Multi-Site Clinical Assessment of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (MCAM): Design and Implementation of a Prospective/Retrospective Rolling Cohort Study

Abstract

In the Multi-Site Clinical Assessment of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (MCAM), we relied on expert clinician diagnoses to enroll patients from 7 specialty clinics in the United States in order to perform a systematic collection of data on measures of myalgic encephalomyelitis (ME)/chronic fatigue syndrome (CFS). Healthy persons and those with other illnesses that share some features with ME/CFS were enrolled in comparison groups. The major objectives were to: 1) use standardized questionnaires to measure illness domains of ME/CFS and to evaluate patient heterogeneity overall and between clinics; 2) describe the course of illness, identify the measures that best correlate with meaningful clinical differences, and assess the performances of questionnaires as patient/person-reported outcome measures; 3) describe prescribed medications, orders for laboratory and other tests, and management tools used by expert clinicians to care for persons with ME/CFS; 4) collect biospecimens for future hypothesis testing and for evaluation of morning cortisol profiles; and 5) identify measures that best distinguish persons with ME/CFS from those in the comparison groups and detect subgroups of persons with ME/CFS who may have different underlying causes. Enrollment began in 2012 and is planned to continue in multiple stages through 2017. We present the MCAM methods in detail, along with an initial description of the 471 patients with ME/CFS who were enrolled in stage 1.

Keywords: chronic fatigue syndrome; myalgic encephalomyelitis; patient-reported outcome measures; study methods.

Figure 1

Percentages of patients with specific symptoms (based on the CDC Symptom Inventory for chronic fatigue syndrome) in stage 1, Multi-Site Clinical Assessment of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome, 2012–2013. The CDC Symptom Inventory asks about symptoms experienced in the past month. Symptoms that have been present for less than 6 months were assigned a score of 0 and were not included. A frequency of 1 indicates a little of the time, and a frequency of 2 indicates some of the time. A severity of 1 indicates very mild or mild, and a severity of 2.5 indicates moderate. The gray bars indicate the percentages of patients who reported the specified symptom with both frequency and severity of 2 or greater. The black bars indicate the percentages of patients reporting that symptom with frequency and severity of 1 or greater. Symptoms are listed by increasing percentages of patients who reported symptoms with a frequency and a severity of at least 2.

Figure 2

Distribution of 36-Item Short Form Survey Subscale (Short Form-36) scores in patients with myalgic encephalomyelitis/chronic fatigue syndrome in stage 1, Multi-Site Clinical Assessment of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome, 2012–2013. The boxplots display the 5-number summary: minimum, first quartile, median, third quartile, and maximum. The central rectangle spans from the first quartile to the third quartile (the interquartile range), a segment inside the rectangle shows the median, and the dotted lines (sometimes referred to as whiskers) are extended to the extrema of the distribution in the data set. The mean value in each boxplot is indicated by a diamond. The circles indicate outliers, and the thick black bars indicate the means among the 213 healthy controls with data as of September 2015 (collected 2013–2015). Lower scores indicate more disability. Adapted from the Centers for Disease Control and Prevention (34).