03000nas a2200337   4500000000100000008004100001100001400042700001400056700001600070700001500086700001800101700001200119700001200131700001300143700001500156700001500171700001400186700001500200700001500215700001300230700001900243700001100262700001700273700001400290245013800304856007800442300001300520490000700533520210800540022001402648       2019                            d1 aGerardo C1 aVissoci J1 aOliveira LP1 aAnderson V1 aQuackenbush E1 aLewis B1 aRose RS1 aGreene S1 aToschlog E1 aCharlton N1 aMullins M1 aSchwartz R1 aDenning DW1 aSharma K1 aKleinschmidt K1 aBush S1 aBrandehoff N1 aLavonas E00aThe validity, reliability and minimal clinically important difference of the patient specific functional scale in snake envenomation.  uhttps://journals.plos.org/plosone/article?id=10.1371/journal.pone.0213077  ae02130770 v143 a<p><strong>OBJECTIVE: </strong>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.</p>

<p><strong>METHODS: </strong>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.</p>

<p><strong>RESULTS: </strong>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.</p>

<p><strong>CONCLUSIONS: </strong>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.</p>
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