There are more than 7,000 rare diseases (RDs), which are individually rare but have a large collective impact on patients and families, the health system, and society. There are few treatments for RD; where treatments do exist, they are often exceptionally expensive. Understanding the socioeconomic burden (SEB) of RD is crucial to properly valuing these treatments and informing health technology assessment. Our team has developed a framework of cost elements for inclusion in studies of the costs of RDs using an evidence-informed consensus-based approach.

We conducted a scoping review to identify published economic evaluations studies in RD, searching five electronic databases to identify English language RD studies published 2010-2021. We applied our framework of cost elements to assess studies regarding what cost elements were included.

Of 4,890 records identified, 48 studies were screened for inclusion. Most were from the US (n=27), UK (n=6), and Canada (n=6), and focused on hemophilia (n=14) or cystic fibrosis (n=11). Healthcare system and payer perspectives were most often reported (n=41), with only seven studies reporting a societal perspective. Cost elements most often included were medications (n=41), hospitalizations (n=35), surgery (n=20) medical tests (n=16), and outpatient (unspecified) visits (n=16). Costs to patients, families, and society were less commonly included: productivity (n=5), travel/accommodation (n=3), government benefits (n=2), family impacts (n=0), or other costs relevant to RD (n=1). While unsurprising, given that most analyses focused on healthcare or payer perspectives, this finding illustrates the extent to which the burden of RD is largely unstudied.

Our scoping review demonstrated that most studies are conducted from a healthcare system/payer perspective, and largely consider only medical costs. These studies undercount the hidden burden of rare disease borne by patients and families leading to a gap in our global understanding of the full impact of rare diseases on families. To properly account for the these and value emerging treatments for RD, patient- and family-borne costs must be considered in economic evaluations for health technology assessment.