The Patient Experiences and Satisfaction with Medications (PESaM) questionnaire was recently developed. It consists of two disease-specific modules for evaluating drug treatment of idiopathic pulmonary fibrosis (IPF) and atypical hemolytic uremic syndrome (aHUS): (i) a generic module applicable to any medication, and (ii) a patient expectations module. This study assessed the validity and reliability of the generic module in a large sample of patients in the Netherlands.

In 2017, the PESaM-questionnaire was sent out to IPF patients on pirfenidone or nintedanib, aHUS patients receiving eculizumab, and patients using advagraf after kidney transplantation. The generic module consists of 16 items related to the domains effectiveness, side-effects and ease of use, and assesses patient experiences regarding the impact of the medication on daily life and health, and satisfaction. Mean scores for each domain were calculated using a scoring algorithm. Content validity, construct validity, and reliability were assessed using recommended methods.

Patients (n=188) completed the generic module of whom 48 percent used pirfenidone, 36 percent nintedanib, 11 percent advagraf, and 5 percent eculizumab. Content validity was established. Expected associations between patient experiences, satisfaction, and quality of life (QoL) were generally confirmed, demonstrating construct validity. For example, a moderate to strong positive association was found between patient experiences and satisfaction with side-effects (correlation coefficient 0.625, p < 0.05), and low (positive) associations were found between patient experiences and QoL. Importantly, the PESaM-questionnaire was able to discriminate between patients using different medications. Intraclass correlation coefficients, for test-retest reliability, ranged between good and excellent for most domains.

The PESaM questionnaire is a promising tool to provide scientific evidence regarding the patient's perspective in health technology assessments and reimbursement decision-making regarding (expensive) medications, but can also support shared decision-making and appropriate use of medication at the individual patient level. Further research will assess the questionnaire's responsiveness and generalizability of results to other patient populations.