Development of the Presbyopia Impact and Coping Questionnaire

INTRODUCTION: Presbyopia is a progressive, age-related visual condition that is characterized by reduced ability to focus on near/close objects, causing impacts on individuals’ daily function and health-related quality of life. The Presbyopia Impact and Coping Questionnaire (PICQ) is a new patient-reported outcome (PRO) instrument that assesses presbyopia impact and use of coping behaviors among presbyopic individuals. METHODS: To document the impacts of presbyopia and associated coping behaviors, concept elicitation (CE) interviews were conducted with 20 presbyopic participants. Results from the CE interviews were used to develop draft items for additional testing. Following item generation, the draft PICQ was cognitively debriefed with 20 participants. Data from a phase 2 controlled clinical trial were used for psychometric analyses of the PICQ. The PICQ was administered at site visits throughout a 28-day treatment period. Confirmatory factor analysis (CFA) methods were used to guide the development of the scoring algorithm. The reliability (internal consistency, test–retest), construct validity (convergent and discriminant validity, known-groups methods), and responsiveness (Guyatt's responsiveness statistic [GRS]) of the PICQ scores were evaluated. Finally, anchor-based and distribution-based methods were used to inform thresholds for interpreting meaningful within-patient change. RESULTS: CE interviews identified the important and relevant presbyopia-related impacts and coping behaviors and 22 items were drafted and cognitively debriefed. Following minor revisions and item addition/deletion, a version of the PICQ including 23 items was subjected to psychometric testing. The analysis sample included 151 participants. The CFA established two PICQ domain scores, Coping and Impact, on 0-to-4 scales that demonstrate good model fit (root mean square error of approximation = 0.06, comparative fit index = 0.98, Tucker-Lewis index = 0.98, standardized root mean square = 0.07). Cronbach’s alphas for the Coping and Impact scores were 0.89 and 0.84, respectively. Test–retest intraclass correlation coefficients were 0.77 for Coping and 0.67 for Impact. The pattern of results assessing construct validity was acceptable for the PICQ Coping and Impact scores, with the magnitude of correlations and effect sizes generally meeting a priori expectations. The corresponding GRS effect sizes for the PICQ Coping scores were −1.23 (i.e., large) for Patient Global Impression of Change (PGIC) and −0.72 (i.e., medium) for uncorrected near visual acuity (UNVA). The GRS effect sizes for the PICQ Impact scores were −0.60 (i.e., medium) for PGIC and −0.35 (i.e., small) for UNVA. Across three sets of anchor-based analyses for interpreting individual-level change, a responder threshold of −1.00 was identified for both PICQ Coping and PICQ Impact scores. CONCLUSIONS: The totality of evidence from the qualitative and quantitative research establishes that the PICQ scores produced are valid and reliable measures of presbyopia impacts and coping behaviors that are important and relevant for assessing presbyopia treatment outcomes. CLINICALTRIALS.GOV IDENTIFIER: NCT02780115; date of registration May 19, 2016.