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In the most recent American Society for Apheresis Guidelines on the Use of Therapeutic Apheresis in Clinical Practice, employing therapeutic plasma exchange (TPE) for long-term treatment of myasthenia gravis (MG) patients is a new indication and carries a category II, grade 2B recommendation. As data for this indication is evolving and subjective assessments of these patients are often uninformative, we sought to better characterize the impacts of long-term TPE in these MG patients using validated instruments.


In this prospective observational study, we used a combination of validated instruments and openended questions clarifying concerns that are routinely applied to MG patients. The two validated instruments were the MG Activities of Daily Living (MG-ADL) and MG Quality of Life 15 (MG-QoL15r) profiles. Based on previous literature, a 2-point change in the MG-ADL and a 10-point change in the MGQoL15r indicates significant improvement or worsening. Over a 3-month period, MG patients receiving long-term TPE were assessed using a single-form questionnaire that integrated all of the MG-ADL and MG-QoL15r elements and was completed at every visit. Patients unable to complete the survey due to their medical condition were exempted.


In total, 9 patients were eligible and received long-term TPE at frequencies from 3 times per week to 1 time per month. Five patients (56%) were female, 6 (67%) were white, and mean age was 54 years. Active pharmacotherapy included prednisone, azathioprine, mycophenolate, rituximab, and pyridostigmine. All patients reported that lengthening the interval between successive TPE treatments, even by a few days, resulted in noticeable MG changes. Five patients (56%) were clinically stable during the study period and had no significant changes in MG-ADL or MG-QoL15r profiles, though these patients still documented issues with sight, speech, muscular weakness, and fatigue. During the study period, 4 patients (44%) had significant changes identified by the MG-ADL, a mean of 5.5 times per patient (range 2-8) and 2 (22%) had significant changes identified by the MG-QoL15r, a mean of 2 times per patient (range 1-3). MG-ADL appeared to be more sensitive in correlating with patient-reported clinical changes, with clinical improvements identified a mean of 3.2 times per patient and clinical deteriorations identified a mean of 2.3 times per patient (compared to 1.5 and 1 times per patient, respectively, for the MG-QoL15r; p=0.03 for interaction effect). In the 4 patients with significant changes in profile scores, associated clinical changes in breathing, swallowing, sight, speech, muscular strength, and fatigue were reported. Importantly, for all of 4 of these patients, subjective clinical deteriorations in conjunction with objectively worsening MG-ADL scores were used as evidence to medically justify intensification of TPE therapy.


Objective longitudinal assessments in MG patients receiving long-term TPE may be helpful for accurate disease monitoring. A subset of MG patients receiving long-term TPE still has dynamic changes in disease status as assessed by clinical history and two different validated instruments. In all patients with stable MG, both the MD-ADL and MG-QoL15r accurately indicated no significant changes. However, in those with fluctuating disease status, MG-ADL was more sensitive to both clinical improvement and worsening. These findings need to be validated in larger studies.


Presented at the University of New Mexico Health Science 2020 Annual Quality Improvement and Patient Safety Symposium



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