Age at Disease Onset, Exercise Among Factors Seen to Affect Patients’ Life Quality

Joana Carvalho, PhD avatar

by Joana Carvalho, PhD |

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Quality of life tends to be poorer in people with myasthenia gravis (MG) who develop the disease later in life, have more severe symptoms and little physical activity, or are either overweight or obese, a study found.

Life quality tended to be better for those who exercise regularly, have higher levels of education, and regular employment but work that is not physically demanding.

These findings are in the study, “Determinants of Quality of Life in Myasthenia Gravis Patients,” published in the journal Frontiers in Neurology.

MG is caused by the abnormal production of self-reactive antibodies that target proteins needed for muscle contraction. This leads to extreme fatigue and muscle weakness that can be generalized, or less severe and limited to a specific group of muscles as with ocular MG.

Disease treatment is often lifelong, and usually consists on a combination of immunosuppressants and therapies that lower the levels of harmful self-reactive antibodies, including plasma exchange and intravenous immunoglobulin infusion (IVIG).

Although the disease is known to impact patients’ mental health and social life, a better understanding of factors working for and against a quality life would help in optimizing treatment goals for those with chronic disease.

Researchers at the Medical University of Warsaw analyzed data on 339 adults — 220 women and 119 men, mean age of 51.6 — who had been diagnosed with either ocular or generalized MG and treated at their center between 2010 and 2015.

Patients had been living with MG for a mean of 7.5 years, and more than half (55%) started experiencing disease symptoms before age 50 (early onset disease).

The Myasthenia Gravis Foundation of America scale (MGFA) was used to assess disease severity, and the Polish version of the Short-Form 36-item (SF-36) questionnaire to assess quality of life. The Physical Composite Score (PCS) and the Mental Composite Score (MCS) were both used to summarize data on the different components of the SF-36.

No statistically significant differences in SF-36 scores were found in these patients by gender, but lower PCS and MCS scores — indicative of a poor physical and mental quality of life — were both associated with more severe disease (a worse MGFA class).

In agreement, results  showed that patients who fell into class I or II on the MGFA (meaning little or mild muscle weakness) had significantly higher (better) PCS and MCS scores compared with those with more severe symptoms.

Researchers also found that people diagnosed with MG later in life tended to have a poorer overall life quality and worse PCS scores, than did those with early onset disease.

Women who were either overweight or obese also had poorer PCS and MCS scores compared with those with a normal body mass index (BMI). Men showed a similar, but not statistically significant, trend with BMI.

Patients with higher levels of education, like a university degree, tended to have better PCS scores than did those with primary or secondary education. Current employment was also associated with better PCS and MCS scores than were seen for patients on disability pensions.

Among those who were employed, white-collar workers (those typically in a professional office) had higher PCS scores than did people whose work was more physical.

Moderate regular exercise, or physical activity undertaken at least twice weekly, was also associated with higher PCS scores. Patients who lived with family rather than alone tended to have higher MCS scores.

“Our study confirmed that greater severity of symptoms, age but also BMI, employment status and type of work, disablement pension, education status and physical activity affect QoL [quality of life],” the researchers wrote.