Life quality can be low, disease burden high with LEMS: Study

Survey responses of patients in Germany compared with those of MG patients

Andrea Lobo, PhD avatar

by Andrea Lobo, PhD |

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A man is shown walking with a cane and burdened a presence, representing fatigue and depression, weighing on him.

People with Lambert-Eaton myasthenic syndrome (LEMS) have a lower quality of life and a higher disease burden than do those with myasthenia gravis (MG) or adults in the general population, according to a survey-based study in Germany.

“Quality of life reflects one aspect of the burden of disease. Our data demonstrate that many LEMS related as well as unrelated factors contribute like pieces of a puzzle to the burden of disease,” the researchers wrote.

These factors can include a person’s gender, economic and social status, ability to carry out daily life activities, emotional well-being, and fatigue levels.

The study, “Burden of disease in Lambert-Eaton myasthenic syndrome: taking the patient’s perspective,” was published in the Journal of Neurology.

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Questionnaires aimed to address patients’ physical and mental health

An autoimmune disease, LEMS is caused by immune system attacks on specific calcium channels, called voltage-gated calcium channels (VGCCs), that are found in nerve cell endings and play a key role in muscle movement control.

The disease’s hallmark symptoms include muscle weakness, lack of reflexes, fatigue, and problems with the autonomic nervous system that controls unconscious body processes, such as digestion or breathing. All can weigh on a person’s overall well-being.

However, “few studies have analysed health-related quality of life (HRQoL) and perceived physical and mental health in LEMS patients,” the scientists wrote.

To better understand LEM’s burden and associated risk factors, researchers in Berlin used questionnaires to collect demographic, population, and clinical data from 46 adults with LEMS, all members of the German Myasthenia Gravis Society.

Survey responses from these LEMS patients were compared with those from 92 age- and sex-matched MG patients and 92 adults in the German general population, both serving as control groups. All in the group with MG — an autoimmune disease also marked by immune system attacks on proteins involved in nerve-muscle communication and muscle weakness — had answered similar questionnaires as part of a 2021 published study by these scientists.

The mean age of the LEMS patients, mostly women (78.3%), was 64.3.

Women were found to start experiencing disease symptoms earlier than men (41.8 vs. 52.8 years of age), and to wait longer for a diagnosis (4.2 vs. 2.8 years). Overall disease severity was rated as moderate by most patients (70.2%), with six women reporting high disease severity.

Signs of autonomic system issues were highly prevalent, with most patients reporting mouth dryness (80.9%) and dry eyes (74.5%). Among the men, 60% reported erectile dysfunction.

More than half of the patients had autoantibodies, mainly anti-VGCCs (88.5%), with some patients having anti-acetylcholine antibodies (11.5%), and others having both (15.4%).

Differences in physical and mental well-being seen with LEMS, MG

LEMS patients showed lower levels of physical functioning, as measured using the Short Form Health (SF-36) questionnaire, compared with the general population (mean score of 34.2 vs. 78.6) and MG patients (a 61.3 mean score).

They also had lower mental health subscores compared with the general population (mean score, 62.7 vs. 75.7) and MG patients (mean score of 66).

More specifically, about one-third (36.4%) of the LEMS patients surveyed had symptoms of anxiety, and 17.8% had signs of mild depression, the researchers found, while about 40% reported fatigue. LEMS patients with a high levels of symptom severity had a significantly lower quality of life compared with those reporting low or moderate disease symptoms.

“Results from SF-36 analyses indicate that physical limitations are even greater for LEMS [patients surveyed] compared to matched MG patients,” the researchers wrote.

Compared with men, women reported higher degrees of difficulties in activities of daily living, a poorer quality of life, lower perceived social support, and more symptoms of depression, anxiety, and fatigue. However, these differences were not statistically significant.

Female sex, and having a lower income, more difficulties in daily life activities, and symptoms of depression, anxiety, and fatigue were associated with a lower quality of life in LEMS patients, the researchers concluded.

Compared with MG patients, the disease burden in LEMS patients also was seen to be greater.

“A more disease-specific view of patient’s individual burden of disease” with LEMS is needed, the researchers wrote.

But for such work to be conducted, “development of a LEMS-specific questionnaire encompassing motoric [muscular movement] as well as autonomic symptoms that integrates other influencing factors besides quality of life, such as functional level, depression and anxiety, fatigue, and social participation would be desirable,” they added.

Special attention also “should be paid to gender-aspects as women suffering from LEMS do have a higher burden of disease,” the researchers wrote.