IVIgs, immunosuppressants add up to higher MG healthcare costs in US

Considerable healthcare costs incurred with chronic use of IVIGs, NSISTs

Patricia Inacio, PhD avatar

by Patricia Inacio, PhD |

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Myasthenia gravis (MG) patients on long-term treatment with intravenous immunoglobulin (IVIg) or nonsteroidal immunosuppressants have significantly higher rates of disease crises and exacerbations, and subsequent greater healthcare costs, according to a retrospective analysis of insurance claims from a U.S. database.

Overall, these findings highlight that treatments capable of “consistently controlling and managing symptoms in patients with MG might improve health outcomes, prevent acute clinical deterioration, and reduce indirect costs,” researchers wrote.

The study, “Burden of illness and costs in patients with myasthenia gravis currently receiving treatment in the United States,” was published in the journal Muscle & Nerve.

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Hard-to-treat MG often requires long-term treatment

MG is an autoimmune disease where self-reactive antibodies attack and disrupt the normal communication between nerves and muscles, resulting in episodes of muscle weakness and fatigue.

Patients with hard-to-treat (refractory) MG often need long-term treatment with IVIg alone or in combination with multiple nonsteroidal immunosuppressant therapies (NSISTs). However, in the U.S., “little is known about the burden of disease, healthcare resource utilization (HCRU), and associated costs in these patients.”

With this in mind, a team led by researchers at the University of California and at Alexion, reviewed medical and pharmacy claims from 3,516 MG patients (mean age 55.8 years) in the U.S.-based IQVIA (formerly PharMetrics Plus) claims database.

Patients were divided into three groups according to their treatment over a median follow-up of 2.9 years: those treated with four or more IVIgs (the chronic IVIg group, 324 patients); patients treated with two or more NSISTs sequentially (multiple NSIST group, 324 patients); and those treated with neither chronic IVIg nor multiple NSISTs (reference group, 2,992 patients).

Patients in the reference group were significantly older than patients in the other groups, and those in the chronic IVIg group had a higher number of other health conditions (comorbidities). The most common comorbidity across all groups was uncomplicated high blood pressure.

Patients in the chronic IVIg and multiple NSIST groups were followed for a significantly longer time, a median of 3.3 and 3.53 years, compared with the reference group (2.85 years). The number of self-insured patients was lower in the reference group and a higher proportion of patients in this group used Medicare (federal health insurance for people 65 or older)/Medicaid (joint federal and state program that helps cover medical costs for some people with limited income).

In the overall study population, 2,844 (80.9%) patients received acetylcholinesterase inhibitors, 2,615 (74.4%) received steroids, and 1,362 (38.7%) received NSISTs.

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Chronic IVIg group underwent more treatments

Patients in the chronic IVIg group had a mean of 23.8 IVIg courses during the study period, with a mean duration of 2.6 days. Approximately a third of patients received 12 or more courses of IVIg. A similar proportion (31%) in the reference group received one NSIST during the study period, most commonly azathioprine (45%) and CellCept (mycophenolate mofetil, 40%).

Azathioprine was also the most frequently prescribed first NSIST in the multiple NSIST group (47%), followed by CellCept (45%).

It took patients a mean of eight months from their MG diagnosis to start their first NSIST. The mean duration of first and second NSIST administration was about 1.3 years and 1.5 years, respectively. The majority of patients (82%) received two NSISTs, and 18% of patients received three or more.

A total of 385 patients (11%) experienced at least one MG crisis, a serious complication marked by respiratory failure requiring assisted ventilation. The first crisis occurred after a median of 10.6 months. A total of 21.6% of patients in the chronic IVIg and 23% in the multiple NSIST group experienced an MG crisis, which was nearly twice as high as those in the reference group (9.2%).

MG exacerbations, or periods of worsening symptoms, were experienced by 1,793 patients (51%), with a first exacerbation appearing after a median of 1.13 months. The MG exacerbation rate was 4.3 times higher in the chronic IVIg group and 2.9 times higher in the multiple NSIST group when compared with the reference group.

However, the number of hospitalizations due to exacerbations was lower in the chronic IVIg (38.8%) versus the multiple NSIST (50.2%) and reference groups (43.2%).

The duration of hospital stay due to MG crises or exacerbations was similar across the chronic IVIg and multiple NSIST groups when compared with the reference group. However, the duration of the stay was higher for an MG crisis.

The median annual MG healthcare costs were nearly 32 times higher in the chronic IVIg group ($81,900) and 12 times higher in the multiple NSIST group ($30,300) than those in the reference group ($2,540).

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Medical, outpatient costs made up most of healthcare financial burden

Medical and outpatient costs were the main contributors to the healthcare financial burden.

Median annual MG-related medical, outpatient, and total healthcare costs were higher in the chronic IVIg and multiple NSIST groups compared with the reference group. However, inpatient costs were similar across the three groups.

Median annual MG-related pharmacy costs were relatively low across all groups, but highest in the multiple NSIST group.

Overall, “future research should investigate these outcomes in order to demonstrate the short- and long-term value of such treatments and the impact on patients and society,” the researchers concluded.