Risk of bone fractures in patients with narcolepsy: a nationwide population-based cohort study

Narcolepsy and risk of traumatic injury: a population-based matched cohort study

STUDY OBJECTIVES

We evaluated the risk of traumatic injury in patients with narcolepsy compared to the general population.

METHODS

We conducted a population-based matched cohort study using a Japanese health insurance claims database. For each patient with narcolepsy, up to 5 individuals from the general population without narcolepsy were matched by variables such as sex, age, and cohort entry month. The primary outcome was traumatic injury, and the secondary outcome was fracture. The study population was followed for up to 5 years from the cohort entry date. We estimated crude incidence rates, adjusted incidence rate differences, adjusted hazard ratios, and their 95% confidence intervals (CIs) for study outcomes using crude and multivariable Poisson and Cox regression models.

RESULTS

We included 2,451 patients with narcolepsy (mean age, 30.3 years; male, 58.0%) and 10,591 matched individuals (mean age, 30.6 years; male, 58.4%). Crude incidence rate of traumatic injury was 11.4 per 100 person-years for patients with narcolepsy compared with 6.2 per 100 person-years for matched individuals (adjusted incidence rate difference, 6.2 excess events per 100 person-years [95% CI, 4.9-7.4]; adjusted hazard ratio, 1.8 [95% CI, 1.5-2.2]). Crude incidence rate of fracture was 2.3 per 100 person-years for patients with narcolepsy compared with 1.3 per 100 person-years for matched individuals (adjusted incidence rate difference, 1.2 excess events per 100 person-years [95% CI, 0.7-1.7]; adjusted hazard ratio, 1.7 [95% CI, 1.4-2.1]).

CONCLUSIONS

Narcolepsy was associated with increased risk of traumatic injury. For patients with narcolepsy, optimized approaches to injury prevention should be considered.

CITATION

Zheng Y, Fukasawa T, Masuda S, Takeuchi M, Kawakami K. Narcolepsy and risk of traumatic injury: a population-based matched cohort study. J Clin Sleep Med. 2024;20(10):1657-1662.

Exploring the association between hypocretin-1 levels and bone mineral content in patients with narcolepsy: A cross-sectional study

INTRODUCTION

Recent studies suggest the existence of a physiologic basis for bone rarefaction and increased risk for fractures. This study aimed to address anthropometric differences between patients with narcolepsy type 1 (NT1) and type 2 (NT2) and discrepancies in bone mineral content (BMC) as a function of hypocretin-1 (Hcrt-1) measured in cerebrospinal fluid (CSF).

METHODS

We have evaluated 31 adult patients (aged 18-65 years) with NT1 and 18 patients with NT2, comparing the groups in terms of anthropometric variables - body mass index (BMI) and waist-to-hip ratio (WHR) - and percentage of bone mineral content (%BMC), measured by bioelectrical impedance analysis (BIA). Statistical analysis assessed the effects of Hcrt-1 levels on CSF, dietary intake, and medication use over these variables. Statistical significance was achieved with a confidence interval of 95 % and p < 0.05.

RESULTS

Patients with NT1 presented with higher BMI (32.04 ± 6.95 vs. 25.38 ± 4.26 kg/m2; p < 0.01) and WHR (0.89 ± 0.09 vs. 0.83 ± 0.09; p = 0.02) compared to NT2, in detriment of %BMC, which was lower for NT1 (4.1 ± 1.02 vs. 4.89 ± 0.59; p < 0.01). Hcrt-1 in CSF showed a positive correlation with %BMC (r = +0.48, p < 0.01) and a negative correlation with anthropometric features (BMI: r = -0.54, p < 0.01; WHR: r = -0.37, p = 0.01). There was a correlation between WHR and diary caloric intake (r = +0.42, p < 0.01).

CONCLUSION

The evaluation of patients with narcolepsy presupposes a syndromic approach comprising symptoms that go far beyond excessive daytime sleepiness. The integrated follow-up, including nutritional profile and anthropometric features, should add value in reducing morbidity in this population.

Narcolepsy: an interface among neurology, immunology, sleep, and genetics

Narcolepsy is a primary disorder of the central nervous system resulting from genetic, environmental, and immunological interactions defined as excessive daytime sleepiness plus cataplexy, hallucinations, sleep paralysis, and sleep fragmentation. The pathophysiology is not entirely known, but the interaction among genetic predisposition, environmental exposition, and immune component with consequent hypocretin-1 deficiency is the model to explain narcolepsy type I. The mechanism of narcolepsy type II is less understood. There is a delay of over ten years for the diagnosis of narcolepsy around the world. Patients with narcolepsy have many comorbidities with a negative impact on quality of life. The treatment of narcolepsy must contain an educational approach for the family, coworkers, and patients. Scheduled naps and sleep hygiene are essential to minimize the dose of medications. Much progress has been seen in the pharmacological treatment of narcolepsy with new stimulants, different presentations of oxybate, and recent studies with orexin agonists. Narcolepsy is a rare disease that needs to be more understood and highlighted to avoid delayed diagnosis and severe disabilities in patients.

Burden of narcolepsy in Japan: A health claims database study evaluating direct medical costs and comorbidities

OBJECTIVE

This study aimed to determine the burden of narcolepsy in terms of direct medical costs and comorbidities and compare it with the respective burden of schizophrenia, epilepsy, and ulcerative colitis as controls.

METHODS

Patients diagnosed with narcolepsy (at least once based on the International Statistical Classification of Diseases and Related Health Problems, 10th Revision, code G47.4) between April 2017 and March 2022 were identified on the health insurance claims database compiled by JMDC Inc. Patients with schizophrenia (F20), epilepsy (G40), and ulcerative colitis (K51) were matched as controls. Direct medical costs (including inpatient, outpatient, and medication costs) and comorbidities were analyzed.

RESULTS

We identified 4,594 patients with narcolepsy (≥18 years), 18,376 with schizophrenia, 18,376 with epilepsy, and 4,594 with ulcerative colitis. The total annual direct medical cost per person with narcolepsy was 349,188 JPY. The cost for narcolepsy was less than that for schizophrenia, epilepsy, and ulcerative colitis. Several comorbidities, such as sleep apnea, attention deficit hyperactivity disorder (ADHD), and obesity were more prevalent in the narcolepsy group.

CONCLUSIONS

The total direct cost for narcolepsy was approximately three times higher than the national medical expense for people aged 15-44 years (122,000 JPY in 2020), but lower than the total cost for all control diseases. The patients with narcolepsy were also likely to have comorbidities that affected their burden. These findings can contribute to future discussions on medical expense assistance programs for patients with narcolepsy.

Chronic Sleep Deprivation Impaired Bone Formation in Growing Rats and Down-Regulated PI3K/AKT Signaling in Bone Tissues

BACKGROUND

This study aimed to assess the effects of chronic sleep deprivation (CSD) on bone metabolism in growing rats and the likely underlying mechanism.

METHODS

Twenty 5-week-old male Wistar rats and randomly divided into the CSD and normal control (NC) groups after one-week acclimatization. After a 6-week intervention of sleep deprivation, the distal femurs of both groups were harvested for micro-computed tomography scans and histological analysis. Meanwhile, the femur tissues were measured the mRNA and protein expression via RNA sequencing and immunohistochemical analysis. Serum bone turnover markers were evaluated at 0, 2, 4, and 6 weeks.

RESULTS

CSD impaired the bone growth, showing an imbalance of bone turnover status, dysphasia in the metaphysis growth plate, and deterioration of bone microarchitecture. Further, CSD suppressed bone formation, showing that the expression of osteogenesis-related proteins (col1α1 and osteocalcin) and mRNA (igf1, bglap, runx2, col1α1, pth1r) are down-regulated. Differentially expressed genes were detected, and functional enrichment analyses revealed that the PI3K/AKT pathway was significantly down-regulated in the CSD group.

CONCLUSION

These results suggest that CSD can significantly impaire bone health, and it may exert these effects in part by suppressing bone formation and osteoblast differentiation, and inactivating the PI3K/AKT signaling pathway.

Obstructive sleep apnea and fractures in children and adolescents

STUDY OBJECTIVES

To examine, among girls and boys, associations between site-specific extremity fracture and sleep apnea diagnosis or treatment.

METHODS

A cross-sectional analysis of claims data from 2016-2018 for children aged 2-18. Children with sleep apnea, continuous positive airway pressure, adenotonsillectomy, and fracture were identified using ICD10, CPT and HCPCS codes. We examined sex-stratified associations between site-specific fracture, sleep apnea and sleep apnea treatment.

RESULTS

Among 2,327,104 children, 9,547 (0.41%) had sleep apnea and nearly 61% were treated. Girls with sleep apnea, treated or untreated, had increased odds of lower, but not upper, extremity fracture compared to those without sleep apnea (treated 1.56, 95% CI 1.11, 2.21; untreated OR 1.63, 95% CI 1.09, 2.44). Only boys untreated for sleep apnea had increased odds of lower extremity fracture in comparison to those without a diagnosis of sleep apnea (OR 1.65, 95% CI 1.20,2.27). Interestingly, boys treated for sleep apnea but not those untreated, in comparison to boys without sleep apnea, had different (reduced) odds of upper extremity fracture (OR 0.74, 95% CI 0.59, 0.95).

CONCLUSIONS

These large datasets provide evidence that both boys and girls with untreated sleep apnea have higher odds of lower extremity fractures. However, treatment for sleep apnea was associated with improved odds of lower extremity fracture only in boys. Upper extremity data were less clear. These data are cross-sectional and cannot show causality, but they suggest that treatment for sleep apnea may lower risk for extremity fractures in boys.

Living with Narcolepsy: Current Management Strategies, Future Prospects, and Overlooked Real-Life Concerns

Narcolepsy is a neurological disorder of the sleep-wake cycle characterized by excessive daytime sleepiness (EDS), cataplexy, nighttime sleep disturbances, and REM-sleep-related phenomena (sleep paralysis, hallucinations) that intrude into wakefulness. Dysfunction of the hypocretin/orexin system has been implicated as the underlying cause of narcolepsy with cataplexy. In most people with narcolepsy, symptom onset occurs between the ages of 10 and 35 years, but because the disorder is underrecognized and testing is complex, delays in diagnosis and treatment are common. Narcolepsy is treated with a combination of lifestyle modifications and medications that promote wakefulness and suppress cataplexy. Treatments are often effective in improving daytime functioning for individuals with narcolepsy, but side effects and/or lack of efficacy can result in suboptimal management of symptoms and, in many cases, significant residual impairment. Additionally, the psychosocial ramifications of narcolepsy are often neglected. Recently two new pharmacologic treatment options, solriamfetol and pitolisant, have been approved for adults, and the indication for sodium oxybate in narcolepsy has been expanded to include children. In recent years, there has been an uptick in patient-centered research, and promising new diagnostic and therapeutic options are in development. This paper summarizes current and prospective pharmacological therapies for treating both EDS and cataplexy, discusses concerns specific to children and reproductive-age women with narcolepsy, and reviews the negative impact of health-related stigma and efforts to address narcolepsy stigma.

Factors Affecting Treatment with Life-Saving Interventions, Computed Tomography Scans and Specialist Consultations

Background: Emergency treatments determined by emergency physicians may affect mortality and patient satisfaction. This paper attempts to examine the impact of patient characteristics, health status, the accredited level of hospitals, and triaged levels on the following emergency treatments: immediate life-saving interventions (LSIs), computed tomography (CT) scans, and specialist consultations (SCs). Methods: A multivariate logistic regression model was employed to analyze the impact of patient characteristics, including sex, age, income and the urbanization degree of the patient's residence; patient health status, including records of hospitalization and the number of instances of ambulatory care in the previous year; the Charlson Comorbidity Index (CCI) score; the accredited level of hospitals; and the triaged level of emergency treatments. Results: All the patient characteristics were found to impact receiving LSI, CT and SC, except for income. Furthermore, a better health status was associated with a decreased probability of receiving LSI, CT and SC, but the number of instances of ambulatory care was not found to have a significant impact on receiving CT or SC. This study also found no evidence to support impact of CCI on SC. Hospitals with higher accredited levels were associated with a greater chance of patients receiving emergency treatments of LSI, CT and SC. A higher assigned severity (lower triaged level) led to an increased probability of receiving CT and SC. In terms of LSI, patients assigned to level 4 were found to have a lower chance of treatment than those assigned to level 5. Conclusions: This study found that several patient characteristics, patient health status, the accredited level of medical institutions and the triaged level, were associated with a higher likelihood of receiving emergency treatments. This study suggests that the inequality of medical resources among medical institutions with different accredited levels may yield a crowding-out effect.