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Pain Research and Treatment
Volume 2017, Article ID 6080648, 11 pages
https://doi.org/10.1155/2017/6080648
Research Article

Evaluating the Measurement Properties of the Self-Assessment of Treatment Version II, Follow-Up Version, in Patients with Painful Diabetic Peripheral Neuropathy

1Astellas Pharma Global Development, Leiden, Netherlands
2Evidera, London, UK
3Evidera, Bethesda, MD, USA

Correspondence should be addressed to Floortje van Nooten; moc.liamtoh@netoonnavejtroolf

Received 7 November 2016; Accepted 6 December 2016; Published 16 January 2017

Academic Editor: Giustino Varrassi

Copyright © 2017 Floortje van Nooten et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background. The Self-Assessment of Treatment version II (SAT II) measures treatment-related improvements in pain and impacts and impressions of treatment in neuropathic pain patients. The measure has baseline and follow-up versions. This study assesses the measurement properties of the SAT II. Methods. Data from 369 painful diabetic peripheral neuropathy (PDPN) patients from a phase III trial assessing capsaicin 8% patch (Qutenza®) efficacy and safety were used in these analyses. Reliability, convergent validity, known-groups validity, and responsiveness (using the Brief Pain Inventory-Diabetic Neuropathy [BPI-DN] and Patient Global Impression of Change [PGIC]) analyses were conducted, and minimally important differences (MID) were estimated. Results. Exploratory factor analysis supported a one-factor solution for the six impact items. The SAT II has good internal consistency (Cronbach’s alpha: 0.96) and test-retest reliability (intraclass correlation coefficients: 0.62–0.88). Assessment of convergent validity showed moderate to strong correlations with change in other study endpoints. Scores varied significantly by level of pain intensity and sleep interference () defined by the BPI-DN. Responsiveness was shown based on the PGIC. MID estimates ranged from 1.2 to 2.4 (pain improvement) and 1.0 to 2.0 (impact scores). Conclusions. The SAT II is a reliable and valid measure for assessing treatment improvement in PDPN patients.