Reflection of power Doppler activity in the subacromial space on nocturnal pain in patients with rotator cuff tears: A cross-sectional study.

BACKGROUND: Nocturnal shoulder pain is seen in patients with rotator cuff tears. The purpose of the present study was to determine whether Doppler ultrasound parameters predict the intensity of nocturnal pain in patients with rotator cuff tears. METHODS: A total of 60 patients with rotator cuff tears were included. Doppler ultrasound parameters (peak systolic velocity in the anterior humeral circumflex artery, Doppler activity in the glenohumeral joint and subacromial space) and clinical parameters were examined. For the presence of nocturnal pain, the clinical parameters were compared with and without nocturnal pain. For the intensity of the nocturnal pain, a multivariate analysis of clinical parameters and nocturnal pain intensity was performed. RESULTS: In all, 39 patients (65%) reported nocturnal pain, and the mean pain intensity was 47.0 (standard deviation, 26.0) on the visual analogue scale. In nocturnal pain presence analysis, Doppler activity in the subacromial space showed significant associations (p < 0.001). In nocturnal pain intensity analysis, Doppler activity in the subacromial space and diabetes showed significant associations (p < 0.001, p = 0.01, respectively). CONCLUSION: Doppler activity in the subacromial space emerges as an independent factor associated with the presence and intensity of nocturnal pain in patients with rotator cuff tears. Our findings may provide a basis for further exploration and refinement of treatment strategies.

Development and validation of a shoulder-specific body-perception questionnaire in people with persistent shoulder pain.

BACKGROUND: There is evidence that people with persistent shoulder pain exhibit findings consistent with the presence of sensorimotor dysfunction. Sensorimotor impairments can manifest in a variety of ways, and further developing our understanding of sensorimotor dysfunction in shoulder pain may improve current models of care. The Fremantle Back Awareness Questionnaire (FreBAQ) has been developed to assess disturbed body perception specific to the back. The purpose of the present study was to develop a shoulder-specific self-perception questionnaire and evaluate the questionnaire in people with persistent shoulder pain. METHODS: The Fremantle Shoulder Awareness Questionnaire (FreSHAQ-J) was developed by modifying the FreBAQ. One hundred and twelve consecutive people with persistent shoulder pain completed the FreSHAQ-J. Thirty participants completed the FreSHAQ-J again two-weeks later to assess test-retest reliability. Rasch analysis was used to assess the psychometric properties of the FreSHAQ-J. Associations between FreSHAQ-J total score and clinical status was explored using correlational analysis. RESULTS: The FreSHAQ-J has acceptable category order, unidimensionality, no misfitting items, and excellent test-retest reliability. The FreSHAQ-J was moderately correlated with disability and pain catastrophization. CONCLUSIONS: The FreSHAQ-J fits the Rasch measurement model well and is suitable for use with people with shoulder pain. Given the relationship between the FreSHAQ-J score and clinical status, change in body perception may be worth assessing when managing patients with shoulder pain.

Association between the Critical Shoulder Angle and Rotator Cuff Tears in Japan.

Distinct anatomic variants of the scapula such as the critical shoulder angle (CSA) were found to be associated with rotator cuff tears (RCTs), but it is unclear whether the CSA is a risk factor in Japanese. Here we sought to determine whether the CSA is associated with RCTs in a Japanese population, and whether the CSA is a more useful parameter than the conventionally used parameters. Our RCT group and non-RCT group each consisted of 54 consecutive cases. We compared the groups' values of CSA, the acromion index (AI), and the lateral acromion angle (LAA) obtained by X-ray imaging. Receiver operating characteristic (ROC) analyses were performed to determine cutoff values and the area under the curve (AUC), and to assess the odds ratio. The means of the CSA and the AI in the RCT group were significantly larger (36.3° vs. 33.7°, 0.74 vs 0.68), but the LAA did not show a significant between-group difference. The AUCs for the CSA and AI were 0.678 and 0.658, the cutoff values were 35.0° and 0.72, and the odds ratios were 3.1 and 2.5, respectively. In conclusion, the CSA was a strong risk factor compared to the AI and LAA for rotator cuff tears.

Differences in Risk Factors for Rotator Cuff Tears between Elderly Patients and Young Patients.

It has been unclear whether the risk factors for rotator cuff tears are the same at all ages or differ between young and older populations. In this study, we examined the risk factors for rotator cuff tears using classification and regression tree analysis as methods of nonlinear regression analysis. There were 65 patients in the rotator cuff tears group and 45 patients in the intact rotator cuff group. Classification and regression tree analysis was performed to predict rotator cuff tears. The target factor was rotator cuff tears; explanatory variables were age, sex, trauma, and critical shoulder angle≥35°. In the results of classification and regression tree analysis, the tree was divided at age 64. For patients aged≥64, the tree was divided at trauma. For patients aged<64, the tree was divided at critical shoulder angle≥35°. The odds ratio for critical shoulder angle≥35° was significant for all ages (5.89), and for patients aged<64 (10.3) while trauma was only a significant factor for patients aged≥64 (5.13). Age, trauma, and critical shoulder angle≥35° were related to rotator cuff tears in this study. However, these risk factors showed different trends according to age group, not a linear relationship.

Psychometric properties of the Japanese version of short forms of the Pain Catastrophizing Scale in participants with musculoskeletal pain: A cross-sectional study.

BACKGROUND: The Pain Catastrophizing Scale (PCS) is a commonly used as measure of pain catastrophizing. The scale comprises 13 items related to magnification, rumination, and helplessness. To facilitate quick screening and to reduce participant's burden, the four-item and six-item short forms of the English version of the PCS were developed. The purpose of the present study was to evaluate the psychometric properties of a Japanese version of the short forms of PCS using a contemporary approach called Rasch analysis. METHODS: A total of 216 patients with musculoskeletal disorders were recruited in this study. Participants completed study measures, which included the pain intensity, the Pain Catastrophizing Scale (PCS), and the Tampa Scale of Kinesiophobia (TSK). Furthermore, the four-item (items 3, 6, 8, and 11) and six-item (items 4, 5, 6, 10, 11, and 13) short forms of the Japanese version of PCS were measured. We used Rasch analysis to analyze the psychometric properties of the original, four-item, and six-item short forms of PCS. RESULTS: Rasch analysis showed that both short forms of PCS had acceptable internal consistency, unidimensionality, and no notable DIF and were functional on the category rating scale. However, four-item short form of PCS had two misfit items. CONCLUSIONS: Six-item short form of PCS has acceptable psychometric properties and is suitable for use in participants with musculoskeletal pain. Thus, six-item can be used as brief instruments to evaluate pain catastrophizing.

Variability of laboratory parameters is associated with frailty markers and predicts non-cardiac mortality in hemodialysis patients.

BACKGROUND: The levels of many laboratory parameters are associated with the outcomes of dialysis patients, but the significance of their variability has not been well studied. METHODS: A total of 384 patients receiving stable hemodialysis treatment during 2002 were followed up for mortality until the end of 2013. The within-patient coefficients of variation (CV) were calculated for 13 laboratory parameters from 1 year of data. We defined variability as CV and analyzed the survival of the patients according to the baseline CV values of each parameter by proportional hazard modeling. RESULTS: During the 11-year observation period, 125 patients died. Higher CV levels for eight parameters, namely, blood urea nitrogen (BUN), sodium, hemoglobin, creatinine, total protein, albumin, potassium and phosphate, were significantly associated with all-cause mortality. The adjusted hazard ratios for a high BUN-CV (>15 %) and a high Na-CV (>1.3 %) against a lower CV were 1.92 (95 % CI 1.31-2.81) and 1.95 (1.36-2.80), respectively. The increased mortality risk associated with each variability was attributed to excess non-cardiac deaths. The CV values of most parameters were correlated with each other and often exhibited negative associations with age, diabetes, and mobility as well as the levels of hemoglobin, albumin, creatinine, Na, the protein catabolic rate, and the creatinine generation rate. Therefore, a high variability was generally associated with frailty-related adverse prognostic factors. CONCLUSIONS: The variability of several blood parameters had a significant impact on all-cause and non-cardiac mortality. The levels of the variabilities were most likely related to poor physical conditions of the patients.

[Questionnaire survey of ocular injuries due to fireworks in Japan].

PURPOSE: To report the results of a questionnaire survey of ocular injuries caused by fireworks in 2011. METHODS: A survey was performed by recovery of questionnaire postcards asking details of firework-related ocular injuries which were sent to 1,094 institutes recognized as training hospitals by the Japan Ophthalmological Society. RESULTS: The cards were recovered from 57.9% institutes, and showed that 23 eyes of 20 patients (17 men and 3 women) with firework-related ocular injuries were seen in 19 institutes. The patients' ages ranged from 1 to 45 (average 18.4) years old. Injuries were caused by either carelessness or accidents in 18 eyes of 15 patients, and by wrong usage of fireworks in 5 eyes of 5 young men (15-27 years old). These 5 eyes showed severe injuries involving the lens and/or retina, and required surgical treatment with finally measured visual acuities 0.4 or less. CONCLUSIONS: In Japan, hazardous use of fireworks seems to cause severe eye injuries from which at least 5 young adults suffered during one fireworks' season. Therefore, preventive measures should be taken including public education on the usage of fireworks.

Blood flow velocity in the anterior humeral circumflex artery and tear size can predict synovitis severity in patients with rotator cuff tears.

BACKGROUND: Rotator cuff tears are often associated with synovitis, but the ability of noninvasive ultrasonography to predict the severity of synovitis remains unclear. We investigated whether ultrasound parameters, namely peak systolic velocity in the anterior humeral circumflex artery and Doppler activity in the glenohumeral joint and subacromial space, reflect synovitis severity. METHODS: A total of 54 patients undergoing arthroscopic rotator cuff repair were selected. Doppler ultrasound was used to measure peak systolic velocity in the anterior humeral circumflex artery and Doppler activity in the glenohumeral joint and subacromial space, and these values were compared with the intraoperative synovitis score in univariate and multivariate analyses. RESULTS: Univariate analyses revealed that tear size, peak systolic velocity in the anterior humeral circumflex artery, and Doppler activity in the glenohumeral joint were associated with synovitis in the glenohumeral joint (P=0.02, P<0.001, P=0.02, respectively). In the subacromial space, tear size, peak systolic velocity in the anterior humeral circumflex artery, and Doppler activity in the subacromial space were associated with synovitis severity (P=0.02, P<0.001, P=0.02, respectively). Multivariate analyses indicated that tear size and peak systolic velocity in the anterior humeral circumflex artery were independently associated with synovitis scores in both the glenohumeral joint and the subacromial space (all P<0.05). CONCLUSIONS: These findings demonstrate that tear size and peak systolic velocity in the anterior humeral circumflex artery, which can both be measured noninvasively, are useful indicators of synovitis severity. Level of evidence: IV.

A new perspective on tissue gliding dysfunction bordered by deep fascia as an indicator of delayed onset muscle soreness: A case report.

INTRODUCTION: The deep fascia, especially its thickness and stiffness, plays an important role in the mechanism of delayed onset muscle soreness (DOMS). Here, we present a patient with DOMS associated with a tissue gliding dysfunction bordered by the deep fascia. CASE PRESENTATION: A 25-year-old woman developed DOMS of the left upper arm. We confirmed the tissue gliding dysfunction during manual skin traction by ultrasound imaging and treated with acupuncture aimed at stimulating the deep fascia. Tissue gliding between subcutaneous and muscle tissues bordered by the deep fascia was analyzed qualitatively and quantitatively, i.e., phases and distance of displacement. At the initial examination, the tissue gliding phases were in the same direction synchronously and the distance of displacement was 0.66mm. After the DOMS symptoms improved with direct acupuncture to the deep fascia, the phases changed independently in opposite directions and their displacement was 7.04mm. CONCLUSIONS: In this patient, tissue gliding played an important role in the symptoms of DOMS. This case report focusing on tissue gliding provides a new perspective on understanding the pathogenesis of DOMS.

Discovering the Forgotten Trauma Behind Chronic Shoulder Pain: The Critical Role of a Thorough Medical Interview.

We report a rare case of a patient experiencing pain and dysfunction attributable to bone fragments from a trauma sustained over two decades prior. A 43-year-old Japanese woman presented with persistent left shoulder pain. Initial radiographs revealed glenohumeral joint osteoarthritis, an unusual finding for her age. Her medical history included a previously overlooked traumatic dislocation of the left acromioclavicular joint over 20 years ago. Computed tomography scans later uncovered bone fragments below the coracoid process without signs of scapular or tuberosity fractures. The fragments were arthroscopically removed, resulting in significant pain relief. The patient's Shoulder Pain and Disability Index score improved from 60 to 9 at the six-month postoperative follow-up. This case underscores the importance of considering historical trauma in patients presenting with atypical shoulder pain and highlights the potential diagnostic value of revisiting a patient's medical history when unusual lesions are discovered.

Intercorrelated variability in blood and hemodynamic biomarkers reveals physiological network in hemodialysis patients.

Increased intra-individual variability of a variety of biomarkers is generally associated with poor health and reflects physiological dysregulation. Correlations among these biomarker variabilities should then represent interactions among heterogeneous biomarker regulatory systems. Herein, in an attempt to elucidate the network structure of physiological systems, we probed the inter-variability correlations of 22 biomarkers. Time series data on 19 blood-based and 3 hemodynamic biomarkers were collected over a one-year period for 334 hemodialysis patients, and their variabilities were evaluated by coefficients of variation. The network diagram exhibited six clusters in the physiological systems, corresponding to the regulatory domains for metabolism, inflammation, circulation, liver, salt, and protein. These domains were captured as latent factors in exploratory and confirmatory factor analyses (CFA). The 6-factor CFA model indicates that dysregulation in each of the domains manifests itself as increased variability in a specific set of biomarkers. Comparison of a diabetic and non-diabetic group within the cohort by multi-group CFA revealed that the diabetic cohort showed reduced capacities in the metabolism and salt domains and higher variabilities of the biomarkers belonging to these domains. The variability-based network analysis visualizes the concept of homeostasis and could be a valuable tool for exploring both healthy and pathological conditions.

Video Evidence of Tissue Sliding Improvement by Ultrasound-Guided Hydrorelease on Scars After Arthroscopic Knee Surgery: A Case Report.

Postoperative scarring is a complication of arthroscopic knee surgery that causes a lack of terminal extension and tissue sliding defects. We present video evidence of tissue sliding before and after ultrasound-guided hydrorelease in a 53-year-old man. The patient presented with pain in the scarred area following arthroscopic knee surgery. His active and passive extension was -5° with restricted patellar mobility. Dynamic ultrasonography revealed scar tissue sliding defects. For ultrasound-guided hydrorelease, a needle (22G, 60 mm) was aimed at a site within 10 mm depth of the hypoechoic change in the scar area below the patella, and saline solution (10 mL) mixed with 1% lidocaine (10 mL) and 10 mg prednisolone was injected. Immediately after injection, the patient's extension was 0° with no pain or limitation of patellar mobility, and dynamic ultrasonography showed tissue sliding improved. Video evidence from dynamic ultrasonography clarifies the direction of the inadequate slide and the indication for and efficacy of ultrasound-guided hydrorelease. This case highlights the benefits of video evidence from dynamic ultrasonography before and after ultrasound-guided hydrorelease.

Effects of a chair for ophthalmic microsurgery on pressure distribution and pelvic tilt in surgeons.

BACKGROUND: Ophthalmic surgeons experience high levels of physical strain in the neck, lower back, and buttocks. While ergonomic interventions may help to solve these problems, only a few studies have reported chair designs for ophthalmic microsurgery. OBJECTIVE: To design a chair that reduces the physical strain on surgeons and examine its effectiveness in improving posture and reducing seat pressure. METHODS: A prototype chair with a three-dimensional seat surface and a sliding adjustment mechanism for the backrest was designed to fit the surgeon's body. A conventional chair (A) and the prototype chair (B) were compared during microsurgeries performed by five surgeons. Seat pressure was measured using a pressure-sensing device, and the pelvic tilt angle was measured using a gyroscope sensor. RESULTS: A paired t-test indicated significant differences between the chairs: average seat pressure was 70.4±12.7 mmHg for A and 40.5±3.8 mmHg for B (p = 0.008); the maximum seat pressure was 242.2±19.7 mmHg for A and 170.5±38.5 mmHg for B (p = 0.024); contact area was 906.1±114.5 cm2 for A and 1,255.9±60.1 cm2 for B (p < 0.001); and relative value of the pelvic tilt angle was -13.7°±3.7° for A and -7.1°±4.9° for B (p = 0.032). CONCLUSIONS: The prototype chair was associated with lower seat pressure and maintenance of a more neutral posture than the conventional chair, indicating that it may help to reduce physical strain in ophthalmic surgeons.

Synchronization of Blood Flow Velocity in the Anterior Humeral Circumflex Artery and Reduction in Night Pain After Arthroscopic Rotator Cuff Repair: A Case Report.

Rotator cuff tears are commonly associated with pain at rest and at night particularly if lying on the affected shoulder. This case describes a 54-year-old man who reported concerns of severe night pain in his left shoulder and had to undergo arthroscopic rotator cuff repair. The severity of night pain and blood flow velocity in the anterior humeral circumflex artery (AHCA) were measured over time. The patient reported his night pain as 10/10 on the numerical rating scale in the first week after surgery. In the fourth week, he rated his night pain as 6/10, and in the fifth week, his pain was <2/10. We measured blood flow velocity in the AHCA using a 3-11MHz color Doppler and power Doppler ultrasound (SONIMAGE HS2, Konica Minolta, Tokyo, Japan), and we calculated peak systolic velocity. The course of peak systolic velocity in the AHCA ranged from 27.7 to 62.4 cm/s until four weeks after surgery when his night pain was severe; AHCA flow velocity ranged from 16.7 to 19.3 cm/s five weeks after surgery when his night pain had reduced. The initially high blood flow velocity in the AHCA decreased almost simultaneously with the improvement in night pain. Our case highlights that blood flow velocity in the AHCA synchronized with the severity of night pain, which may contribute to the understanding of sleep disturbances in patients after arthroscopic rotator cuff repair.

Successful Pain Relief With Duloxetine in a Patient With Chronic Postsurgical Pain After Open Reduction and Internal Fixation: A Case Report.

Chronic postsurgical pain (CPSP) is a common complication of surgery. We report that a patient with CPSP after open reduction and internal fixation (ORIF) had pain relief with duloxetine, and that the conditioned pain modulation (CPM) efficiency may predict the efficacy of duloxetine. A 54-year-old woman with CPSP after ORIF due to proximal humeral fracture was presented to our orthopedic clinic one month after surgery. Despite several analgesics, she still had pain three months after surgery, pain during activity was 74 on the visual analogue scale (VAS), 16 on the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), 18 on the PainDETECT questionnaire, and CPM efficiency was -5.7%. The patient was treated with duloxetine, starting at 20mg/day and increasing every week. Three months after starting duloxetine, pain on the VAS was 18, ASES was 61, PainDETECT questionnaire was 6, and CPM efficiency was -39.8%. The dose of duloxetine was decreased every week and then withdrawn. Neuropathic pain may be involved even in patients with CPSP after ORIF, and duloxetine may be efficacious in such cases. CPM testing may provide useful information for clinicians in selecting appropriate drugs and in determining when to withdraw drugs.

Generalizability of Eccentric Exercise for Patients with Subacromial Pain Syndrome to Real-world Clinical Practice: A Propensity Score-based Analysis.

OBJECTIVES: Subacromial pain syndrome is a common problem in primary care. Although several randomized controlled trials have shown that eccentric exercise is effective in patients with subacromial pain syndrome, its generalizability to real-world clinical practice is unknown. This study aimed to investigate, using propensity score analysis, the generalizability of eccentric exercise for patients with subacromial pain syndrome to real-world daily clinical practice. METHODS: In this study, 78 patients underwent eccentric exercise in addition to traditional exercise, and 77 patients underwent only traditional exercise for 4 weeks. Outcomes measured using a visual analog scale (VAS) and American Shoulder and Elbow Surgeons Society Standardized Shoulder Assessment Form (ASES) scores were assessed at baseline and at 4 weeks. RESULTS: In the propensity score-matched analysis, 65 patients in each group were successfully matched (130 of 155 patients, 84% overall). After 4 weeks of exercise, pain intensity was lower in the eccentric exercise group than in the traditional exercise group (VAS -14.5, 95% CI -21.2 to -7.9, P<0.001). No significant difference in the improvement in function was found between the two groups (ASES 4.1, 95% CI -2.0 to 10.2, P=0.18). CONCLUSIONS: Eccentric and traditional exercise in combination could reduce pain in patients with subacromial pain syndrome to a greater extent than traditional exercise alone. These findings have clinical relevance to primary care practitioners who provide conservative treatment for patients with subacromial pain syndrome.

Association between Cerebral Oxygenation, as Evaluated with Near-Infrared Spectroscopy, and Cognitive Function in Patients Undergoing Hemodialysis.

INTRODUCTION: The prevalence of cognitive impairment in patients undergoing hemodialysis (HD) is higher than that in healthy controls. To date, studies on the association between cognitive function and cerebral oxygenation in these patients are limited. Therefore, in this study, we aimed to cross-sectionally investigate the association between cognitive assessment scores and clinical factors, including cerebral oxygenation, in patients undergoing HD. METHODS: In this observational study, 193 HD patients were included. Cerebral regional oxygen saturation (rSO2) was monitored using an INVOS 5,100c oxygen saturation monitor. Poor cognition was defined as a Mini-Mental State Examination (MMSE) score ≤23. We analyzed the association between MMSE score and clinical factors, including cerebral rSO2. RESULTS: MMSE score in HD patients included in this study was 26.8 ± 3.3. There were 164 patients (85%) with MMSE score ≥24 and 29 patients (15%) with an MMSE score ≤23. In the patients with MMSE score ≥24, cerebral rSO2 (53.8% ± 8.3%) was significantly higher than that in patients with MMSE score ≤23 (49.5% ± 9.8%; p = 0.013). Multivariable linear regression analysis was performed using the following confounding factors: age, mean blood pressure, cerebral rSO2, HD duration, ultrafiltration rate, hemoglobin, serum Cr, serum calcium, serum phosphate, total cholesterol, high-density lipoprotein cholesterol levels, serum albumin, presence of diabetes mellitus or chronic glomerulonephritis, history of comorbid cardiovascular or cerebrovascular disease, and use of renin-angiotensin-aldosterone system inhibitors or vitamin D analogs. MMSE score was independently and significantly associated with age (standardized coefficient: -0.244) and cerebral rSO2 (standardized coefficient: 0.180). CONCLUSIONS: MMSE score was independently associated with age (negative effect) and cerebral rSO2 (positive effect) in this cross-sectional study. Further prospective studies are needed to clarify whether maintaining cerebral oxygenation prevents the deterioration of cognitive function in patients undergoing HD.

A New Procedure for Ultrasound-Guided Hydrorelease for the Scarring After Arthroscopic Knee Surgery.

Postoperative scarring is one of the complications after arthroscopic knee surgery, which is usually treated with manual therapy or arthroscopic debridement. The incidence of symptomatic scarring requiring surgery within six months postoperatively has been reported to be approximately 0.06-6.00%. We treated a patient after arthroscopic surgery with a new "ultrasound-guided hydrorelease" procedure and we describe it. A 50-year-old woman with a history of arthroscopic anterior cruciate ligament reconstruction of the right knee presented to our clinic 10 months ago with a complaint of right anterior knee pain. Ultrasound imaging showed an infrapatellar fat pad (IPFP) scarring and sliding defects. The pre-treatment Kujala scale was 62 points and the visual analogue scale was 72. The inferolateral side of the patella was palpated to identify the scarring after arthroscopy at the IPFP area. An ultrasound probe was applied vertically to identify the site of adhesion of interest. Ultrasound-guided hydrorelease was performed using 7.0mL saline injected by needle (22G, 60mm) directed at the site with hypoechoic changes in the IPFP. After the procedure, the normalization of the IPFP sliding was confirmed by an ultrasound image. Four weeks after this procedure, the patient improved, with a Kujala scale of 82 points and a visual analogue scale of 28. The most important finding from this patient's course is that her chief complaint of anterior knee pain improved by ultrasound-guided hydrorelease into the IPFP scarring after arthroscopic knee surgery. The procedure should be considered as a treatment for scarring after arthroscopic knee surgery.

Estimation of homeostatic dysregulation and frailty using biomarker variability: a principal component analysis of hemodialysis patients.

Increased intraindividual variability in several biological parameters is associated with aspects of frailty and may reflect impaired physiological regulation. As frailty involves a cumulative decline in multiple physiological systems, we aimed to estimate the overall regulatory capacity by applying a principal component analysis to such variability. The variability of 20 blood-based parameters was evaluated as the log-transformed coefficient of variation (LCV) for one year's worth of data from 580 hemodialysis patients. All the LCVs were positively correlated with each other and shared common characteristics. In a principal component analysis of 19 LCVs, the first principal component (PC1) explained 27.7% of the total variance, and the PC1 score exhibited consistent correlations with diverse negative health indicators, including diabetes, hypoalbuminemia, hyponatremia, and relative hypocreatininemia. The relationship between the PC1 score and frailty was subsequently examined in a subset of the subjects. The PC1 score was associated with the prevalence of frailty and was an independent predictor for frailty (odds ratio per SD: 2.31, P = 0.01) using a multivariate logistic regression model, which showed good discrimination (c-statistic: 0.85). Therefore, the PC1 score represents principal information shared by biomarker variabilities and is a reasonable measure of homeostatic dysregulation and frailty.

Associations of cerebral oxygenation with hemoglobin levels evaluated by near-infrared spectroscopy in hemodialysis patients.

Hemoglobin (Hb) is associated with cerebral oxygenation status owing to its important role of carrying oxygen to systemic tissues. However, data concerning the associations between Hb levels and cerebral regional oxygen saturation (rSO2) of hemodialysis (HD) patients is limited. We aimed to identify these associations to consider a target Hb level for renal anemia management. This study included 375 HD patients. Cerebral rSO2 before HD was monitored using the INVOS 5100c oxygen saturation monitor. Multivariable linear regression analysis showed that cerebral rSO2 was independently associated with natural logarithm (Ln)-HD duration (standardized coefficient: -0.36), mean blood pressure (standardized coefficient: 0.13), pH (standardized coefficient: -0.10), serum albumin (standardized coefficient: 0.14), presence of diabetes mellitus (standardized coefficient: -0.20), and Hb level (standardized coefficient: 0.29). Furthermore, a generalized linear model with restricted cubic spline function was used to investigate the non-linear association between cerebral rSO2 and Hb levels. In the multivariable analysis for the adjustment with Ln-HD duration, mean blood pressure, pH, serum albumin, and presence of diabetes mellitus, a linear relationship was demonstrated between the two variables (p for linearity = 0.79). Hb levels revealed the positive and significant association with cerebral rSO2 in this study. Moreover, the relationship between cerebral rSO2 and Hb level was proven to be linear. Therefore, the target Hb level in renal anemia management would be considered to be the upper limits for the appropriate management of renal anemia by previous guidelines and position statement from the viewpoint of maintaining cerebral oxygenation in HD patients.