OBJECTIVES: (X-Linked) Myotubular Myopathy (MTM) is a rare, life-threatening condition characterized by profound skeletal muscle weakness, often leading to chronic ventilator dependency and impaired motor development. Healthcare system dependency is largely unknown. This study provides estimates on healthcare resource utilization (HCRU) and associated costs of care for patients with MTM in England.

METHODS: A retrospective study using data from 16.9 million males (all ages) from the general population of England. The data comprised of de-identified linked electronic medical records from primary (CPRD Gold,Aurum) and secondary (HES outpatient,APC,A&E) care from 01Jan2000 to 31Dec2019. MTM cases were identified by narrow definition (Readcode:F390300 or ICD10 code:G71.2) and a broader definition of myopathies. Follow-up continued until death, study period end or last data collection date. Hospital episodes (any reason) and the National Health Service Grouper Tool were used to derive HCRU and costs in 2021 GBP.

RESULTS: Using the narrow definition, there were 377 cases, with median (IQR) age 14 years (4-29) and follow-up 4.1 years (1.7-8.9). During follow-up, the median (IQR) HCRU and costs per patient per year (PPPY) were: 6.1 (2.8-13.2) GP visits and £239 (£110-£515); 5.2 (1.7-10.3) outpatient visits and £443 (£102-£1,190); 0.94 (0.2-3.0) inpatient admissions with length of stay 1.9 (0.3-9.5) days and £1,573 (£401-£9,317). Some patients had considerably higher HCRU and costs indicating symptom severity; median (IQR) total costs PPPY were £4,049 (£1,658-£16,214) and the 95^th centile £67,864.

CONCLUSIONS: MTM patients have a very high dependency on the healthcare system. Under a broader perspective including e.g. home support, costs would be significantly higher. Economic evaluations of MTM need to emphasise probabilistic sensitivity analyses to reflect the true potential economic burden of this condition.