Meaningful Within-Patient Change of the IWQOL-Lite-CT Physical Function Composite in Adults With Obesity
Author(s)
Ronette Kolotkin, PhD1, Andrew G. Bushmakin, M.S.2, Nini Liu-Péré, MSc3, Joseph C. Cappelleri, PhD2, Susan Martin, MSPH4, Joshua T. Swan, PharmD2, Xuemei Luo, PhD2.
1Quality of Life Consulting, Durham, NC, USA, 2Pfizer Inc., New York City, NY, USA, 3Pfizer Inc., Paris, France, 4RTI Health Solutions, Ann Arbor, MI, USA.
1Quality of Life Consulting, Durham, NC, USA, 2Pfizer Inc., New York City, NY, USA, 3Pfizer Inc., Paris, France, 4RTI Health Solutions, Ann Arbor, MI, USA.
OBJECTIVES: The Impact of Weight on Quality of Life-Lite Clinical Trials Version (IWQOL-Lite‐CT) patient-reported outcome (PRO) measure can assess the effects of weight management therapy on physical function (PF) in clinical trials. This study aimed to establish meaningful within-patient change (MWPC) thresholds—to refine and calibrate a range of MWPC thresholds to aid in the interpretation of change—of the IWQOL-Lite-CT PF Composite in adults with obesity.
METHODS: This analysis used blinded patient data from the randomized, double-blind, phase 2 trial of lotiglipron (NCT05579977) in adults with obesity without diabetes. PF MWPC thresholds were estimated using anchor-based regression analyses. Patient Global Impression of Severity (PGI-S) and Patient Global Impression of Change (PGI-C) for physical limitation were used as anchors and change from baseline in the IWQOL-Lite-CT PF Composite was used as the outcome. The IWQOL-Lite-CT PF Composite was assessed at baseline and at week 20.
RESULTS: The trial population (N=389; mean age, 49.1 years) was mostly female (60.9%), White (81.7%), with a mean body mass index of 37.8 kg/m2 and a mean IWQOL-Lite-CT PF Composite score of 64.10 at baseline. MWPC analyses included all available data from 298 patients. Estimated PF MWPC threshold values of 12.16 (PGI-S based) and 7.91 (PGI-C based) corresponded to a 2-category change in the anchor. These thresholds can be interpreted in terms of the effect sizes as “medium” (effect sizes of 0.54, PGI-S based) and “small-to-medium” (0.35, PGI-C based), respectively, based on the PF standard deviation value at baseline.
CONCLUSIONS: A threshold of 12.16 can be considered as MWPC for the IWQOL-Lite-CT PF Composite. This threshold complements a published responder threshold of 14.16 (PGI-S based), and these thresholds can be used together to determine clinical meaningfulness of the change in IWQOL-Lite-CT PF Composite.
METHODS: This analysis used blinded patient data from the randomized, double-blind, phase 2 trial of lotiglipron (NCT05579977) in adults with obesity without diabetes. PF MWPC thresholds were estimated using anchor-based regression analyses. Patient Global Impression of Severity (PGI-S) and Patient Global Impression of Change (PGI-C) for physical limitation were used as anchors and change from baseline in the IWQOL-Lite-CT PF Composite was used as the outcome. The IWQOL-Lite-CT PF Composite was assessed at baseline and at week 20.
RESULTS: The trial population (N=389; mean age, 49.1 years) was mostly female (60.9%), White (81.7%), with a mean body mass index of 37.8 kg/m2 and a mean IWQOL-Lite-CT PF Composite score of 64.10 at baseline. MWPC analyses included all available data from 298 patients. Estimated PF MWPC threshold values of 12.16 (PGI-S based) and 7.91 (PGI-C based) corresponded to a 2-category change in the anchor. These thresholds can be interpreted in terms of the effect sizes as “medium” (effect sizes of 0.54, PGI-S based) and “small-to-medium” (0.35, PGI-C based), respectively, based on the PF standard deviation value at baseline.
CONCLUSIONS: A threshold of 12.16 can be considered as MWPC for the IWQOL-Lite-CT PF Composite. This threshold complements a published responder threshold of 14.16 (PGI-S based), and these thresholds can be used together to determine clinical meaningfulness of the change in IWQOL-Lite-CT PF Composite.
Conference/Value in Health Info
2025-11, ISPOR Europe 2025, Glasgow, Scotland
Value in Health, Volume 28, Issue S2
Code
PCR153
Topic
Patient-Centered Research
Topic Subcategory
Instrument Development, Validation, & Translation
Disease
Diabetes/Endocrine/Metabolic Disorders (including obesity)