Impact of methodological choices in comparative effectiveness studies: application in natalizumab versus fingolimod comparison among patients with multiple sclerosis

Background

Natalizumab and fingolimod are used as high-efficacy treatments in relapsing–remitting multiple sclerosis. Several observational studies comparing these two drugs have shown variable results, using different methods to control treatment indication bias and manage censoring. The objective of this empirical study was to elucidate the impact of methods of causal inference on the results of comparative effectiveness studies.

Methods

Data from three observational multiple sclerosis registries (MSBase, the Danish MS Registry and French OFSEP registry) were combined. Four clinical outcomes were studied. Propensity scores were used to match or weigh the compared groups, allowing for estimating average treatment effect for treated or average treatment effect for the entire population. Analyses were conducted both in intention-to-treat and per-protocol frameworks. The impact of the positivity assumption was also assessed.

Results

Overall, 5,148 relapsing–remitting multiple sclerosis patients were included. In this well-powered sample, the 95% confidence intervals of the estimates overlapped widely. Propensity scores weighting and propensity scores matching procedures led to consistent results. Some differences were observed between average treatment effect for the entire population and average treatment effect for treated estimates. Intention-to-treat analyses were more conservative than per-protocol analyses. The most pronounced irregularities in outcomes and propensity scores were introduced by violation of the positivity assumption.

Conclusions

This applied study elucidates the influence of methodological decisions on the results of comparative effectiveness studies of treatments for multiple sclerosis. According to our results, there are no material differences between conclusions obtained with propensity scores matching or propensity scores weighting given that a study is sufficiently powered, models are correctly specified and positivity assumption is fulfilled.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-022-01623-8.

MSCopilot, a new multiple sclerosis self-assessment digital solution: results of a comparative study versus standard tests

BACKGROUND AND PURPOSE

Assessing patients' disability in multiple sclerosis (MS) requires time-consuming batteries of hospital tests. MSCopilot is a software medical device for the self-assessment of patients with MS (PwMS), combining four tests: walking, dexterity, cognition and low contrast vision. The objective was to validate MSCopilot versus the Multiple Sclerosis Functional Composite (MSFC).

METHODS

This multicentre, open-label, randomized, controlled, crossover study enrolled 141 PwMS and 76 healthy controls (HCs). All participants performed MSCopilot and MSFC tests at day 0. To assess reproducibility, 46 PwMS performed the same tests at day 30 ± 3. The primary end-point was the validation of MSCopilot versus MSFC for the identification of PwMS against HCs, quantified using the area under the curve (AUC). The main secondary end-point was the correlation of MSCopilot z-scores with MSFC z-scores.

RESULTS

In all, 116 PwMS and 69 HCs were analysed. The primary end-point was achieved: MSCopilot performance was non-inferior to that of MSFC (AUC 0.92 and 0.89 respectively; P = 0.3). MSCopilot and MSFC discriminated PwMS and HCs with 81% and 76% sensitivity and 82% and 88% specificity respectively. Digital and standard test scores were highly correlated (r = 0.81; P < 0.001). The test-retest study demonstrated the good reproducibility of MSCopilot.

CONCLUSION

This study confirms the reliability of MSCopilot and its usability in clinical practice for the monitoring of MS-related disability.

Neuraxial analgesia is not associated with an increased risk of post-partum relapses in MS

Background:

Obstetrical analgesia remains a matter of controversy because of the fear of neurotoxicity of local anesthetics on demyelinated fibers or their potential relationship with subsequent relapses.

Objective:

To assess the impact of neuraxial analgesia on the risk of relapse during the first 3 months post-partum, with a focus on women who experienced relapses during pregnancy.

Methods:

We analyzed data of women followed-up prospectively during their pregnancies and at least 3 months post-partum, collected in the Pregnancy in Multiple Sclerosis (PRIMS) and Prevention of Post-Partum Relapses with Progestin and Estradiol in Multiple Sclerosis (POPARTMUS) studies between 1992–1995 and 2005–2012, respectively. The association of neuraxial analgesia with the occurrence of a post-partum relapse was estimated by logistic regression analysis.

Results:

A total of 389 women were included, 215 from PRIMS and 174 from POPARTMUS. In total, 156 women (40%) had neuraxial analgesia. Overall, 24% experienced a relapse during pregnancy and 25% in the 3 months post-partum. Women with a pregnancy relapse were more likely to have a post-partum relapse (odds ratio (OR) = 1.83, p = 0.02), independently of the use of neuraxial analgesia. There was no association between neuraxial analgesia and post-partum relapse (OR = 1.08, p = 0.78).

Conclusion:

Neuraxial analgesia was not associated with an increased risk of post-partum relapses, whatever multiple sclerosis (MS) activity during pregnancy.

[Spasticity and everyday life in multiple sclerosis]

Spasticity is one of the most commonly seen symptoms in patients with multiple sclerosis. However, evaluation of the symptom often uses clinical scales that do not incorporate its impact on activities of daily living and quality of life. The everyday life of patients is affected primarily in actions related to mobility and walking capacity, such as the use of transport, gardening, household activities and, ultimately, basic activities such as bathing and dressing. Yet, so far, no study has described the impact of spasticity on the daily life of patients with multiple sclerosis. Nevertheless, assessing the effects of spasticity on such a young population would appear to be essential for meeting the needs of these patients with appropriate therapeutic interventions.

[Imaging of non-traumatic and non-tumoral cord lesions]

There is a wide range of spinal cord pathologies (vascular, inflammatory, infectious, metabolic, degenerative). They present clinically as acute partial or complete cord syndromes, or chronic myelopathies (more than 4 weeks in duration). MRI examination should be undertaken with a very strict protocol. Spinal cord lesions should be evaluated with regards to their T1W and T2W signal characteristics, involvement of grey and/or white matter, axial and sagittal extension, cord volume changes, contrast uptake and associated lesions (perimedullary, radicular or brain). The correlation of MR imaging features with clinical and biological data (blood and CSF) should suggest a differential diagnosis.

[Recurrent inflammatory optic neuropathy]

PURPOSE

To analyze clinical and paraclinical characteristics of recurrent isolated optic neuropathy.

PATIENTS

and method: In three university hospitals (Montpellier, Nimes, and Strasbourg), between October 2005 and September 2006, the charts of patients with corticosensitive recurrent isolated optic neuropathy and normal cerebral magnetic resonance imaging included prospectively were reviewed. The following parameters were analyzed: date of the first relapse, age at onset, duration at the time of inclusion, recurrence after steroid withdrawal, unilateral or bilateral involvement, number of relapses, visual acuity, retinal nerve fiber layer thickness, diagnostic workup, and long-term treatment with immunosuppressive or immunomodulatory drugs.

RESULTS

During the predefined period, 13 patients (11 women, 2 men; age, 17-54 years at onset) matched the inclusion criteria. Between two and six relapses of optic neuropathy were observed. The median duration was 4 years. In untreated patients (n=7), a significant (Spearman p=0.0156) inverse correlation was observed between visual acuity and duration of the disease; this correlation was not found in the group of patients (n=6) with long-term treatment (Spearman p=0.1032).

CONCLUSION

The progressive loss of vision over time in this retrospective study of recurrent isolated optic neuropathy could be related to axonal loss. A prospective cohort study is necessary to confirm this hypothesis and to evaluate the benefit of long-term treatment on this progression.

[Cortical blindness associated with Guillain-Barre syndrome: a complication of dysautonomia?]

INTRODUCTION

We report a case of a Guillain-Barre syndrome (GBS) with subarachnoid hemorrhage and regressive occipital white matter lesions.

OBSERVATION

A 62-year-old woman developed ascendant progressive paresthesia and weakness of arms and legs, 48 hours after enteritis infection. Neurological examination showed tetraparesia with loss of deep tendon reflexes and alteration of proprioception tests. Nerve conduction studies revealed polyradiculoneuritis. Then she presented an acute blindness and hypertension. Brain magnetic resonance imaging showed bilateral occipital lesions and subarachnoid hemorrhage. Cerebrospinal fluid analysis revealed an elevated protein level (1.54 g/l) and red blood cells without meningitis. Brain arteriography was normal. Intravenous immunoglobulins improved neurological symptoms.

CONCLUSION

Posterior localisation of reversible white matter lesions evoked a reversible posterior leukoencephalopathy. The implication of arterial hypertension caused by dysautonomia during GBS could be suspected.

[Candida albicans meningo-encephalo-myelo-radiculitis at an addict]

Beside immunodepression induced by the human immunodeficiency virus, fungal infections of the central nervous system are extremely rare in heroin-addict patients. We report here a case of meningo-encephalitis with myelo-radicular lesions in a 25-year-old intravenous heroin addict but non-HIV patient, who was admitted for an acute confusion associated with gait disorders. The diagnosis of Candida albicans meningo-encephalo-myelo-radiculitis was established by magnetic resonance imagery and mycological and serological examinations of cerebrospinal fluid. The infection was cured with amphotericin B lipid complex and 5-fluorocytosine. Early diagnosis and antifungal therapy for 6 months resulted in a favorable outcome. The detection of circulating Candida mannan in cerebrospinal fluid with a more sensitive technique combined to MRI were particularly decisive to confirm Candida infection diagnosis, allowing an appropriate antifungal therapy.

Troubles psychiatriques révélateurs d’une maladie de Niemann-Pick de type C à l’âge adulte

INTRODUCTION

Niemann-Pick Type C disease (NPC) is an autosomal recessive neurovisceral lysosomal lipid storage disorder.

CASE REPORT

A 31-year-old right-handed woman had suffered from schizophrenia for 13 years. At 25 years of age, she developed a gait disorder with a static and kinetic cerebellar syndrome, dysarthria, vertical supranuclear gaze palsy and cognitive impairment. Brain MRI was normal. Abdominal ultrasonography was performed because of hypercholesterolemia and elevated transaminases and revealed hepatosplenomegaly, which in conjunction with other signs and symptoms, suggested the diagnosis of NPC. The diagnosis was confirmed by demonstration of lysosomal storage of unesterified cholesterol (filipin staining) and of a reduced rate of LDL-induced cholesterol esterification. Implication of the NPC1 gene was assessed by genetic complementation analysis.

DISCUSSION

The phenotypic presentation of NPC is remarkably variable. The rarer adult-onset form has a slowly progressive course. Psychotic manifestations are often prominent and may precede neurologic symptoms. Exposure to neuroleptics delays the diagnosis of NPC.

CONCLUSION

Psychotic manifestations associated with cerebellar syndrome, vertical supranuclear gaze palsy, and splenomegaly are very suggestive of NPC disease which can be reliably diagnosed on cultured skin fibroblasts by filipin staining.

[BCcogSEP: a French test battery evaluating cognitive functions in multiple sclerosis]

In French language, there is no standardized procedure to assess cognitive function in patients with multiple sclerosis (MS). Such an assessment is however very useful to determine the consequences of the disease on cognitive function, to evaluate the disease progression and the consequences of usual treatments on cognition. This study aimed to develop and validate a French language battery based on "the Brief Repeatable Battery of Neuropsychological tests for Multiple Sclerosis" (BRB-N) often used in other countries. In an initial phase, the battery was composed of the French version of the 5 BRB-N tests to which were added 4 tests assessing immediate and working memory as well as executive function. 52 healthy control subjects (20-50 years) participated in the study. A principal component analysis (PCA) of their data examined the contribution of each test into the battery. 93 other healthy subjects participated in a second phase where analyses of variance were carried out to investigate the effect of the main demographical variables. Finally, the performance of two patient groups (20 with a EDSS score<or=3 et 31 with a EDSS score>3) was compared to the healthy controls in order to investigate the ability of our battery to detect cognitive impairment in MS patients. The PCA showed that each test, except one, had a specific contribution to the battery. The final battery (BCcogSEP) was thus comprised of 8 tests. MANOVA and ANOVA showed significant effects of age, sex and educational level on performance. In consequence, a procedure allowing to take into account these factors was developed. The battery was able to detect cognitive impairment in MS patients, even when the disease is not severe. In this case, deficits were observed in tests assessing executive function, information processing speed, immediate and working memory. This short battery with reliable psychometric qualities allows the interpretation of a MS patient's performance considering his/her demographical characteristics and is able to detect cognitive abnormalities even in case of mild physical handicap.

[MRI aspect and course of supra-tentorial sarcoidosic lesions]

Central nervous system lesions resulting from sarcoidosis occur in 5% of cases, but supratentorial mass lesions are uncommon. We report 3 cases of intracranial pseudo-tumoral lesions, due to sarcoidosis: 1 woman and 2 men. Clinical features included left facial myoclonus, headache and vertigo, right hemiparesis and unique general seizure. Sarcoidosis was diagnosed upon conjonctival biopsy in the first case, infiltrative lesions of the lungs and mediastinal lymph nodes in the second case, and intracerebral lesion plus lymph nodes biopsies in the last case. In the first case, CT scan and MRI images showed diffuse subcortical high signal, suggesting pachymeningitis with vasogenic oedema. In the second case, GT scan and MRI revealed numerous small granuloma in the left rolandic area, and one in the striatum. In the third case, CT scan showed an enlargement of the left temporal horn, due to an enhanced left periventricular lesion. MRI with gadolinium showed that the lesion encircled the ventricle horn. In all cases, clinical and radiological improvement was obtained after corticoid therapy.

[Acute and reversible myoclonic encephalopathy, extrapyramidal syndrome, polyneuropathy caused by chronic disulfiram poisoning]

This 44-year woman was admitted for weight loss and global intellectual slowing. She had mild chronic alcoholic neuropathy. She was discontinued alcoholic consumption for 6 months and was given disulfiram (1.5 g/day) since then. She developed over a 5-day period acute neuropathy, confusion and extrapyramidal symptoms with oculo-cephalogyric and dystonic movements and myoclonus. Electromyography revealed a severe polyneuropathy. After disulfiram withdrawal, confusion and extrapyramidal symptoms disappeared within a few days, but sensitivo-motor deficit improved more slowly. Nerve biopsy was suggestive of a pure axonal neuropathy.