Safety of urgent surgery for the patients with proximal femur fracture treated with platelet aggregation inhibitors: a propensity-score matching analysis

INTRODUCTION

To compare the various perioperative outcomes in an urgent surgery setting among patients with proximal femur fracture (PFF) who received platelet aggregation inhibitors (PAIs) and those who did not.

METHODS

We retrospectively reviewed the data of 1,838 patients who underwent surgery for PFF between January 2011 and January 2021. We conducted 1:1 propensity-score matching and compared the perioperative outcomes, including operation time, postoperative complications, hospital stay, mortality, and variables related to bleeding risk (e.g., number of transfusion profiles, hemoglobin levels, and laboratory data, including coagulation battery).

RESULTS

Of the 492 patients who were treated with PAIs, 484 were 1:1 matched to the untreated control group. The PAI group showed shorter operation time than the matched control group (72.3 min for PAI vs. 77.7 min for control; P = 0.041), and the control group showed more pulmonary thromboembolism (0.2% for PAI vs 1.7% for control; P = 0.046) than the PAI group. The other complications and length of hospital stay, mortality rate, transfusion profile, and the laboratory test (except preoperative international normalized ratio, INR) showed no significant difference between the groups. Subgroup analyses of the patients treated with only aspirin (aspirin: 306, matched control: 306), only clopidogrel (clopidogrel: 100, matched control: 100), and others who were treated with dual anticoagulation (dual anticoagulation: 78, matched control: 78) showed no significant differences in perioperative outcomes among the groups.

CONCLUSION

The patients who were treated with PAI could undergo PFF surgery safely without delay, which led to no significant difference in operation time, postoperative complication risk, perioperative blood transfusion, and variables related to bleeding risk. Therefore, we believe that it is unnecessary to delay surgery for patients with PFF who receive PAI.

Effect of motivated physicians and elderly patients with hypertension or type 2 diabetes mellitus in prepared communities on health behaviours and outcomes: A population-based PS matched retrospective cohort study during five-year follow-up period

Effective chronic disease management requires the active participation of patients, communities, and physicians. The objective of this study was to estimate the effectiveness of the Community-based Registration and Management for elderly patients with Hypertension or Type 2 Diabetes mellitus Project (CRMHDP) by using motivated primary care physicians and patients supported by prepared communities, to utilise healthcare and health outcomes in four cities in South Korea. We conducted a propensity score-matched retrospective cohort study using 2010-2011 as the baseline years, alongside a follow-up period until 2015/2016, based on the Korean National Health Insurance database. Both a CRMHDP group (n = 46,865) and a control group (n = 93,730) were applied against healthcare utilisation and difference-in-differences estimations were performed. For the health outcome analysis, the intervention group (n = 27,242) and control group (n = 54,484) were analysed using the Kaplan-Meier method and Cox proportional hazard regression. Results: The difference-in-differences estimation of the average annual clinic visits per person and the average annual days covered were 1.26 (95% confidence interval, 1.13-1.39) and 22.97 (95% CI, 20.91-25.03), respectively, between the intervention and control groups. The adjusted hazard ratio for death in the intervention group, compared to the control group, was 0.90 (95% CI, 0.86-0.93). For stroke and chronic renal failure, the adjusted hazard ratios for the intervention group compared to the control group were 0.94 (95% CI, 0.88-0.99) and 0.80 (95% CI 0.73-0.89), respectively. Our study suggests that for effective chronic disease management both elderly patients and physicians need to be motivated by community support.

Association between the incidence of type 1 diabetes mellitus and tuberculosis or bacillus Calmette-Guérin immunization in children and adolescents

PURPOSE

The correlation between the incidence of type 1 diabetes mellitus (T1DM) and tuberculosis or bacillus Calmette-Guérin (BCG) vaccination rate in individuals aged <15 years was investigated using worldwide data.

METHODS

The incidence of T1DM, rate of BCG vaccination, and incidence of tuberculosis were obtained from the Diabetes Atlas 9th edition of the International Diabetes Federation and the Global Health Observatory data repository of the World Health Organization. Gross domestic product (GDP) per capita and population data by country were obtained from the World Bank and United Nations, respectively.

RESULTS

GDP per capita negatively correlated with the incidence of tuberculosis and positively correlated with the incidence of T1DM (coefficient=-0.630 and 0.596, respectively; all P<0.001). The incidence of T1DM and tuberculosis was significantly associated with the Organisation for Economic Cooperation and Development (OECD) status (P<0.001). After adjusting for GDP per capita, regional grouping, and OECD status, the incidence of T1DM negatively correlated with that of tuberculosis (R2 =0.729, P=0.009). However, there was no association between the BCG vaccination rate and incidence of T1DM (P=0.890).

CONCLUSION

There was a negative correlation between the incidence of tuberculosis and T1DM in children and adolescents aged <15 years at the country level.

Delayed tension pneumocephalus and pneumorrhacis after routine cervical spine surgery treated successfully without burr holes

Tension pneumocephalus (TP) after spinal surgery is very rare with only a few cases reported in the English literature. Most cases of TP occur rapidly after spinal surgery. Traditionally, TP is managed using burr holes to relieve intracranial pressure. However, our case highlights a rare delayed presentation of TP and pneumorrhacis 1 month after routine cervical spine surgery. It is to our knowledge the first case of TP after spinal surgery to be treated using dural repair and supportive care. A 75-year-old woman presented with TP after having routine cervical decompression and stabilisation for cervical myelopathy. She re-presented 1 month after her initial operation with a leaking wound and altered mental status, which deteriorated rapidly shortly after admission. This, in combination with her radiographic features, influenced the decision to explore her surgical wound emergently. She made a full recovery and was discharged after 2 weeks in hospital. We hope to emphasise the need for a high index of suspicion for cerebrospinal fluid leaks and the low threshold to return to theatre to repair a potential dural defect, as well as illustrate that TP after spinal surgery can be treated successfully without burr holes.

Zero-Inflated Time Series Clustering Via Ensemble Thick-Pen Transform

This study develops a new clustering method for high-dimensional zero-inflated time series data. The proposed method is based on thick-pen transform (TPT), in which the basic idea is to draw along the data with a pen of a given thickness. Since TPT is a multi-scale visualization technique, it provides some information on the temporal tendency of neighborhood values. We introduce a modified TPT, termed 'ensemble TPT (e-TPT)', to enhance the temporal resolution of zero-inflated time series data that is crucial for clustering them efficiently. Furthermore, this study defines a modified similarity measure for zero-inflated time series data considering e-TPT and proposes an efficient iterative clustering algorithm suitable for the proposed measure. Finally, the effectiveness of the proposed method is demonstrated by simulation experiments and two real datasets: step count data and newly confirmed COVID-19 case data.

Immune Responses After Vaccination With Primary 2-Dose ChAdOx1 Plus a Booster of BNT162b2 or Vaccination With Primary 2-Dose BNT162b2 Plus a Booster of BNT162b2 and the Occurrence of Omicron Breakthrough Infection

BACKGROUND

Before the omicron era, health care workers were usually vaccinated with either the primary 2-dose ChAdOx1 nCoV-19 (Oxford-AstraZeneca) series plus a booster dose of BNT162b2 (Pfizer-BioNTech) (CCB group) or the primary 2-dose BNT162b2 series plus a booster dose of BNT162b2 (BBB group) in Korea.

METHODS

The two groups were compared using quantification of the surrogate virus neutralization test for wild type severe acute respiratory syndrome coronavirus 2 (SVNT-WT), the omicron variant (SVNT-O), spike-specific IgG, and interferon-gamma (IFN-γ), as well as the omicron breakthrough infection cases.

RESULTS

There were 113 participants enrolled in the CCB group and 51 enrolled in the BBB group. Before and after booster vaccination, the median SVNT-WT and SVNT-O values were lower in the CCB (SVNT-WT [before-after]: 72.02-97.61%, SVNT-O: 15.18-42.29%) group than in the BBB group (SVNT-WT: 89.19-98.11%, SVNT-O: 23.58-68.56%; all P < 0.001). Although the median IgG concentrations were different between the CCB and BBB groups after the primary series (2.677 vs. 4.700 AU/mL, respectively, P < 0.001), they were not different between the two groups after the booster vaccination (7.246 vs. 7.979 AU/mL, respectively, P = 0.108). In addition, the median IFN-γ concentration was higher in the BBB group than in the CCB group (550.5 and 387.5 mIU/mL, respectively, P = 0.014). There was also a difference in the cumulative incidence curves over time (CCB group 50.0% vs. BBB group 41.8%; P = 0.045), indicating that breakthrough infection occurred faster in the CCB group.

CONCLUSION

The cellular and humoral immune responses were low in the CCB group so that the breakthrough infection occurred faster in the CCB group than in the BBB group.

Comparison between Conventional Breath-hold and Respiratory-triggered Magnetic Resonance Cholangiopancreatography with and without Compressed Sensing: Cross-sectional Study

AIM

The application of compressed sensing (CS) has enabled breath-hold 3D-MRCP with a shorter acquisition time in clinical practice.

INTRODUCTION

To compare the image quality of breath-hold (BH) and respiratory-triggered (RT) 3D-MRCP with or without CS application in the same study population.

METHODS

In this retrospective study, from February to July 2020, a total of 98 consecutive patients underwent four different acquisition types of 3D-MRCP.; 1) BH MRCP with the generalized autocalibrating partially parallel acquisition (GRAPPA) (BH-GRAPPA), 2) RT-GRAPPA-MRCP, 3) RT-CS-MRCP and 4) BH-CS-MRCP. Relative contrast of common bile duct, 5-scale visibility score of biliary pancreatic ducts, 3-scale artifact score and 5-scale overall image quality score were evaluated by two abdominal radiologists.

RESULTS

Relative contrast value was significantly higher in BH-CS or RT-CS than in RT-GRAPPA (0.90 ± 0.057 and 0.89 ± 0.079, respectively, vs. 0.82 ± 0.071, p < 0.01) or BH-GRAPPA (vs. 0.77 ± 0.080, p < 0.01). The area affected by artifact was significantly lower in BH-CS among 4 MRCPs (p < 0.08). Overall image quality score in BH-CS was significantly higher than BH-GRAPPA (3.40 vs. 2.71, p < 0.01). There were no significant differences between RT-GRAPPA and BH-CS (vs. 3.13, p = 0.67) in overall image quality.

CONCLUSION

In this study, our results revealed BH-CS had higher relative contrast and comparable or superior image quality among four MRCP sequences.

Natural history of functional mitral regurgitation: a systematic review and individual patient data meta-analysis

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): Ching-Hui Sia was supported by the National University of Singapore Yong Loo Lin School of Medicine's Junior Academic Fellowship Scheme.

Background

Functional mitral regurgitation (FMR) precipitates a vicious cycle of left ventricular volume overload and remodelling, leading to perpetual worsening of FMR and left ventricular dysfunction, with a resultant poor prognosis. However, there is a lack of conclusive data on the natural progression of FMR in patients who do not undergo valvular intervention.

Purpose

We performed a one-stage meta-analysis on reconstructed individual patient data (IPD) to elucidate the natural history of FMR.

Methods

Four databases (PubMed, Embase, Scopus, Cochrane) were searched for randomised controlled trials or cohorts, published from inception to March 13, 2022, reporting clinical outcomes in patients with FMR not receiving valvular intervention. IPD meta-analysis, as the gold standard approach for evidence synthesis, was performed with reconstructed IPD obtained from the survival curves reported in the included studies. Pooled survival estimates were derived. Quality assessment of included studies was conducted using the Cochrane risk-of-bias tool and Newcastle Ottawa Scale. This study was registered on the International Prospective Register of Systematic Reviews.

Results

A total of five studies were included, comprising a total cohort of 691 patients with FMR who did not undergo valvular intervention. The mean age of the cohort was 72.4 years (95% CI 67.6 to 77.1) and the proportion of males was 61.1% (95% CI 43.8 to 76.0). All-cause mortality was analysed over a follow-up duration of five years, while hospitalisation for heart failure, cardiovascular death, and the composite of all-cause mortality and hospitalisation for heart failure were analysed over a follow-up duration of three years. The probability of survival of patients with FMR without intervention was 79.4% (95% CI 76.2 to 82.3), 50.9% (95% CI 46.6 to 55.1), and 39.6% (95% CI 33.1 to 46.0) at one, three, and five years respectively. The probability of survival free from the composite of all-cause mortality and hospitalisation for heart failure was 51.3% (95% CI 46.8 to 55.6) and 12.0% (95% CI 8.9 to 15.7) at one year and three years respectively. The probability of survival free from hospitalisation for heart failure was 58.3% (95% CI 54.0 to 62.3) and 19.7% (95% CI 16.0 to 23.7) at one and three years respectively. The probability of survival free from cardiovascular death was 75.4% (95% CI 68.9 to 80.8) and 45.6% (95% CI 29.1 to 60.7) at one and three years respectively. All included studies were of low to moderate risk of bias.

Conclusion

FMR in the absence of valvular intervention is associated with poor survival and cardiovascular outcomes. Further research should focus on the role of interventions to mitigate its poor prognosis.

A study on changes in lung function, neutralizing antibodies, and symptoms of adult patients hospitalized with COVID-19

BACKGROUND/AIMS

To identify changes in symptoms and pulmonary sequelae in patients with coronavirus disease 2019 (COVID-19).

METHODS

Patients with COVID-19 hospitalized at seven university hospitals in Korea between February 2020 and February 2021 were enrolled, provided they had ≥ 1 outpatient follow-up visit. Between January 11 and March 9, 2021 (study period), residual symptom investigations, chest computed tomography (CT) scans, pulmonary function tests (PFT), and neutralizing antibody tests (NAb) were performed at the outpatient visit (cross-sectional design). Additionally, data from patients who already had follow-up outpatient visits before the study period were collected retrospectively.

RESULTS

Investigation of residual symptoms, chest CT scans, PFT, and NAb were performed in 84, 35, 31, and 27 patients, respectively. After 6 months, chest discomfort and dyspnea persisted in 26.7% (4/15) and 33.3% (5/15) patients, respectively, and 40.0% (6/15) and 26.7% (4/15) patients experienced financial loss and emotional distress, respectively. When the ratio of later CT score to previous ones was calculated for each patient between three different time intervals (1-14, 15-60, and 61-365 days), the median values were 0.65 (the second interval to the first), 0.39 (the third to the second), and 0.20 (the third to the first), indicating that CT score decreases with time. In the high-severity group, the ratio was lower than in the low-severity group.

CONCLUSION

In COVID-19 survivors, chest CT score recovers over time, but recovery is slower in severely ill patients. Subjects complained of various ongoing symptoms and socioeconomic problems for several months after recovery.

Prediction of Deterioration of Left Ventricular Function Using 3-Dimensional Speckle-Tracking Echocardiography in Patients With Left Bundle-Branch Block

Background Previous studies have demonstrated that 2-dimensional (2D) global longitudinal strain (GLS) is associated with cardiovascular outcomes in patients with left bundle-branch block. However, the predictive value of 3-dimensional (3D) speckle-tracking echocardiography has not yet been investigated in these patients. Methods and Results The authors retrospectively identified 290 patients with left bundle-branch block who underwent echocardiography more than twice. Using speckle-tracking echocardiography, 2D-GLS, 3D-GLS, 3D-global circumferential strain, 3D global radial strain, and 3D global area strain were acquired. The association between 2D and 3D strains and the follow-up left ventricular (LV) ejection fraction (LVEF) was analyzed. The study population was divided into 2 sets: a group with preserved LVEF (baseline LVEF ≥40%) and a group with reduced LVEF (baseline LVEF <40%). After a median follow-up of 29.1 months (interquartile range, 13.1-53.0 months), 14.9% of patients progressed to LV dysfunction in the group with preserved LVEF, and 51.0% of patients showed improved LV function in the group with reduced LVEF. Multivariable analysis of 2D and 3D strains revealed that higher 2D-GLS (odds ratio [OR], 0.65 [95% CI, 0.54-0.78], P<0.001) was highly associated with maintaining LVEF in patients with preserved LVEF. However, a lower 3D-global circumferential strain (OR, 0.61 [95% CI, 0.47-0.78], P<0.001) showed a strong association with persistently reduced LVEF in patients with reduced LVEF. Conclusions Although 2D-GLS showed a powerful predictive value for the deterioration of LV function in the preserved LVEF group, 3D strain, especially 3D-global circumferential strain, can be helpful to predict consistent LV dysfunction in patients with left bundle-branch block who have reduced LVEF.

Neuromuscular blockade in mechanically ventilated pneumonia patients with moderate to severe hypoxemia: A multicenter retrospective study

BACKGROUND/PURPOSE

The benefit of neuromuscular blockades (NMBs) in critically ill patients receiving mechanical ventilation remains uncertain. Therefore, we aimed to investigate whether NMB use is associated with improved survival of mechanically ventilated pneumonia patients with moderate to severe hypoxemia.

METHODS

This retrospective multicenter study was conducted at five university-affiliated hospitals. Data of pneumonia patients aged 18 years and older who received mechanical ventilation between January 1, 2011, and December 31, 2020, were analyzed.

RESULTS

In a total of 1,130 patients, the mean patient age was 73.1 years (SD±12.6), and the overall mortality rate at 30 d was 29.5% (n = 333). NMB users had a higher 30 d mortality rate than NMB nonusers (33.9% vs. 26.8%, P = 0.014). After PS matching, the 30 d mortality rate was not significantly different between NMB users and nonusers (33.4% vs. 27.8%, p = 0.089). However, 90 d mortality rate was significantly increased in NMB users (39.7% vs. 31.9%, p = 0.021). Univariable Cox proportional hazard regression analyses showed that NMB use ≥ 3 d was significant risk factor for the 90 d mortality than those with < 3 d use (90 d mortality HR 1.39 [95% CI: 1.01-1.91], P = 0.045).

CONCLUSIONS

NMB use was not associated with lower 30 d mortality among mechanically ventilated pneumonia patients with moderate to severe hypoxemia. Rather, NMB users had higher 90 d mortality, furthermore, and NMB use ≥ 3 d was associated with a higher risk of long-term mortality compared to NMB use < 3 d. Therefore, care should be taken to avoid extended use of NMB in critically ill pneumonia patients during mechanical ventilation.

Relationship between SARS-CoV-2 antibody titer and the severity of COVID-19

BACKGROUND

It remains unclear whether high titers of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies aggravate clinical manifestations in patients or whether severe clinical manifestations result in high antibody titers. Thus, we investigated the cause-effect relationship between SARS-CoV-2 antibody titers and disease severity.

METHODS

We prospectively enrolled patients admitted with the diagnosis of coronavirus disease-19 (COVID-19) from February 2020 to August 2020. We measured SARS-CoV-2 antibody titers, namely anti-receptor-binding domain (RBD) antibody and neutralizing antibody (NAb), from blood samples and calculated the chest radiograph (CXR) scores of the patients to evaluate the severity of COVID-19.

RESULTS

Overall, 40 patients with COVID-19 were enrolled. Pneumonia was observed in more than half of the patients (25/40, 60%). SARS-CoV-2 antibody titers were higher in patients who were aged >60 years (anti-RBD antibodies, P = 0.003 and NAb, P = 0.009), presented with pneumonia (P = 0.006 and 0.007, respectively), and required oxygen therapy (P = 0.003 and 0.004, respectively) than in those who were not. CXR scores peaked (at 15-21 days after the onset of symptoms) statistically significantly earlier than SARS-CoV-2 antibody titers (at 22-30 days for NAb and at 31-70 days for anti-RBD antibody). There was a close correlation between the maximum CXR score and the maximum SAR-CoV-2 antibody titer.

CONCLUSIONS

Based on the comparison of the peak time of SARS-CoV-2 antibody titers with the CXR score after symptom onset, we suggest that severe clinical manifestations result in high titers of SARS-CoV-2 antibodies.

Effect of follow-up raloxifene therapy after denosumab discontinuation in postmenopausal women

Follow-up raloxifene therapy after denosumab discontinuation resulted in a decrease in bone mass to the pre-denosumab levels and a rebound increase of bone turnover markers. The decrease in lumbar bone mineral density was particularly evident when the body mass index was low, there were previous vertebral fractures, or lumbar bone mineral density before denosumab administration was low.

INTRODUCTION

Selective estrogen receptor modulators may be an alternative to bisphosphonates for treating rebound resorption after discontinuing denosumab. This study aimed to investigate the effects of follow-up raloxifene therapy after denosumab discontinuation in postmenopausal women.

METHODS

This retrospective observational study included 61 patients who received 12-month follow-up raloxifene therapy after denosumab discontinuation. The primary endpoint was the bone mineral density change. The secondary endpoints were the changes in bone turnover markers and the incidence of new vertebral fractures.

RESULTS

Raloxifene administration for 12 months after denosumab discontinuation resulted in a significantly lower bone mineral density at all sites compared to the level at 6 months after the last denosumab treatment (lumbar spine, - 5.48%; femoral neck, - 2.95%; total hip, - 3.52%; all, p < 0.001). The decrease in lumbar bone mineral density was particularly evident when the body mass index was low, there were previous vertebral fractures, or lumbar bone mineral density before denosumab administration was low. Marked increases in the bone turnover markers from baseline were noted after switching to raloxifene. However, no new vertebral fractures occurred during raloxifene treatment.

CONCLUSIONS

Follow-up raloxifene therapy after denosumab discontinuation resulted in a decrease in bone mass to the pre-denosumab levels and a rebound increase of bone turnover markers. Therefore, raloxifene administered sequentially after denosumab discontinuation was not effective in preventing rebound phenomenon.

AB0978 Effect of atorvastatin on skeletal muscles of patients with knee osteoarthritis: post-hoc analysis of a randomised controlled trial

Background

Statins are often discontinued due to muscle-related side effects. The effect of statin on skeletal muscles in populations with osteoarthritis is unknown.

Objectives

This study aims to examine the effect of atorvastatin on skeletal muscle biochemistry, strength, size and symptoms in patients with symptomatic knee osteoarthritis.

Methods

This is a post-hoc analysis of a multicentre randomised, double-blind, placebo-controlled trial over 2 years in which participants with knee osteoarthritis who met the American College of Rheumatology clinical criteria received atorvastatin 40mg daily (n=151) or placebo (n=153). Outcomes included levels of creatinine kinase (CK), aspartate transaminases (AST) and alanine transaminases (ALT) at baseline, 4 weeks, 6, 12 and 24 months; muscle strength measured by dynamometry at baseline, 12 and 24 months; vastus medialis cross-sectional area (CSA) on magnetic resonance imaging at baseline and 24 months; and self-reported myalgia during the trial.

Results

304 participants [mean age 55.7 (SD 7.6) years, 55.6% female] were randomised. There were no significant differences in CK and AST levels between atorvastatin and placebo groups at 4 weeks (CK median 107 vs 110, p=0.76; AST 22 vs 21, p=0.14), 6 (CK 109 vs 101.5, p=0.37; AST 21 vs 20, p=0.45), 12 (CK 103 vs 103, p=0.93; AST 22 vs 21, p=0.99), and 24 (CK 103 vs 93.5, p=0.17; AST 22 vs 21, p=0.34) months. The atorvastatin group had higher ALT levels than the placebo group at 4 weeks [26 vs 21, p=0.0004] and 6 months [25 vs 22, p=0.007] but no between-group differences at 12 [24 vs 21, p=0.08] and 24 [24 vs 21, p=0.053] months. Muscle strength significantly increased in the atorvastatin group but not the placebo group over 24 months with no between-group differences [mean 8.5 (95% CI 2.6,14.4) vs 5.6 (-0.3,11.5), p=0.50]. Change in vastus medialis CSA over 24 months showed between-group differences favouring the atorvastatin group [+0.12 (-0.09,0.34) vs -0.24 (-0.48,0.01), p=0.03] but of uncertain clinical significance. There was a trend for more myalgia in the atorvastatin group over 2 years (8/151 vs 2/153, p=0.06), mostly occurring within 6 months (7/151 vs 1/153, p=0.04). Of the 10 participants with myalgia, there was no relationship between the incidence of myalgia and CK levels.

Conclusion

In those with symptomatic knee osteoarthritis, despite a trend for more myalgia, there was no clear evidence of an adverse effect of atorvastatin on skeletal muscles, including those most relevant to knee joint health.

Disclosure of Interests

Yuan Lim: None declared, Flavia Cicuttini: None declared, Anita Wluka: None declared, Graeme Jones Speakers bureau: GJ received honoraria for talks from BMS, Roche, AbbVie, Amgen, Lilly, Novartis, and Janssen, Grant/research support from: GJ received grant for a clinical trial from Covance, Catherine Hill: None declared, Andrew Forbes: None declared, Andrew Tonkin Speakers bureau: AT received honoraria for lectures from Pfizer; honoraria for lectures and advisory board participation from Amgen, Consultant of: AT received honoraria for lectures and advisory board participation from Amgen, honoraria for data and safety monitoring board participation from Merck, and honoraria for data and safety monitoring board participation from Novartis, Sofia Berezovskaya: None declared, Lynn Tan: None declared, Changhai Ding: None declared, Yuanyuan Wang: None declared

AB0979 Recommendations for weight management in osteoarthritis: a systematic review of clinical practice guidelines

Background

Weight loss interventions are often recommended to target overweight and obesity in the clinical practice guidelines (CPGs) for the management of osteoarthritis. This is despite evidence from meta-analyses of clinical trials that significant weight loss results in modest improvements in symptoms and minimal effects on disease progression1,2. There is evidence that weight gain is associated with increase in knee pain3,4. In countries such as USA, adults gain on average 0.5 to 1 kilogram per year from early to middle adulthood Preventing weight gain is easier to achieve and sustain than losing weight.

Objectives

Given that weight loss is accepted as fundamental to osteoarthritis management, we systematically reviewed the recommendations and approaches for weight management in all current osteoarthritis CPGs.

Methods

Nine databases were searched (1st January 2010 to 30th September 2021) to identify guidelines informing the non-pharmacological management of osteoarthritis. Three reviewers appraised guidelines according to the AGREE II instrument, and independently extracted data on their characteristics. One author extracted and summarised guideline recommendations on weight management. This systematic review is registered on PROSPERO (CRD42021274195).

Results

Fifteen CPGs from developed and developing countries were included. Weight loss was recommended for knee (12 of 13 guidelines) and hip (10 of 11 guidelines) but not hand osteoarthritis (0 of 4 guidelines). Combination approaches of diet and/or exercise were recommended for overweight or obese individuals (knee: 8 of 12; hip: 4 of 10), with 2 guidelines specifying ≥5% weight loss for knee and hip osteoarthritis. One of 15 guidelines specified strategies for weight loss and maintenance of lost weight. Two of 15 guidelines recommended controlling body weight for osteoarthritis, regardless of obesity status.

Conclusion

Most CPGs for knee and hip osteoarthritis include recommendations for weight loss in those with overweight or obesity as key to managing osteoarthritis, despite evidence of modest at best effect of weight loss on symptoms and no effect on joint structure1,2. Given obesity is a major risk factors for osteoarthritis, the prevention of weight gain may be more effective and practical in improving clinical outcomes for osteoarthritis, and hence should be considered as part of the key management in osteoarthritis.

References

[1]Chu IJH, Lim AYT, Ng CLW. Effects of meaningful weight loss beyond symptomatic relief in adults with knee osteoarthritis and obesity: a systematic review and meta-analysis. Obes Rev. 2018;19(11):1597-1607.

[2]Daugaard CL, Hangaard S, Bartels EM, Gudbergsen H, Christensen R, Bliddal H, et al. The effects of weight loss on imaging outcomes in osteoarthritis of the hip or knee in people who are overweight or obese: a systematic review. Osteoarthritis Cartilage. 2020;28(1):10-21.

[3]Tanamas SK, Wluka AE, Davies-Tuck M, Wang Y, Strauss BJ, Proietto J, et al. Association of weight gain with incident knee pain, stiffness, and functional difficulties: a longitudinal study. Arthritis Care Res (Hoboken). 2013;65(1):34-43.

[4]Teichtahl AJ, Wluka AE, Tanamas SK, Wang Y, Strauss BJ, Proietto J, et al. Weight change and change in tibial cartilage volume and symptoms in obese adults. Annals of the rheumatic diseases. 2015;74(6):1024-1029.

[5]Zheng Y, Manson JE, Yuan C, Liang MH, Grodstein F, Stampfer MJ, et al. Associations of Weight Gain From Early to Middle Adulthood With Major Health Outcomes Later in Life. JAMA. 2017;318(3):255-269.

Disclosure of Interests

None declared

POS1118 METFORMIN AS A POTENTIAL DISEASE-MODIFYING DRUG IN OSTEOARTHRITIS: A SYSTEMATIC REVIEW OF PRE-CLINICAL AND HUMAN STUDIES

Background

Osteoarthritis causes significant pain and disability with no approved disease-modifying drugs. There is evidence emerging from pre-clinical and human studies suggesting metformin may have disease-modifying properties in osteoarthritis1-5. Given its pleiotropic effects and safety profile, metformin has the potential to be a novel therapy for osteoarthritis.

Objectives

We systematically reviewed the evidence from both pre-clinical and human studies for the potential disease-modifying effect of metformin in osteoarthritis.

Methods

Ovid Medline, Embase and CINAHL were searched between inception and June 2021 using MeSH terms and key words to identify studies examining the association between metformin use and outcome measures related to osteoarthritis. Two reviewers performed the risk of bias assessment and 3 reviewers extracted data independently. Qualitative evidence synthesis was performed. This systematic review is registered on PROSPERO (CRD42021261052 and CRD42021261060).

Results

Fifteen (10 pre-clinical and 5 human) studies were included. Most studies (10 pre-clinical and 3 human) assessed the effect of metformin using knee osteoarthritis models. In pre-clinical studies, metformin was assessed for the effect on structural outcomes (n=10); immunomodulation (n=5); pain (n=4); and molecular pathways of its effect in osteoarthritis (n=7). For human studies, metformin was evaluated for the effect on structural progression (n=3); pain (n=1); and immunomodulation (n=1). Overall, pre-clinical studies consistently showed metformin having a chondroprotective, immunomodulatory and analgesic effect in osteoarthritis, predominantly mediated by adenosine monophosphate-activated protein kinase activation. Evidence from human studies, although limited, was consistent with findings in pre-clinical studies.

Conclusion

We found consistent evidence across pre-clinical and human studies to support a favourable effect of metformin on chondroprotection, immunomodulation and pain reduction in knee osteoarthritis. Further high-quality clinical trials are needed to confirm these findings as metformin could be a novel therapeutic drug for the treatment of osteoarthritis.

References

[1]Li H, Ding X, Terkeltaub R, Lin H, Zhang Y, Zhou B, et al. Exploration of metformin as novel therapy for osteoarthritis: preventing cartilage degeneration and reducing pain behavior. Arthritis Res Ther. 2020;22(1):34.

[2]Li J, Zhang B, Liu WX, Lu K, Pan H, Wang T, et al. Metformin limits osteoarthritis development and progression through activation of AMPK signalling. Ann Rheum Dis. 2020;79(5):635-645.

[3]Na HS, Kwon JY, Lee SY, Lee SH, Lee AR, Woo JS, et al. Metformin Attenuates Monosodium-Iodoacetate-Induced Osteoarthritis via Regulation of Pain Mediators and the Autophagy-Lysosomal Pathway. Cells. 2021;10(3).

[4]Lu CH, Chung CH, Lee CH, Hsieh CH, Hung YJ, Lin FH, et al. Combination COX-2 inhibitor and metformin attenuate rate of joint replacement in osteoarthritis with diabetes: A nationwide, retrospective, matched-cohort study in Taiwan. PLoS ONE [Electronic Resource]. 2018;13(1):e0191242.

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Disclosure of Interests

Yuan Lim: None declared, Yuanyuan Wang: None declared, Mahnuma Estee: None declared, Jawad Abidi: None declared, Maushmi Udaya Kumar: None declared, Sultana Monira Hussain: None declared, Anita Wluka: None declared, Christopher Little Grant/research support from: CBL receives research funding from pharmaceutical companies (Fidia Farmaceutici, Cynata Therapeutics, Ceva Animal Health Pty Ltd and Regeneus Pty Ltd) to investigate efficacy of novel osteoarthritis therapeutics in pre-clinical models, through specific services/testing-contract research agreements between and managed by The University of Sydney or the Northern Sydney Local Health District, Flavia Cicuttini: None declared

Ultrasonographic characteristics of Hurthle cell: prediction of malignancy

Purpose

This study investigated the ultrasound (US) features of malignancy in patients with Hürthle cell neoplasms (HCNs) of the thyroid gland.

Methods

The present study included 139 HCNs that had undergone surgical excision at a single institution from 1996 to 2020 and had preoperative US images. The sonographic characteristics of HCNs were correlated with their pathological results. The US findings associated with malignancy were explored using logistic regression analysis, and the diagnostic performance and cutoff were assessed using receiver operating characteristic analysis.

Results

The most common US findings of HCNs were a solid content (76.3%), oval to round shape (100%), hypoechogenicity (70.5%), a smooth margin (95.0%), the halo sign (90.6%), and no calcifications (93.5%). HCNs were commonly smaller in pathologic measurements than in US measurements (smaller, same, and greater than US measurements in 60.4%, 21.6%, and 18.0% of HCNs, respectively; P<0.001). On US, malignant nodules were significantly larger than benign nodules (3.4±1.6 cm vs. 2.2±1.2 cm, P<0.001). Multiple logistic regression showed that the US tumor size was an independent predictor of malignancy (P=0.001; odds ratio, 1.730 for a 1-cm increase [95% confidence interval, 1.258 to 2.375]). The best cutoff US tumor size for predicting malignancy was 3.35 cm (sensitivity, 53.1%; specificity, 87.9%).

Conclusion

The US tumor size was found to be an independent predictor of malignancy in HCNs, and a US tumor size >3.35 cm might be used as a criterion to suggest malignancy. The size of HCNs often showed discrepancies between US and pathologic measurements.

Comparison of fracture risk between type 1 and type 2 diabetes: a comprehensive real-world data

Population-based cohort study of 6,548,784 Korean subjects demonstrates that the risk of fracture was higher in patients with diabetes than in nondiabetic subjects. Furthermore, patients with type 1 diabetes were associated with a higher risk of fracture than patients with type 2 diabetes for all measurement sites.

INTRODUCTION

Diabetes mellitus is associated with increased fracture risk. Although the pathophysiologic effect on bone metabolism differs according to the type of diabetes, a higher risk of fracture in patients with diabetes than in nondiabetic patients has been consistently demonstrated. Considering the ever-increasing number of patients with diabetes, we aimed to provide updated information on whether this phenomenon remains valid in real-world settings by using large-scale population datasets.

METHODS

We conducted a retrospective longitudinal study using data from the Korean National Health Insurance Service dataset of preventive health check-ups between January 2009 and December 2016. The hazard ratios were calculated for any fracture, vertebral fracture, and hip fracture and were analyzed according to the presence and type of diabetes. Among 10,585,818 subjects, 6,548,784 were eligible for the analysis (2418 patients with type 1 diabetes mellitus [T1DM] and 506,208 patients with type 2 diabetes mellitus [T2DM]).

RESULTS

The mean follow-up duration (in years) was 7.0 ± 1.3 for subjects without diabetes, 6.4 ± 2.0 for those with T1DM, and 6.7 ± 1.7 for T2DM. Patients with T1DM had a higher incidence rate for all types of fractures per 1000 person-years. The fully adjusted hazard ratios (HRs) for any fracture, vertebral fracture, and hip fracture were higher in T1DM than in T2DM (1.37 [95% confidence interval (CI): 1.23-1.52] for any fracture, 1.33 [95% CI: 1.09-1.63] for vertebral fracture, and 1.99 [95% CI: 1.56-2.53] for hip fracture).

CONCLUSIONS

In this large-scale population analysis, diabetes was associated with a higher risk of all types of fractures. Patients with T1DM had a higher risk of fracture than those with T2DM for all measurement sites, and hip fractures had the highest risk. Therefore, fracture prevention training for patients with diabetes is advisable.

Global Microscopic Description of Nucleon-Nucleus Scattering with Quantified Uncertainties

We develop for the first time a microscopic global nucleon-nucleus optical potential with quantified uncertainties suitable for analyzing nuclear reaction experiments at next-generation rare-isotope beam facilities. Within the improved local density approximation and without any adjustable parameters, we begin by computing proton-nucleus and neutron-nucleus optical potentials from a set of five nuclear forces from chiral effective field theory for 1800 target nuclei in the mass range 12≤A≤242 for energies between 0  MeV<E≲150  MeV. We then parameterize a global optical potential for each chiral force that depends smoothly on the projectile energy as well as the target nucleus mass number and isospin asymmetry. Uncertainty bands for elastic scattering observables are generated from a full covariance analysis of the parameters entering in the description of our global optical potential and benchmarked against existing experimental data for stable target nuclei. Since our approach is purely microscopic, we anticipate a similar quality of the model for nucleon scattering on unstable isotopes.

The role of histogram analysis of grayscale sonograms to differentiate thyroid nodules identified by 18F-FDG PET-CT

The role of histogram based on ultrasound (US) images for thyroid nodules found in fluorine-18 fluorodeoxyglucose (18F-FDG) Positron Emission Tomography/Computed Tomography (PET-CT) is unknown. We aimed to assess whether histogram analysis using gray scale US could differentiate thyroid nodules detected by PET-CT.In this study, 71 thyroid nodules ≥1 cm were identified in 71 patients by conducting 18F-FDG PET-CT, from January 2010 to June 2013. Subsequently, either grayscale US-guided fine needle aspirations or core needle biopsies were performed on each patient. Each grayscale US feature was categorized according to the Korean Thyroid Imaging Reporting and Data System (K-TIRADS). Histogram parameters (skewness, kurtosis, intensity, uniformity, and entropy) were extracted from the grayscale US images followed by statistical analysis using the Chi-Squared or Mann-Whitney U tests.The 71 nodules comprised 30 (42.3%) benign nodules, 30 (42.3%) primary thyroid malignancies, and 11 (15.4%) metastatic lesions. Tumor size, US findings, and histogram parameters were significantly different between the benign and malignant thyroid nodules (P = .011, P = .000, and P < .02, respectively). A comparison showed that parallel orientation and an absence of calcifications were found more frequently in metastatic thyroid nodules than in primary thyroid malignancies (P = .04, P < .000, respectively). However, histogram parameters and K-TIRADS were not significantly different between primary thyroid malignancies and metastatic lesions.There is a limit to replacing cytopathological confirmation with texture analysis for the differentiation of thyroid nodules detected by PET-CT. Therefore, cytopathological confirmation of nodules appearing malignant on US images cannot be avoided for an ultimate diagnosis of metastasis.

A generalization of functional clustering for discrete multivariate longitudinal data

This paper presents a new model-based generalized functional clustering method for discrete longitudinal data, such as multivariate binomial and Poisson distributed data. For this purpose, we propose a multivariate functional principal component analysis (MFPCA)-based clustering procedure for a latent multivariate Gaussian process instead of the original functional data directly. The main contribution of this study is two-fold: modeling of discrete longitudinal data with the latent multivariate Gaussian process and developing of a clustering algorithm based on MFPCA coupled with the latent multivariate Gaussian process. Numerical experiments, including real data analysis and a simulation study, demonstrate the promising empirical properties of the proposed approach.

Ensemble clustering for step data via binning

This paper considers the clustering problem of physical step count data recorded on wearable devices. Clustering step data give an insight into an individual's activity status and further provide the groundwork for health-related policies. However, classical methods, such as K-means clustering and hierarchical clustering, are not suitable for step count data that are typically high-dimensional and zero-inflated. This paper presents a new clustering method for step data based on a novel combination of ensemble clustering and binning. We first construct multiple sets of binned data by changing the size and starting position of the bin, and then merge the clustering results from the binned data using a voting method. The advantage of binning, as a critical component, is that it substantially reduces the dimension of the original data while preserving the essential characteristics of the data. As a result, combining clustering results from multiple binned data can provide an improved clustering result that reflects both local and global structures of the data. Simulation studies and real data analysis were carried out to evaluate the empirical performance of the proposed method and demonstrate its general utility.

Comparison Between Fine Needle Aspiration and Core Needle Biopsy for the Diagnosis of Thyroid Nodules: Effective Indications According to US Findings

Thyroid nodules are initially handled by fine needle aspiration (FNA). However, the stance of thyroid core needle biopsy (CNB) still is a challenge. This study aimed to compare the diagnostic performances and conclusive rates of FNA and CNB for the diagnosis of thyroid nodules and to define effective indications of CNB. This retrospective study enrolled 1,060 consecutive thyroid nodules in 1,037 patients who underwent FNA from January 2008 to May 2008, and 462 consecutive nodules in 453 patients who underwent CNB from January 2014 to December 2015 at our institution. Ultrasound (US) features were classified according to the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) and Korean TIRADS (K-TIRADS). We compared diagnostic performances and conclusive rates between FNA and CNB groups. Propensity score matching was conducted to match FNA patients with CNB patients. After matching, the diagnostic performances for selecting surgical candidates and predicting malignancy were comparable between the two biopsy groups. Based on US findings, conclusive results were obtained significantly more in CNB than in FNA when thyroid nodules were classified as ACR TI-RADS or K-TIRADS category 4 and measured larger than 2 cm. Diagnostic performances between FNA and CNB were comparable. Superiority of CNB to FNA was found for thyroid nodules larger than 2 cm and classified as ACR TI-RADS or K-TIRADS category 4.

Comparison of ultrasonography and CT for preoperative nodal assessment of patients with papillary thyroid cancer: diagnostic performance according to primary tumor size

Background

Indications for computed tomography (CT) in preoperative patients with thyroid cancer are still controversial.

Purpose

To determine the value of CT and ultrasonography (US) in preoperative lymph node assessment of patients with papillary thyroid carcinoma (PTC) according to primary tumor size.

Material and Methods

A total 453 patients with surgically proven PTC who underwent US and CT for preoperative evaluation in 2010 at our tertiary referral center were included. The diagnostic sensitivity, specificity, and accuracy of US, CT, and the combination of US and CT (US/CT) in the preoperative nodal assessment were compared. We performed subgroup analysis to compare the findings according to primary tumor size.

Results

In overall tumors, adding CT to US had greater sensitivity, lower specificity, and greater accuracy in predicting central lymph node metastasis (LNM) but lower accuracy in prediction of lateral LNM. In smaller cancers (≤1 cm), US alone had greater specificity and accuracy than CT alone or US/CT in predicting lateral LNM. In larger cancers (>1 cm), CT had greater sensitivity and accuracy than US in predicting central LNM, while US had greater specificity and accuracy than CT in predicting lateral LNM. There were no patients with smaller tumors who showed retropharyngeal and superior mediastinal LNM diagnosed by CT alone.

Conclusion

CT is superior to US for detecting central LNM in preoperative patients with PTCs > 1 cm. However, there are no benefits to adding CT to US to predict lateral LNM in small cancers (≤1 cm).

A GEE approach to estimating accuracy and its confidence intervals for correlated data

In this paper, we provide a method for constructing confidence interval for accuracy in correlated observations, where one sample of patients is being rated by two or more diagnostic tests. Confidence intervals for other measures of diagnostic tests, such as sensitivity, specificity, positive predictive value, and negative predictive value, have already been developed for clustered or correlated observations using the generalized estimating equations (GEE) method. Here, we use the GEE and delta-method to construct confidence intervals for accuracy, the proportion of patients who are correctly classified. Simulation results verify that the estimated confidence intervals exhibit consistent/appropriate coverage rates.

Radiomics signature on 3T dynamic contrast-enhanced magnetic resonance imaging for estrogen receptor-positive invasive breast cancers: Preliminary results for correlation with Oncotype DX recurrence scores

To evaluate the ability of a radiomics signature based on 3T dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) to distinguish between low and non-low Oncotype DX (OD) risk groups in estrogen receptor (ER)-positive invasive breast cancers.Between May 2011 and March 2016, 67 women with ER-positive invasive breast cancer who performed preoperative 3T MRI and OD assay were included. We divided the patients into low (OD recurrence score [RS] <18) and non-low risk (RS ≥18) groups. Extracted radiomics features included 8 morphological, 76 histogram-based, and 72 higher-order texture features. A radiomics signature (Rad-score) was generated using the least absolute shrinkage and selection operator (LASSO). Univariate and multivariate logistic regression analyses were performed to investigate the association between clinicopathologic factors, MRI findings, and the Rad-score with OD risk groups, and the areas under the receiver operating characteristic curves (AUC) were used to assess classification performance of the Rad-score.The Rad-score was constructed for each tumor by extracting 10 (6.3%) from 158 radiomics features. A higher Rad-score (odds ratio [OR], 65.209; P <.001), Ki-67 expression (OR, 17.462; P = .007), and high p53 (OR = 8.449; P = .077) were associated with non-low OD risk. The Rad-score classified low and non-low OD risk with an AUC of 0.759.The Rad-score showed the potential for discrimination between low and non-low OD risk groups in patients with ER-positive invasive breast cancers.

Prediction of follicular thyroid carcinoma associated with distant metastasis in the preoperative and postoperative model

BACKGROUND

Only clinicopathological findings are reported for predicting follicular thyroid carcinoma (FTC) associated with distant metastasis, and preoperative ultrasound (US) findings are unknown.

METHODS

Associations between distant metastases of FTC and predicting factors were evaluated by using logistic regression analysis in the preoperative and postoperative models.

RESULTS

Distant metastasis was present in 37 (11.5%) of the 321 patients with FTC. In the preoperative model, independent predictors of distant metastasis were age, marked hypoechogenicity, nodule-in-nodule appearance, and rim calcification on US. Postoperative predictors were marked hypoechogenicity, rim calcification, and widely invasive histology. Sensitivities, specificities, and the area under the curves for predicting distant metastasis were 86.5%, 80.3%, and 0.889 on preoperative status and 86.5%, 78.5%, and 0.908 on postoperative status. Although not statistically significant, all four patients with gross extrathyroidal extension had metastasis.

CONCLUSION

Age, ultrasound features, and widely invasive histology allow preoperative and postoperative prediction of FTC associated with distant metastasis.

The ProSeal™ Laryngeal Mask Airway is an Effective Alternative to Laryngoscope-Guided Tracheal Intubation for Gynaecological Laparoscopy

We tested the hypothesis that the ProSeal™ laryngeal mask airway is superior to laryngoscope-guided tracheal intubation for gynaecological laparoscopy. One-hundred and eighty consecutive patients (ASA grade 1-2, aged 18-80y) were divided into two equal-sized groups for airway management with the ProSeal™ laryngeal mask airway or tracheal tube. Induction was with fentanyl/propofol, maintenance with sevoflurane and muscle relaxation with atracurium. The following primary variables were tested: time to achieve an effective airway, ventilatory capability, peak airway pressure before and after pneumoperitoneum, duration of surgery and pneumoperitoneum and haemodynamic responses. Data about gastric size, airway trauma and sore throat were collected. The number of attempts for successful insertion were similar, but effective airway time was shorter for the ProSeal™ laryngeal mask airway (20±2s vs 37±3s, P<0.001). All devices were successfully inserted within three attempts. There was no episode of failed ventilation or hypoxia. The haemodynamic stress responses to insertion and removal were greater for the tracheal tube than the ProSeal™ laryngeal mask airway. The duration of surgery, duration of pneumoperitoneum and intraabdominal pressures were similar. Gastric size was similar at the start and end of surgery. There were no differences in the frequency of complications or sore throat.

We conclude that the ProSeal™ laryngeal mask airway is a similarly effective airway device to conventional laryngoscope-guided tracheal intubation for gynaecological laparoscopy, but is more rapidly inserted and associated with an attenuated haemodynamic response to insertion and removal.

Comparison of the AMBU® Laryngeal Mask and the LMA Classic in Anaesthetised, Spontaneously Breathing Patients

There may be a role for single-use laryngeal mask airways with concerns about inability to adequately sterilise laryngeal mask airways to eradicate prion proteins. A single-blinded prospective randomised controlled trial was conducted to compare the clinical performance of the single-use AMBU®LMA with the reuseable LMA Classic. There was no difference in time to insertion, successful insertion at first attempt, oropharyngeal leak pressure, haemodynamic response to insertion or complications of placement. The AMBU®LMA was easier to insert. There was a suggestion of reduced postoperative sore throat and pharyngeal trauma for the AMBU® LMA group. The AMBU®LMA is a viable alternative to the LMA Classic for airway management in spontaneously breathing patients.

A Comparison of the GlideScope® with the Macintosh Laryngoscope for Tracheal Intubation in Patients with Simulated Difficult Airway

We compared the use of the GlideScope® and the conventional Macintosh laryngoscope in a simulated difficult airway. The primary hypothesis was that time to intubation would be shorter using the GlideScope® than using the Macintosh laryngoscope.

After obtaining approval from the ethics committee and written informed consent, we recruited 60 ASA 1 and 2 patients to our randomized controlled trial. Group G (n=30) had tracheal intubation performed using the GlideScope® and Group M (n=30) were intubated using a Macintosh laryngoscope. We simulated a difficult airway in each patient by having an experienced assistant provide in-line manual stabilization of the head and neck. We recorded the best laryngeal view; difficulty of the tracheal intubation; time taken for successful tracheal intubation; manoeuvre needed to aid tracheal intubation and complications associated with the tracheal intubation.

The median Cormack and Lehane grade was significantly better in Group G than Group M. Group G had a significantly shorter intubation time than group M (mean 41.8s±SD 20.2 vs mean 56.2s±26.6, P<0.05).

The GlideScope® improved the laryngeal view and decreased time for tracheal intubation time when compared with the Macintosh laryngoscope in patients with simulated difficult airway. The GlideScope® may be a good alternative for managing the difficult airway but clinical trials evaluating its use on patients with an actual difficult airway are needed.

A new software scheme for scatter correction based on a simple radiographic scattering model

In common radiography, image contrast is often limited due mainly to scattered x-rays and noise, decreasing the quantitative usefulness of x-ray images. Several scatter reduction methods based on software correction schemes have been extensively investigated in an attempt to overcome these difficulties, most of which are based on measurement, mathematical-physical modeling, or a combination of both. However, those methods require special equipment, system geometry, and extra manual work to measure scatter characteristics. In this study, we investigated a new software scheme for scatter correction based on a simple radiographic scattering model where the intensity of the scattered x-rays was directly estimated from a single x-ray image using a weighted l¹-norm contextual regularization framework. We implemented the proposed algorithm and performed a systematic simulation and experiment to demonstrate its viability. We also conducted some clinical image studies using patient's image data of breast and L-spine to verify the clinical effectiveness of the proposed scheme. Our results indicate that the degradation of image characteristics by scattered x-rays and noise was effectively recovered by using the proposed software scheme, thus improving radiographic visibility considerably. Graphical abstract The schematic illustrations of scatter suppression methods by using a an antiscatter grid and b a scatter estimation algorithm.