Brief Report: The Role of Substance Use in Structural Heart Disease Among Women Living With HIV

BACKGROUND

People living with HIV have increased risk of cardiovascular disease, but few studies focus on women with HIV (WWH) and few account for the use of multiple substances.

SETTING

We recruited WWH from San Francisco shelters, free meal programs, street encampments, and a safety net HIV clinic.

METHODS

Between 2016 and 2019, participants completed 6 monthly interviews, specimen collection, and a transthoracic echocardiogram. We assessed associations between 3 echocardiographic indices of cardiac hypertrophy (concentric hypertrophy, concentric remodeling, and eccentric hypertrophy) and study factors, including cardiovascular risk factors, substance use, and HIV-specific factors (CD4 + count, viral load, HIV medication).

RESULTS

Among 62 participants, the average age was 53 years and 70% were ethnic minority women. Just over 70% had elevated blood pressure. Toxicology-confirmed substance use included tobacco (63%), cannabis (52%), cocaine (51%), methamphetamine (29%), and alcohol (26%). Concentric hypertrophy was detected in 26% of participants. It was positively associated with cocaine use [adjusted relative risk (aRR) = 32.5, P < 0.01] and negatively associated with cannabis use (aRR = 0.07, P < 0.01). Concentric remodeling was detected in 40% of participants. It was positively associated with cocaine use (aRR = 11.2, P < 0.01) and negatively associated with cannabis use (aRR = 0.17, P = 0.02). Eccentric hypertrophy was not significantly associated with factors studied here.

CONCLUSIONS

Routine evaluation of stimulant use as a contributing factor to cardiovascular risk may improve risk assessment in WWH. Whether cannabis use mitigates the impact of cocaine use on structural heart disease among WWH merits further investigation.

Dense Oil in Water Emulsions using Vortex-Based Hydrodynamic Cavitation: Effective Viscosity, Sauter Mean Diameter, and Droplet Size Distribution

Vortex-based hydrodynamic cavitation offers an effective platform for producing emulsions. In this work, we have investigated characteristics of dense oil in water emulsions with oil volume fractions up to 60% produced using a vortex-based cavitation device. Emulsions were prepared using rapeseed oil with oil volume fractions of 0.15, 0.3, 0.45, and 0.6. For each of these volume fractions, the pressure drop as a function of the flow rate of emulsions through the cavitation device was measured. These data were used for estimating the effective viscosity of the emulsions. The droplet size distribution of the emulsions was measured using the laser diffraction technique. The influence of the number of passes through the cavitation device on droplet size distributions and the Sauter mean diameter was quantified. It was found that the Sauter mean diameter (d32) decreases with an increase in the number of passes as n-0.2. The Sauter mean diameter was found to be almost independent of oil volume fraction (αo) up to a certain critical volume fraction (αoc). Beyond αoc, d32 was found to be linearly proportional to a further increase in oil volume fraction. As expected, the turbidity of the produced emulsions was found to be linearly proportional to the oil volume fraction. The slope of turbidity versus oil volume fraction can be used to estimate the Sauter mean diameter. A suitable correlation was developed to relate turbidity, volume fraction, and Sauter mean diameter. The droplet breakage efficiency of the vortex-based cavitation device for dense oil in water emulsions was quantified and reported. The breakage efficiency was found to increase linearly with an increase in oil volume fraction up to αoc and then plateau with a further increase in the oil volume fraction. The breakage efficiency was found to decrease with an increase in energy consumption per unit mass (E) as E-0.8. The presented results demonstrate the effectiveness of a vortex-based cavitation device for producing dense oil in water emulsions and will be useful for extending its applications to other dense emulsions.

A Comparative analysis of PESC and PPSC copolyesters: Insights into viscosity, thermal behavior, crystallinity, and biodegradability

The study examined various properties of synthesized copolyesters PESC and PPSC. Inherent viscosities of the copolyesters, measured in 1,4-dioxane at 32 °C, were 0.65 dL/g for PESC and 0.73 dL/g for PPSC. Fourier-Transform Infrared Spectroscopy (FT-IR) revealed distinct absorption bands associated with ester carbonyl stretching, C-H bending vibration, C-H group symmetry stretching, and C-O stretching vibrations. 1H and 13C Nuclear magnetic Resonance (NMR) spectroscopy were used to identify specific protons and carbon groups in the polymer chain, revealing the molecular structure of the copolyesters. Differential Scanning Calorimetry (DSC) identified the glass transition, melting, and decomposition temperatures for both copolyesters, indicating variations in the crystalline nature of the copolymers. XRD Spectral studies further elaborated on the crystalline nature, indicating that PPSC is less amorphous than PESC. Biodegradation analysis showed that PESC degrades more quickly than PPSC, with degradation decreasing as the number of methylene groups increase. Scanning Electron Microscopy (SEM) images depicted the surface morphology of the copolyesters before and after degradation, revealing a more roughened surface with pits post-degradation. These findings provide comprehensive insights into the structural and degradable properties of PESC and PPSC copolyesters.

Cocaine Use is Associated With Increased LVMI in Unstably Housed Women With Polysubstance Use

BACKGROUND

While substance use is known to influence cardiovascular health, most prior studies only consider one substance at a time. We examined associations between the concurrent use of multiple substances and left ventricular mass index (LVMI) in unhoused and unstably housed women.

METHODS

Between 2016 and 2019, we conducted a cohort study of unstably housed women in which measurements included an interview, serum/urine collection, vital sign assessment, and a single transthoracic echocardiogram at baseline. We evaluated independent associations between 39 separate substances confirmed through toxicology and echocardiography-confirmed LVMI.

RESULTS

The study included 194 participants with a median age of 53.5 years and a high proportion of women of color (72.6%). Toxicology-confirmed substance use included: 69.1% nicotine, 56.2% cocaine, 28.9% methamphetamines, 28.9% alcohol, 23.2% opioid analgesics, and 9.8% opioids with catecholaminergic effects. In adjusted analysis, cocaine was independently associated with higher LVMI (Adjusted linear effect: 18%; 95% CI 9.9, 26.6). Associations with other substances did not reach levels of significance and did not significantly interact with cocaine.

CONCLUSION

In a population of vulnerable women where the use of multiple substances is common, cocaine stands out as having particularly detrimental influences on cardiac structure. Blood pressure did not attenuate the association appreciably, suggesting direct effects of cocaine on LVMI. Routinely evaluating stimulant use as a chronic risk factor during risk assessment and preventive clinical care planning may reduce end organ damage, particularly in highly vulnerable women.

Governance of Electronic Health Record Modification at U.S. Academic Medical Centers

OBJECTIVES

A key aspect of electronic health record (EHR) governance involves the approach to EHR modification. We report a descriptive study to characterize EHR governance at academic medical centers (AMCs) across the United States.

METHODS

We conducted interviews with the Chief Medical Information Officers of 18 AMCs about the process of EHR modification for standard requests. Recordings of the interviews were analyzed to identify categories within prespecified domains. Responses were then assigned to categories for each domain.

RESULTS

At our AMCs, EHR requests were governed variably, with a similar number of sites using quantitative scoring systems (7, 38.9%), qualitative systems (5, 27.8%), or no scoring system (6, 33.3%). Two (11%) organizations formally review all requests for their impact on health equity. Although 14 (78%) organizations have trained physician builders/architects, their primary role was not for EHR build. Most commonly reported governance challenges included request volume (11, 61%), integrating diverse clinician input (3, 17%), and stakeholder buy-in (3, 17%). The slowest step in the process was clarifying end user requests (14, 78%). Few leaders had identified metrics for the success of EHR governance.

CONCLUSION

Governance approaches for managing EHR modification at AMCs are highly variable, which suggests ongoing efforts to balance EHR standardization and maintenance burden, while dealing with a high volume of requests. Developing metrics to capture the performance of governance and quantify problems may be a key step in identifying best practices.

Dosimetric Predictors of Toxicities and Quality of Life Following Two-Fraction Stereotactic Body Radiotherapy for Prostate Cancer

PURPOSE/OBJECTIVE(S)

There is emerging interest in two-fraction stereotactic body radiotherapy (2#SBRT) for localized prostate cancer. However, there is limited data to guide organs at risk (OAR) dose constraints in 2#SBRT. We aim to identify dosimetric predictors of toxicities and quality of life (QoL) using real life patient data from two prospective 2#SBRT trials.

MATERIALS/METHODS

We included 60 patients who had 2#SBRT in the 2STAR (NCT02031328) and 2SMART (NCT03588819) phase 2 trials. The prescribed dose was 26Gy to the prostate +/- focal boost of 32Gy to the dominant intraprostatic lesions. Toxicities and QoL data were prospectively collected using CTCAEv4 and EPIC26 questionnaires. For QoL, we reported the minimal clinical important changes (MCIC), defined as changes in QoL score of >0.5 standard deviation from baseline QoL score. We evaluated the bladder, urethra, rectum, and penile bulb dosimetry (urethra dosimetry only available in 30 patients in 2SMART trial). Some of the dosimetric parameters were log-transformed to normalize the distribution. Cox regression was used to identify dosimetric predictors for acute and late grade ≥2 GU toxicities. Logistic regression was used to identify dosimetric predictors for late MCIC in urinary, bowel and sexual QoL domains. Backward stepwise selection was used to identify significant dosimetric parameters. For GU toxicities and urinary QoL, three additional clinical factors (age, prostate volume and IPSS) were included in the final model as confounding factors. Receiver operating characteristics curve was used to identify cut-off for significant dosimetric parameters.

RESULTS

The median follow-up for the cohort was 56 months (range: 39-78 months). The cumulative acute and late grade ³2 GU toxicities were 62% (37/60) and 57% (34/60) respectively. No bladder or urethra dosimetric parameter was associated with acute grade ≥2 GU toxicities. Bladder D0.5cc was significant predictor of late grade ≥2 GU toxicities in univariate model (P = 0.05), but not in multivariate model. Baseline IPSS score was the single strongest predictor for late grade ≥2 GU toxicities (HR = 1.9; 95% CI = 1.1-3.4; P = 0.03). For late QoL outcomes, there were 36% (21/58), 28% (16/58), and 29% (17/58) of patients with MCIC in urinary, bowel and sexual QoL domains respectively. Bladder V10Gy was associated with late urinary MCIC in multivariate model after adjusting for clinical confounders (HR = 2.6, 95% CI = 1.1-6.6; P = 0.04). 48% (14/29) and 24% (7/29) of patients with bladder V10Gy>13.9% and V10Gy≤13.9% respectively had late urinary MCIC. No rectum and penile bulb dosimetry parameters was identified to be associated with late bowel or sexual QoL.

CONCLUSION

Using real life patient data from prospective clinical trials with medium term follow-up, we identified statistically significant bladder dosimetry parameter predictive of late urinary QoL. This finding could be useful to guide OAR dose constraints in prostate 2#SBRT trials.

Large Language Models and Medical Education: Preparing for a Rapid Transformation in How Trainees Will Learn to Be Doctors

Artificial intelligence has the potential to revolutionize health care but has yet to be widely implemented. In part, this may be because, to date, we have focused on easily predicted rather than easily actionable problems. Large language models (LLMs) represent a paradigm shift in our approach to artificial intelligence because they are easily accessible and already being tested by frontline clinicians, who are rapidly identifying possible use cases. LLMs in health care have the potential to reduce clerical work, bridge gaps in patient education, and more. As we enter this era of healthcare delivery, LLMs will present both opportunities and challenges in medical education. Future models should be developed to support trainees to develop skills in clinical reasoning, encourage evidence-based medicine, and offer case-based training opportunities. LLMs may also change what we continue teaching trainees with regard to clinical documentation. Finally, trainees can help us train and develop the LLMs of the future as we consider the best ways to incorporate LLMs into medical education. Ready or not, LLMs will soon be integrated into various aspects of clinical practice, and we must work closely with students and educators to make sure these models are also built with trainees in mind to responsibly chaperone medical education into the next era.

Multiple substance use and blood pressure in women experiencing homelessness

Background

Substance use increases risk of cardiovascular events, particularly among women with additional risk factors like housing instability. While multiple substance use is common among unstably housed individuals, relationships between multiple substance use and cardiovascular risk factors like blood pressure are not well characterized.

Methods

We conducted a cohort study between 2016 and 2019 to examine associations between multiple substance use and blood pressure in women experiencing homelessness and unstable housing. Participants completed six monthly visits including vital sign assessment, interview, and blood draw to assess toxicology-confirmed substance use (e.g., cocaine, alcohol, opioids) and cardiovascular health. We used linear mixed models to evaluate the outcomes of systolic and diastolic blood pressure (SBP; DBP).

Results

Mean age was 51.6 years; 74 % were women of color. Prevalence of any substance use was 85 %; 63 % of participants used at least two substances at baseline. Adjusting for race, body mass index and cholesterol, cocaine was the only substance significantly associated with SBP (4.71 mmHg higher; 95 % CI 1.68, 7.74) and DBP (2.83 mmHg higher; 95 % CI 0.72, 4.94). Further analysis found no differences in SBP or DBP between those with concurrent use of other stimulants, depressants, or both with cocaine, compared to those who used cocaine only.

Conclusions

Cocaine was the only substance associated with higher SBP and DBP, even after accounting for simultaneous use of other substances. Along with interventions to address cocaine use, stimulant use screening during cardiovascular risk assessment and intensive blood pressure management may improve cardiovascular outcomes among women experiencing housing instability.

Effect of Recent Abortion Legislation on Twitter User Engagement, Sentiment, and Expressions of Trust in Clinicians and Privacy of Health Information: Content Analysis

BACKGROUND

The Supreme Court ruling in Dobbs v Jackson Women's Health Organization (Dobbs) overrules precedents established by Roe v Wade and Planned Parenthood v Casey and allows states to individually regulate access to abortion care services. While many states have passed laws to protect access to abortion services since the ruling, the ruling has also triggered the enforcement of existing laws and the creation of new ones that ban or restrict abortion. In addition to denying patients the full spectrum of reproductive health care, one major concern in the medical community is how the ruling will undermine trust in the patient-clinician relationship by influencing perceptions of the privacy of patient health information.

OBJECTIVE

This study aimed to study the effect of recent abortion legislation on Twitter user engagement, sentiment, expressions of trust in clinicians, and privacy of health information.

METHODS

We scraped tweets containing keywords of interest between January 1, 2020, and October 17, 2022, to capture tweets posted before and after the leak of the Supreme Court decision. We then trained a Latent Dirichlet Allocation model to select tweets pertinent to the topic of interest and performed a sentiment analysis using Robustly Optimized Bidirectional Encoder Representations from Transformers Pre-training Approach model and a causal impact time series analysis to examine engagement and sentiment. In addition, we used a Word2Vec model to study the terms of interest against a latent trust dimension to capture how expressions of trust for our terms of interest changed over time and used term frequency, inverse-document frequency to measure the volume of tweets before and after the decision with respect to the negative and positive sentiments that map to our terms of interest.

RESULTS

Our study revealed (1) a transient increase in the number of daily users by 576.86% (95% CI 545.34%-607.92%; P<.001), tweeting about abortion, health care, and privacy of health information postdecision leak; (2) a sustained and statistically significant decrease in the average daily sentiment on these topics by 19.81% (95% CI -22.98% to -16.59%; P=.001) postdecision leak; (3) a decrease in the association of the latent dimension of trust across most clinician-related and health information-related terms of interest; (4) an increased frequency of tweets with these clinician-related and health information-related terms and concomitant negative sentiment in the postdecision leak period.

CONCLUSIONS

The study suggests that the Dobbs ruling has consequences for health systems and reproductive health care that extend beyond denying patients access to the full spectrum of reproductive health services. The finding of a decrease in the expression of trust in clinicians and health information-related terms provides evidence to support advocacy and initiatives that proactively address concerns of trust in health systems and services.

Development and Internal Validation of an Interpretable Machine Learning Model to Predict Readmissions in a United States Healthcare System

(1) One in four hospital readmissions is potentially preventable. Machine learning (ML) models have been developed to predict hospital readmissions and risk-stratify patients, but thus far they have been limited in clinical applicability, timeliness, and generalizability. (2) Methods: Using deidentified clinical data from the University of California, San Francisco (UCSF) between January 2016 and November 2021, we developed and compared four supervised ML models (logistic regression, random forest, gradient boosting, and XGBoost) to predict 30-day readmissions for adults admitted to a UCSF hospital. (3) Results: Of 147,358 inpatient encounters, 20,747 (13.9%) patients were readmitted within 30 days of discharge. The final model selected was XGBoost, which had an area under the receiver operating characteristic curve of 0.783 and an area under the precision-recall curve of 0.434. The most important features by Shapley Additive Explanations were days since last admission, discharge department, and inpatient length of stay. (4) Conclusions: We developed and internally validated a supervised ML model to predict 30-day readmissions in a US-based healthcare system. This model has several advantages including state-of-the-art performance metrics, the use of clinical data, the use of features available within 24 h of discharge, and generalizability to multiple disease states.

Improvements to emergency department length of stay and user satisfaction after implementation of an integrated consult order

Objective

Subspecialty consultation in the emergency department (ED) is a vital, albeit time consuming, part of modern medicine. Traditional consultation requires manual paging to initiate communication. Although consult orders through the electronic health record (EHR) may help, they do not facilitate 2‐way communication. However, the impact of combining these systems within the EHR is unknown. We estimated the effect of implementing an integrated paging system on ED workflow efficiency and user attitudes.

Methods

We integrated a messaging system into order entry at our tertiary care academic ED, such that placing a consult order simultaneously paged the consultant. We measured ED workflow efficiency metrics (length of stay [LOS], consult initiation time) and MD/nurse practitioner (NP)/physician assistant (PA) attitudes (perceived mis‐pages, efficiency, and workflow preference) 3 months before and 6 months after the implementation.

Results

Six months after implementation, there was 25% use of the new workflow. During the pre‐implementation phase, the median time to consult initiation and ED LOS were 150 and 621 minutes, respectively. Implementation of the order was associated with a 15‐minute reduction in median time to consult initiation (P < 0.001), and a 52‐minute reduction in median ED LOS (P < 0.001). ED MDs/NPs/PAs perceived a reduction in the rate of mis‐pages, improved efficiency, and overall preferred the new workflow.

Conclusions

We consolidated steps in the ED consult workflow using an integrated consult order, which improved user satisfaction, and reduced consult initiation time and ED LOS for patients requiring a consult at an urban tertiary care ED.

Quantitative analysis of MGMT promoter methylation in glioblastoma suggests nonlinear prognostic effect

Background

Epigenetic inhibition of the O6-methylguanine-DNA-methyltransferase (MGMT) gene has emerged as a clinically relevant prognostic marker in glioblastoma (GBM). Methylation of the MGMT promoter has been shown to increase chemotherapy efficacy. While traditionally reported as a binary marker, recent methodological advancements have led to quantitative methods of measuring promoter methylation, providing clearer insight into its functional relationship with survival.

Methods

A CLIA assay and bisulfite sequencing was utilized to develop a quantitative, 17-point, MGMT promoter methylation index. GBMs of 240 newly diagnosed patients were sequenced and risk for mortality was assessed. Nonlinearities were captured by fitting splines to Cox proportional hazard models and plotting smoothed residuals. Covariates included age, Karnofsky performance status, IDH1 mutation, and extent of resection.

Results

Median follow-up time and progression-free survival were 16 and 9 months, respectively. A total of 176 subjects experienced death. A one-unit increase in promoter CpG methylation resulted in a 4% reduction in hazard (95% CI 0.93-0.99, P < .005). GBM patients with low levels of promoter methylation (1-6 CpG sites) fared markedly worse (HR = 1.62, 95% CI 1.03-2.54, P < .036) than individuals who were unmethylated. Subjects with medium levels of promoter methylation (7-12 sites) had the greatest reduction in hazard (HR = 0.48, 95% CI 0.29-0.80, P < .004), followed by individuals in the highest promoter methylation tertile (HR = 0.62, 95% CI 0.40-0.97, P < .035).

Conclusions

Our findings suggest that the relationship between the extent of MGMT promoter methylation and survival in GBM may be nonlinear. These findings challenge the current understanding of MGMT and underlines the clinical importance of determining its prognostic utility. Potential limitations include censoring, sample size, and extraneous mutations.

Supervised machine learning algorithms demonstrate proliferation index correlates with long-term recurrence after complete resection of WHO grade I meningioma

OBJECTIVE

Meningiomas are the most common primary intracranial tumor, and resection is a mainstay of treatment. It is unclear what duration of imaging follow-up is reasonable for WHO grade I meningiomas undergoing complete resection. This study examined recurrence rates, timing of recurrence, and risk factors for recurrence in patients undergoing a complete resection (as defined by both postoperative MRI and intraoperative impression) of WHO grade I meningiomas.

METHODS

The authors conducted a retrospective, single-center study examining recurrence risk for adult patients with a single intracranial meningioma that underwent complete resection. Uni- and multivariate nominal logistic regression and Cox proportional hazards analyses were performed to identify variables associated with recurrence and time to recurrence. Two supervised machine learning algorithms were then implemented to confirm factors within the cohort that were associated with recurrence.

RESULTS

The cohort consisted of 823 patients who met inclusion criteria, and 56 patients (6.8%) had recurrence on imaging follow-up. The median age of the cohort was 56 years, and 77.4% of patients were female. The median duration of head imaging follow-up for the entire cohort was 2.7 years, but for the subgroup of patients who had a recurrence, the median follow-up was 10.1 years. Estimated 1-, 5-, 10-, and 15-year recurrence-free survival rates were 99.8% (95% confidence interval [CI] 98.8%-99.9%), 91.0% (95% CI 87.7%-93.6%), 83.6% (95% CI 78.6%-87.6%), and 77.3% (95% CI 69.7%-83.4%), respectively, for the entire cohort. On multivariate analysis, MIB-1 index (odds ratio [OR] per 1% increase: 1.34, 95% CI 1.13-1.58, p = 0.0003) and follow-up duration (OR per year: 1.12, 95% CI 1.03-1.21, p = 0.012) were both associated with recurrence. Gradient-boosted decision tree and random forest analyses both identified MIB-1 index as the main factor associated with recurrence, aside from length of imaging follow-up. For tumors with an MIB-1 index < 8, recurrences were documented up to 8 years after surgery. For tumors with an MIB-1 index ≥ 8, recurrences were documented up to 12 years following surgery.

CONCLUSIONS

Long-term imaging follow-up is important even after a complete resection of a meningioma. Higher MIB-1 labeling index is associated with greater risk of recurrence. Imaging screening for at least 8 years in patients with an MIB-1 index < 8 and at least 12 years for those with an MIB-1 index ≥ 8 may be needed to detect long-term recurrences.

Ultrasonic assisted synthesis of RGO supported HoVO4-ZnO nanocomposites, their enhanced photocatalytic activities and Rhodamine B degradation

The RGO-supported HoVO₄-ZnO nanocomposite was synthesized using the ultra sonication process. X-ray diffraction patterns, Field emission scanning electron microscopy, high resolution transmission electron microscopy, Diffractive Reflectance spectroscopy, and photoluminescence spectroscopy were employed to examine the heterostructured photocatalyst in this research study. The photocatalytic efficiency of the RGO-supported HoVO₄-ZnO nanoparticles, under UV light irradiation, in the degradation of Rhodamine-B dye was investigated. Undoped ZnO, bare HoVO4, and HoVO₄ -ZnO, degraded at 55.6, 57.5, and 74.33 percent in 45 min, respectively. This new RGO coupled HoVO₄-ZnO exhibits enhanced photocatalytic efficiency compared to the bare ZnO and HoVO₄-ZnO nanocomposite.

System cost minimisation in hybrid energy storage systems connected to microgrids: A comparative approach

Electricity is the most critical facility for humans. All traditional energy supplies are rapidly depleting. As a result, the energy resources are moved from traditional to non-conventional. In this research, mixture of two energy tools, namely wind and solar energy are used. Using a Hybrid Energy Storage System (HESS), continuous power can be provided. Electricity can be produced at a cost that is affordable. The integration of solar and wind in a hybrid system cause an increase in the system’s stability, which is the key benefit of this research. The system’s power transmission efficiency and reliability can be greatly enhanced by integrating these two intermittent sources. When one of the energy source is unavailable or inadequate to meet load demands, the other energy source will supply the power. The major contribution in this research is that, the proposed bidirectional single-inductor multiple-port (BSIMP) converter significantly lowers the component count, smaller circuit size and lower cost, allowing HESS to be integrated into DC microgrid. Minimum number of components are used for the same number of ESs in HESS in the proposed BSIMP converter. The hybridization of battery and supercapacitor (SC) for storage purpose is more cost effective, as compared to the battery energy storage system, thus improving the battery stress and hence used for large scale grid energy storage. SC’s are accepted as backup and found very useful in delivering high power, not possible with batteries. The use of SC in addition to batteries can be one solution for achieving the low life cycle economy. The Single Objective Adaptive Firefly Algorithm (SOAFA) is introduced for optimising the Proportional-Integral (PI) controller parameters. The system cost is reduced by about 32%, with the constraints on wind turbine swept area, PV area, total battery and SC capacity with the proposed optimisation algorithm.

BIOM-07. QUANTITATIVE MGMT PROMOTER METHYLATION INDEX INDICATES A NON-LINEAR PROGNOSTIC EFFECT IN GLIOBLASTOMA, SUGGESTING THAT USE OF OPTIMAL CUTOFF POINTS MAY BE CLINICALLY DISADVANTAGEOUS

BACKGROUND

Epigenetic inhibition of the O6-methylguanine-DNA-methyltransferase (MGMT) gene has emerged as a clinically relevant prognostic marker in glioblastoma (GBM). Methylation of the MGMT promoter has been shown to increase chemotherapy efficacy. While traditionally reported as a binary marker, recent methodological advancements have led to quantitative approaches that measure methylation, providing clearer insights into methylation’s functional relationship with survival.

METHODS

A CLIA assay and bisulfite sequencing was utilized to develop a quantitative, 17-point MGMT promoter methylation index derived from the number of methylated CpG sites. Retrospective review of 240 newly diagnosed GBM patients was performed in order to discern how risk for mortality transforms as promoter methylation increases. Non-linearities were captured by fitting splines to Cox proportional hazard models, plotting smoothed residuals, and creating survival plots. Covariates included age, KPS, IDH1 mutation, and extent of resection.

RESULTS

Median follow-up time and progression free survival were 16 and 9 months, respectively. 176 subjects experienced death. A one-unit increase in CpG methylation on a scale of 1-17 resulted in a 4% reduction in hazard (95% CI 0.93–0.99, P&lt; 0.005). Moreover, GBM patients with low-levels of methylation (1-6 CpG sites) fared markedly worse (HR=1.62, 95% CI 1.03-2.54, P&lt; 0.036) than individuals who were unmethylated (reference group). Subjects with medium-levels of methylation (7-12 CpG sites) had the greatest reduction in hazard (HR=0.48, 95% CI 0.29-0.80, P&lt; 0.004), followed by individuals in the highest methylation tertile (HR=0.62, 95% CI 0.40-0.97, P&lt; 0.035).

CONCLUSION

This novel approach offers greater bisulfite conversion efficiency when compared to alternative methods, reducing the likelihood of false positives. Analysis of the resulting methylation index scores demonstrates a non-linear relationship between MGMT methylation and survival, suggesting conformation of the marker’s protective effect. These findings challenge the current understanding of MGMT’s functional form and underline why implementing an “optimal cutoff point” may be disadvantageous.

P–587 Highly purified human menopausal gonadotrophin (HP-hMG, Menopur) as a ready-to-use solution for injection in pre-filled pen is bioequivalent to HP-hMG powder for reconstitution

Study question

Are serum FSH levels after single subcutaneous dosing of HP-hMG in a liquid formulation and a powder formulation bioequivalent?

Summary answer

The 90% CIs for the geometric mean ratios of serum FSH AUCt and Cmax were both within 0.8000–1.2500, thus the two formulations are bioequivalent.

What is known already

For several decades, HP-hMG (Menopur) has been used for the treatment of infertility; its efficacy and safety compared to other gonadotropins have been consistently demonstrated in several prospective, randomised controlled trials and meta-analyses (Deeks et al 2018; Bordewijk et al 2019). Menopur powder for reconstitution is available in multidose and single dose formulations. Up to 3 single dose vials (each containing 75 IU) may be dissolved into 1 mL solvent for administration. Recently, and for the first time, Menopur has been successfully formulated in a stable, ready-to-use solution for injection, which may be administered by a pre-filled pen.

Study design, size, duration

This was a randomised, two-way crossover, single dose, bioequivalence trial comparing Menopur liquid injected by pre-filled pen, with Menopur powder injected by conventional syringe and needle. The primary endpoints were AUCt and Cmax of baseline-adjusted FSH. Pituitary-suppressed, healthy women were randomised to receive one treatment sequence including a single subcutaneous injection of 450 IU Menopur liquid (600 IU/0.96 mL) and of 450 IU Menopur powder by two subcutaneous injections of 225 IU in 1 mL.

Participants/materials, setting, methods

Blood samples were collected pre- and post-dose, until 9 days after each injection. The PK parameters of FSH and hCG were assessed by noncompartmental methods with adjustment for endogenous pre-dose levels. Highly sensitive and specific electrochemiluminescence immunoassays were used for quantification and the LLOQ of the FSH and hCG assays were 1.47 mIU/mL and 0.5 mIU/mL, respectively, and the total validated CV was within 5% for both assays.

Main results and the role of chance

In total, 76 women were randomised and 56 completed the trial. The main reason for discontinuation was insufficient pituitary suppression prior to the second administration of HP-hMG. The mean FSH and hCG serum concentration-time profiles were comparable between the two HP-hMG formulations. The geometric mean ratios and 90% confidence intervals of FSH for HP-hMG liquid versus HP-hMG powder were 1.12 [1.0562; 1.1889] for AUCt and 1.17 [1.0946; 1.2490] for Cmax, showing that the two formulations were bioequivalent. Maximal serum FSH concentrations were reached at 18.19 h for HP-HMG liquid and 15.55 h for HP-hMG powder. In addition to FSH, the PK parameters for hCG were compared between the two HP-hMG formulations. The geometric mean ratios and 90% confidence intervals for HP-hMG liquid versus HP-hMG powder were 0.93 [0.86; 1.01] for AUCt and 0.94 [0.86; 1.02] for Cmax. There was no difference between the two groups in the incidence or severity of adverse events, and both preparations were well tolerated. Mild injection site reactions were less common after administration of HP-hMG liquid by a single injection compared to HP-hMG powder by two injections and were mostly related to pain and erythema after drug administration.

Limitations, reasons for caution

This bioequivalence study is based on the comparison of single dose administrations in healthy female volunteers of reproductive age.

Wider implications of the findings: The new HP-hMG solution for injection in a pre-filled pen will deliver the efficacy and safety of Menopur in a convenient delivery device.

Trial registration number

NA

NGMA-6. Quantitative MGMT Promoter Methylation Index Indicates Non-Linear, Prognostic Effect in Glioblastoma

Background

Epigenetic inhibition of the O6-methylguanine-DNA-methyltransferase (MGMT) gene has emerged as a clinically relevant prognostic marker in glioblastoma (GBM). Methylation of the MGMT promoter has been shown to increase chemotherapy efficacy. While traditionally reported as a binary marker, recent methodological advancements have led to quantitative methods of measuring methylation, allowing for clearer insights into methylation’s functional relationship with survival.

Methods

A CLIA assay and bisulfite sequencing was utilized to develop a quantitative, 17-point MGMT promoter methylation index derived from the number of methylated CpG sites. Retrospective review of 242 newly diagnosed GBM patients was performed in order to discern how risk for mortality transforms as promoter methylation increases. Non-linearities were captured by fitting splines to Cox proportional hazard models, plotting smoothed residuals, and creating survival plots. Covariates included age, KPS, IDH1 mutation, and extent of resection.

Results

Median follow-up time and progression free survival were 15.9 and 9 months, respectively. 176 subjects experienced death. A one-unit increase in CpG methylation resulted in a 4% reduction in hazard (95% CI 0.93–0.99, P&lt;0.005). Moreover, GBM patients with low levels of methylation (1–6 CpG islands) fared markedly worse (HR=1.62, 95% CI 1.03–2.54, P&lt;0.036) than individuals who were unmethylated (reference group). Subjects with medium levels of methylation (7–12 sites) had the greatest reduction in hazard (HR=0.48, 95% CI 0.29–0.80, P&lt;0.004), followed by individuals in the highest methylation tertile (HR=0.62, 95% CI 0.40–0.97, P&lt;0.035).

Conclusion

The extent of MGMT methylation shares a non-linear relationship with survival, suggesting conformation of the marker’s protective effect. This finding challenges the current understanding of MGMT and underlines the clinical importance of determining its prognostic utility. Potential limitations include censoring, sample size, and extraneous mutations. Future research is warranted to examine whether the location of CpG site methylation contributes to a reduction in mortality hazard.

Relationship of Urethral Dose and Genitourinary Toxicity Among Patients Receiving Vaginal High Dose Rate Interstitial Brachytherapy

AIMS

Interstitial brachytherapy (ISBT) plays an important role in the management of locally advanced gynaecological malignancies. However, the relationship between urinary toxicity and dose to the urethra is not well understood. We sought to evaluate the correlation between urethral dose and the incidence of genitourinary complications among patients undergoing vaginal high dose rate ISBT.

MATERIALS AND METHODS

Eighty-three patients treated with ISBT between August 2014 and April 2018 were retrospectively reviewed. CTCAE version 5.0 was used to grade toxicity. Individual treatment plans were evaluated to collect dose parameters. Urethral contours were added to the structure sets using a uniform 1 cm diameter brush and minimum doses to the hottest 0.1, 0.2 and 0.5 cm³ (D0.1cm³, D0.2cm³ and D0.5cm³) of the urethra were obtained. Total (ISBT ± external beam radiotherapy) equivalent doses in 2 Gy fractions (EQD2) received by the targets and organs at risk were calculated. Numerical counts (%) and medians (interquartile range) were used to characterise the data. Fisher's exact and the Mann-Whitney-Wilcox tests were used as appropriate. Receiver operator curve analysis was used to define the urethral threshold dose that correlated to genitourinary toxicity.

RESULTS

The median age and follow-up times were 67 years (59-75) and 25 months (16-37), respectively. Patients had predominantly primary endometrial (49%) and vaginal (37%) cancer, with four (5%) patients with metastatic rectal cancer to the vagina. Twenty-four of 79 (30%) patients experienced acute genitourinary toxicity and 34 of 71 (48%) experienced late genitourinary toxicity. In both analyses, the median urethral dose was significantly higher among those with toxicity. Receiver operator curve analysis indicated that D0.1cm³, D0.2cm³ and D0.5cm³ of the urethra were associated with the development of toxicity at doses >78, >71 and >62 Gy, respectively.

CONCLUSION

Urethral dose seems to predict genitourinary toxicity in ISBT of vaginal tumours. Further study with an expanded cohort and longer follow-up is warranted.

Results of 15 Gy HDR-BT boost plus EBRT in intermediate-risk prostate cancer: Analysis of over 500 patients

PURPOSE/OBJECTIVE

To report biochemical control associated with single fraction 15 Gy high-dose-rate brachytherapy (HDR-BT) boost followed by external beam radiation (EBRT) in patients with intermediate-risk prostate cancer.

MATERIALS AND METHODS

A retrospective chart review of all patients with intermediate-risk disease treated with a real-time ultrasound-based 15 Gy HDR-BT boost followed by EBRT between 2009 and 2016 at a single quaternary cancer center was performed. Freedom from biochemical failure (FFBF), cumulative incidence of androgen deprivation therapy use for biochemical or clinical failure post-treatment (CI of ADT) and metastasis-free survival (MFS) outcomes were measured.

RESULTS

518 patients met the inclusion criteria for this study. Median age at HDR-BT was 67 years (IQR 61-72). 506 (98%) had complete pathologic information available. Of these, 146 (28%) had favorable (FIR) and 360 (69%) had unfavorable (UIR) intermediate-risk disease. 83 (16%) received short course hormones with EBRT + HDR. Median overall follow-up was 5.2 years. FFBF was 91 (88-94)% at 5 years. Five-year FFBF was 94 (89-99)% and 89 (85-94)% in FIR and UIR patients, respectively (p = 0.045). CI of ADT was 4 (2-6)% at 5 years. Five-year CI of ADT was 1 (0-3)% and 5 (2-8)% in FIR and UIR patients, respectively (p = 0.085). MFS was 97 (95-98)% at 5 years. Five-year MFS was 100 (N/A-100)% and 95 (92-98)% in FIR and UIR patients, respectively (p = 0.020).

CONCLUSION

In this large cohort of intermediate-risk prostate cancer patients, 15 Gy HDR-BT boost plus EBRT results in durable biochemical control and low rates of ADT use for biochemical failure.

Prostate-specific Antigen Bounce After Stereotactic Body Radiotherapy for Prostate Cancer: A Pooled Analysis of Four Prospective Trials

AIMS

We conducted a pooled analysis of four prospective stereotactic body radiotherapy (SBRT) trials of low- and intermediate-risk prostate cancer to evaluate the incidence of prostate-specific antigen (PSA) bounce and its correlation with the time-dose-fraction schedule. The correlation between bounce with PSA response at 4 years (nadir PSA < 0.4 ng/ml) and biochemical failure-free survival (BFFS) was also explored.

MATERIALS AND METHODS

The study included four treatment groups: 35 Gy/five fractions once per week (QW) (TG-1; n = 84); 40 Gy/five fractions QW (TG-2; n = 100); 40 Gy/five fractions every other day (TG-3; n = 73); and 26 Gy/two fractions QW (TG-4; n = 30). PSA bounce was defined as a rise in PSA by 0.2 ng/ml (nadir + 0.2) or 2 ng/ml (nadir + 2.0) above nadir followed by a decrease back to nadir. Patients with fewer than three follow-up PSA tests were excluded from the pooled analysis.

RESULTS

In total, 287 patients were included, with a median follow-up of 5.0 years. The pooled 5-year cumulative incidence of bounce by nadir + 2.0 was 8%. The 2-year cumulative incidences of PSA bounce by nadir + 0.2 were 28.9, 21, 19.6 and 16.7% (P = 0.12) and by nadir + 2.0 were 7.2, 8, 2.7 and 6.7% (P = 0.32) for TG-1 to TG-4, respectively. Multivariable analysis revealed that for nadir + 2.0, pre-treatment PSA (odds ratio 0.49; 95% confidence interval 0.26-0.97) correlated with PSA bounce. Although PSA bounce by nadir + 0.2 (odds ratio 0.10; 95% confidence interval 0.04-0.24) and nadir + 2.0 (odds ratio 0.29; 95% confidence interval 0.09-0.93) was associated with a lower probability of PSA response at 4 years, there was no association between bounce by nadir + 0.2 (hazard ratio 0.36; 95% confidence interval 0.08-1.74) or nadir + 2 (hazard ratio 1.77; 95% confidence interval 0.28-11.07) with BFFS.

CONCLUSION

The incidence of PSA bounce was independent of time-dose-fraction schedule for prostate SBRT. One in 13 patients experienced a bounce high enough to be misinterpreted as biochemical failure, and clinicians should avoid early salvage interventions in these patients. There was no association between PSA bounce and BFFS.

Absolute percentage of biopsied tissue positive for Gleason pattern 4 disease (APP4) appears predictive of disease control after high dose rate brachytherapy and external beam radiotherapy in intermediate risk prostate cancer

BACKGROUND AND PURPOSE

To identify if, in intermediate risk prostate cancer (IR-PCa), the absolute percentage of biopsied tissue positive for pattern 4 disease (APP4) may be a predictor of outcome.

MATERIALS AND METHODS

411 patients with IR-PCa were retrospectively reviewed. APP4 was calculated based on biopsy reports. Multivariable competing risk analysis was then performed on optimized APP4 cutpoints to predict for biochemical failure (BF), androgen deprivation use for BF (ADT-BF) and development of metastases (MD).

RESULTS

Median follow-up for the cohort was 5.2 (Inter Quartile Range: 2.9-6.6) years. Median baseline PSA was 7.3 (5.3-9.8) ng/mL. 234 (56.9%) patients had T1 and 177 (43.1%) had T2 disease. Median APP4 was 2.00 (0.75-7.50)%. 38 (9.3%) patients experienced BF. The optimal cutpoint of APP4 for BF was >3.3% with an area under the curve (AUC) of 0.66. 17 (4.1%) received ADT-BF. The ADT-BF cutpoint was >6.6% with an AUC of 0.72. Eight (2.0%) developed MD. The MD cutpoint was >17.5% with an AUC of 0.86. Using APP4 >3.3 vs ≤ 3.3, log-transformed baseline PSA ln(PSA) (HR 2.5, 1.1-6.1; p = 0.037) and APP4 (HR 2.3, 1.1-4.7; p = 0.031) predicted for BF. Using APP4 >6.6 vs ≤ 6.6, ln(PSA) (HR 4.2, 1.4-12.4; p = 0.010) and APP4 (HR 3.7, 1.4-10.0; p = 0.009) were predictive of ADT-BF. APP4 >17.5 vs ≤ 17.5 alone was predictive of MD (HR 25.7, 4.9-135.3; p < 0.001).

CONCLUSION

APP4 cutpoints of >3.3%, >6.6% and >17.5% were strongly associated with increased risk of BF, ADT-BF and developing MD respectively. These findings may inform future practice when treating IR-PCa but require external validation.