Early Swallowing Difficulty Tied to Worse Outcomes

People with myasthenia gravis (MG) who have difficulty swallowing are more likely to have poor clinical outcomes, according to a recent study.

Data from the study also indicates that low levels of albumin — a protein found in the blood that helps transporting hormones and other key molecules in the bloodstream — are associated with worse MG-related outcomes.

The clinical research short report, “Assessment of clinical factors affecting outcome of myasthenia gravis,” was published in the journal Muscle & Nerve.

Previous studies have identified multiple factors linked to MG prognosis. While pneumonia and sepsis (blood poisoning) in patients with late-onset MG have been linked to poor outcomes, thymus removal surgery (thymectomy) and the presence of purely ocular (vision-related) symptoms have been associated with favorable outcomes.

“However, it is unclear to what extent clinical factors, which are usually evaluated before starting treatment, contribute to the prognosis,” the researchers wrote.

In this study, researchers at Osaka Medical College in Japan reported data from 104 MG patients seen at their clinic. Their goal was to look for clinical measurements, taken early on, that were predictive of patients’ outcomes later.

“In this study, we assessed whether easily measurable factors could help make MG prognosis more accurate,” the team wrote.

Researchers classified patients into two groups, based on whether they achieved a status of minimal manifestations or better on the Myasthenia Gravis Foundation of America Post-Intervention Status scale (MFGA-PIS). Minimal manifestations, or MM, basically means that patients did not have any symptoms that affected their day-to-day life, even though they might have subtle muscle weakness upon clinical examination.

Among the 104 patients included in the analyses, 80 achieved a status of MM or better at their most recent clinical visit, while the remaining 24 did not.

Researchers then used a battery of statistical analyses to look for factors assessed prior to treatment was started (baseline) that could predict whether patients would achieve a good outcome (defined as attaining MM or better).

Multivariate analyses — statistical analyses that take into account many different factors that could contribute to clinical outcomes — showed that patients who had dysphagia (difficulty swallowing) at baseline were significantly less likely to achieve a status of MM or better.

Likewise, hypoalbuminemia, or abnormally low levels of albumin in the blood, at baseline also was associated with a lower likelihood of achieving a positive outcome.

In agreement with statistical analyses, investigators found the proportion of patients who had dysphagia at baseline was much higher among those who failed to achieve a status of MM or better compared with those who did (83% vs. 40%).

Moreover, blood albumin levels at baseline were significantly lower in the group of those who never attained MM or better compared with those who did (3.9 vs. 4.3 g/dL).

Researchers speculated that dysphagia could be a contributing factor for hypoalbuminemia. Simply put, swallowing difficulties could lead to malnutrition, which could affect albumin’s production in the liver. The team also noted that hypoalbuminemia has been linked with increased inflammation.

The team acknowledged its study had several limitations, including that it was conducted at single center in Japan, making its findings unlikely to apply to everyone with MG. Also, different patients analyzed likely received different types of treatment and care, which could have affected their outcomes.

The team noted that further studies are needed to better define how clinical parameters can be used to make accurate prognoses for MG. They also noted a need to study whether symptomatically treating hypoalbuminemia might improve MG-related outcomes.