US study highlights high cost burden of IgG4-RD
Frequent doctor visits, lengthy hospitalizations drive costs higher
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People with immunoglobulin-G4-related disease (IgG4-RD) often attend dozens of outpatient doctors’ visits in the months immediately before and after diagnosis, and many are hospitalized for more than a week at a time.
That’s according to a study based on U.S. commercial insurance records that also showed healthcare-related costs increase by more than 50% in the year after diagnosis, driven mainly by frequent doctor visits and hospitalizations. The researchers said the study “provides important insights into the high clinical and economic burden observed in IgG4-RD.”
The study, “Real-world clinical and economic burden of immunoglobulin-G4-related disease in the United States: A retrospective claims-based analysis,” was published in Medicine. It was funded by Amgen, which markets Uplizna (inebilizumab), the only approved therapy for IgG4-RD.
IgG4-RD is a rare inflammatory disorder characterized by abnormal clumps of immune cells that can form in various organs, leading to a wide range of symptoms and clinical profiles. Because the disease is so rare and variable, misdiagnoses are common, leading to delays in treatment. And even once the disease is correctly identified and treated, it’s relatively common for patients to experience relapses, or sudden periods of symptom worsening.
“Given the frequent delays in diagnosis and treatment, as well as the relapsing nature of the disease, which contributes to patient distress, both patients and the healthcare system face substantial clinical and economic burdens,” the researchers wrote. Yet, they added, “there remains scarce data assessing the burden of IgG4-RD in a large representative sample of patients in the United States and quantifying the within-patient increase in HRU [healthcare resource utilization] and costs from before to after diagnosis.”
Quantifying costs
The team of scientists in the U.S. and Canada retrospectively analyzed health plan claims data from nearly 300 commercially insured adults with IgG4-RD obtained from a large U.S. insurance database.
Patients’ mean age was 49.8, about half were women, and more than a third (39.3%) lived in the South region of the country. Many patients had other co-occurring health issues, most commonly high blood pressure, hyperlipidemia (high blood fat levels), or type 2 diabetes.
The researchers looked at rates of medication use, doctor visits, and hospitalizations in the year before and after the IgG4-RD diagnosis. They used these rates to estimate healthcare-related costs, based on the value of the dollar in 2022 after adjusting for inflation.
“To our knowledge, this is among the first studies to assess healthcare costs among patients with IgG4-RD,” the scientists wrote.
Results showed that, in the year before diagnosis, the average patient had about 30 outpatient visits with their doctor, and nearly a quarter (22.7%) had at least one hospitalization. These rates were even higher in the year after diagnosis, when the average patient had more than 40 outpatient visits, and more than a third (35.3%) were hospitalized.
In both periods, nearly half of the patients had at least one emergency room visit, and the average length of hospitalization was slightly longer than one week.
More than half (60.3%) received anti-inflammatory and/or immunosuppressive treatments before diagnosis. The rate increased to 87.8% after diagnosis. Body-wide glucocorticoids, one of these treatments, were the most commonly used therapy in both periods.
The increases in doctor visits, hospitalizations, and medication use in the year after diagnosis translated into higher healthcare costs, driven mainly by frequent doctor visits and hospitalizations. Mean annual healthcare costs were $45,844 in the year before diagnosis and $69,753 in the year after diagnosis, reflecting a more than 50% increase.
Patients whose IgG4-RD affected the digestive system tended to accrue higher healthcare costs, which indicates “that organ-specific complications may represent a key driver of economic burden in this population,” the team wrote.
The scientists noted that the analysis was limited to commercially insured patients, so the results may not reflect the broader population of people with IgG4-RD in the U.S. They also stressed that their analysis only considered direct medical costs. The actual economic impact of IgG4-RD, including factors such as time missed from work and transportation expenses, could be far higher.
