Objectives <p>The EQ-5D-5L may not adequately capture the health-related quality of life in patients with sleep disturbances. We examined the psychometric properties of a hybrid PROM comprising a module of four sleep-related bolt-ons and EQ-5D-5L.</p> Methods <p>We employed a sequential exploratory mixed method by first qualitatively testing the face validity of “<i>sleep</i>”, “c<i>ognition</i>”, “<i>tiredness</i>” and “<i>relationship</i>” and refining these bolt-ons through in-depth interviews with 23 patients and clinicians. We then quantitatively assessed their performance by administering the four bolt-ons, appended to EQ-5D-5L, and three condition-specific patient-reported outcome measures (cPROMs) during two clinical visits of patients with respiratory-related sleep disorders. We compared ceiling effects and construct validity of EQ-5D-5L with and without the bolt-ons by testing a priori hypotheses about the cPROMs and polysomnographic characteristics via correlation and areas under the curves (AUC) analyses, respectively. We examined their responsiveness among “<i>treated/improved</i>” participants using standardized response means (SRM) and AUC analysis, and reliability among “<i>untreated/no change</i>” participants using intra-class correlation coefficient (ICC) or Cohen’s Kappa (k).</p> Results <p>110 participants (mean [SD] age: 47[13]) were recruited and 90 returned for their review assessments (mean [SD] interval: 2.2 [2.1] months). The bolt-ons led to a reduction of 42.7% in ceiling effects. The bolt-ons were better correlated with cPROMs and exhibited higher discriminatory power and responsiveness, with comparable reliability to EQ-5D-5L. A combined module of the four bolt-ons provided better results than individual bolt-ons.</p> Conclusions <p>A “hybrid” PROM of sleep bolt-ons module added to EQ-5D-5L improved its psychometric properties among patients with sleep disturbances.</p>