Evaluating the Role of High-Dimensional Proxy Data in Confounding Adjustment in Multiple Sclerosis Research: A Case Study.

Purpose: Given the historical use of limited confounders in multiple sclerosis (MS) studies utilizing administrative health data, this brief report evaluates the impact of incorporating high-dimensional proxy information on confounder adjustment in MS research. We have implemented high-dimensional propensity score (hdPS) and high-dimensional disease risk score (hdDRS) methods to assess changes in effect estimates for the association between disease-modifying drugs (DMDs) and all-cause mortality in an MS cohort from British Columbia (BC), Canada.

Methods: We conducted a population-based retrospective study using linked administrative databases from BC, including health insurance registries, demographics, physician visits, hospitalizations, prescriptions, and vital statistics.

Healthcare use is elevated two decades before a first demyelinating event and differs by age and sex.

Objective: Elevated healthcare use before multiple sclerosis (MS) onset suggests earlier opportunity to identify MS. Yet their timing and sociodemographic effects are unclear. We examined rates of healthcare use (and by age/sex) for >two decades pre-MS onset.

The fungal gut microbiota in pediatric-onset multiple sclerosis.

Evidence suggests that the gut microbiome may play a role in multiple sclerosis (MS). However, the majority of the studies have focused on gut bacterial communities; none have examined the fungal microbiota (mycobiota) in persons with pediatric-onset multiple sclerosis (POMS). We examined the gut mycobiota in persons with and without POMS through a cross-sectional examination of the gut mycobiota from 46 participants' stool samples (three groups: 18 POMS, 13 acquired monophasic demyelinating syndromes [monoADS], and 15 unaffected controls).

Symptoms Prior to Diagnosis of Multiple Sclerosis in Individuals Younger Than 18 Years.

Importance: A growing body of literature suggests the presence of a prodromal period with nonspecific signs and symptoms before onset of multiple sclerosis (MS).

Objective: To systematically assess diseases and symptoms diagnosed in the 5 years before a first MS- or central nervous system (CNS) demyelinating disease-related diagnostic code in pediatric patients compared with controls without MS and controls with another immune-mediated disorder, juvenile idiopathic arthritis (JIA).

Design, Setting, And Participants: This population-based, matched case-control study included children and adolescents (aged <18 years) in Germany with statutory health insurance from January 2010 to December 2020.

The misclassification of depression and anxiety disorders in the multiple sclerosis prodrome: A probabilistic bias analysis.

Background: Studies suggest that depression/anxiety form part of the multiple sclerosis (MS) prodrome. However, several biases have not been addressed. We re-examined this association after correcting for: (i) misclassification of individuals not seeking healthcare, (ii) differential surveillance of depression/anxiety in the health system, and (iii) misclassified person-time from using the date of the first MS-related diagnostic claim (i.