Sex and age differences in the Multiple Sclerosis prodrome

Prodromal multiple sclerosis: considerations and future utility

A multiple sclerosis (MS) prodrome has recently been described and is characterised by increased rates of healthcare utilisation and an excess frequency of fatigue, bladder problems, sensory symptoms and pain, in the years leading up to clinical onset of disease. This important observation may have several potential applications including in the identification of risk factors for disease, the potential to delay or prevent disease onset and early opportunities to alter disease course. It may also offer possibilities for the use of risk stratification algorithms and effective population screening. If standardised, clearly defined and disease specific, an MS prodrome is also likely to have a profound influence on research and clinical trials directed at the earliest stages of disease. In order to achieve these goals, it is essential to consider experience already gleaned from other disorders. More specifically, in some chronic neurological disorders the understanding of disease pro-drome is now well advanced and has been successfully applied. However, understanding of the MS prodrome remains at an early stage with key questions including the length of the prodrome, symptom specificity and potential benefits of early intervention as yet unanswered. In this review we will explore the evidence available to date and suggest future research strategies to address unanswered questions. In addition, whilst current understanding of the MS prodrome is not yet sufficient to justify changes in public health policy or MS management, we will consider the practical utility and future application of the MS prodrome in a wider health care setting.

Prodromes in demyelinating disorders, amyotrophic lateral sclerosis, Parkinson disease, and Alzheimer's dementia

A prodrome is an early set of symptoms, which indicates the onset of a disease; these symptoms are often non-specific. Prodromal phases are now recognized in multiple central nervous system diseases. The depth of understanding of the prodromal phase varies across diseases, being more nascent for multiple sclerosis for example, than for Parkinson disease or Alzheimer's disease. Key challenges when identifying the prodromal phase of a disease include the lack of specificity of prodromal symptoms, and consequent need for accessible and informative biomarkers. Further, heterogeneity of the prodromal phase may be influenced by age, sex, genetics and other poorly understood factors. Nonetheless, recognition that an individual is in the prodromal phase of disease offers the opportunity for earlier diagnosis and with it the opportunity for earlier intervention.

Association Between Diseases and Symptoms Diagnosed in Primary Care and the Subsequent Specific Risk of Multiple Sclerosis

BACKGROUND AND OBJECTIVES

Previous studies have reported a possible prodrome in multiple sclerosis (MS) defined by nonspecific symptoms including mood disorder or genitourinary symptoms and increased health care use detected several years before diagnosis. This study aimed to evaluate agnostically the associations between diseases and symptoms diagnosed in primary care and the risk of MS relative to controls and 2 other autoimmune inflammatory diseases with similar population characteristics, namely lupus and Crohn disease (CD).

METHODS

A case-control study was conducted using electronic health records from the Health Improvement Network database in the United Kingdom and France. We agnostically assessed the associations between 113 diseases and symptoms in the 5 years before and after diagnosis in patients with subsequent diagnosis of MS. Individuals with a diagnosis of MS were compared with individuals without MS and individuals with 2 other autoimmune diseases, CD and lupus.

RESULTS

The study population consisted of patients with MS (n = 20,174), patients without MS (n = 54,790), patients with CD (n = 30,477), and patients with lupus (n = 7,337). Twelve ICD-10 codes were significantly positively associated with the risk of MS compared with controls without MS. After considering ICD-10 codes suggestive of neurologic symptoms as the first diagnosis of MS, 5 ICD-10 codes remained significantly associated with MS: depression (UK: odds ratio 1.22, 95% CI 1.11-1.34), sexual dysfunction (1.47, 1.11-1.95), constipation (1.5, 1.27-1.78), cystitis (1.21, 1.05-1.39), and urinary tract infections of unspecified site (1.38, 1.18-1.61). However, none of these conditions was selectively associated with MS in comparisons with both lupus and CD. All 5 ICD-10 codes identified were still associated with MS during the 5 years after diagnosis.

DISCUSSION

We identified 5 health conditions associated with subsequent MS diagnosis, which may be considered not only prodromal but also early-stage symptoms. However, these health conditions overlap with prodrome of 2 other autoimmune diseases; hence, they lack specificity to MS.

Socioeconomic, health-care access and clinical determinants of disease severity in Multiple Sclerosis in Chile

BACKGROUND

MS severity may be affected by genetic, patient-related, disease-related and environmental factors. Socioeconomic status, including income and healthcare access, amongst others, may also have a role in affecting diagnostic delay or therapy prescription. In Chile, two main healthcare systems exist, public-healthcare and private-healthcare, nonetheless universal care laws (e.g., access to High Efficacy Therapy-HET), including both systems, have been recently enacted for people with MS.

OBJECTIVE

To assess the role of Socioeconomic Conditions (SEC), clinical variables and public health policies on the impact of disease severity of MS patients in Chile.

METHODS

Multicentric, observational, cross-sectional study including patients from two reference centres (1 national reference centre from the private-health system and 1 regional reference centre from the public-health system). SEC and clinical variables included healthcare insurance (private or public), subclassification of health insurance according to monthly income, sex, age at onset, diagnostic delay, disease duration, diagnosis before HET law (as a proxy of HET delay), and current HET treatment. Progression Index (PI), EDSS ≥6.0 and Progressive MS diagnosis were used as outcome measures. Multivariable binary logistic regression was performed.

RESULTS

We included 604 patients (460 private-health, 144 public-health), 67% women, 100% white/mestizo, 88% RRMS, mean age 42±12 years, mean age at onset 32±11 years, mean disease duration 10±6 years, median diagnostic delay 0 (0-34) years, 86% currently receiving any DMT, 55% currently receiving HET, median EDSS at last visit of 2.0 (0-10), and median PI 0.17 (0-4.5). Lower monthly income was associated with higher EDSS and higher PI. In the multivariable analysis, public-healthcare (OR 10.2), being diagnosed before HET-law (OR 4.89), longer diagnostic delay (OR 1.26), and older age at onset (OR 1.05) were associated with a higher risk of PI>0.2, while current HET (OR 0.39) was a protective factor. Diagnosis before HET-law (OR 7.59), public-healthcare (OR 6.49), male sex (OR 2.56), longer disease duration (OR 1.2) and older age at onset (OR 1.1) were associated with a higher risk of Progressive MS. Public-healthcare (OR 5.54), longer disease duration (OR 1.14) and older age at onset (OR 1.08) were associated with a higher risk of EDSS ≥6.0 while current treatment with HET had a trend as being a protective factor (OR 0.44, p = 0.05).

CONCLUSION

MS severity is impacted by non-modifiable factors such as sex and age at onset. Interventions focused on shortening diagnostic delay and encouraging early access to high-efficacy therapies, as well as initiatives that may reduce the disparities inherent to lower socioeconomic status, may improve outcomes in people with MS.