and symptom measurement instruments used. The most widely used instruments for measuring dyspnoea were the Borg scale, the Baseline Dyspnoea Index and the Transitional Dyspnoea Index. None of the instruments used had published evidence of rigorous psychometric testing. CONCLUSIONS: Numerous methods have been employed to assess the symptoms of COPD in clinical trials, making it difficult to compare the results of different trials. No single measurement instrument predominates, and none of the measures identified in the review have undergone rigorous psychometric testing in this patient population. There is a clear need for a fully developed and validated tool for measuring the effects of therapeutic interventions on symptoms in COPD in clinical trials.

Dyspnea↗
PubMed1990

Comparison of measurement variability using a standard and constant force periodontal probe.

This study compared the intra- and inter-examiner reliability of the Florida Probe, Florida Disk Probe, and conventional periodontal probe. Using these instruments, each of three examiners made repeated measurements of probing depth (using the Florida Probe and conventional probe), relative attachment level (using the Florida Disk Probe), and clinical attachment level (using a conventional probe) at posterior, proximal sites in 10 subjects with early periodontitis. The mean intra-examiner standard deviation of differences in repeated probing depth measurements ranged from 0.46 to 0.77 mm demonstrating similar levels of reproducibility between the Florida Probe and conventional probe. The mean intra-examiner standard deviation of differences in repeated relative attachment level measurements using the Florida Disk Probe ranged from 0.44 to 0.57 mm using double passes and from 0.98 to 1.41 mm using single passes of measurements. For clinical attachment level measurements obtained using single passes of measurements with a conventional probe, the mean intra-examiner standard deviation of differences ranged from 0.78 to 0.95 mm. Inter-examiner variability was generally greater than intra-examiner variability for all instruments. It was concluded that double passes with the Florida Disk Probe offers significant advantages for measuring relative attachment level in longitudinal studies of early periodontitis when decisions for change must be made as soon as possible.

Bias↗
PubMed2002

Race: predictor versus proxy variable? Outcomes after spinal cord injury.

OBJECTIVE: To examine the impact of race on acute, rehabilitation, and long-term outcomes after spinal cord injury (SCI). DESIGN: Two case control studies (study 1: acute and rehabilitation outcomes, study 2: long-term outcomes) in which white and nonwhite individuals were matched case for case on multiple demographic, medical, and geographic characteristics with the rationale being that a case-control methodology would increase the internal validity of the design, thereby increasing confidence in the assertion that any between-group differences observed may be specifically attributed to race. SETTING: Data drawn from the Spinal Cord Injury Model Systems. Institutional practice and general community. PARTICIPANTS: Study 1: 187 pairs of individuals, study 2: 158 pairs of matched individuals. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Outcome measures assessed included economic (eg, cost of care), treatment-related (eg, length of hospital stay), functional (eg, FIM instrument), and medical (eg, number of medical complications) variables, as well as self-reported life satisfaction, level of handicap, and mental and physical health. RESULTS: In study 1, none of the outcome measures differed significantly across racial groups. Similarly, study 2 failed to indicate significant differences in any of the outcome variables across racial groups, with the exception that nonwhites were at increased risk of greater self-reported handicap in the area of mobility. Power analyses indicated these finding were not merely the result of inadequate power. CONCLUSION: For the outcomes assessed in studies 1 and 2, race appeared to act primarily as a proxy for other variables (eg, injury severity, age, educational achievement), which in turn may be associated with poor outcome after SCI. Theoretical implications and recommendations are discussed.

Activities of Daily Living↗
PubMed1999

Predictive factors for cholelithiasis complications.

BACKGROUND: Cholelithiasis is a benign disease that is very frequently encountered throughout the world. Its surgical mortality is usually minimal (0.1%), but the risk is considerably greater (2-10%) in patients developing complications particularly if they are elderly. The identification of possible predictive signs of complications is therefore crucial for the indication of preventive surgery. METHODS: The present study retrospectively examined 490 patients admitted to hospital because of complicated and uncomplicated cholelithiasis in order to establish the existence of previous (clinical or instrumental) symptoms that may be predictive of the course of the disease. The analysis of some variables (age, sex, pregnancy, diet, ethanol consumption, smoking, previous/concomitant diseases, and blood chemistry and instrumental test results) and the specific symptoms of cholelithiasis made it possible to identify two potential risk factors: an age of more than 60 years and the onset of biliary colic. RESULTS: The risk of developing complications is 3.2 times greater in patients aged more than 60 years than in those who are younger, and 3.3 times greater in symptomatic than in asymptomatic patients. Statistical analysis also revealed that the risk of complications is about ten times greater in patients with both risk factors than in those with neither. CONCLUSIONS: In conclusion, the indication for surgery must be considered absolute in symptomatic patients aged more than 60 years and relative to younger symptomatic patients.

Adolescent↗
PubMed2001

Clinical and radiological amelioration of refractory peripheral spondyloarthritis by pulse intravenous pamidronate therapy.

OBJECTIVE: To examine the potential therapeutic properties of an aminobisphosphonate, pamidronate, using clinical and laboratory outcome variables together with dynamic magnetic resonance imaging (MRI) and gadolinium augmentation in patients with spondyloarthropathy (SpA) refractory to nonsteroidal antiinflammatory drugs (NSAID). METHODS: We studied 9 patients (7 male, 2 female) of mean age 27.9 years (range 19-38) and mean disease duration of 5.5 years (range 0.5-20). Five had ankylosing spondylitis (AS), 3 had undifferentiated SpA, and one had reactive arthritis. Seven were HLA-B27 positive. Two had inflammatory bowel disease. Pamidronate (60 mg) was given intravenously on Days 1, 2, 14, 28, and 56, over 4 h in 500 ml of 5% dextrose. Clinical outcome assessments included the BASDAI (disease activity), BASFI (function), BASGI (global well being) composite visual analog instruments, and swollen and tender joint count. Laboratory variables included the erthrocyte sedimentation rate (ESR) and C-reactive protein (CRP). Dynamic MRI with gadolinium augmentation of synovium and bone was performed at baseline and at Day 84 in the first 6 patients enrolled in the study. RESULTS: All patients completed the study and there was a significant improvement in all clinical and laboratory variables assessed. Mean swollen and tender joint count decreased by 93.8% (p = 0.017) and 98.2% (p = 0.012), respectively, and complete clinical resolution of synovitis was noted in 5 patients. BASDAI decreased by 44.2% (p = 0.028), BASFI by 47.3% (p = 0.015), and BASGI by 42.2% (p = 0.011). ESR and CRP declined by 49.4% (p = 0.012) and 66.9% (p = 0.008), respectively. Acute lymphopenia accompanied by elevated CRP levels was noted in 8 patients in the 48 h after first pamidronate infusion. Maximal rate and magnitude of enhanced MRI signal after gadolinium augmentation decreased after pamidronate therapy, especially in the bone marrow. CONCLUSION: Preliminary data from uncontrolled studies support the efficacy of pamidronate therapy for NSAID refractory SpA and warrant further evaluation in controlled trials.

Adult↗
PubMedDate not supplied

Concordance of cancer patient and caregiver symptom reports.

PURPOSE: This study investigated whether family caregiver reports of cancer patients' symptoms (specifically: nausea, pain, poor appetite, insomnia, fatigue, cough, constipation, and diarrhea) were in concordance with patient reports, and whether variables such as patient depression, caregiver depression, caregiver optimism, and perceived impact of caring on caregiver health would explain discrepancies in patients' and caregivers' reports. DESCRIPTION OF STUDY: A sample of 216 patients and their family caregivers was recruited through six community-based cancer treatment centers located in lower Michigan. Data on the study variables were obtained from two separate, multifaceted survey instruments completed by the patients and their family caregivers, respectively. RESULTS: The rate of agreement between patient and caregiver was highest for fatigue and lowest for insomnia, whether the entire sample, male caregivers, or female caregivers were considered. Female caregivers had a higher percentage agreement with their patients, and a higher level of association between patient and caregiver responses than male caregivers, uniformly for all symptoms. The overall accuracy of caregiver reports was approximately 71% and seemed to be relatively independent of the number of symptoms reported by the patient. CLINICAL IMPLICATIONS: Health professionals caring for patients with cancer must recognize that patient and caregiver reports of patient symptoms may not always be in agreement. Awareness of variables that may cloud family caregivers' observations is needed, so that accurate symptom reporting occurs, and appropriate management can be initiated to enhance quality of life for the patient as much as possible. It is also important for health professionals to educate family caregivers about the nuances of symptom distress presentation and to teach caregivers techniques to elicit accurate information so that timely, appropriate palliative management can be initiated.

Aged↗
PubMed2002

Development of questionnaires to measure physical activity cognitions among Taiwanese adolescents.

BACKGROUND: Although a number of studies have investigated perceived self-efficacy, perceived benefits, and perceived barriers and their relationship to adolescents' participation in physical activity, the validity and reliability of the instruments used have not been consistently examined. The purpose of the present study was to develop culturally sensitive, reliable, and valid instruments to measure physical activity cognitions among Taiwanese adolescents. METHODS: The items generated for the instruments were drawn from a comprehensive literature review and a focus group interview. The instruments were translated using the back-translation technique and evaluated by a panel of experts. Psychometric testing was performed and confirmed with convenience samples of 110 and 969 Taiwanese adolescents. RESULTS: Psychometric testing demonstrated satisfactory internal consistency and validity of the instrument for this group of Taiwanese adolescents. Cronbach's alpha's ranged from 0.79 to 0.90. Construct validity was supported by exploring the factor structure of the instrument using confirmatory factor analysis and correlation with the outcome variable of physical activity. CONCLUSIONS: The study identified culturally sensitive items to measure physical activity cognitions in urban Taiwanese students in their early adolescence. Clinicians or practitioners can use the instruments developed and tested in this study for clinical assessment to identify risk factors for inactivity as well as for further research in similar populations.

Adolescent↗
PubMed2005

Risk-adjusted analysis of early mortality after ruptured abdominal aortic aneurysm repair.

PURPOSE: Ruptured abdominal aortic aneurysms (RAAAs) continue to result in early mortality in up to 50% of patients. Additionally, it remains difficult to compare outcomes given the variability in patient comorbidities and presentation. The purpose of this study was to describe an instrument that permits the prospective analysis of outcomes after RAAA repair while adjusting for the variability in preoperative risk. METHODS: Consecutive patients undergoing attempted open RAAA repair over a 5-year period (1999 to 2003) at our center were reviewed. Thirty-day or in-hospital mortality was the main outcome variable. Preoperative mortality risk was estimated for each patient by using a validated modification of the POSSUM scoring system (V-POSSUM). A risk-adjusted cumulative sum method (RA-CUSUM) was used to compare observed versus predicted outcomes by assigning a risk-adjusted score, based on log-likelihood ratios, to each patient. These scores were sequentially plotted with preset control limits to allow for "signaling" when results were substantially different from expected (doubling or halving of odds ratios). RESULTS: A total of 136 patients were reviewed, with an early mortality rate of 45.6%. V-POSSUM scores were accurate in predicting mortality for the entire cohort, with an observed-to-predicted mortality ratio of 0.92 (P = .80). Each patient's risk-adjusted score was plotted sequentially. In one segment of the resulting plot, the graph adopted a negative slope and crossed the lower control limit, indicating improved results compared with predicted. CONCLUSIONS: V-POSSUM scores in this series accurately predicted early mortality after RAAA surgery. The RA-CUSUM method allows for the prospective evaluation of outcomes, while taking into account patient variability. In the current study, this resulted in the identification of a series of patients who had improved outcomes compared with predicted.

Adult↗
PubMed1999

Monitoring respiratory function and sleep in the obese Vietnamese pot-bellied pig.

Development of drug treatments for obstructive sleep-disordered breathing has been impeded by the lack of animal models. The obese pig may be a suitable animal model, as it has been reported to experience sleep-disordered breathing resembling human obstructive sleep apnea. The purpose of this paper is to describe in detail techniques for chronic instrumentation of the obese Vietnamese pot-bellied pig and to study respiratory function during sleep. Under general anesthesia, four obese pigs were instrumented for long-term recording of intrapleural and tracheal pressures, genioglossal EMG, and bioelectric signals related to sleep. A custom-fitted face mask was used to record respiratory variables including airflow, snoring, and expired CO(2). Most chronic instrumentation provided robust signals for up to 6 wk after installation. All pigs displayed sleep-disordered breathing characterized by increased resistance to airflow, snoring, inspiratory flow limitation, and possible sleep disruption. Apneas and hypopneas were not a feature of breathing during sleep in these animals. Nonetheless, this animal preparation may be useful for exploring possible drug treatments for obstructive sleep-disordered breathing.

Animals↗
PubMed2004

Automated flagging influences the inconsistency and bias of band cell and atypical lymphocyte morphological differentials.

This study evaluated inter- and intra-observer variabilities of band cell and atypical lymphocyte differentials and the influence of instrument flagging information on resulting microscopic differentials. Five stained slides with a range of band cell counts and five with variable numbers of atypical lymphocytes were sent for morphological review by 30 technicians. No supplementary full blood cell count information was provided. Two months later, the same slides were sent, together with their corresponding analyzer reports comprising the full blood cell count, automated differentials and flags, to the same technicians. The first and second appraisals of band cells and variant lymphocytes both showed poor levels of inter-observer consistency. Observed values for all slides were very wide and suggested a high inherent predisposition to erroneous reporting practices. Analysis of category trends showed that analyzer left shift or immature granulocytes flags had no influence on observer band cell assessments as downward vs. upward category revisions were evenly balanced. The findings for atypical lymphocytes were, however, somewhat different. Two slides with no flags both showed balanced category revisions, whereas two of the three slides with atypical lymphocyte flags showed clear evidence of upward category revision. The third slide with an atypical lymphocyte flag did not show any overall category trend, but six of the seven observers who in the first examination recorded atypical lymphocyte estimates of < or = 30% revised their estimates upward when the slides were examined the second time. These results suggest that morphologist access to an analyzer report and flagging information is unlikely to affect the "randomness" of band cell determinations but it may induce observer bias in variant lymphocyte estimates.

Automation↗
PubMed2002

State and chemical drive modulate respiratory variability.

The quantification of respiratory variability may provide insight into the integrative control of breathing. To test the hypothesis that sleep and/or increased chemical drive modifies respiratory variability, six male adult Sprague-Dawley rats were instrumented with diaphragm electromyographic (EMG) electrodes and exposed to 0, 2.5, and 5.0% CO2 with a balance of room air during wakefulness and behaviorally determined sleep. Respiratory interval (Ttot), peak diaphragm EMG, and ventilation index (peak diaphragm EMG/Ttot) were calculated for 1,024 sequential breaths. The variability of breathing was quantified with a measurement of signal complexity, the approximate entropy, and two autocorrelation measurements, the autoregressive power spectrum slope and the detrended fluctuation analysis slope. Elevated chemical drive and/or sleep significantly modulated the variability of ventilation index and Ttot. There were also significant interactions between state and CO2 drive in all respiratory parameters. We conclude that state (sleep or wakefulness) and increased chemical drive affect respiratory variability differentially.

Animals↗
PubMed2003

Relations among asthma knowledge, treatment adherence, and outcome.

BACKGROUND: Asthma knowledge is frequently assumed to be a prerequisite for optimal asthma treatment. However, the validity of existing asthma knowledge questionnaires has not been rigorously examined, and no contemporary measure of asthma knowledge has received widespread acceptance. OBJECTIVE: To construct and examine the psychometric properties of an asthma knowledge instrument, and its association with demographic and psychosocial variables, asthma medication adherence, and treatment outcome. METHODS: A 25-item Asthma Knowledge Questionnaire was developed with input from national pediatric asthma experts. Parents of 155 children with asthma completed the Asthma Knowledge Questionnaire as well as demographic, family functioning, and home environment measures. Asthma outcomes and adherence with inhaled medication was measured across 12 months. RESULTS: Despite the many steps taken to develop a strong measure of asthma knowledge, reliability was relatively poor. There was also no association between asthma knowledge and treatment adherence or outcomes. Furthermore, asthma knowledge was not a unidimensional construct and was not a simple function of education. CONCLUSIONS: Findings from this study, in combination with previous studies of asthma knowledge questionnaires, suggest that the construction of a simple self-report asthma knowledge instrument for use as a primary outcome measure demonstrating mastery of asthma self-management skills may not be achievable.

Adolescent↗
PubMed1991

The structure of disfluency behaviors in the speech of adult stutterers.

Throughout the stuttering literature numerous references to a twofold classification of disfluency types are found. However, no rigorous empirical test of that dichotomous classification has been reported in the literature. This investigation was designed to conduct such a test in order to provide an empirical foundation for that distinction. The hypotheses stated that the relationships among disfluency behaviors were consistent with an underlying two-dimensional structure and specified the group of variables (disfluency behaviors) having primary association with each dimension. Instrumentation and procedures permitting reliable identification and coding of nine disfluency behaviors were developed. This observational system was applied to baseline monologues obtained from 180 adult stutterers. Results of factor analyses supported the hypotheses on the two-factor structure and on the disposition of the disfluency variables.

Adult↗
PubMedDate not supplied

Issues associated with measuring symptom status: HIV/AIDS case illustration.

The purpose of this article is to illustrate issues associated with measuring one aspect of health, symptom status, through a comparison of two specific symptom scales developed for use with persons with HIV/AIDS. A number of decisions are necessary to evaluate the appropriateness of different health measurement instruments. These include: whether the purpose is to evaluate a program of care or to study individual patients; characteristics that are being assessed; the time frame being assessed; how broad-ranging an assessment is desired; and the scope of detail that is desired. This descriptive survey with a HIV+ sample (N = 100) found that there were 8 items that assessed identical symptoms on the Sign and Symptom Checklist-HIV and the HIV Assessment Tool. There were no significant correlations between similar items on the two instruments. There were significant differences between the mean scores only for headaches (t = -3.4, p = .001). Issues related to symptom appraisal, the time frame, and the nature of symptom-related variables need to be carefully considered before choosing a measurement instrument.

Adult↗