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PubMed2002

Trunk control as an early predictor of comprehensive activities of daily living function in stroke patients.

BACKGROUND AND PURPOSE: Prediction of activities of daily living (ADL) functions at an early stage after a stroke is critical because it enables clinicians to set treatment programs and goals. The objective of this study was to assess the relationship between trunk control at an early stage and comprehensive ADL function (as assessed by combining basic ADL and instrumental ADL [IADL]) in patients at 6 months after stroke. METHODS: A total of 169 stroke patients participated in this prospective study. Trunk control was measured with the use of the trunk control items of the Postural Assessment Scale for Stroke Patients (PASS-TC). In addition to the PASS-TC score, age, sex, type of stroke, side of hemiparesis, urinary incontinence, limb paresis (measured by the Fugl-Meyer motor test), balance (measured by the Fugl-Meyer balance test), and basic ADL (measured by the Barthel Index) were also selected as predictor variables. These variables were assessed at 14 days after stroke or earlier. The Barthel Index and Frenchay Activities Index (measuring IADL) were administered at 6 months after stroke. The sum of the standardized Barthel Index and standardized Frenchay Activities Index scores was used to assess comprehensive ADL function. RESULTS: Multivariable stepwise linear regression analysis showed that PASS-TC score, age, Fugl-Meyer motor test score, and Barthel Index score (listed by the order of forward selection) were the strongest predictors of comprehensive ADL function. These results were internally validated with the use of the bootstrap resampling technique. The PASS-TC score alone accounted for 45% of the variance in predicting comprehensive ADL function. Results also indicated that the PASS-TC score had slightly more power in predicting comprehensive ADL function than either the Fugl-Meyer motor test score or Barthel Index score. CONCLUSIONS: The findings of this study provide strong evidence of the predictive value of trunk control on comprehensive ADL function in stroke patients. The results imply that early assessment and management of trunk control after stroke should be emphasized.

Abdomen↗

PubMed2006

The stroke-thrombolytic predictive instrument: a predictive instrument for intravenous thrombolysis in acute ischemic stroke.

BACKGROUND AND PURPOSE: Many patients with ischemic stroke eligible for recombinant tissue plasminogen activator (rt-PA) are not treated in part because of the risks and benefits perceived by treating physicians. Therefore, we aimed to develop a Stroke-Thrombolytic Predictive Instrument (TPI) to aid physicians considering thrombolysis for stroke. METHODS: Using data from 5 major randomized clinical trials (n=2184) testing rt-PA in the 0- to 6-hour window, we developed logistic regression equations using clinical variables as potential predictors of a good outcome (modified Rankin Scale score < or =1) and of a catastrophic outcome (modified Rankin Scale score > or =5), with and without rt-PA. The models were internally validated using bootstrap re-sampling. RESULTS: To predict good outcome, in addition to rt-PA treatment, 7 variables significantly affected prognosis and/or the treatment-effect of rt-PA: age, diabetes, stroke severity, sex, previous stroke, systolic blood pressure, and time from symptom onset. To predict catastrophic outcome, only age, stroke severity, and serum glucose were significant; rt-PA treatment was not. For patients treated within 3 hours, the median predicted probability of a good outcome with rt-PA was 42.9% (interquartile range [IQR]=18.6% to 64.7%) versus 25.3% (IQR=9.8% to 46.2%) without rt-PA; the median predicted absolute benefit was 12.5% (IQR=5.1% to 21.0%). The median probability for a catastrophic outcome, with or without, rt-PA was 15.2% (IQR=8.0% to 31.2%). The area under the receiver-operator characteristic curve was 0.788 for the model predicting good outcome and 0.775 for the model predicting bad outcome. CONCLUSIONS: The Stroke-TPI predicts good and bad functional outcomes with and without thrombolysis. Incorporated into a usable tool, it may assist in decision-making.

Aged↗

PubMed2000

A predictive risk model for outcomes of ischemic stroke.

BACKGROUND AND PURPOSE: The great variability of outcome seen in stroke patients has led to an interest in identifying predictors of outcome. The combination of clinical and imaging variables as predictors of stroke outcome in a multivariable risk adjustment model may be more powerful than either alone. The purpose of this study was to determine the multivariable relationship between infarct volume, 6 clinical variables, and 3-month outcomes in ischemic stroke patients. METHODS: Included in the study were 256 eligible patients from the Randomized Trial of Tirilazad Mesylate in Acute Stroke (RANTTAS). Six clinical variables and 1-week infarct volume were the prespecified predictor variables. The National Institutes of Health Stroke Scale, Barthel Index, and Glasgow Outcome Scale were the outcomes. Multivariable logistic regression techniques were used to develop the model equations, and bootstrap techniques were used for internal validation. Predictive performance of the models was assessed for discrimination with receiver operator characteristic (ROC) curves and for calibration with calibration curves. RESULTS: The predictive models had areas under the ROC curve of 0.79 to 0.88 and demonstrated nearly ideal calibration curves. The areas under the ROC curves were statistically greater (P<0.001) with both clinical and imaging information combined than with either alone for predicting excellent recovery and death or severe disability. CONCLUSIONS: Combined clinical and imaging variables are predictive of 3-month outcome in ischemic stroke patients. Demonstration of this relationship with acute clinical variables and 1-week infarct information supports future attempts to predict 3-month outcome with all acute variables.

Aged↗

PubMed2006

Prediction of coronary heart disease in a population with high prevalence of diabetes and albuminuria: the Strong Heart Study.

BACKGROUND: The present article presents equations for the prediction of coronary heart disease (CHD) in a population with high rates of diabetes and albuminuria, derived from data collected in the Strong Heart Study, a longitudinal study of cardiovascular disease in 13 American Indian tribes and communities in Arizona, North and South Dakota, and Oklahoma. METHODS AND RESULTS: Participants of the Strong Heart Study were examined initially in 1989-1991 and were monitored with additional examinations and mortality and morbidity surveillance. CHD outcome data through December 2001 showed that age, gender, total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein cholesterol, smoking, diabetes, hypertension, and albuminuria were significant CHD risk factors. Hazard ratios for ages 65 to 75 years, hypertension, LDL cholesterol > or = 160 mg/dL, diabetes, and macroalbuminuria were 2.58, 2.01, 2.44, 1.66, and 2.11 in men and 2.03, 1.69, 2.17, 2.26, and 2.69 in women, compared with ages 45 to 54 years, normal blood pressure, LDL cholesterol <100 mg/dL, no diabetes, and no albuminuria. Prediction equations for CHD and a risk calculator were derived by gender with the use of Cox proportional hazards model and the significant risk factors. The equations provided good discrimination ability, as indicated by a c statistic of 0.70 for men and 0.73 for women. Results from bootstrapping methods indicated good internal validation and calibration. CONCLUSIONS: A "risk calculator" has been developed and placed on the Strong Heart Study Web site, which provides predicted risk of CHD in 10 years with input of these risk factors. This may be valuable for diverse populations with high rates of diabetes and albuminuria.

Aged↗

PubMed2006

Bedside tool for predicting the risk of postoperative dialysis in patients undergoing cardiac surgery.

BACKGROUND: Estimation of an individual patient's risk for postoperative dialysis can support informed clinical decision making and patient counseling. METHODS AND RESULTS: To develop a simple bedside risk algorithm for estimating patients' probability for dialysis after cardiac surgery, we evaluated data of 449,524 patients undergoing coronary artery bypass grafting (CABG) and/or valve surgery and enrolled in >600 hospitals participating in the Society of Thoracic Surgeons National Database (2002-2004). Logistic regression was used to identify major predictors of postoperative dialysis. Model coefficients were then converted into an additive risk score and internally validated. The model also was validated in a second sample of 86,009 patients undergoing cardiac surgery from January to June 2005. Postoperative dialysis was needed in 6451 patients after cardiac surgery (1.4%), ranging from 1.1% for isolated CABG procedures to 5.1% for CABG plus mitral valve surgery. Multivariable analysis identified preoperative serum creatinine, age, race, type of surgery (CABG plus valve or valve only versus CABG only), diabetes, shock, New York Heart Association class, lung disease, recent myocardial infarction, and prior cardiovascular surgery to be associated with need for postoperative dialysis (c statistic=0.83). The risk score accurately differentiated patients' need for postoperative dialysis across a broad risk spectrum and performed well in patients undergoing isolated CABG, off-pump CABG, isolated aortic valve surgery, aortic valve surgery plus CABG, isolated mitral valve surgery, and mitral valve surgery plus CABG (c statistic=0.83, 0.85, 0.81, 0.75, 0.80, and 0.75, respectively). CONCLUSIONS: Our study identifies the major patient risk factors for postoperative dialysis after cardiac surgery. These risk factors have been converted into a simple, accurate bedside risk tool. This tool should facilitate improved clinician-patient discussions about risks of postoperative dialysis.

Aged↗

PubMed2004

An assessment of self-reported disease classification in epidemiological studies of dry eye.

PURPOSE: To evaluate the reliability of self-reported dry eye disease status and patient-related predictors of misclassification in contact lens wearers. METHODS: Patients completed the Contact Lens Dry Eye Questionnaire (CLDEQ) short form on two occasions. Test-retest reliability of the CLDEQ composite score was determined using the 95% limits of agreement (LoA) and an intraclass correlation coefficient (ICC). The kappa statistic was used to determine reliability of disease-classification-based CLDEQ composite score cutoff points. Predictors of misclassification were determined by multivariate logistic regression. RESULTS: The sample included 274 patients. The range of CLDEQ composite scores from both visits was -1.83 to 4.50 and the mean difference between administrations was -0.05 +/- 0.75 (P = 0.30). The 95% LoA of the CLDEQ composite score were -1.51 to 1.42 and the ICC was 0.61 (95% confidence interval [CI]: 0.53-0.68). Calculations using the lower limit of the 95% CI showed that three administrations of the survey would be required to obtain a more desirable ICC (0.70). The kappa statistic for reliability of dry eye disease classification was 0.58 (95% CI: 0.48-0.67). Logistic regression showed a significant interaction between gender (females) and younger age (P = 0.02) in relation to misclassification of self-reported dry eye disease status. CONCLUSIONS: The reliability of self-reported dry eye disease classification in contact lens wearers is moderate. In epidemiologic studies of factors associated with self-reported disease status, investigators may be well advised to consider using multiple administers of such outcome instruments and controlling for sociodemographic characteristics to maintain internal validity.

Adult↗

PubMed1981

Overview: deinstitutionalization of psychiatric patients, a critical review of outcome studies.

The authors performed a critical review of experimental studies on the outcomes for psychiatric patients of 1) alternatives to hospital admission, 2) modifications of conventional hospitalization, and 3) alternatives to continued long-term hospitalization. The internal validity of many of the studies was compromised by shortcomings in design and performance and generalizability limited by selection of patient populations. With these qualifications experimental alternatives to hospital care of patients have led to psychiatric outcomes not different from and occasionally superior to those of patients in control groups. This conclusion is best supported for alternatives to admission and for modifications of conventional hospitalization. The available studies do not permit firm conclusions regarding alternatives to continued long-term hospitalization of chronically ill patients or for a critical analysis of the optimal management of specific subpopulations of psychiatric patients. Satisfactory deinstitutionalization appears to depend on the availability of appropriate programs for care in the community.

Adult↗

PubMed2000

Cost-effectiveness of services for mentally ill homeless people: the application of research to policy and practice.

OBJECTIVE: About one-quarter of homeless Americans have serious mental illnesses. This review synthesizes research findings on the cost-effectiveness of services for this population and their relevance for policy and practice. METHOD: Service interventions for seriously mentally ill homeless people were grouped into three overlapping categories: 1) outreach, 2) case management, and 3) housing placement and transition to mainstream services. Data were reviewed both from experimental studies with high internal validity and from observational studies, which better reflect typical community practice. RESULTS: In most studies, specialized interventions are associated with significantly improved outcomes, most consistently in the housing domain, but also in mental health status and quality of life. These programs are also associated with increased use of many types of health service and housing assistance, resulting in increased costs in most cases. The value of these programs to the public thus depends on whether their greater effectiveness is deemed to be worth their additional cost. CONCLUSIONS: Innovative programs for seriously mentally ill homeless people are effective and are also likely to increase costs in many cases. Their value ultimately depends on the moral and political value society places on caring for its least-well-off members.

Ambulatory Care↗

PubMedDate not supplied

Diagnostic criteria for psychosomatic research and psychosocial variables in breast cancer patients.

The aim of the study was to examine the relationship of the Diagnostic Criteria for Psychosomatic Research (DCPR) with psychosocial variables and quality of life among cancer patients. Of 105 women with breast cancer who participated in the study, 40 (38.1%) had symptoms meeting the criteria for at least one DCPR syndrome, and 30 (28.6%) had more than one DCPR syndrome. Health anxiety, demoralization, and alexithymia were the most frequent DCPR syndromes. Patients who were diagnosed with DCPR syndromes reported higher levels of cancer-related worries and poorer quality of life than those without a DCPR diagnosis. Analysis of the single DCPR clusters and coping with cancer indicated that health anxiety was related to higher scores on the Mini-Mental Adjustment to Cancer (Mini-MAC) anxious preoccupation subscale, DCPR demoralization was related to higher scores on the Mini-MAC hopelessness subscale, and DCPR alexithymia was related to higher scores on the Mini-MAC avoidance subscale. The study indicates the usefulness of the application of the DCPR in breast cancer, although further research is needed to improve the feasibility and internal validity of DCPR constructs.

Anxiety↗

PubMed2003

Adherence to research protocols in a clinical context: challenges and recommendations from behavioral intervention trials.

Conducting clinical interventions in a research setting poses numerous challenges to clinicians, researchers, supervisors, and research participants. These issues often reflect a tension between the rigorous demands of a research protocol needed to ensure internal validity of the research and clinical flexibility that is representative of an externally valid intervention. In this paper, we explore difficulties in defining the roles of clinicians and research participants, delineating the scope of the intervention, and problems encountered at the intersection of clinical intervention delivery and such methodological techniques as randomization, blinding, and incentive payments. We provide guidance for setting frames for the intervention and clinical relationship, conducting training and supervision of clinical staff, and structuring quality-assurance procedures in order to meet these challenges.

Biomedical Research↗

PubMedDate not supplied

A meta-analysis of single-subject-design intervention research for students with LD.

This article summarizes single-subject-design intervention studies that include students with learning disabilities. Effect sizes of 85 studies were analyzed across instructional domains (e.g., reading, mathematics); sample characteristics (e.g., age, intelligence); intervention parameters (e.g., number of instructional sessions, instructional components); and methodological procedures (e.g., internal validity, treatment integrity, sample representation). The major findings were as follows: (a) All domain areas except handwriting yielded effect sizes at or above Cohen's .80 threshold for a substantial finding; (b) instructional components related to drill-repetition-practice-review, segmentation, small interactive groups, and the implementation of cues to use strategies contributed significant variance (15%) to estimates of effect size; (c) strategy instruction (SI) models better predicted effect size estimates than direct instruction (DI) models when the results were qualified by the reported intellectual and reading levels of the participants; (d) high-IQ discrepancy groups yielded lower effect sizes compared to low-IQ discrepancy groups in the domain of reading, whereas the reverse effect occurred when treatment outcomes were not reading measures; and (e) the low-IQ discrepancy groups yielded higher effect sizes for a Combined DI and SI Model when compared to competing models. The results are supportive of the pervasive influence of cognitive strategy and direct instruction models across treatment domains and of the notion that variations in sample definition moderate treatment outcomes.

Child↗

PubMed2006

A multilevel approach to the relationship between birth order and intelligence.

Many studies show relationships between birth order and intelligence but use cross-sectional designs or manifest other threats to internal validity. Multilevel analyses with a control variable show that when these threats are removed, two major results emerge: (a) birth order has no significant influence on children's intelligence and (b) earlier reported birth order effects on intelligence are attributable to factors that vary between, not within, families. Analyses on 7- to 8 - and 13- to 14-year-old children from the National Longitudinal Survey of Youth support these conclusions. When hierarchical data structures, age variance of children, and within-family versus between-family variance sources are taken into account, previous research is seen in a new light.

Adolescent↗

PubMed1984

Carry-over of medical information system influence to control patients.

Evaluations of medical information systems (MIS) often compare one or more dependent variables between experimental patients having the MIS available and control patients. Typically, physicians who are exposed to and therefore are potentially influenced by the MIS during visits with experimental patients also see control patients, thus possibly weakening the internal validity of subsequent comparisons between the MIS and the control conditions. The present study examines the possible bias due to carry-over of MIS influence to control patients in the context of a prospective, randomized design.

Diagnostic Tests, Routine↗

PubMedDate not supplied

The relevance of searching for effects under a clinical-trial lamppost: a key issue.

In economic evaluations of new medical technologies, analysts often need to use data from randomized controlled trials. Trials are designed to achieve high internal validity; however, their selected populations and often highly artificial environments may imply low external validity. Thus, the use of trial data in an economic evaluation may bias the results, since economic evaluation is concerned not with theoretical capability in a trial but with likely performance in the practice environment. This paper indicates both the probable bias of one aspect of artificiality in the trial environment--selected populations--and a method of adjusting the analysis so that results will be more likely to reflect actual practice. The judicious use of extra-trial information can be used to correct the biases of clinical trials.

Antibodies, Monoclonal↗

PubMedDate not supplied

Willingness to pay for reductions in angina pectoris attacks.

To compare the costs of health care programs, with the benefits, the values of changes in health status must be expressed in monetary terms. The development of methods to estimate willingness to pay for changes in health status is therefore of interest. This paper reports the results of a contingent valuation study measuring willingness to pay for reductions in angina pectoris attacks. An innovative study design allowed analysis on the data on willingness to pay using two approaches, a binary question and a bidding-game technique. Percentage reductions in anginal attacks were varied randomly in different subsamples, and data were collected about angina pectoris status, attack rate, and income to test the internal validity of the contingent valuation method. Willingness to pay for a 50% reduction in the attack rate for three months was estimated to be about SEK 2,500 ($345) with the binary approach, and about SEK 2,100 ($290) using the bidding-game technique. Regression analyses showed that income, angina pectoris status, attack rate, and percentage reduction in attack rate were all related to willingness to pay, in agreement with the authors' hypothesis.

Aged↗

PubMed2005

ThOMAs: the other means of assessment.

We describe a pilot study to investigate whether drawing "Thomas the Tank Engine" could be as effective a measure of developmental progress as the Goodenough-Harris Draw A Man test against the ThOMAs test (The Other Means of Assessment), with internal validation. The study included 95 children aged between 3 and 11 years of age, including a subgroup of 13 children with registered special needs from community and general pediatric clinics within Birmingham, UK, as a means of validation. There was no significant evidence that ThOMAS was either culturally or sex biased. Using regression analysis, nine items were found to correlate highly with actual age, and their total score gave a correlation of 0.563 with age. Adding further items did not increase this. After being converted into age-standardized scores, ThOMAS was as sensitive and specific as the Draw A Man test, and more so above a defined age-standardized threshold. This pilot study suggests that drawing Thomas the Tank Engine would appear to be as sensitive and specific a means of identifying children with special needs as the Goodenough-Harris Draw A Man test. The relatively small sample size means that further research is necessary to further define the age standardizations and to refine the ThOMAs test.

Age Factors↗

PubMed1995

In situ caries models.

By using in situ models, we have the potential to study both fundamental aspects of the caries process as well as more applied research problems such as the effect of food on dental caries and the role of fluoride in caries prevention in human subjects without actually causing caries in the natural dentition. The key experimental parameters that need to be considered in the development of an in situ model are the characteristics of the subject panel, the physical design of the model, the type of hard tissue substrate and the method of assessing mineral status, and the study design and clinical protocol. Each parameter must be carefully considered in relation to the objectives of the research, study design requirements, ethical considerations, impact on clinical relevance, and impact on the control of variation. The major source of variation associated with in situ models should be of biological and not experimental origin. The design and conduct of proper in situ model studies require a clear understanding of the caries process, sound analytical support, and a knowledge of how to work with research subjects to achieve a high level of compliance. Given the complex nature of caries, a combination of hard tissue substrates--including sound, surface-softened lesions and subsurface lesions--may be necessary to model all aspects of caries progression and prevention successfully. Internal validation of in situ models using fluoride dose-response controls is considered to be necessary for studies evaluating the efficacy of new fluoride dentifrice formulations.

Animals↗

PubMed1999

Developing an instrument to study the tuberculosis screening behaviors of Mexican migrant farmworkers.

This article details the use of qualitative data in the construction of a Spanish-language, quantitative research instrument designed for a study of Mexican migrant farmworkers' participation in tuberculosis screening. In the qualitative study, 19 Mexican migrant farmworkers were interviewed in Spanish to elicit their explanatory models (EMs) about tuberculosis. The Tuberculosis Interview Instrument (TII) was developed from the results of the qualitative study and concepts from a theoretical framework consisting of a combination of the Health Belief Model (HBM) and the Theory of Reasoned Action (TRA). After its development, the TII was subjected to translation and back-translation procedures to insure the equivalency of the English and Spanish versions, and it was reviewed for content validity. Internal consistency reliability, based on the responses of 206 subjects, was satisfactory for all subscales. Future testing of the TII is recommended to evaluate its stability among Mexican migrant farmworkers in other parts of the United States.

Adolescent↗