UK Study: Most Patients With MG Require Hospitalization, Driving Health Care Resource Use

High rates of hospitalizations among patients with myasthenia gravis (MG) result in significant healthcare resource utilization and costs, showhospital data from England.

The observational study, published in Therapeutic Advances in Neurological Disorders, included patients first diagnosed with MG between 2015 and 2020. The researchers retrospectively analyzed data from 9000 patients. Over a median follow-up time of nearly 3 years, 72.8% of patients were hospitalized and half visited the accident and emergency department. Nearly all patients (92.4%) had an outpatient visit throughout the follow-up period, and 9.7% had a critical care visit.

For patients who were hospitalized, the average length of stay was 9.7 days, with the most common complications being myopathy and neuropathy.

Rescue therapy was given to a subgroup of these patients. Intravenous immunoglobulin (IVIg) was given to 6.6% of patients and 1.8% of patients received plasma exchange (PLEX), similar to rates seen among real-world data from the US. Other interventions, including with rituximab, ventilation, and thymectomy, were also given to a small subset of patients.

“In our study, the administration of IVIg was more frequent than PLEX, which is consistent with clinical practice trends. IVIg is often preferred due to its availability and lower risk of adverse events, such as hypotension, coagulopathy, and sepsis, compared to PLEX. The 599 patients with recorded IVIg use during all follow-ups appear underreported as the National Immunoglobulin Database Report estimates 666 MG patients annually receive IVIg [or 189,534 g, the equivalent of £13 m (based on an average price of £70/g)]. However, despite its preferred use over PLEX, the use of IVIg has its limitations: It is a human blood product that may be subject to supply issues and there is a risk of passing infections.”

In this study, common complications leading to hospital stay were myopathy and neuropathy | Image Credit: wladimir1804 - stock.adobe.com

Use of IVIg decreased slightly between the study period, which the researchers suggest may be a result of rituximab use as an alternative to IVIg for refractory disease, as well as stricter guidelines over IVIg use.

The group underscored recent evidence pointing to PLEX being more cost-effective than IVIg for treating MG and other autoimmune neurological conditions; however, there is currently a limited amount of PLEX centers available for patients, and treatment requires multiple days of administration, which may drive preference for IVIg.

Among patients receiving IVIg throughout follow-up, the cumulative average annual cost for hospital admission was £907,072(approximately US$1,100,000). Cumulative annual costs for those receiving PLEX was£689,979 (approximately US$860,000) and for the 0.9% of patients receiving rituximab was £146,726 (approximatelyUS$180,000).

Based on an average of 1800 MG diagnoses per year, the researchers estimated an annual incidence of MG of 4.32 cases per 100,000 lives. The estimation, said the researchers, aligns with previous German research, which estimated an incidence of 4.6 cases per 100,000 using insurance claims data.

“Limitations exist regarding the precision of this estimate due to the absence of direct denominator data in secondary healthcare settings. Notably, certain MG patients, particularly those with ocular or mild MG, may never require hospitalization, potentially leading to a skew toward patients with more severe MG. The lack of mandatory recording of outpatient diagnosis in [hospital episode statistics] may have led to an underestimate of the true incidence of MG and an overrepresentation of recorded inpatient MG diagnosis,” explained the researchers.

The group cited a previous study from the United Kingdom, which showed an MG incidence of 2.46 per 100,000 person-years based on primary care data.

Reference

vanEnkhuizen J, Binns J, Betts A, et al. A retrospective observational study on characteristics, treatment patterns, and healthcare resource use of patients with myasthenia gravis in England. Ther Adv Neurol Disord. Published online April 16, 2024. doi:10.1177/17562864241237495