Visit-to-visit systolic blood pressure variability is associated with increased fatigue symptoms in multiple sclerosis patients.

OBJECTIVE: To evaluate the relationship between visit-to-visit systolic blood pressure variability (SBPv) and fatigue symptoms in Multiple Sclerosis (MS) patients. METHODS: This is a cross-sectional study using data for MS patients who completed the Fatigue Subscale in the Performance Scales (PS), a validated, self-reported measure of MS-related disability, between 2011 and 2015 at an academic medical center. Those who had at least 3 available SBP measures within the prior 12 months of the survey were included in the analysis. Ordinal logistic regression was used to model fatigue as a function of SBP variability, adjusting for demographic factors and mean SBP. RESULTS: Data for 91 MS subjects were analyzed. We found that, compared to those with the lowest SBP variability (Tertile 1), subjects in Tertile 2 had 2.2 times higher odds (OR = 2.19; 95% CI, 0.82-5.87; p = 0.120) and those in Tertile 3 (highest variability) 4.2 times higher odds (OR = 4.16; 95% CI, 1.56-11.13; p = 0.005) of being in a higher fatigue level group, independent of age, sex, race/ethnicity, and mean SBP. CONCLUSIONS: Our data show that MS patients with higher SBP variability had a greater degree of fatigue. Future research is needed to further explore this relationship and the potential for therapeutic opportunities to improve fatigue.

Six-Minute Walk as a Measure of Walking Capacity and Endurance in Patients With Pediatric-Onset Multiple Sclerosis.

BACKGROUND: Despite low levels of disability, youth with pediatric-onset MS (POMS) engage in less physical activity compared to peers. The contribution of walking capacity, endurance, behavior, and MS co-morbidities remain relatively undefined and may provide valuable insights into the limitations toward physical activity in youth with MS. OBJECTIVE: Investigate differences in walking capacity, endurance and real-world behaviors of daily activity between youth with POMS and controls. DESIGN/METHODS: Youth diagnosed with MS prior to 18 years and aged ≤21 years were recruited in addition to healthy controls. Subjects completed questionnaires to quantify fatigue, depression, and physical activity levels and the timed 2- and 6-minute walk (2MW, 6MW) as an assessment of walk capacity and endurance. Subjects were sent home with a waist-worn accelerometer to assess real-world walking behavior. RESULTS: Forty-five POMS and 85 control subjects were enrolled. The POMS cohort had a mean age of 16.9±2.7 years with a mean disease duration of 2.8±2.6 years. A greater proportion of the POMS cohort was overweight/obese compared to controls (60% versus 33%). Subjects with MS walked a significantly shorter distance in 6 minutes compared to controls (1848 feet vs 2134 feet, p<0.0001) and, unlike controls, were unable to accelerate to their peak speed at the end of the 6MW. BMI category and MS disease significantly impacted 6MW performance. Using continuous accelerometry, subjects with MS spent less time in moderate-to-vigorous physical activity compared to controls (20.4 minutes/day vs 35.4 minutes/day, p=0.0003). The POMS cohort reported significantly higher levels of depression and fatigue, but self-reported similar levels of daily physical activity as controls. CONCLUSIONS: Youth with POMS exhibit slower 6MW performance and less daily engagement in moderate-to-vigorous physical activity, suggesting limitations in functional walking capacity, endurance, and daily activity behavior. Limitations in walking endurance and capacity are most prominent in those youth who are overweight/obese and living with MS. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that, compared to healthy controls, patients with pediatric-onset MS walk shorter distances on the 6 minute walk test, are less able to accelerate to peak speed at the end of the test, and are less physically active.

Retrospective cohort study of the relationship between systolic blood pressure variability and multiple sclerosis disability.

OBJECTIVE: To examine the relationship between visit-to-visit systolic blood pressure (SBP) variability and patient-reported outcome measure of disability in multiple sclerosis (MS) patients. DESIGN: A retrospective cohort study of individuals with MS who completed a patient-determined disease steps (PDDS) scale between 2011 and 2015 at an MS specialty clinic. PARTICIPANTS: Individuals with MS for whom both a completed PDDS scale and ≥3 SBP measures within the prior 12 months of the survey were available. MAIN OUTCOME MEASURE: Participants were grouped into three classes of disability (no or mild (PDDS 0-1), moderate (2-3), severe (4-7)). SBP variability was calculated as within-subject SD using all SBP measures taken during the past 12 months. SBP variability was analysed by Tertile groups. RESULTS: Ninety-two subjects were included in this analysis. Mean PDDS score was 2.22±1.89. Compared with subjects in Tertile 1 (lowest variability), the odds of being in a higher disability group was 3.5 times higher (OR=3.48; 95% CI: 1.08 to 11.25; p=0.037) in Tertile 2 and 5.2 times higher (OR=5.19; 95% CI: 1.53 to 17.61; p=0.008) in Tertile 3 (highest variability), independent of mean SBP, age, sex, race/ethnicity, body mass index and comorbidities (p for trend=0.008). Mean PDDS scores were 1.52±1.18 in Tertile 1, 2.73±1.02 in Tertile 2 and 2.42±0.89 in Tertile 3 after adjusting for the same covariates. CONCLUSIONS: Our results show a significant gradient relationship between SBP variability and MS-related disability. More research is needed to determine the underlying pathophysiological relationship between SBP variability and MS disability progression.