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The validity, reliability and minimal clinically important difference of the patient specific functional scale in snake envenomation.

ABSTRACT: OBJECTIVE:Valid, reliable, and clinically relevant outcome measures are necessary in clinical studies of snake envenomation. The aim of this study was to evaluate the psychometric (validity and reliability) and clinimetric (minimal clinically important difference [MCID]) properties of the Patient-Specific Functional Scale (PSFS) in snakebite envenomation. METHODS:We performed a secondary analysis of two existing snakebite trials that measured clinical outcomes using the PSFS as well as other quality of life and functional assessments. Data were collected at 3, 7, 10, and 17 days. Reliability was determined using Cronbach's alpha for internal consistency and the intraclass correlation coefficient (ICC) for temporal stability at 10 and 17 days. Validity was assessed using concurrent validity correlating with the other assessments. The MCID was evaluated using the following criteria: (1) the distribution of stable patients according to both standard error of measurement (SEM) and responsiveness techniques, and (2) anchor-based methods to compare between individuals and to detect discriminant ability of a positive change with a receiver operator characteristic (ROC) curve and optimal cutoff point. RESULTS:A total of 86 patients were evaluated in this study. The average PSFS scores were 5.37 (SD 3.23), 7.95 (SD 2.22), and 9.12 (SD 1.37) at 3, 7, and 10 days, respectively. Negligible floor effect was observed (maximum of 8% at 3 days); however, a ceiling effect was observed at 17 days (25%). The PSFS showed good reliability with an internal consistency of 0.91 (Cronbach's alpha) (95% CI 0.88, 0.95) and a temporal stability of 0.83 (ICC) (95% CI 0.72, 0.89). The PSFS showed a strong positive correlation with quality of life and functional assessments. The MCID was approximately 1.0 for all methods. CONCLUSIONS:With an MCID of approximately 1 point, the PSFS is a valid and reliable tool to assess quality of life and functionality in patients with snake envenomation.

SUBMITTER: Gerardo CJ

PROVIDER: S-EPMC6400437 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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The validity, reliability and minimal clinically important difference of the patient specific functional scale in snake envenomation.

Gerardo Charles J CJ Vissoci Joao R N JRN de Oliveira Leonardo P LP Anderson Victoria E VE Quackenbush Eugenia E Lewis Brandon B Rose S Rutherfoord SR Greene Spencer S Toschlog Eric A EA Charlton Nathan P NP Mullins Michael E ME Schwartz Richard R Denning David D Sharma Kapil K Kleinschmidt Kurt K Bush Sean P SP Brandehoff Nicklaus P NP Lavonas Eric J EJ

PloS one 20190305 3

<h4>Objective</h4>Valid, reliable, and clinically relevant outcome measures are necessary in clinical studies of snake envenomation. The aim of this study was to evaluate the psychometric (validity and reliability) and clinimetric (minimal clinically important difference [MCID]) properties of the Patient-Specific Functional Scale (PSFS) in snakebite envenomation.<h4>Methods</h4>We performed a secondary analysis of two existing snakebite trials that measured clinical outcomes using the PSFS as we ...[more]

PMID: 30835744

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Project description:BackgroundA minimal clinically important difference has not been established for the Abnormal Involuntary Movement Scale in patients with tardive dyskinesia. Valbenazine is a vesicular monoamine transporter 2 inhibitor approved for the treatment of tardive dyskinesia in adults. Efficacy in randomized, double-blind, placebo-controlled trials was defined as the change from baseline in Abnormal Involuntary Movement Scale total score (sum of items 1-7).ObjectivesTo estimate an minimal clinically important difference for the Abnormal Involuntary Movement Scale using valbenazine trial data and an anchor-based method.MethodsData were pooled from three 6-week double-blind, placebo-controlled trials: KINECT (NCT01688037), KINECT 2 (NCT01733121), and KINECT 3 (NCT02274558). Valbenazine doses were pooled for analyses as follows: "low dose," which includes 40 or 50 mg/day; and "high dose," which includes 75 or 80 mg/day. Mean changes from baseline in Abnormal Involuntary Movement Scale total score were analyzed in all participants (valbenazine- and placebo-treated) with a Clinical Global Impression of Change-Tardive Dyskinesia or Patient Global Impression of Change score of 1 (very much improved) to 3 (minimally improved).ResultsThe least squares mean improvement from baseline to week 6 in Abnormal Involuntary Movement Scale total score was significantly greater with valbenazine (low dose: -2.4; high dose: -3.2; both, P < 0.001) versus placebo (-0.7). An minimal clinically important difference of 2 points was estimated based on least squares mean changes in Abnormal Involuntary Movement Scale total score in participants with a Clinical Global Impression of Change-Tardive Dyskinesia score ≤3 at week 6 (mean change: -2.2; median change: -2) or Patient Global Impression of Change score ≤3 at week 6 (mean change: -2.0; median change: -2).ConclusionsResults from an anchor-based method indicate that a 2-point decrease in Abnormal Involuntary Movement Scale total score may be considered clinically important. © 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Project description:BACKGROUND:Using a real dataset, we highlighted several major methodological issues raised by the estimation of the Minimal Clinically Important Difference (MCID) of a Patient-Reported Outcomes instrument. We especially considered the management of missing data and the use of more than two times of measurement. While inappropriate missing data management and inappropriate use of multiple time points can lead to loss of precision and/or bias in MCID estimation, these issues are almost never dealt with and require cautious considerations in the context of MCID estimation. METHODS:We used the LIGALONGO study (French Randomized Controlled Trial). We estimated MCID on the SF-36 General Health score by comparing many methods (distribution or anchor-based). Different techniques for imputation of missing data were performed (simple and multiple imputations). We also consider all measurement occasions by longitudinal modeling, and the dependence of the score difference on baseline. RESULTS:Three hundred ninety-three patients were studied. With distribution-based methods, a great variability in MCID was observed (from 3 to 26 points for improvement). Only 0.2 SD and 1/3 SD distribution methods gave MCID values consistent with anchor-based methods (from 4 to 7 points for improvement). The choice of missing data imputation technique clearly had an impact on MCID estimates. Simple imputation by mean score seemed to lead to out-of-range estimate, but as missing not at random mechanism can be hypothesized, even multiple imputations techniques can have led to an slight underestimation of MCID. Using 3 measurement occasions for improvement led to an increase in precision but lowered estimates. CONCLUSION:This practical example illustrates the substantial impact of some methodological issues that are usually never dealt with for MCID estimation. Simulation studies are needed to investigate those issues. TRIAL REGISTRATION:NCT01240772 (ClinicalTrials.gov) registered on November 15, 2010.

Project description:BackgroundThe discriminatory ability of multi-attribute utility (MAU) measures compared to condition-specific measures (CSM) in assessing health-related quality of life (HRQoL) among patients with chronic obstructive pulmonary disease (COPD) is an unsettled issue. This study investigated the quality of life of patients with COPD with three different HRQoL instruments and examined whether they could differentiate between adjacent severity groups in a statistically and clinically meaningful manner. In the process, the minimal clinically important differences (MCID) of the EQ-5D utility index were estimated.MethodsCross-sectional survey data were collected from patients with mild to very severe COPD in South Korea. In addition to demographic and clinical information, the following HRQoL questionnaires were used: The three-level five-dimensional Euro-Quality of Life tool (EQ-5D-3L), the EQ-Visual Analog Scale (EQ-VAS), and the Chronic Obstructive Pulmonary Disease Assessment Test (CAT). Patients' health-related quality of life was analyzed with reference to severity groups based on the Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification. To investigate the discriminatory ability of the HRQoL instruments between COPD severity groups, tests examining variance, covariance, and standardized mean difference were performed. After estimating the MCID of the EQ-5D utility index using the anchor-based method, we investigated whether the differences in the EQ-5D utility scores between groups exceeded the clinically meaningful minimum level.ResultsA total of 298 patients completed this study. All the quality of life scores showed statistically significant differences between the GOLD severity groups. The pooled MCID estimate for the EQ-5D utility index was 0.028 (range: 0.017-0.033). Even after adjusting for other factors affecting quality of life, the EQ-5D utility index differentiated the GOLD groups well.ConclusionsWe conclude that the EQ-5D utility index is a valid instrument for measuring the quality of life of patients with COPD, and the pooled MCID estimate for the EQ-5D utility index was 0.028.

Project description:OBJECTIVES:Although more than 1.8 million people survive snakebite envenomation each year, their recovery is understudied. Obtaining long-term follow-up is challenging in both high- and low-resource settings. The Patient-Specific Functional Scale (PSFS) is an easily administered, well-accepted patient-reported outcome that is validated for assessing limb recovery from snakebite envenomation. We studied whether the PSFS is valid and reliable when administered by telephone. METHODS:This is a secondary analysis of data from a randomized clinical trial. We analyzed the results of PSFS collected in-person on days 3, 7, 14, 21, and 28 and by telephone on days 10, 17, and 24. We assessed the following scale psychometric properties: (a) content validity (ceiling and floor effects), (b) internal structure and consistency (Cronbach's alpha), and (c) temporal and external validity using Intraclass Correlation Coefficient (ICC). Temporal stability was assessed using Spearman's correlation coefficient and agreement between adjacent in-person and telephonic assessments with Cohen's kappa. Bland Altman analysis was used to assess differential bias in low and high score results. RESULTS:Data from 74 patients were available for analysis. Floor effects were seen in the early post-injury time points (median: 3 (IQR: 0, 5) at 3 days post-enrollment) and ceiling effects in the late time points (median: 9 (IQR: 8, 10). Internal consistency was good to excellent with both in-person (Cronbach ?: 0.91 (95%CI 0.88, 0.95)) and telephone administration (0.81 (0.73, 0.89). Temporal stability was also good (ICC: 0.83 (0.72, 0.89) in-person, 0.80 (0.68, 0.88) telephone). A strong linear correlation was found between in-person and telephone administration (Spearman's ?: 0.83 (CI: 0.78, 0.84), consistency was assessed as excellent (Cohen's ? 0.81 (CI: 0.78, 0.84), and Bland Altman analysis showed no systematic bias. CONCLUSIONS:Telephone administration of the PSFS provides valid, reliable, and consistent data for the assessment of recovery from snakebite envenomation.

Project description:Introduction and motivationMany health studies measure a continuous outcome and compare means between groups. Since means for biological data are often difficult to interpret clinically, it is common to dichotomise using a cut-point and present the 'percentage abnormal' alongside or in place of means. Examples include birthweight where 'abnormal' is defined as <2500 g (low birthweight), systolic blood pressure with abnormal defined as >140 mm Hg (high blood pressure) and lung function with varying definitions of the 'limit of normal'. In vulnerable populations with low means, for example, birthweight in a population of preterm babies, a given difference in means between two groups will represent a larger difference in the percentage with low birthweight than in a general population of babies where most will be full term. Thus, in general, the difference in percentage of patients with abnormal values for a given difference in means varies according to the reference population's mean value. This phenomenon leads to challenges in interpreting differences in means in vulnerable populations and in defining an outcome-specific minimal clinically important difference (MCID) in means since the proportion abnormal, which is useful in interpreting means, is not constant-it varies with the population mean. This has relevance for study power calculations and data analyses in vulnerable populations where a small observed difference in means may be difficult to interpret clinically and may be disregarded, even if associated with a relatively large difference in percentage abnormal which is clinically relevant.MethodsTo address these issues, we suggest both difference in means and difference in percentage (proportion) abnormal are considered when choosing the MCID, and that both means and percentages abnormal are reported when analysing the data.ConclusionsWe describe a distributional approach to analyse proportions classified as abnormal that avoids the usual loss of precision and power associated with dichotomisation.

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The validity, reliability and minimal clinically important difference of the patient specific functional scale in snake envenomation.

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The validity, reliability and minimal clinically important difference of the patient specific functional scale in snake envenomation.

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