Health-related quality of life (HRQoL) data generated by generic, preference-based instruments (i.e., EQ-5D) are highly demanded in health policy decision making, because they allow for direct comparisons of HRQoL outcomes between disease areas. We aimed to quantify HRQoL outcomes in breast cancer (BC), rheumatoid arthritis (RA), multiple sclerosis (MS), rare cancers (RC), and rare disease (RD) patients and understand the patterns that differentiate HRQoL outcomes between these disease areas, and more specifically between rare and more common disease population groups.

An international, Web survey of patients measured HRQoL (EQ-5D-5L), self-perceived health (EQ-5D-5L Visual Analogue Scale), and additional QoL dimensions, such as patient disability level.

We received 675 completed responses. Average utility loss was 53.5 percent, 32.5 percent, and 33.3 percent for RD, RA, and MS patients, respectively, in contrast to 18.6 percent for BC and RC patients. Statistically significant differences (p < .05) were observed between disease groups in all EQ-5D-5L domain outcomes, apart from that of “Anxiety/Depression.” Severe and/or extreme problems were reported in performing usual activities for RD and RC (34 percent and 13 percent of overall problems reported respectively), mobility for MS (18 percent), pain/discomfort for RA (13 percent), and anxiety/depression for BC (7 percent) patients.

We demonstrated significant differences in the dimensions that drive HRQoL outcomes between rare and more common diseases and showcased that the same EQ-5D utility may reflect very different severities depending on the patient population under investigation. Future research should examine whether outcomes in other, critical HRQoL domains not included in generic measures also highlight significant differences across disease areas.