Lower Quality of Life in Women Linked to Coexisting Diseases, Chinese Study Finds

Women with myasthenia gravis (MG) have a diminished quality of life compared with male patients, and are particularly affected by the number of additional diseases (comorbidities) they experience, a new study from China reports.

They also have a less active lifestyle, which may reveal more severe disease.

According to the researchers, these findings among female patients suggest that “future interventions should cope with these factors to improve their quality of life.”

The study, “Gender differences in quality of life among patients with myasthenia gravis in China,” was published in the journal Health and Quality of Life Outcomes. 

Previous studies have shown that women with MG have worse mental and physical health outcomes than men with the neuromuscular condition. Women also have roughly twice the prevalence of MG as men, and experience earlier disease onset.

In addition to affecting overall quality of life, a patient’s sex also has been found to play a role in responsiveness to treatments — but women experience more positive outcomes following thymectomy (thymus removal) than men do.

While sex is a known factor in MG patients’ health-related quality of life (HRQoL), specifics on how it influences disease onset, severity, and factors related to social and mental well-being are still unknown.

Now, researchers from the Chinese University of Hong Kong and their collaborators analyzed sex differences in the HRQoL of 1,815 Chinese MG patients.

Using a questionnaire adapted from a U.S. Myasthenia Gravis Patient Registry, the researchers collected metrics related to socio-demographics, diagnosis, treatment history, comorbidities, and social support.

The team assessed symptoms and daily activity performance with the MG activities of daily living scale (MG-ADL), and evaluated the impact of MG on patients’ physical, physiological, and emotional well-being with the 15-item Myasthenia Gravis Quality-of-Life Revised Scale (MG-QoL15r). The Chinese General Social Survey was used to assess whether the participants had an active lifestyle.

The patients, all adults, were assessed using three models based on (I) all metrics except sex, (II) all metrics including sex, and (III) all metrics plus an additional sex and comorbidity interaction metric. 

Included in the analysis were 621 men (34%) and 1,194 women (66%). Overall, the women were younger, with a mean age of 39.8 compared with 43.4 for the men. Despite being younger, the women had a longer disease duration (median 4.75 years) compared with the men (median 5.54 years).

Female patients also were more likely to be unemployed, and reported lower household income than their male counterparts. In addition, they were an average of 4.5 years younger than men at disease onset, and had a higher rate of MG exacerbations compared with men (35.26% vs. 30.92%).

Concerning additional coexisting disorders, the women were more likely to also have autoimmune thyroid disease (15.35% vs. 9.62%). Meanwhile, the men were more likely to also have been diagnosed with psoriasis (4.62% vs. 2.05%), type 2 diabetes (12.38% vs. 5.77%), and high blood pressure (21.55% vs 11.83%).

Women had significantly lower HRQoL, and also had a less active lifestyle and a higher MG-ADL score, which may suggest more severe symptoms, the scientists said.

The team found that a higher number of additional diseases was associated with lower quality of life, particularly in women. Notably, better emotional quality of life correlated with less MG exacerbations and a more active lifestyle, but not with sex differences.

“We showed that, with an increasing burden of comorbidities, the negative impact on physical and social components of HRQoL is stronger in the female group than in their male counterparts,” the researchers wrote. 

The study found that prednisone treatment, active lifestyle, employment status, and recent MG exacerbations are among the most significant influences on quality of life. An active lifestyle was associated with better overall quality of life. Meanwhile, unemployment, current use of prednisone, and MG exacerbations in the previous six months negatively affected quality of life. 

Such findings may be due to hormonal differences, sex-related effects of treatments, and ineffective therapy in women due to lower treatment dosages, the researchers suggested.

Among the study’s limitations was a lack of more accurate information on both patients’ clinical status and prednisone dosage. In addition, a potential selection bias of patients volunteering for the study cannot be ruled out, the researchers noted.

“Future study is recommended to further explore the effect of the dose of prednisone in Chinese patients with MG,” the scientists wrote, given that this immunosuppressant was associated with lower quality of life.

Yet, “such findings should be interpreted with cautions since they only show association, rather than causality, between the current use prednisone and HRQoL,” they added.