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Development and validation of a visual acuity chart for Australian Aborigines and Torres Strait Islanders.

BACKGROUND: A new visual acuity chart was designed for use with Australia's indigenous population to overcome perceived inadequacies of conventional English letter charts for this group. This chart, which incorporates a black and white turtle icon, is described, and validation data are presented. METHODS: The chart is based on logarithm of the minimum angle of resolution (logMAR) principles and incorporates a turtle symbol modified from the design of an indigenous artist. The task is one of discrimination, with subjects being required to distinguish the split tail of the turtle from its head, which has the same overall shape and average luminance; the body of the turtle provides no directional cues which might assist in this judgment. The chart was validated in two ways: Experiment I. Performance was compared with the Bailey-Lovie and Konig bar charts in terms of unaided visual acuity data for 90 subjects (mean age: 38.3 +/- 20.3 years) and Experiment II. Data were obtained for 10 young subjects for these 3 charts and an Illiterate E chart, with refractive blur imposed with trial lenses over habitual distance corrections (spherical: +0.50, +1.00, +2.00, and +4.00 D; cylindrical: +1.00 and +2.00 D, axes 45, 90, and 180 degrees). To avoid cultural and literacy issues as possible sources of differences in performance between the charts in this validation study, subjects were selected from the wider Australian population rather than specifically from its indigenous segment. RESULTS: Experiment I: The Turtle chart performed most like the Konig Bar chart for this component of the validation exercise. Nonetheless, results for the Turtle chart correlated highly with those for the Bailey-Lovie chart as well as the Konig Bar chart, although there were subtle differences between charts in the rate of decline of visual acuity as visual performance decreased. Experiment II: The turtle chart behaved most like the Illiterate E chart with imposed spherical focusing errors, with the Bailey-Lovie chart showing a faster decline and the Konig Bar chart showing a slower decline in performance, with increasing defocus. All 4 charts showed similar directional biases with astigmatic defocus, being most affected by oblique (45 degrees) astigmatism. CONCLUSION: The Turtle chart met the criteria set for its validation as a visual acuity chart in that it gave comparable results to the other commonly used visual acuity charts, both in the case of unaided vision and when refractive blur was imposed.

Adolescent↗

Further development and validation of the Scoliosis Research Society (SRS) outcomes instrument.

STUDY DESIGN: Outcome study to determine response distribution, internal consistency, and validity of a Modified SRS Outcomes Instrument (MSRSI). OBJECTIVES: Refinement and validation of the SRS Outcomes Instrument for idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Experience with the SRS Outcomes Instrument suggested several refinements and the need for validation. METHODS: Following experience-based modification, the Modified SRS Outcomes Instrument and Short Form 36 (SF-36) questionnaires were administered to 35 previously surveyed postoperative idiopathic scoliosis patients. RESULTS: Thirty (86%) patients with an average age of 25 years returned the questionnaires at an average of 10 years postoperative. Distribution of scores was acceptable. Internal consistency utilizing Cronbach's alpha was 0.80, 0.81, 0.77, 0.89, and 0.88 for pain, self-image/appearance, function/activity, mental health, and satisfaction with surgery, respectively. Validity, determined by Pearson correlation coefficients with comparable SF-36 domains, was 0.70 or greater for 13 of the 14 relevant domains between SF-36 and MSRSI (P < 0.001). CONCLUSION: The SRS Outcomes Instrument is simple and internally consistent. Based on experience, a number of modifications have been made that improve the instruments scope and internal consistency. Finally, the instrument is valid in comparison to SF-36.

Adult↗

Validation of population pharmacokinetic parameters of phenytoin using the parallel Michaelis-Menten and first-order elimination model.

This study was conducted to assess whether the parallel Michaelis-Menten and first-order elimination (MM+FO) model fitted the data better than the Michaelis-Menten (MM) model, and to validate the MM+FO model and its parameter estimates. The models were fitted to 853 steady state dose: serum concentration pairs obtained in 332 adults with epilepsy using nonlinear mixed-effects modeling (NONMEM). The MM+FO model fitted the data better than the MM model. The validity of the pharmacokinetic models and the estimated population parameter values was tested using the naive prediction method. The estimation and validation of the pharmacokinetic parameters were undertaken in two separate patient groups (cross-validation) obtained by splitting the data set. Patients were randomly allocated to two equally matched groups (groups 1 and 2). The predictive performance was assessed using 770 paired predicted versus actual dose or measured serum concentrations. The population pharmacokinetic parameters estimated by NONMEM in group 1 were validated in group 2 and vice versa. When predicting steady state serum concentration, the MM+FO model was clearly superior to the MM model (mean bias of 0.91 and 8.13 mg/L, respectively).

Adolescent↗

Development, implementation, and validation of the Canadian Intercollegiate Sport Injury Registry.

PURPOSE: To outline the development and implementation of the Canadian Intercollegiate Sport Injury Registry (CISIR), to examine its validity, including the data collection forms, the recording of athlete exposure, and the mechanism of injury, and to determine the ability of the CISIR to meet its stated objectives of assessing rates and risk of injury. DESIGN: Prospective cohort study. SETTING: Canadian intercollegiate athletics. SUBJECTS: 344 varsity football players from five western Canadian universities. ASSESSMENT OF RISK FACTORS AND OUTCOME MEASURES: Three data collection instruments were developed to capture the principle types of information forming the cornerstones of the CISIR: a medical form for preseason assessment of risk factors, a weekly exposure sheet (WES) for the documentation of daily individual athlete participation, and an individual injury report form (IIRF) for collection of injury-related information. Design and implementation input was provided by therapists and physicians through initial meetings, pilot testing, site visits, questionnaire, and final consensus meeting. The completeness of injury reporting was assessed through cross-referencing with participation time loss data. An item analysis was conducted on the principal elements of the IIRF. The categorization of participation itself was also examined, as was the diagnostic agreement between the therapists and physicians involved in data collection. The recorded mechanism of injury was compared with that noted through a video analysis for game-related injuries. Lastly, a test analysis was conducted to extract data and compute rates and risks of injury. RESULTS: This developmental phase was successful, with 99.7% subject enrollment, high therapist satisfaction, and good flow of data. A relational database, incorporating dual-entry data verification, was designed and functioned well. The collection process revealed that 100% of the WESs were submitted, and the data therein was 99.7% complete. The injuries resulting in participation time loss were recorded on an IIRF 97.9% of the time. The exposure (participation) codes were thought to be overly precise, and a simplification of these categories is suggested. The diagnostic agreement between physicians and therapists was 70%. It was possible to validate game exposures, but no standard was identified to permit validation of the categories of exposure. Likewise, the mechanism of injury as recorded by the therapists was thought to be more precise than the video analysis. After two modifications in the table structure of the relational database, it was possible to extract data relating to rates and risks of injury. CONCLUSIONS: This study demonstrated a high degree of validity for many elements of the CISIR. One limitation was that no reference standard existed for some components, limiting some aspects of validity assessment. With the suggested revisions, the CISIR represents the current standard in athletic injury reporting in terms of individual injury risk assessment. This system will be used in the future to explore the prediction and prevention of sport injuries.

Adult↗

Value of electronic data for model validation and refinement: bacteremia risk in children with fever and neutropenia.

BACKGROUND: Validating published risk models in a different time and setting can be a labor-intensive process. Data in electronic format provide the potential to test the validity of risk models without labor-intensive chart reviews and data capture. The authors attempted to use readily available electronic data to find appropriate cases and to validate and refine a previously developed risk model for predicting bacteremia in children with cancer who had fever and neutropenia. PATIENTS AND METHODS: By applying a largely automated case-finding algorithm to linked, electronic clinical and administrative data systems, the authors identified and acquired data regarding 157 episodes of fever and neutropenia in children with cancer admitted to a children's hospital during an 11-month period in 1997. The authors applied a previously developed and validated risk model for bacteremia to this 1997 cohort by assessing the odds ratios among risk groups. The model assigns encounters with absolute monocyte count of 100 cells or more/mm3 to a low-risk group and encounters with an absolute monocyte count of less than 100 cells/mm3 to intermediate-risk (temperature <39.0 degrees C) or high-risk (> or = 39.0 degrees C) groups. In addition, the authors explored whether the new data would have generated the same model. Univariate and multivariable analyses were performed to determine whether there were additional independent predictors of bacteremia. Recursive partitioning of admission absolute monocyte count and temperature was used to assess whether similar cutpoints would be found. RESULTS: There were 12 episodes of bacteremia (7.6%) among the 157 encounters. The previously developed model correctly predicted increasing rates of bacteremia in this 1997 cohort, ranging from 2.5% in the low-risk group (one episode in a child with an infected central line) to 24% in the high-risk group. The odds ratio for the high-risk versus intermediate-risk group was 4.09 (95% confidence interval 1.05-15.91), comparable to the odds ratio of 3.96 in the previously published derivation cohort (95% confidence interval 1.4-11.1). Multivariate analysis of the new data revealed no independent risk factors for bacteremia other than admission absolute monocyte count and temperature. Recursive partitioning of absolute monocyte count and temperature generated risk categories that were somewhat different from those of the original model. The new data yielded three categories: low risk (temperature < or = 39.5 degrees C and absolute monocyte count >10/mm3), intermediate risk (temperature < or = 39.5 degrees C and absolute monocyte count < or = 10/mm3), and high risk (temperature >39.5 degrees C). CONCLUSIONS: Existing electronic data provide an efficient means for case-finding and model validation and refinement. The previously developed bacteremia model had good but not optimal predictive performance in the new data set. Admission absolute monocyte count and temperature remain significant risk factors for bacteremia. Redefining the risk categories, including a much lower cutpoint for admission absolute monocyte count, improved the model's discrimination, which suggests that predictive models need periodic updating.

Adolescent↗

Validation up-date.

With the increasing marketing of automated and semi-automated devices for the measurement of blood pressure, there is a need for potential purchasers to be able to satisfy themselves that such devices have been evaluated according to agreed criteria. Since their introduction a large number of blood pressure measuring devices have been evaluated according to one or both protocols. However, experience has demonstrated that the conditions demanded by the protocols are extremely difficult to fulfil. The European Society of Hypertension (ESH) protocol, named the International Protocol, which will be published shortly, is based on the data from 19 validation studies performed according to the AAMI and BHS protocols. Critical assessment of this data base of evidence has permitted rationalisation and simplification of validation procedures without loosing the merits of the much more complicated earlier protocols. This has been achieved by elimination of pre-validation phases, improving observer recruitment and training, minimising observer error during validation, reducing the number of subjects recruited, relaxing the range of blood pressures required and eliminating 'hopeless' devices early in the validation procedure.

Blood Pressure Determination↗

New approach to the validity of the alcohol use disorders identification test: stratum-specific likelihood ratios analysis.

BACKGROUND: Previous validation studies of the Alcohol Use Disorders Identification Test (AUDIT) used either the fixed-threshold approach or receiver operating characteristic (ROC) analyses. This study was aimed to conduct a stratum-specific likelihood ratio (SSLR) analysis on the validity of the AUDIT for detecting alcohol use disorders. METHODS: A two-phase validation study was conducted among nonpsychiatric inpatients at a general hospital, using the AUDIT for phase 1 screening and the Schedules for Clinical Assessment in Neuropsychiatry for the phase 2 interview. All of the patients with positive screening results and a subsample of the patients with negative screening results were interviewed in the second phase. The validity of the AUDIT for current alcohol use disorders was estimated using the ROC first, and an SSLR analysis was performed subsequently. RESULTS: In 422 inpatients who completed the screening, 193 had a negative result with a zero score, 103 had a negative result with a nonzero score, and 126 had a positive result. Twenty screened patients with a negative result and a nonzero score and 107 patients with a positive result were interviewed in the second phase, in which 59 patients were found to have current alcohol use disorders according to DSM-IV criteria. The area under the ROC curve of the AUDIT for current alcohol use disorders was 0.98. The sensitivity and specificity of the AUDIT at the optimal cutoff of 8 were 0.97 and 0.90, respectively. Three strata of the AUDIT scores (0-7, 8-13, and > or = 14) were derived for alcohol use disorders, with the SSLRs being 0.04, 3.67, and 49.72, and the corresponding posttest probabilities being 0.01, 0.42, and 0.91, respectively. CONCLUSIONS: The AUDIT is a valid screening tool for alcohol use disorders, and the three strata derived from the SSLR analysis are informative and readily applicable in clinical practice.

Adult↗

Physical impairment index: reliability, validity, and responsiveness in patients with acute low back pain.

STUDY DESIGN: Cohort study of patients with acute low back pain undergoing physical therapy. OBJECTIVES: Examine the reliability and validity of the Physical Impairment Index in a group of patients with acute low back pain and determine the responsiveness and minimum detectable change of the index and its component tests. SUMMARY OF THE BACKGROUND DATA: The Physical Impairment Index was originally described as a reliable and valid means of assessing physical impairment in patients with low back pain. The psychometric properties of the index have not been reported in patients with acute low back pain, nor has its responsiveness been examined. METHODS: Seventy-eight patients with acute (<3 weeks duration) low back pain participating in a clinical trial were assessed at baseline and after 4 weeks. Interrater reliability of the index was examined in a subgroup of 20 patients. Validity was examined through correlations with concurrent measures of pain, disability, and psychosocial variables. Changes in the index over 4 weeks were used to assess responsiveness and minimum detectable change. RESULTS: Interrater reliability of the index was high (intraclass correlation coefficient = 0.89), and its validity was generally supported by the pattern of correlations. The index was more responsive to change than any of its component tests but was less responsive than the Oswestry disability score. The minimum detectable change on the index was approximately 1 point. CONCLUSIONS: The Physical Impairment Index appears to be a reliable and valid measure of physical impairment for patients with acute low back pain and may be useful as an adjunct outcome measure for studies involving these patients. Further research on patients with chronic pain is needed before it can be advocated for outcomes research with this population.

Acute Disease↗

Reliability, validity, and responsiveness of the short form 12-item survey (SF-12) in patients with back pain.

STUDY DESIGN: Secondary analysis of data collected from spine patients' normal clinic visits from 1998 to 2001. OBJECTIVE: To evaluate the reliability, validity, and responsiveness of the short form 12-item survey in patients with back pain. SUMMARY OF BACKGROUND DATA: The reliability, validity, and responsiveness of the short form 12-item survey in patients with back pain has not been previously evaluated. METHODS: Patients were asked to complete a comprehensive computerized survey questionnaire during their regular clinic visits. A total of 2520 patients who indicated in their first surveys that they had back pain were included in the study of the reliability and validity of the short form 12-item survey. Of these, 506 patients completed another survey within 3-6 months of follow-up and were included in the responsiveness evaluation. RESULTS: The two summary scales of the short form 12-item survey, physical component summary and mental component summary, demonstrated internal consistency reliability, with Cronbach alpha for both scales exceeding the recommended level of 0.70. Correlation of physical component summary and mental component summary with six other measures theoretically related or unrelated to these scales performed as expected without exception, demonstrating the construct validity of the short form 12-item survey. The responsiveness of the short form 12-item survey was supported by several pieces of evidence. First, the changes in physical component summary and mental component summary scores were correlated with the changes in back pain intensity. Second, for patients whose back pain improved, there was a significant increase in the follow-up physical component summary and mental component summary scores as compared to the baseline. Third, small to moderate effect size was observed for patients whose back pain became improved or became worse. CONCLUSIONS: The short form 12-item survey demonstrated good internal consistency reliability, construct validity, and responsiveness in patients with back pain.

Academic Medical Centers↗

Development and validation of a nomogram predicting the outcome of prostate biopsy based on patient age, digital rectal examination and serum prostate specific antigen.

PURPOSE: We developed and validated a nomogram which predicts presence of prostate cancer (PCa) on needle biopsy. MATERIALS AND METHODS: We used 3 cohorts of men who were evaluated with sextant biopsy of the prostate and whose presenting prostate specific antigen (PSA) was not greater than 50 ng/ml. Data from 4,193 men from Montreal, Canada were used to develop a nomogram based on age, digital rectal examination (DRE) and serum PSA. External validation was performed on 1,762 men from Hamburg, Germany. Data from these men were subsequently used to develop a second nomogram in which percent free PSA (%fPSA) was added as a predictor. External validation was performed using 514 men from Montreal. Both nomograms were based on multivariate logistic regression models. Predictive accuracy was evaluated with areas under the receiver operating characteristic curve and graphically with loess smoothing plots. RESULTS: PCa was detected in 1,477 (35.2%) men from Montreal, 739 (41.9%) men from Hamburg and 189 (36.8%) men from Montreal. In all models all predictors were significant at 0.05. Using age, DRE and PSA external validation AUC was 0.69. Using age, DRE, PSA and %fPSA external validation AUC was 0.77. CONCLUSIONS: A nomogram based on age, DRE, PSA and %fPSA can highly accurately predict the outcome of prostate biopsy in men at risk for PCa.

Adolescent↗

External validation and comparison of recently described prediction rules for suspected pulmonary embolism.

PURPOSE OF REVIEW: The assessment of pretest probability, allowing the categorization of patients clinically suspected of having pulmonary embolism in low, intermediate, and high clinical probability, is an essential step in contemporary diagnostic strategies because it permits limiting the number of additional diagnostic tests, especially invasive tests. Clinical probability can be evaluated implicitly or by prediction rules. Two prediction rules for pulmonary embolism have been described: the Canadian prediction rule (the Wells score) and the Geneva prediction rule. Their original descriptions were published in 2000 and 2001, respectively. These prediction rules need to be externally validated, and, ideally, outcome studies should demonstrate that patients may be safely treated on the basis of the assessment of the clinical probability they provide. Therefore, the purpose of this review is to discuss the external validation of these rules, because this particular point has been only recently achieved. RECENT FINDINGS: Application of both rules in an external setting and in a prospective study have confirmed their validity. A recent study suggests that the best evaluation is probably based on a prediction rule associated with possible clinical override. SUMMARY: Studies comparing an empiric assessment with explicit assessment, such as the Wells simplified score or the Geneva score, have shown that the three tools show similar accuracy. External validation and use of both rules in prospective management studies have only recently been performed and have confirmed their validity. Some reports suggest that empiric assessment may be influenced by level of training. Objective prediction rules seems to be less influenced by experience and should be preferred by more junior doctors. The tool used for clinical probability assessment is probably less important than the principle of a careful clinical probability assessment in each patient with suspected pulmonary embolism.

Diagnostic Techniques, Respiratory System↗

Validity and reliability of a pediatric reach test.

PURPOSE: The purpose of this study was to develop and evaluate the validity and reliability of a Pediatric Reach Test (PRT). METHODS: The Functional Reach Test was modified to incorporate side reaching in addition to forward reaching in both sitting and standing. Nineteen children developing typically (age 3.0 to 12.5 years) completed the standing section of the PRT as well as laboratory force platform tests of standing balance. On two separate occasions, two different raters evaluated 10 children with cerebral palsy (age 2.6 to 14.1 years) in both the sitting and standing sections of the PRT. RESULTS: Concurrent validity was supported with the observation of moderate-to-high correlations between the standing section of the PRT and laboratory tests of limits of stability (r = 0.42 to 0.77). Construct validity was supported with the observation of high correlations between the standing section of the PRT and a laboratory test of steadiness in quiet stance (r = -0.79) and age (r = 0.83). Construct validity was also supported with a high correlation between the total PRT score and Gross Motor Function Classification System level (rs = -0.88) among the sample of children with cerebral palsy. Test-retest reliability and inter-tester reliability with children with cerebral palsy ranged from intraclass correlation coefficients of 0.54 to 0.88 and 0.50 to 0.93, respectively. CONCLUSIONS: This study provides evidence that the PRT is a simple, valid, and reliable measure with potential for use with children.

Journal Article↗

Reliability and validity of the gross motor function classification system for cerebral palsy.

PURPOSE: The purposes of this study were to evaluate interrater reliability using videotapes and criterion-related and construct validity of the Gross Motor Function Classification System (GMFCS), aspects of reliability and validity not previously published. METHODS: Two experienced pediatric physical therapists rated 30 videotapes of children with cerebral palsy (CP) or Down syndrome (DS) to test interrater reliability. Criterion-related validity was evaluated by comparing GMFCS levels with tests of motor and nonmotor development. Construct validity was assessed by comparing GMFCS trends over time in children with CP and DS. RESULTS: Interrater reliability was 0.84. Correlation was higher between GMFCS level and tests of motor development than GMFCS level and tests of nonmotor development. The GMFCS level remained relatively stable in children with CP but tended to improve in children with DS. CONCLUSIONS: This study extends reliability and validity of the GMFCS, supporting its use in clinical practice and research.

Journal Article↗

Timed up and down stairs test: preliminary reliability and validity of a new measure of functional mobility.

PURPOSE: The reliability and validity of a new test, the Timed Up and Down Stairs (TUDS), were examined in children with and without cerebral palsy (CP). METHODS: A convenience sample of 47 children age eight to 14 years participated, 20 with CP and 27 with typical development (TD). Using intraclass correlation coefficients (ICC), interrater, intrarater, and test-retest reliability of the TUDS were examined by two raters simultaneously testing nine children, by one rater who then rescored at a later time a video of the testing of 24 children, and by one rater testing 25 children twice with a two-hour separation, respectively. Concurrent validity was examined using Spearman rank correlations between TUDS scores and performance on the Timed Up and Go (TUG), the Functional Reach Test (FRT), and a Timed One Legged Stance (TOLS), which were completed in a random order on all children. Construct validity was examined by correlation and Kruskal-Wallis analysis of variance of scores across ages and three functional level groups. RESULTS: The TUDS demonstrated excellent intrarater, interrater, and test-retest reliability [ICC (2,1) > or =0.94] and moderate to high concurrent validity (Spearman r(s) = 0.78, -0.57, and -0.77, with the TUG, FRT, and TOLS, respectively). Age accounted for 37% and 56% of the variance in the TUDS for the TD group and for the Gross Motor Function Classification Scale level I CP group, respectively. Significant differences in TUDS scores were found between all three functional level groups. CONCLUSION: The TUDS has adequate reliability and validity in children with and without CP and appears to complement current clinical measures of functional mobility and balance. Further investigations on across larger age ranges and samples are warranted.

Journal Article↗

Three types of skin-surface thermometers: a comparison of reliability, validity, and responsiveness.

OBJECTIVE: To compare the reliability, validity, and responsiveness of a thermistor thermometer (thermistor) and two different infrared thermometers (one designed to measure tympanic temperature and one for skin temperature). DESIGN: Reliability and validity were evaluated by making two separate measurements from the skin at identical spots of each hand, forearm, shoulder, thigh, shin, and foot in 17 healthy subjects. Intramuscular temperature was recorded at the hand and shin sites. Test-retest reliability was calculated using intraclass correlation for each instrument. Pearson correlation assessed the relationship between the skin and intramuscular temperatures at the hand and shin sites (validity). Each instrument's ability to measure temperature change (responsiveness) was assessed by measuring skin temperatures serially from 17 limbs of ten patients with complex regional pain syndrome undergoing intravenous regional sympathetic blockade. Responsiveness index values were calculated. RESULTS: Reliability was strong and similar for each device (intraclass correlation: thermistor = 0.96, tympanic = 0.96, skin = 0.97), as was validity (r: thermistor = 0.90, tympanic = 0.92, skin = 0.92). Responsiveness was marginally better for the infrared skin device (responsiveness index: skin = 4.2, tympanic = 3.6, thermistor = 3.6). CONCLUSIONS: For the purposes of clinical electrodiagnostic laboratory and other physiatry applications, the performance of the infrared thermometers is equal to or superior to that of the traditionally used thermistor. All three devices are highly reliable and valid, whereas the infrared skin device is slightly more responsive. Infrared thermometers have the advantage of being quicker to operate and more portable.

Adult↗

The Depression Interview and Structured Hamilton (DISH): rationale, development, characteristics, and clinical validity.

OBJECTIVE: The Depression Interview and Structured Hamilton (DISH) is a semistructured interview developed for the Enhancing Recovery in Coronary Heart Disease (ENRICHD) study, a multicenter clinical trial of treatment for depression and low perceived social support after acute myocardial infarction. The DISH is designed to diagnose depression in medically ill patients and to assess its severity on an embedded version of Williams' Structured Interview Guide for the Hamilton Depression scale (SIGH-D). This article describes the development and characteristics of the DISH and presents a validity study and data on its use in ENRICHD. METHODS: In the validity study, the DISH and the Structured Clinical Interview for DSM-IV (SCID) were administered in randomized order to 57 patients. Trained interviewers administered the DISH, and clinicians administered the SCID. In ENRICHD, trained research nurses administered the DISH and recorded a diagnosis. Clinicians reviewed 42% of the interviews and recorded their own diagnosis. The Beck Depression Inventory (BDI) was administered in both studies. RESULTS: In the validity study, the SCID diagnosis agreed with the DISH on 88% of the interviews (weighted kappa = 0.86). In ENRICHD, the clinicians agreed with 93% of the research nurses' diagnoses. The BDI and the Hamilton depression scores derived from the DISH in the two studies correlated 0.76 (p < .0001) in the validity study and 0.64 (p < .0001) in ENRICHD. CONCLUSIONS: These findings support the validity of the DISH as a semistructured interview to assess depression in medically ill patients. The DISH is efficient in yielding both a DSM-IV depression diagnosis and a 17-item Hamilton depression score.

Analysis of Variance↗

Design of validation studies for estimating the odds ratio of exposure-disease relationships when exposure is misclassified.

We compared several validation study designs for estimating the odds ratio of disease with misclassified exposure. We assumed that the outcome and misclassified binary covariate are available and that the error-free binary covariate is measured in a subsample, the validation sample. We considered designs in which the total size of the validation sample is fixed and the probability of selection into the validation sample may depend on outcome and misclassified covariate values. Design comparisons were conducted for rare and common disease scenarios, where the optimal design is the one that minimizes the variance of the maximum likelihood estimator of the true log odds ratio relating the outcome to the exposure of interest. Misclassification rates were assumed to be independent of the outcome. We used a sensitivity analysis to assess the effect of misspecifying the misclassification rates. Under the scenarios considered, our results suggested that a balanced design, which allocates equal numbers of validation subjects into each of the four outcome/mismeasured covariate categories, is preferable for its simplicity and good performance. A user-friendly Fortran program is available from the second author, which calculates the optimal sampling fractions for all designs considered and the efficiencies of these designs relative to the optimal hybrid design for any scenario of interest.

Biometry↗

Short Form 36 in the intensive care unit: assessment of acceptability, reliability and validity of the questionnaire.

The aim of this study was to assess the acceptability, validity and reliability of the Short Form 36 quality of life questionnaire in 166 adult patients following discharge from a general intensive care unit. Reliability was quantified by measuring internal consistency using correlation among items and Cronbach's alpha coefficient. Reliability coefficients were calculated from two-way analysis of variance. Construct validity was tested by examining differences in scores between sex and age groups. Content validity was reflected by the spread of dimension scores. Acceptability to patients appeared reasonable, although considerable nursing time was required to administer the questionnaire. The measures of reliability exceeded recognised statistical standards in all but two instances. Construct validity was confirmed by lower scores being reported by women and older age groups. The scores of six of the eight dimensions were spread throughout the entire range of possible scores suggesting acceptable content validity.

Adolescent↗