The relationship of relapses to long-term disability in multiple sclerosis is uncertain. Relapse reduction is a common therapeutic target but clinical trials have shown dissociation between relapse suppression and disability accumulation. We investigated relationships between relapses and disability progression for outcomes of requiring assistance to walk, being bedridden and dying from multiple sclerosis [Disability Status Scale 6, 8, 10] by analysing 28 000 patient-years of evolution in 806-bout onset patients from the London Ontario natural history cohort. Having previously shown no effect of relapse frequency among progressive multiple sclerosis subtypes, here we examined these measures in the pre-progressive or relapsing–remitting phase. Survival was compared among groups stratified by (i) early relapses—number of attacks during the first 2 years of multiple sclerosis; (ii) length of first inter-attack interval; (iii) interval between onset and Disability Status Scale 3 (moderate disability); (iv) number of attacks from the third year of disease up to onset of progression; and (v) during the entire relapsing–remitting phase. Early clinical features can predict hard disability outcomes. Frequent relapses in the first 2 years and shorter first inter-attack intervals predicted shorter times to reach hard disability endpoints. Attack frequencies, in the first 2 years, of 1 versus ≥3, gave differences of 7.6, 12.8 and 20.3 years in times from disease onset to Disability Status Scale 6, 8 and 10, respectively. Time to Disability Status Scale 3 highly and independently predicted time to Disability Status Scale 6, 8 and 10. In contrast, neither total number of relapsing–remitting phase attacks nor of relapses experienced during the relapsing–remitting phase after the second year up to onset of progression showed a deleterious effect on times from disease onset, from progression onset and from Disability Status Scale 3 to these hard endpoints. The failure of a regulatory mechanism tied to neurodegeneration is suggested. Relapse frequency beyond Year 2 does not appear to predict the key outcome of secondary progression or times to Disability Status Scale 6, 8 or 10, highlighting two distinct disease phases related to late outcome. These appear to be separated by a watershed within the relapsing–remitting phase, just a few years after clinical onset. Higher early relapse frequencies and shorter first inter-attack intervals herald more rapid deterioration via interaction with the neurodegeneration characterizing secondary progression. They increase the probability of its occurrence, its latency and influence—to a lesser degree—its slope. The prevention or delay of the progressive phase of the disease is implicated as a key therapeutic target in relapsing–remitting patients.
Development of SP is the dominant determinant of long-term prognosis, independent of disease duration and early relapse frequency. Age independently affects disability development primarily by changing probability and latency of SP onset, with little effect on the progressive course.
Objectives To assess factors affecting the rate of conversion to secondary progressive (SP) multiple sclerosis (MS) and its subsequent evolution. Methods Among 806 patients with relapsing remitting (RR) onset MS from the London Ontario database, we used Kaplan-Meier, Cox regression and multiple logistic regression analyses to investigate the effect of baseline clinical and demographic features on (1) the probability of, and the time to, SP disease, (2) the time to bedbound status (Disability Status Scale (DSS 8)) from onset of progression. Results The risk of entering the SP phase increased proportionally with disease duration (OR=1.07 for each additional year; p<0.001). Shorter latency to SP was associated with shorter times to severe disability. The same association was found even when patients were grouped by number of total relapses before progression. However, the evolution of the SP phase was not influenced by the duration of the RR phase. Male sex (HR=1.41; p<0.001), older age at onset (age ≤20 and 21-30 vs >30 HR=0.52 ( p<0.001), 0.65 ( p<0.001), respectively) and high early relapse frequency (1-2 attacks vs ≥3 HR=0.63 ( p<0.001), 0.75 ( p=0.04), respectively) predicted significantly higher risk of SP MS and shorter latency to progression. Times to DSS 8 from onset of progression were significantly shorter among those with high early relapse frequency (≥3 attacks), and among those presenting with cerebellar and brainstem symptoms. Conclusions The onset of SP MS is the dominant determinant of long-term prognosis, and its prevention is the most important target measure for treatment. Baseline clinical features of early relapse frequency and age at onset can be used to select groups at higher risk of developing severe disability based on the probability of their disease becoming progressive within a defined time period.
Acute ischaemic stroke accounts for 6.5 million deaths per year, and by 2030 will result in the annual loss of over 200 million disability-adjusted life years globally. There have been considerable recent advances in the gold standard of acute ischaemic stroke treatment, some aspects of which-aspirin to prevent recurrence, and treating patients in specialized stroke wards-are widely applicable. Recanalization of the occluded artery through thrombolysis and/or endovascular thrombectomy is restricted to only a small proportion of patients, due to contra-indications and the costs associated with establishing the infrastructure to deliver these treatments. The use of neuroprotective agents in stroke has been a notable failure of translation from medical research into clinical practice. Yet, with the advent of endovascular thrombectomy and the ability to investigate patients in much greater detail through advanced imaging modalities, neuroprotective agents can and should be re-examined as adjunct therapies to recanalization. In parallel, this requires appropriate planning on behalf of the preclinical stroke research community: there is a need to reinvestigate these therapies in a more collaborative manner, to enhance reproducibility through reduced attrition, improved reporting, and adopting an approach to target validation that more closely mimics clinical trials. This review will describe some of the novel strategies being used in stroke research, and focus on a few key examples of neuroprotective agents that are showing newfound promise in preclinical models of stroke therapy. Our primary aim is to give an overview of some of the challenges faced by preclinical stroke research, and suggest potential ways to improve translational success.
ContextWalking speed is a fundamental parameter of human motion and is increasingly considered as an important indicator of individuals' health status.ObjectiveTo evaluate the relationship of gait parameters, and demographic and physical characteristics in healthy men and women.Design, Setting, and ParticipantsRecruitment of a subsample (n = 358) of male and female blood donors taking part in the Cambridge CardioResource study. Collection of demographic data, measurement of physical characteristics (height, weight and blood pressure) and assessment of 7-day, free-living activity parameters using accelerometry and a novel algorithm to measure walking speed. Participants were a median (interquartile range[IQR]) age of 49 (16) years; 45% women; and had a median (IQR) BMI of 26 (5.4).Main Outcome MeasureWalking speed.ResultsIn this study, the hypothesis that walking speed declines with age was generated using an initial ‘open’ dataset. This was subsequently validated in a separate ‘closed’ dataset that showed a decrease of walking speed of −0.0037 m/s per year. This is equivalent to a difference of 1.2 minutes, when walking a distance of 1 km aged 20 compared to 60 years. Associations between walking speed and other participant characteristics (i.e. gender, BMI and blood pressure) were non-significant. BMI was negatively correlated with the number of walking and running steps and longest non-stop distance.ConclusionThis is the first study using accelerometry which shows an association between walking speed and age in free-living, healthy individuals. Absolute values of gait speed are comparable to published normal ranges in clinical settings. This study highlights the potential use of mobile accelerometry to assess gait parameters which may be indicative of future health outcomes in healthy individuals.
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