Pemafibrate protects the rupture of experimental aortic aneurysm in mice through anti-oxidative stress with induced catalase

Background

Abdominal aortic aneurysm (AAA) is a life-threatening disease, while effective and preventive medical treatments remain unestablished.

Purpose

The aim of this study was to evaluate the effect of selective peroxi- some proliferator-activated receptor alpha (PPARα) modulator pemafibrate on AAA formation in mice.

Methods

AAA was induced by subcutaneous infusion of angiotensin II (AngII) in apolipoprotein E-deficient mice for 4 weeks. Treatment by pemafibrate or vehicle was started one week before AngII infusion. Oxidative stress was evaluated by dihydroethidium (DHE) staining.

Results

Prognosis after AngII infusion in pemafibrate-treated mice was significantly better than that in vehicle-treated mice (log-rang test, p=0.035) by reducing the occurrence of fatal AAA rupture. Meanwhile pemafibrate did not significantly reduce maximal diameter of the aorta. Histological findings demonstrated that the expression of collagen in adventitia in pemafibrate-treated mice was significantly greater than that in vehicle-treated mice (p<0.05). Oxidative stress in aorta of pemafibrate-treated mice was significantly reduced comparing to vehicle-treated mice, accompanying by the reduction of mRNA expression of matrix metalloproteinase 2, tumor necrosis factor-α, and interleukin-6 (all p<0.05). Catalase expression in abdominal aortic tissue was increased 1.5-fold in mice treated with pemafibrate than in mice treated with vehicle (p=0.032). In human vascular smooth muscle cells (hVSMC), pemafibrate attenuated AngII-induced oxidative stress (p<0.001), which was canceled by administrating small interfering RNA (siRNA) of PPARα (p<0.001). Furthermore, in hVSMC, pemafibrate increased catalase expression significantly (p<0.001), while this increase was significantly suppressed by knockdown of PPAR-α with siRNA. (p<0.001).

Conclusion

Pemafibrate reduced the rupture of AAA in this murine model, which is associated with anti-oxidative stress via catalase induction.

Funding Acknowledgement

Type of funding source: None

Impact of Consultation Length on Satisfaction in Patients with Chronic Low Back Pain: A Nationwide Multicenter Study in Japan

Introduction

Chronic low back pain (CLBP) is a major health burden worldwide and requires patient satisfaction with treatment. Consultation length can be an important factor in patient satisfaction, but few studies have investigated the impact of consultation length on satisfaction in patients with CLBP. This study tried to elucidate the impact of consultation length on clinical outcomes in patients with CLBP.

Methods

This study is part of an analysis using the database of the nationwide, multicenter cohort for CLBP performed by the Project Committee of the Japanese Society for Spine Surgery and Related Research. A total of 427 patients aged 20-85 years (median age, 73.0 years; female, 58.6%) with CLBP were prospectively followed-up monthly for 6 months. Multivariable nonlinear regression analyses were performed to assess the effect of consultation length on outcome measures including subjective satisfaction score, EuroQol 5-dimension, Japanese Orthopaedic Association (JOA) score, Roland-Morris Disability Questionnaire, JOA Back Pain Evaluation Questionnaire, visual analog scale (VAS) and Medical Outcome Survey short-form 8-item health survey that evaluated at the next phase. Furthermore, we assessed whether the effect of consultation length on patient satisfaction was modified by the baseline Brief Scale for Psychiatric Problems in Orthopaedic Patients (BS-POP) score for patient and physician versions.

Results

VAS for CLBP was the only score that correlated significantly with consultation length (P = 0.018). Satisfaction score showed a significant positive correlation with consultation length in patients with the highest baseline BS-POP scores (P < 0.2). Moreover, consultation lengths more than 7.6 min and 15.1 min offered increase of satisfaction if patients show the highest BS-POP scores on patient and physician versions, respectively.

Conclusions

These findings suggest that a sufficiently long consultation is an important factor for subjective satisfaction in the patients with CLBP, particularly in patients with psychological problems.

Microendoscopic decompression for lumbosacral foraminal stenosis: a novel surgical strategy based on anatomical considerations using 3D image fusion with MRI/CT

OBJECTIVE

Persistent lumbar foraminal stenosis (LFS) is one of the most common reasons for poor postoperative outcomes and is a major contributor to "failed back surgery syndrome." The authors describe a new surgical strategy for LFS based on anatomical considerations using 3D image fusion with MRI/CT analysis.

METHODS

A retrospective review was conducted on 78 consecutive patients surgically treated for LFS at the lumbosacral junction (2013-2017). The location and extent of stenosis, including the narrowest site and associated pathology (bone or soft tissue), were measured using 3D image fusion with MRI/CT. Stenosis was defined as medial intervertebral foraminal (MF; inner edge to pedicle center), lateral intervertebral foraminal (LF; pedicle center to outer edge), or extraforaminal (EF; outside the pedicle). Lumbar (low-back pain, leg pain) and patient satisfaction visual analog scale (VAS) scores and Japanese Orthopaedic Association (JOA) scores were evaluated. Surgical outcome was evaluated 2 years postoperatively.

RESULTS

Most instances of stenosis existed outside the pedicle's center (94%), including LF (58%), EF (36%), and MF (6%). In all MF cases, stenosis resulted from soft-tissue structures. The narrowest stenosis sites were localized around the pedicle's outer border. The areas for sufficient nerve decompression were extended in MF+LF (10%), MF+LF+EF (14%), LF+EF (39%), LF (11%), and EF (26%). No iatrogenic pars interarticularis damage occurred. The JOA score was 14.9 ± 2.6 points preoperatively and 22.4 ± 3.5 points at 2 years postoperatively. The JOA recovery rate was 56.0% ± 18.6%. The VAS score (low-back and leg pain) was significantly improved 2 years postoperatively (p < 0.01). According to patients' self-assessment of the minimally invasive surgery, 62 (79.5%) chose "surgery met my expectations" at follow-up. Nine patients (11.5%) selected "I did not improve as much as I had hoped but I would undergo the same surgery for the same outcome."

CONCLUSIONS

Most LFS existed outside the pedicle's center and was rarely noted in the pars region. The main regions of stenosis were localized to the pedicle's outer edge. Considering this anatomical distribution of LFS, the authors recommend that lateral fenestration should be the first priority for foraminal decompression. Other surgical options including foraminotomy, total facetectomy, and hemilaminectomy likely require more bone resections than LFS treatment. The microendoscopic surgery results were very good, indicating that this minimally invasive surgery was suitable for treating this disease.

Prevalence of cervical anterior and posterior spondylolisthesis and its association with degenerative cervical myelopathy in a general population

The purpose of this study was to examine the prevalence of cervical spondylolisthesis according to age and vertebral level and its association with degenerative cervical myelopathy (DCM). This study included 959 participants (319 men and 640 women; mean age, 66.4 years) in the Wakayama Spine Study from 2008 to 2010. The outcome measures were cervical spinal canal (CSC) diameter at C5 level on plain radiographs, the degree of cervical spondylosis using the Kellgren-Lawrence (KL) grade, cervical cord compression on sagittal T2-weighted magnetic resonance imaging, and physical signs related to DCM. The prevalence of cervical anterior and posterior spondylolisthesis was investigated in men and women by age. In addition, logistic regression analysis determined the association between CSC diameter, posterior spondylolisthesis, and clinical DCM after overall adjustment for age, sex, and body mass index. The prevalence of anterior spondylolisthesis was 6.0% in men and 6.3% in women, and that of posterior spondylolisthesis was 13.2% and 8.9%, respectively. In addition, posterior spondylolisthesis prevalence increased with age in both sexes. Logistic regression analysis revealed that developmental canal stenosis (≤13 mm) and cervical posterior spondylolisthesis are independent significant predictive factors for DCM. The prevalence of degenerative cervical posterior spondylolisthesis was increasing with age and more frequent in men than in women. Narrow canal and degenerative cervical posterior spondylolisthesis on X-ray may be useful in predicting or diagnosing DCM.

The incidence and risk factors for adjacent vertebral fractures in community-dwelling people with prevalent vertebral fracture: the 3rd and 4th survey of the ROAD study

In this 3-year follow-up study of 66 community-dwelling adults with severely deformed vertebral fractures, the annual incidence of adjacent vertebral fracture (AVF) was 6.1%/year. Lower bone mineral density at the femoral neck and spinopelvic malalignment were risk factors for AVF.

PURPOSE

This study aimed to clarify the incidence and risk factors of adjacent vertebral fractures (AVFs)-fractures adjacent to a prevalent vertebral fracture (VF)-using an established population-based cohort from the ROAD study.

METHODS

Among the 1213 participants who underwent whole-spine radiography in ROAD's third (2012-2013, the baseline) and fourth surveys (2015-2016, the follow-up), 66 (12 men, 54 women) had at least one VF at the baseline. VF and AVF were determined radiographically using Genant's semi-quantitative (SQ) method, where VF was SQ ≥ 2 and AVF was a one-level cranial or caudal vertebra with an SQ grade one or more higher at the follow-up. An interviewer-administered questionnaire was applied, and anthropometric measurements and bone mineral density (BMD) measurements at the lumbar spine and femoral neck were performed. Sagittal imbalance of the spine was defined as a mismatch between pelvic incidence and lumbar lordosis (PI-LL) of > 20°. Multivariate logistic regression analyses were performed to identify risk factors for AVF.

RESULTS

AVF occurred in 12 participants (1 man, 11 women). The annual incidence of AVF was estimated at 6.1%/year. Logistic regression analyses revealed that lower BMD at the femoral neck and PI-LL > 20° were risk factors for AVF.

CONCLUSIONS

The annual incidence of AVF in a general population with prevalent VF was 6.1%/year. In addition, lower BMD at the femoral neck and PI-LL > 20° were risk factors for AVF.

Clinical and pathological features affecting cardiac sympathetic denervation in autopsy-confirmed dementia with Lewy bodies

BACKGROUND AND PURPOSE

The aim was to clarify the features affecting cardiac sympathetic denervation in autopsy-confirmed dementia with Lewy bodies (DLB) patients.

METHODS

Fifty-four autopsy-confirmed DLB patients were enrolled. Tissue samples of the left ventricular anterior wall were immunostained with anti-tyrosine hydroxylase antibody to identify catecholaminergic nerve axons. Immunostained areas were quantified as residual cardiac sympathetic nerve (CSN) axons and the relationship between the degree of residual CSN axons and clinical and neuropathological features was examined.

RESULTS

Virtually all patients showed small amounts of residual CSN axons (0.87%, range 0.02%-9.98%), with 50 patients (92.6%) showing <2.0% of residual axons. The patients who showed psychological symptoms within the first year of the disease had significantly more residual CSN axons than the remaining patients did (1.50% vs. 0.40%, P < 0.01). Patients with a short disease duration and neocortical-type Lewy body pathology tended to have more preserved CSN axons, although this difference was not statistically significant. Fifty-three patients (98.1%) who had neurofibrillary tangles in the brain and strong concomitant Alzheimer's disease pathology also had statistically significantly more preserved CSN axons. The patient with the most preserved CSN axons showed different characteristics from the results, except for the first symptom.

CONCLUSION

Psychological symptoms within the first year of the disease, a short disease duration, neocortical-type Lewy body pathology and strong concomitant Alzheimer's disease pathology may be related to mild CSN degeneration in DLB patients. Thus, DLB patients with broad Lewy body pathology in the brain in the early stages may show mild CSN degeneration.

Could automated machine-learned MRI grading aid epidemiological studies of lumbar spinal stenosis? Validation within the Wakayama spine study

BACKGROUND

MRI scanning has revolutionized the clinical diagnosis of lumbar spinal stenosis (LSS). However, there is currently no consensus as to how best to classify MRI findings which has hampered the development of robust longitudinal epidemiological studies of the condition. We developed and tested an automated system for grading lumbar spine MRI scans for central LSS for use in epidemiological research.

METHODS

Using MRI scans from the large population-based cohort study (the Wakayama Spine Study), all graded by a spinal surgeon, we trained an automated system to grade central LSS in four gradings of the bone and soft tissue margins: none, mild, moderate, severe. Subsequently, we tested the automated grading against the independent readings of our observer in a test set to investigate reliability and agreement.

RESULTS

Complete axial views were available for 4855 lumbar intervertebral levels from 971 participants. The machine used 4365 axial views to learn (training set) and graded the remaining 490 axial views (testing set). The agreement rate for gradings was 65.7% (322/490) and the reliability (Lin's correlation coefficient) was 0.73. In 2.2% of scans (11/490) there was a difference in classification of 2 and in only 0.2% (1/490) was there a difference of 3. When classified into 2 groups as 'severe' vs 'no/mild/moderate'. The agreement rate was 94.1% (461/490) with a kappa of 0.75.

CONCLUSIONS

This study showed that an automated system can "learn" to grade central LSS with excellent performance against the reference standard. Thus SpineNet offers potential to grade LSS in large-scale epidemiological studies involving a high volume of MRI spine data with a high level of consistency and objectivity.

Analysis of the cesium distribution in the JT-60SA negative ion sources for steady long-pulse operation

To realize stable negative ion beams for 100 s required in the neutral beam injector of JT-60SA, a physical model to control cesium (Cs) distribution inside the negative ion source has been developed in order to maintain the stable negative ion production at the plasma grid (PG) surface with Cs. In this work, to quantitatively evaluate Cs coverage on the PG, a three-dimensional Cs transportation code was introduced to consider the spatial Cs distribution in the source. The spatial temperature distribution of the chamber wall was also introduced in this model. As a result, the reasonable variation of the Cs coverage for 100 s was obtained, compared to that in the initial model. Based on the modified model, the operational temperature of the chamber wall was proposed to be less than 60 °C to suppress the desorption of Cs in the chamber wall and to sustain the stable negative ion production. In addition, it was also suggested that a slightly higher wall temperature before the operation leads to a decrease in the amount of Cs stored at the chamber wall, resulting in suppression of Cs consumption in the ion source.

Design of photonic-crystal surface-emitting lasers with enhanced in-plane optical feedback for high-speed operation

Photonic-crystal surface-emitting lasers (PCSELs) use the two-dimensional (2D) resonance at the band-edge of a photonic crystal for lasing, and they feature various outstanding functionalities such as high-brightness lasing, arbitrary shaping of beam patterns and on-chip 2D beam steering. In this paper, to investigate the applicability of PCSELs for high-speed operation, we design PCSELs with enhanced in-plane optical feedback, which enable single-mode lasing inside a circular region the diameter of which is less than 10 µm. To realize a strong in-plane confinement of the lasing mode, we increase the one-dimensional coupling coefficients between counter-propagating waves through the careful design of the lattice points. We also introduce an in-plane heterostructure composed of two photonic crystals with different photonic bandgaps and utilize reflection at the boundary of the two photonic crystals in addition to the optical feedback at the band-edge of each photonic crystal. By using three-dimensional finite-difference time-domain method (3D-FDTD), we confirm that the proposed hetero-PCSELs can achieve single-mode lasing operation inside a 9-µm-diameter and possibly realize a 3-dB modulation bandwidth larger than 40 GHz.

Prevalence of Facet Effusion and Its Relationship with Lumbar Spondylolisthesis and Low Back Pain: The Wakayama Spine Study

Introduction

Facet effusion represents a magnetic resonance imaging finding suggesting accumulation of fluid in the facet joint, potentially predictive of lumbar spondylolisthesis and low back pain. However, its prevalence and epidemiological characteristics in the general population remain unclear, because previous studies only included patients or volunteers. The aim of the present study was to investigate the prevalence of facet effusion in the general population and to describe its potential relationship with spondylolisthesis and low back pain.

Material and methods

Our study enrolled 808 participants from the Wakayama Spine Study who underwent magnetic resonance imaging investigations in supine position. Facet effusion was defined as a measurable, curvilinear, high-intensity signal within the facet joint, closely matching that of cerebrospinal fluid on the axial T2 images. We used standing lateral radiographs to diagnose L4 spondylolisthesis.

Results

We found that the prevalence of facet effusion in the lumbar spine was 34.3%, which did not differ significantly between men and women (p=0.13) and did not tend to increase with age, either in men (p=0.81) or in women (p=0.65). Additionally, we found no significant association between facet effusion and low back pain (odds ratio, 1.04–1.49; 95% confidence interval, 0.57–2.64; p=0.17–0.85), or between facet effusion and L4 spondylolisthesis (odds ratio, 1.55; 95% confidence interval, 0.80–2.86; p=0.17). In a subset of participants with L4 spondylolisthesis, we also noted that facet effusion was not significantly associated with low back pain (odds ratio, 1.26; 95% confidence interval, 0.37–4.27; p=0.70).

Discussion

This is the first study of facet effusion employing a population-based cohort, and the findings are thus expected to accurately describe the relationship between facet effusion and low back pain in the general population. We are planning a follow-up survey of the Wakayama Spine Study cohort to clarify the natural history of facet effusion and its relationship with clinical symptoms.

Achievement of high power and long pulse negative ion beam acceleration for JT-60SA NBI

Long pulse acceleration of hydrogen negative ion beams with the power density over 70 MW/m² and the pulse length over 100 s has been demonstrated for the first time by using a multi-aperture 3-stage accelerator. Such long pulse acceleration was achieved by integrating the design of beam optics and voltage holding capability to meet the requirements of JT-60SA. By using the newly designed accelerator for JT-60SA, voltage holding at 500 kV with beam acceleration was stably sustained even after 5 g of cesium was seeded, and heat load on each acceleration grid was reduced below the allowable level for long pulse, less than 5% of total acceleration power. As a result, 500 keV, 154 A/m² for 118 s beam acceleration was achieved, which satisfies the requirement of the negative ion source for JT-60SA. This pulse length of such high-power density beams is longest in the world. In addition, the result contributes to the long pulse acceleration of multi-stage electrostatic accelerators, such as 1 MeV negative ion accelerator for ITER.

A bicortical pedicle screw in the caudad trajectory is the best option for the fixation of an osteoporotic vertebra: An in-vitro experimental study using synthetic lumbar osteoporotic bone models

BACKGROUND

In pedicle screw fixation, the optimal depth and trajectory of insertion are controversial, and this might be because of the wide variations in specimens. The present study aimed to investigate the biomechanically optimal depth and trajectory of screw insertion using synthetic lumbar osteoporotic vertebrae.

METHODS

A total of 27 synthetic osteoporotic lumbar vertebrae (L3) were used to ensure standard vertebral quality and shape. Pedicle screws having two different lengths (unicortical: to the center of the vertebra; bicortical: to the anterior cortex of the vertebra) were inserted in the following three different trajectories: 1) straight-forward (parallel to the superior endplate), 2) cephalad (toward the anterosuperior corner), and 3) caudad (toward the anteroinferior corner). Maximum insertional torque and pull-out strength were measured.

FINDINGS

For the straight-forward, cephalad, and caudad trajectories, the maximum insertional torque (Ncm) values of unicortical screws were 144.4, 143.1, and 148.9, respectively, and those of bicortical screws were 205.5, 156.2, and 207.8, respectively. The maximum insertional torque values were significantly higher for bicortical screws than unicortical screws (p < 0.001). Additionally, regarding bicortical screws, the maximum insertional torque values were significantly lower for the cephalad trajectory than other trajectories (p = 0.002). The pull-out strength (N) values of bicortical screws for the straight-forward, cephalad, and caudad trajectories were 703.3, 783.9, and 981.3, respectively. The pull-out strength values were significantly lower for the straight-forward trajectory than other trajectories (p = 0.034).

INTERPRETATION

A bicortical pedicle screw in the caudad trajectory might be the best option to improve fixation in an osteoporotic lumbar vertebra.

Is radiographic lumbar spondylolisthesis associated with occupational exposures? Findings from a nested case control study within the Wakayama spine study

Background

To explore the relationship between radiographic spondylolisthesis and occupational factors in a case-control study nested within the Wakayama Spine Study (WSS).

Methods

The WSS is a cross-sectional observational study amongst Japanese adults. All participants completed a lifetime occupational history and underwent X-rays of the lumbar spine (L1-S1) according to a pre-defined protocol. One trained surgeon graded the presence of a spondylolisthesis based upon ≥5% anterior or posterior slip at one or more levels. Cases, with lumbar spondylolisthesis, were compared with controls without, for their principal occupation and occupational exposures.

Results

In total, data were available for 722 adults (245 men and 477 women), mean age 70.1 (range 53–93) years. According to the pre-defined radiographic criteria, 117 were defined with spondylolisthesis (cases), leaving 605 controls. Cases were not significantly different from controls for age, gender, BMI, smoking or alcohol intake. However, cases were more than twice as likely to report occupational driving ≥4 h/day (OR 2.39, 95% CI 1.08–5.27) after adjustment for age, gender and BMI. Additionally, after stratification by age using 75 years as a cut-point, cases were more than 3-fold more likely to report having worked in the agricultural/ fishing industries (OR 3.47, 95% CI 1.29–9.29) among those aged < 75 years. A reduced risk of being a case was associated with climbing slopes/steps and walking.

Conclusions

A history of occupational driving and working in the agricultural/fishing industry were associated with radiographic spondylolisthesis in this cross-sectional population study. This finding requires further evaluation in longitudinal studies.

Oral function and vertical jump height among healthy older people in Japan

OBJECTIVE

Vertical jump height and oral function affect the general muscle condition. This study aimed to evaluate the association between vertical jump height and oral function among healthy older individuals.

BASIC RESEARCH DESIGN

Cross-sectional analytic study.

PARTICIPANTS

231 independent older people (mean age, 74.4 ± 5.6 years) who participated in the Kyoto Elders Physical Fitness Measurement Research Project. Individuals with partial or complete edentulousness who did not use a prosthetic device or complained of oral/maxillofacial pain were excluded from the study.

INTERVENTIONS

Grip strength was measured using a Smedley Hand Dynamometer. To measure masticatory performance, the participants were instructed to chew a gummy jelly on their habitual chewing side (left or right) for 20 s. Occlusal force, contact area, and pressure were also assessed.

MAIN OUTCOME MEASURES

The outcome variable was vertical jump height. The predictor variables were physical status (age, body mass index, and grip strength), oral status (number of present teeth and denture use), and oral function (masticatory performance, occlusal force, occlusal contact area, occlusal pressure, and tongue pressure). These relationships were evaluated with univariate analysis, and then multiple regression analysis was performed with age as the covariate for each male and female participant.

RESULTS

Vertical jump height was significantly associated with grip strength in both men and women. Moreover, in women, it was associated with masticatory performance, occlusal force, and occlusal contact area.

CONCLUSIONS

Vertical jump height was closely associated with oral function among healthy older women.

A population-based study identifies an association of THBS2 with intervertebral disc degeneration

OBJECTIVE

To clarify the genetic mechanisms underlying intervertebral disc degeneration (IDD), we examined the associations between single-nucleotide polymorphisms (SNPs) and indicated as coefficient of interaction term (IDD) in a general population in Japan.

METHODS

This was a cross-sectional study. In 1,605 participants, C2-3 to L5/S1 in the total spine magnetic resonance imaging (MRI) were evaluated using the Pfirrmann's scoring system. Disc scores of 4 and 5 were defined as IDD. Eight SNPs in eight genes associated with IDD were examined at each disc level, considering the non-genetic risk factors of age, sex, and body mass index (BMI).

RESULTS

The highest odds ratio was found for rs9406328 in the THBS2 gene at disc level T12-L1 (OR 1.27, 95%CI 1.05 to 1.53), and this association was strengthened after adjustment for age using logistic regression (OR 1.37, 95%CI 1.12 to 1.67). Among participants aged <50 years and 50-59, the average IDD score in those with 2 risk alleles of rs9406328 was markedly higher than in those with 0 or 1 risk allele, and the difference is much wider than the elderly participants. It indicates the genetic effect of rs9406328 is stronger in the younger age groups. Finally, multiple linear regression analyses of the association between rs9406328 and IDD, adjusted for age, sex, and BMI at each disc level, showed a statistical interaction between age and the number of risk alleles at C7-T1, T3-4 and T4-T5 as well as T12-L1.

CONCLUSION

CONCLUSION: The association between rs9406328 in THBS2 and IDD was replicated. The contributions of genetic and environmental factors to IDD differed by disc level.

Cost-effectiveness analysis of the pharmacological management of chronic low back pain with four leading drugs

BACKGROUND

Chronic low back pain is a major health problem that has a substantial effect on people's quality of life and places a significant economic burden on healthcare systems. However, there has been little cost-effectiveness analysis of the treatments for it. Therefore, the purpose of this prospective observational study was to evaluate the cost-effectiveness of the pharmacological management of chronic low back pain.

METHODS

A total of 474 patients received pharmacological management for chronic low back pain using four leading drugs for 6 months at 28 institutions in Japan. Outcome measures, including EQ-5D, the Japanese Orthopaedic Association (JOA) score, the JOA back pain evaluation questionnaire (BPEQ), the Roland-Morris Disability Questionnaire, the Medical Outcomes Study SF-8, and the visual analog scale, were investigated at baseline and every one month thereafter. The incremental cost-utility ratio (ICUR) was calculated as drug cost over the quality-adjusted life years. An economic estimation was performed from the perspective of a public healthcare payer in Japan. Stratified analysis based on patient characteristics was also performed to explore the characteristics that affect cost-effectiveness.

RESULTS

The ICUR of pharmacological management for chronic low back pain was JPY 453,756. Stratified analysis based on patient characteristics suggested that the pharmacological treatments for patients with a history of spine surgery or cancer, low frequency of exercise, long disease period, low scores in lumbar spine dysfunction and gait disturbance of the JOA BPEQ, and low JOA score at baseline were not cost-effective.

CONCLUSIONS

Pharmacological management for chronic low back pain is cost-effective from the reference willingness to pay. Further optimization based on patient characteristics is expected to contribute to the sustainable development of a universal insurance system in Japan.

Differences in prevalence and associated factors between mild and severe vertebral fractures in Japanese men and women: the third survey of the ROAD study

Vertebral fracture (VF) is a common osteoporotic fracture, while its epidemiology varies according to regions and ethnicities, little is known about it in Japan. Using whole-spine radiographs from a population-based cohort study, the Research on Osteoarthritis/Osteoporosis Against Disability study 3rd survey performed in 2012-2013, we estimated the sex- and age-specific prevalence of VF in the Japanese. Genant's semiquantitative method (SQ) was used to define VF; SQ ≥ 1 as VF, SQ = 1 as mild VF, SQ≥ 2 as severe VF. We also revealed accurate site-specific prevalence, and associated factors with mild and severe VF. The participants were 506 men [mean age 66.3 years, standard deviation (SD):13.0] and 1038 women (mean age 65.3 years, SD: 12.6). The prevalence of VF in participants aged under 40, in their 40s, 50s, 60s, 70s, and ≥ 80 years was 17.4, 7.9, 18.5, 25.6, 26.3, and 41.5%, respectively, in men, and 2.9%, 2.4%, 7,3, 10.3, 27.1, and 53.0%, respectively, in women. Men had a significantly higher prevalence of mild VF (21.2%) than women (10.0%, p < 0.001); whereas, severe VF was significantly more prevalent in women (9.1%) than in men (4.7%, p = 0.003). VF was distributed with 2 peaks regarding site; one large peak at the thoracolumbar region, and another at the middle thoracic lesion. Low back pain and decreased walking ability were independently associated with severe VF, but not with mild VF, after adjustment for participant characteristics. Decreased walking ability was associated with multiple VFs in women, but not in men.