AAV Patients Vary on Preference for Plasma Exchange
Those surveyed were more likely to choose treatment if they'd already had procedure
Nearly one-third of adults with ANCA-associated vasculitis (AAV) would choose plasma exchange regardless of varying risks of kidney failure and severe infection, according to an international study.
One-fifth of patients would make that choice only in high-risk scenarios and one-sixth would reject that treatment in all scenarios, however.
Patients who had already had dialysis or plasma exchange were two to five times more likely to opt for plasma exchange than those who hadn’t.
Overall, AAV patients “do not express a consistent choice for plasma exchange, which highlights the need for shared decision making,” the researchers wrote.
The study, “Plasma Exchange for ANCA-Associated Vasculitis: An International Survey of Patient Preferences,” was published in Kidney Medicine.
AAV, marked by inflammation and damage of small blood vessels, is caused by anti-neutrophil cytoplasmic autoantibodies, or ANCAs, being produced that wrongly target healthy proteins at the surface of certain immune cells.
While many organs can be affected, the kidneys are particularly susceptible and dialysis or kidney transplant may be needed if kidney failure occurs.
Plasma exchange has been used for decades for AAV patients to reduce inflammation and organ damage. It involves removing and replacing a person’s plasma — the blood’s liquid portion that contains water, salts, and proteins such as antibodies — potentially removing ANCAs from circulation.
A previous review study found that adding this procedure to standard treatment reduced the risk of kidney failure, but increased that of serious infections. It doesn’t seem to affect the overall mortality in AAV patients, however.
Understanding the ‘why’ and ‘why not’ of plasma exchange
An international research team sought to better understand treatment decisions regarding plasma exchange in people with AAV to help inform future clinical practice and guideline recommendations.
They designed an online survey for adults with the help of four patients and one caregiver. The survey was circulated through kidney and vasculitis networks in the U.S., Canada, and the U.K., and via social media.
Respondents were asked to review five scenarios with one-year risk estimates of kidney failure and severe infection versus without plasma exchange. These scenarios were based on creatinine levels, a marker of kidney dysfunction — 150, 250, 350, 450, and 600 micromoles per liter.
With higher creatinine levels, the risk of both kidney failure and serious infection increases, as well as the risk differences between treatment with and without plasma exchange. Plasma exchange was linked to a reduced risk of kidney failure, but an increased risk of serious infection relative to no such treatment.
For each scenario, patients had to indicate if they would or would not choose plasma exchange.
A total of 470 AAV patients completed the survey and their responses were included in the final analysis. Responders were from 13 countries: 61.7% were from the U.S., 20% from the U.K., 13.8% from Canada, and 4.5% from other countries.
Their mean age was 58.6. Most were women (70.2%), had granulomatosis with polyangiitis, a type of AAV (71.1%), and kidney disease (64.3%).
Results showed 145 participants (30.9%) chose plasma exchange across all scenarios, regardless of the risk of kidney failure and severe infection, while 80 (17%) declined plasma exchange across all scenarios.
Also, 103 respondents (21.9%) decided for the procedure only with higher risk of both complications, while 92 (19.6%) declined plasma exchange with those conditions. Other treatment decision patterns were observed for 50 participants (10.6%).
Older patients were significantly less likely to choose plasma exchange (by 2% for every year increase), while those from the U.K. and those who’d had dialysis were about 2.6 times more likely to favor it. Those who’d already had plasma exchange showed the higher likelihood of choosing it — by 5.62 times.
“Our findings that previous treatment with dialysis or plasma exchange were predictors of choosing treatment with plasma exchange are not surprising given likely response/survivor bias and the harms associated with dialysis, but the rationale for why being from the United Kingdom is also a significant predictor is uncertain,” said the researchers, who noted “[variability] in treatment decisions” underscored the need for “individualized shared decision making.”
“This includes discussing plasma exchange with patients who are potentially at lower risk of kidney failure where some clinicians may not believe the potential benefits justify the potential harms or in patients where clinicians believe that the use of plasma exchange is mandatory,” they said.