Known-groups Discriminant Validity Research Articles

Patient-Reported Pediatric Quality of Life Inventory™ 4.0 Generic Core Scales in Pediatric Patients with Attention-Deficit/Hyperactivity Disorder and Comorbid Psychiatric Disorders: Feasibility, Reliability, and Validity

Objectives The primary objective of the study was to evaluate the feasibility, reliability, and validity of the Pediatric Quality of Life Inventory™ (PedsQL) 4.0 Generic Core Scales as a patient self-reported health-related quality of life measurement instrument in pediatric patients with attention-deficit/hyperactivity disorder (ADHD) and physician-diagnosed comorbid psychiatric disorders being seen in a pediatric psychiatric clinic. The secondary objective was to evaluate parent proxy-reported PedsQL in this population. Methods One hundred seventy-nine children with ADHD and comorbid psychiatric disorders ages 5 to 18 years and 181 parents completed the PedsQL 4.0 Generic Core Scales and parents also completed the Vanderbilt ADHD Diagnostic Rating Scales. Known-groups discriminant validity comparisons were made between the sample of pediatric patients with ADHD and comorbid psychiatric disorders and healthy, cancer, and type 1 diabetes samples. Results The PedsQL evidenced minimal missing responses for patient self-report and parent proxy-report (0.2% and 0.5%, respectively), demonstrated no significant floor or ceiling effects, and achieved excellent reliability for the Total Scale Score (α = 0.85 patient self-report, 0.92 parent proxy-report). Pediatric patients with ADHD and comorbid psychiatric disorders and their parents reported statistically significantly worse PedsQL scores than healthy children, with large effect sizes across all domains, supporting known-groups discriminant validity. Pediatric patients with ADHD and comorbid psychiatric disorders and their parents reported worse PedsQL scores compared to pediatric patients with cancer and diabetes with the exception of physical health, in which pediatric cancer patients manifested lower physical health, indicating the relative severe impact of ADHD and comorbid psychiatric disorders. More severe ADHD symptoms were generally associated with more impaired PedsQL scores, supporting construct validity. Conclusions These data demonstrate the feasibility, reliability, and validity of patient self-reported PedsQL 4.0 Generic Core Scales in this high risk population of pediatric patients and highlight the profound negative impact of ADHD and comorbid psychiatric disorders on generic health-related quality of life, comparable to or worse than serious pediatric chronic physical diseases.

The Adherence Estimator: a brief, proximal screener for patient propensity to adhere to prescription medications for chronic disease

ABSTRACTObjective: To conceptualize, develop, and provide preliminary psychometric evidence for the Adherence Estimator – a brief, three-item proximal screener for the likelihood of non-adherence to prescription medications (medication non-fulfillment and non-persistence) for chronic disease.Research design and methods: Qualitative focus groups with 140 healthcare consumers and two internet-based surveys of adults with chronic disease, comprising a total of 1772 respondents, who were self-reported medication adherers, non-persisters, and non-fulfillers. Psychometric tests were performed on over 150 items assessing 14 patient beliefs and skills hypothesized to be related to medication non-adherence along a proximal–distal con-tinuum. Psychometric tests included, but were not limited to, known-groups discriminant validity at the scale and item level. The psychometric analyses sought to identify: (1) the specific multi-item scales that best differentiated self-reported adherers from self-reported non-adherers (non-fulfillers and non-persisters) and, (2) the single best item within each prioritized multi-item scale that best differentiated self-reported adherers from self-reported non-adherers (non-fulfillers and non-persisters).Results: The two rounds of psychometric testing identified and cross-validated three proximal drivers of self-reported adherence: perceived concerns about medications, perceived need for medications, and perceived affordability of medications. One item from each domain was selected to include in the Adherence Estimator using a synthesis of psychometric results gleaned from classical and modern psychometric test theory. By simple summation of the weights assigned to the category responses of the three items, a total score is obtained that is immediately interpretable and completely transparent. Patients can be placed into one of three segments based on the total score – low, medium, and high risk for non-adherence. Sensitivity was 88% – of the non-adherers, 88% would be accurately classified as medium or high risk by the Adherence Estimator. The three risk groups differed on theoretically-relevant variables external to the Adherence Estimator in ways consistent with the hypothesized proximal-distal continuum of adherence drivers.Conclusions: The three-item Adherence Estimator measures three proximal beliefs related to intentional non-adherence (medication non-fulfillment and non-persistence). Preliminary evidence of the validity of the Adherence Evidence supports its intended use to segment patients on their propensity to adhere to a newly-prescribed prescription medication. The Adherence Estimator is readily scored and is easily interpretable. Due to its brevity and transparency, it should prove to be practical for use in everyday clinical practice and in disease management for adherence quality improvement. Study limitations related to sample representation and self reports of chronic disease and adherence behaviors were discussed.