Lawrence Korngut

A systematic review and meta-analysis on the epidemiology of Duchenne and Becker muscular dystrophy.

The muscular dystrophies are a broad group of hereditary muscle diseases with variable severity. Population-based prevalence estimates have been reported but pooled estimates are not available. We performed a systematic review of worldwide population-based studies reporting muscular dystrophies prevalence and/or incidence using MEDLINE and EMBASE databases. The search strategy included key terms related to muscular dystrophies, incidence, prevalence and epidemiology. Two reviewers independently reviewed all abstracts, full text articles and abstracted data using standardized forms. Pooling of prevalence estimates was performed using random effect models. 1104 abstracts and 167 full text articles were reviewed. Thirty-one studies met all eligibility criteria and were included in the final analysis. The studies differed widely in their approaches to case ascertainment, resulting in significant methodological heterogeneity and varied data quality. The pooled prevalence of DMD and BMD was 4.78 (95% CI 1.94-11.81) and 1.53 (95% CI 0.26-8.94) per 100,000 males respectively. The incidence of DMD ranged from 10.71 to 27.78 per 100,000. This is the first meta-analysis of worldwide prevalence estimates for muscular dystrophies. There is a need for more epidemiological studies addressing global estimates on incidence and prevalence of muscular dystrophies, utilizing standardized diagnostic criteria as well as multiple sources of case ascertainment.

The TREAT‐NMD Duchenne Muscular Dystrophy Registries: Conception, Design, and Utilization by Industry and Academia

Duchenne muscular dystrophy (DMD) is an X‐linked genetic disease, caused by the absence of the dystrophin protein. Although many novel therapies are under development for DMD, there is currently no cure and affected individuals are often confined to a wheelchair by their teens and die in their twenties/thirties. DMD is a rare disease (prevalence <5/10,000). Even the largest countries do not have enough affected patients to rigorously assess novel therapies, unravel genetic complexities, and determine patient outcomes. TREAT‐NMD is a worldwide network for neuromuscular diseases that provides an infrastructure to support the delivery of promising new therapies for patients. The harmonized implementation of national and ultimately global patient registries has been central to the success of TREAT‐NMD. For the DMD registries within TREAT‐NMD, individual countries have chosen to collect patient information in the form of standardized patient registries to increase the overall patient population on which clinical outcomes and new technologies can be assessed. The registries comprise more than 13,500 patients from 31 different countries. Here, we describe how the TREAT‐NMD national patient registries for DMD were established. We look at their continued growth and assess how successful they have been at fostering collaboration between academia, patient organizations, and industry.

An enriched-enrolment, randomized withdrawal, flexible-dose, double-blind, placebo-controlled, parallel assignment efficacy study of nabilone as adjuvant in the treatment of diabetic peripheral neuropathic pain

TOC summary This enriched‐enrollment, randomized, double‐blind, placebo‐controlled, flexible‐dose adjuvant study demonstrated that nabilone provided improvements in pain, anxiety, quality of life and patient satisfaction for patients with diabetic neuropathic pain. ABSTRACT Cannabinoids are emerging as potential options for neuropathic pain treatment. This study evaluated an oral cannabinoid, nabilone, in the treatment of refractory human diabetic peripheral neuropathic pain (DPN). We performed a single‐center, randomized, double‐blind, placebo‐controlled, flexible‐dose study with an enriched enrolment randomized withdrawal design. DPN subjects with a pain score ⩾4 (0‐10 scale) continued regular pain medications and were administered single‐blinded adjuvant nabilone for 4 weeks. Subjects achieving ⩾30% pain relief (26/37) were then randomized and treated with either flexible‐dose nabilone 1‐4 mg/day (n = 13) or placebo (n = 13) in a further 5‐week double‐blind treatment period, with 30% (11/37) of subjects deemed run‐in‐phase nabilone nonresponders. For nabilone run‐in‐phase responders, there was an improvement in the change in mean end‐point neuropathic pain vs placebo (mean treatment reduction of 1.27; 95% confidence interval 2.29‐0.25, P = 0.02), with an average nabilone dose at end point of 2.9 ± 1.1 mg/day, and improvements from baseline for the anxiety subscale of the Hospital Anxiety and Depression Scale, the Medical Outcomes Study sleep scale problems index, and the European Quality of Life‐5‐Domains index score (each P < 0.05). Nabilone run‐in‐phase responders reported greater global end‐point improvement with nabilone than with placebo (100% vs 31%; P < 0.05). Medication‐related confusion led to discontinuation in 2/37 subjects during single‐blind nabilone treatment. Potential unmasking occurred in 62% of both groups. Flexible‐dose nabilone 1‐4 mg/day was effective in relieving DPN symptoms, improving disturbed sleep, quality of life, and overall patient status. Nabilone was well tolerated and successful as adjuvant in patients with DPN.

Calnexin Deficiency Leads to Dysmyelination

Calnexin is a molecular chaperone and a component of the quality control of the secretory pathway. We have generated calnexin gene-deficient mice (cnx−/−) and showed that calnexin deficiency leads to myelinopathy. Calnexin-deficient mice were viable with no discernible effects on other systems, including immune function, and instead they demonstrated dysmyelination as documented by reduced conductive velocity of nerve fibers and electron microscopy analysis of sciatic nerve and spinal cord. Myelin of the peripheral and central nervous systems of cnx−/− mice was disorganized and decompacted. There were no abnormalities in neuronal growth, no loss of neuronal fibers, and no change in fictive locomotor pattern in the absence of calnexin. This work reveals a previously unrecognized and important function of calnexin in myelination and provides new insights into the mechanisms responsible for myelin diseases.

Use of the interRAI CHESS Scale to Predict Mortality among Persons with Neurological Conditions in Three Care Settings

Background Persons with certain neurological conditions have higher mortality rates than the population without neurological conditions, but the risk factors for increased mortality within diagnostic groups are less well understood. The interRAI CHESS scale has been shown to be a strong predictor of mortality in the overall population of persons receiving health care in community and institutional settings. This study examines the performance of CHESS as a predictor of mortality among persons with 11 different neurological conditions. Methods Survival analyses were done with interRAI assessments linked to mortality data among persons in home care (n = 359,940), complex continuing care hospitals/units (n = 88,721), and nursing homes (n = 185,309) in seven Canadian provinces/territories. Results CHESS was a significant predictor of mortality in all 3 care settings for the 11 neurological diagnostic groups considered after adjusting for age and sex. The distribution of CHESS scores varied between diagnostic groups and within diagnostic groups in different care settings. Conclusions CHESS is a valid predictor of mortality in neurological populations in community and institutional care. It may prove useful for several clinical, administrative, policy-development, evaluation and research purposes. Because it is routinely gathered as part of normal clinical practice in jurisdictions (like Canada) that have implemented interRAI assessment instruments, CHESS can be derived without additional need for data collection.

Registry-based randomized controlled trials- what are the advantages, challenges, and areas for future research?

Registry-based randomized controlled trials are defined as pragmatic trials that use registries as a platform for case records, data collection, randomization, and follow-up. Recently, the application of registry-based randomized controlled trials has attracted increasing attention in health research to address comparative effectiveness research questions in real-world settings, mainly due to their low cost, enhanced generalizability of findings, rapid consecutive enrollment, and the potential completeness of follow-up for the reference population, when compared with conventional randomized effectiveness trials. However several challenges of registry-based randomized controlled trials have to be taken into consideration, including registry data quality, ethical issues, and methodological challenges. In this article, we summarize the advantages, challenges, and areas for future research related to registry-based randomized controlled trials.

A Systematic Review and Meta-analysis on the Epidemiology of the Muscular Dystrophies.

BACKGROUND The muscular dystrophies are a heterogeneous group of genetic muscle diseases with variable distribution of weakness and mode of inheritance. METHODS We previously performed a systematic review of worldwide population-based studies on Duchenne and Becker muscular dystrophies; the current study focused on the epidemiology of other muscular dystrophies using Medline and EMBASE databases. Two reviewers independently reviewed all abstracts, full-text articles, and abstracted data from 1985 to 2011. Pooling of prevalence estimates was performed using random-effect models. RESULTS A total of 1104 abstracts and 167 full-text articles were reviewed. Thirty-one studies met all eligibility criteria and were included in the final analysis. The overall pooled prevalence of combined muscular dystrophies was 16.14 (confidence interval [CI], 11.21-23.23) per 100,000. The prevalence estimates per 100,000 were 8.26 (CI, 4.99-13.68) for myotonic dystrophy, 3.95 (CI, 2.89-5.40) for facioscapulohumeral dystrophy, 1.63 (CI, 0.94-2.81) for limb girdle muscular dystrophy, and 0.99 (CI, 0.62-1.57) for congenital muscular dystrophies. CONCLUSIONS The studies differed widely in their approaches to case ascertainment, and substantial gaps remain in the global estimates of many other types of muscular dystrophies. Additional epidemiological studies using standardized diagnostic criteria as well as multiple sources of case ascertainment will help address the economic impact and health care burden of muscular dystrophies worldwide.

The Impact of Enrollment in a Specialized Interdisciplinary Neuropathic Pain Clinic

BACKGROUND Chronic pain clinics have been created because of the increasing recognition of chronic pain as a very common, debilitating condition that requires specialized care. Neuropathic pain (NeP) is a multifaceted, specialized form of chronic pain that often requires input from multiple disciplines for assessment and management. OBJECTIVE To determine the impact of an interdisciplinary clinic for evaluation and treatment of patients with NeP. METHODS Patients with heterogeneous etiologies for NeP were prospectively evaluated using an interdisciplinary approach every six months. Diagnostic evaluation, comorbidity evaluation, education, and pharmacological and⁄or nonpharmacological management were completed. Severity (visual analogue scale) and features of pain (Modified Brief Pain Inventory), sleep difficulties (Medical Outcomes Study - Sleep Scale), mood⁄anxiety disruption (Hospital Anxiety and Depression Scale), quality of life (European Quality-of-Life Five-Domain index), health care resources use, patient satisfaction (Pain Treatment Satisfaction Scale and Neuropathic Pain Symptom Inventory) and self-perceived change in well-being (Patient Global Impression of Change scale) were examined at each visit. RESULTS Pain severity only decreased after one year of follow-up, while anxiety and quality- of-life indexes improved after six months. Moderate improvements of sleep disturbance, less frequent medication use and reduced health care resource use were observed during enrollment at the NeP clinic. DISCUSSION Despite the limitations of performing a real-world, uncontrolled study, patients with NeP benefit from enrollment in a small interdisciplinary clinic. Education and a complete diagnostic evaluation are hypothesized to lead to improvements in anxiety and, subsequently, pain severity. Questions remain regarding the long-term maintenance of these improvements and the optimal structure of specialized pain clinics.

Pompe Disease: Diagnosis and Management. Evidence-Based Guidelines from a Canadian Expert Panel

Pompe disease is a lysosomal storage disorder caused by a deficiency of the enzyme acid alpha-glucosidase. Patients have skeletal muscle and respiratory weakness with or without cardiomyopathy. The objective of our review was to systematically evaluate the quality of evidence from the literature to formulate evidence-based guidelines for the diagnosis and management of patients with Pompe disease. The literature review was conducted using published literature, clinical trials, cohort studies and systematic reviews. Cardinal treatment decisions produced seven management guidelines and were assigned a GRADE classification based on the quality of evidence in the published literature. In addition, six recommendations were made based on best clinical practices but with insufficient data to form a guideline. Studying outcomes in rare diseases is challenging due to the small number of patients, but this is in particular the reason why we believe that informed treatment decisions need to consider the quality of the evidence.

Perspectives on neurological patient registries: a literature review and focus group study

BackgroundPatient registries represent a well-established methodology for prospective data collection with a wide array of applications for clinical research and health care administration. An examination and synthesis of registry stakeholder perspectives has not been previously reported in the literature.MethodsTo inform the development of future neurological registries we examined stakeholder perspectives about such registries through a literature review followed by 3 focus groups comprised of a total of 15 neurological patients and 12 caregivers.Results(1) Literature review: We identified 6,435 abstracts after duplicates were removed. Of these, 410 articles underwent full text review with 24 deemed relevant to perspectives about neurological and non-neurological registries and were included in the final synthesis. From a patient perspective the literature supports altruism, responsible use of data and advancement of research, among others, as motivating factors for participating in a patient registry. Barriers to participation included concerns about privacy and participant burden (i.e. extra clinic visits and associated costs). (2) Focus groups: The focus groups identified factors that would encourage participation such as: having a clear purpose; low participant burden; and being well-managed among others.ConclusionsWe report the first examination and synthesis of stakeholder perspectives on registries broadly with a specific focus on neurological patient registries. The findings of the broad literature review were congruent with the neurological patient and caregiver focus groups. We report common themes across the literature and the focus groups performed. Stakeholder perspectives need to be considered when designing and operating patient registries. Emphasizing factors that promote participation and mitigating barriers may enhance patient recruitment.