The impact of fibrodysplasia ossificans progressiva (FOP) on patients and their family members: results from an international burden of illness survey.

BACKGROUND: Fibrodysplasia ossificans progressiva (FOP) is an ultra-rare, genetic disorder of heterotopic ossification within soft, connective tissues resulting in limited joint function and severe disability. We present results from an international burden of illness survey (NCT04665323) assessing physical, quality of life (QoL), and economic impacts of FOP on patients and family members. METHODS: Patient associations in 15 countries invited their members to participate; individuals with FOP and their family members were eligible. The survey was available online, in 11 languages, from 18 January-30 April 2021. Participants responded to assessments measuring joint function, QoL, healthcare service and living adaptation utilization, out-of-pocket costs, employment, and travel. RESULTS: The survey received 463 responses (patients, n = 219; family members, n = 244). For patients, decreased joint function was associated with reduced QoL and greater reliance on living adaptations. Nearly half of primary caregivers experienced a mild to moderate impact on their health/psychological wellbeing. Most primary caregivers and patients (≥18 years) reported that FOP impacted their career decisions. CONCLUSIONS: Data from this survey will improve understanding of the impact of FOP on patients and family members, which is important for identifying unmet needs, optimizing care, and improving support for the FOP community.

The Natural History of Flare-Ups in Fibrodysplasia Ossificans Progressiva (FOP): A Comprehensive Global Assessment.

Fibrodysplasia ossificans progressiva (FOP) leads to disabling heterotopic ossification (HO) from episodic flare-ups. However, the natural history of FOP flare-ups is poorly understood. A 78-question survey on FOP flare-ups, translated into 15 languages, was sent to 685 classically-affected patients in 45 countries (six continents). Five hundred patients or knowledgeable informants responded (73%; 44% males, 56% females; ages: 1 to 71 years; median: 23 years). The most common presenting symptoms of flare-ups were swelling (93%), pain (86%), or decreased mobility (79%). Seventy-one percent experienced a flare-up within the preceding 12 months (52% spontaneous; 48% trauma-related). Twenty-five percent of those who had received an intramuscular injection reported an immediate flare-up at the injection site, 84% of whom developed HO. Axial flare-ups most frequently involved the back (41.6%), neck (26.4%), or jaw (19.4%). Flare-ups occurred more frequently in the upper limbs before 8 years of age, but more frequently in the lower limbs thereafter. Appendicular flare-ups occurred more frequently at proximal than at distal sites without preferential sidedness. Seventy percent of patients reported functional loss from a flare-up. Thirty-two percent reported complete resolution of at least one flare-up and 12% without any functional loss (mostly in the head or back). The most disabling flare-ups occurred at the shoulders or hips. Surprisingly, 47% reported progression of FOP without obvious flare-ups. Worldwide, 198 treatments were reported; anti-inflammatory agents were most common. Seventy-five percent used short-term glucocorticoids as a treatment for flare-ups at appendicular sites. Fifty-five percent reported that glucocorticoids improved symptoms occasionally whereas 31% reported that they always did. Only 12% reported complete resolution of a flare-up with glucocorticoids. Forty-three percent reported rebound symptoms within 1 to 7 days after completing a course of glucocorticoids. This study is the first comprehensive global assessment of FOP flare-ups and establishes a critical foundation for the design and evaluation of future clinical trials.