Model may help to predict 10-year survival with FA based on 4 factors
Diabetes, overall disability, and heart issues were seen to be predictive
Diabetes, heart rhythm problems, and neurological disability were found to be the clinical factors most likely to influence life expectancy in people with Friedreich’s ataxia (FA) in a recent European registry study.
Scientists used the information to generate a model, which also included left ventricle dysfunction, that doctors might use to stratify patients by their prognosis, or expected outcomes.
“Collectively our findings have relevant implications for disease monitoring, risk stratification, and development of future therapeutic strategies in FA,” the researchers wrote.
The study, “Predictors of Survival in Friedreich’s Ataxia: A Prospective Cohort Study,” was published in the journal Movement Disorders.
Life expectancy with FA, with few disease-targeted treatments, is poor
FA results from the loss of frataxin — a protein important for cellular energy production — that mainly affects the nervous system, muscles and heart, but also can cause damage other organs, such as the pancreas.
Patients experience progressively accumulating disability, as well as disease symptoms like cardiac disorders and diabetes. A shortened lifespan in FA — on average, 35 to 40 years — has mainly been attributed to heart disease.
One treatment, Skyclarys (omaveloxolone), exists that can help to slow FA progression; it was approved in the U.S. in 2023.
Scientists looked at data collected from a large European registry study in an effort to learn more about specific factors influencing life expectancy, and to develop a model to stratify patients’ risk in the clinic.
Annual data covering 631 FA patients were obtained from the European FA Consortium for Translational Studies – EFACTS – registry (NCT02069509), a long-term, observational study of FA patients at 11 treatment centers in Europe that began in 2010.
These 339 women and 292 men had a median age of 31 at the time they joined the EFACTS registry. At the first study visit, 38% had cardiovascular disease, and 7.3% had diabetes. Nearly half (48.7%) needed a wheelchair.
Clinical data were examined over a 12-year period from September 2010 to December 2022, with a median follow-up time of six years. Over those years, 44 patients died and 119 others stopped participating in EFACTS.
The overall 10-year survival rate was 87%. The mean age of death among the 44 patients was 39.
Causes of death included cardiovascular problems (13 people, 29.5%), pneumonia (five people, 11.4%), general deterioration (two people, 4.5%), cancer (two people, 4.5%), euthanasia (two people, 4.5%), and one person died of a traumatic neck injury (2.3%) and another of a blood clot (2.3%). The cause of death for the remaining 18 patients (40.9%) was unknown.
Model aims to identify high-risk patients needing closer surveillance
While early analyses indicated that several clinical variables may be linked to survival, final statistical analyses found that disability stage as reflected in overall neurological burden, cardiac arrhythmias, and diabetes were significant and independent predictors of survival.
Specifically, having diabetes was associated with 2.3 times higher odds of death, while each increase in disability stage linked to odds that were 1.5 times higher. This means that a person with stage 6 disability (wheelchair reliant) is at a 4.5 times higher risk of death than a person at stage 3, who has movement issues (ataxia) but can still walk.
A history of an arrhythmic disorder — or abnormal heartbeats — was the only cardiac issue found to be a significant predictor of survival, raising the risk of death by 2.93 times.
Scientists then used this information to develop a model for estimating FA survival that took into account these three prognostic factors, as well as left ventricular systolic dysfunction. It arises when the heart’s left ventricle is too weak to pump enough oxygen-rich blood out to the body, and can be a cause of heart failure.
Ranging from zero to four — with one point given for each of the model’s four factors — a score of zero indicates a predicted 10-year survival rate near that of the general European population. Higher scores reflect a poorer prognostic trajectory.
Using the model, overall 10-year predicted survival was 96% with a score of zero (no factors evident), 84% with a score of one, 70% for score of two, and 42% with a score of three or four.
“This score may support clinical management by identifying high-risk patients who merit closer clinical surveillance and might benefit from early invasive therapies,” the researchers wrote, noting that the tool “awaits external validation,” in other studies.
Prolonged cardiac monitoring, independent of symptoms, should be use to help detect irregular cardiac arrhythmias in FA patients, they noted.
“In the era of digital biomarkers, portable devices may help accomplish this task in a home setting, especially in patients with advanced disease,” the scientists wrote.
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