A systematic review of allometric scaling exponents for IgG mAbs.

Increasing complexity of mAbs in development creates challenges in predicting human pharmacokinetic (PK) parameters from preclinical data. The aim of this analysis was to identify optimal allometric scaling exponents.Data were extracted from literature to create a central database (currently the largest available published database) of two-compartment model parameters for mAbs (n = 59) in cynomolgus monkey (CM) and human.Global allometric exponents were calculated and drug-dependent factors were investigated as potential variables in determining the optimal scaling factor.The global exponents for scaling CM mAb PK data were 0.74 (CL), 0.80 (CL with Fc-modified mAbs excluded), 0.44 (CL with Fc-modified mAbs only), 0.71 (Q), 1.12 (V1), and 0.99 (V2). These values are in line with previously published literature values.

Natural Cycles app: contraceptive outcomes and demographic analysis of UK users.

PURPOSE: Digital fertility awareness-based contraception offers an alternative choice for women who do not wish to use hormonal or invasive methods. The aim of this study was to investigate the key demographics of current users of the Natural Cycles app and assess the contraceptive outcomes of women preventing pregnancy in a UK cohort of women. MATERIALS AND METHODS: This was a real world observational prospective observational study. The typical-use effectiveness of the method was calculated using both 13-cycle cumulative probability of pregnancy (life table analysis) and Pearl Index for the entire study cohort. Perfect-use PI was calculated using data from cycles where sexual intercourse during the fertile window was marked as protected and no unprotected sex was recorded on fertile days. RESULTS: 12,247 women were included in the study and contributed an average of 9.9 months of data for a total of 10,066 woman years of exposure. The mean age of the cohort was 30, mean BMI 23.4, the majority were in a stable relationship (83.2%) and had a university degree or higher (83%). The one year typical use, PI was 6.1 (95% CI: 5.6, 6.6) and with perfect-use was 2.0 (95% CI: 1.3, 2.8). 13 cycle pregnancy probability was 7.1%. CONCLUSIONS: This is the first study which describes the use of a digital contraceptive by women in the UK. It describes the demographics of users and how they correlate with the apps effectiveness at preventing pregnancy.

Short- and long-term effect of contraceptive methods on fecundity.

Objective: The aim of the study was to compare the effect of previously used contraceptive methods on women's short- and long-term fecundity. Use of hormonal contraception (HC) was compared with the use of a contraceptive mobile application (app). Methods: This real-life prospective observational study comprised 2874 women who were attempting to become pregnant using the Natural Cycles mobile app to monitor their fertility. The women registered to use the app between August 2014 and June 2016 with the intention of planning a pregnancy and had previously either used the same app to prevent pregnancy or had recently discontinued HC use. We calculated the average time to pregnancy (TTP) for all women who became pregnant during the study and performed Kaplan-Meier life-table analysis to examine the cumulative probabilities of pregnancy for all women in the study. Results: The average TTP was 2.3 (95% confidence interval [CI] 2.1, 2.4) and 3.7 (95% CI 3.4, 3.9) cycles for women who had previously used Natural Cycles and HC, respectively. The time to reach 30% pregnancy probability for women previously on HC was 1.6 (95% CI 1.5, 1.8) times longer than for women previously using Natural Cycles. There was no significant difference in the 13 cycle cumulated pregnancy probability between the two groups. Conclusion: The results show that fertility awareness-based methods of contraception increase short-term pregnancy rates relative to HC, but have no effect on long-term pregnancy rates.

Advantages of determining the fertile window with the individualised Natural Cycles algorithm over calendar-based methods.

Purpose: This study aims to compare the accuracy of fertile window identification with the contraceptive app Natural Cycles against the Rhythm Method and Standard Days Method (SDM).Materials and methods: Menstruation dates, basal body temperature (BBT), and luteinising hormone (LH) test results were collected anonymously from Natural Cycles app users. The fraction of green days (GDs) and wrong green days (WGDs) allocated by the various algorithms was determined over 12 cycles. For comparison of Natural Cycles and the Rhythm Method, 26,626 cycles were analysed.Results: Natural Cycles' algorithms allocated 59% GDs (LH, BBT) in cycle 12, while the fraction of WGDs averaged 0.08%. The Rhythm Method requires monitoring of six cycles, resulting in no GDs or WGDs in cycle 1-6. In cycle 7, 49% GDs and 0.26% WGDs were allocated. GDs and WGDs decreased to 43% and 0.08% in cycle 12. The probabilities of WGDs on the day before ovulation with Natural Cycles were 0.31% (BBT) and 0% (LH, BBT), and 0.80% with the Rhythm Method. The probability of WGDs on the day before ovulation was 6.90% with the SDM.Conclusions: This study highlights that individualised algorithms are advantageous for accurate determination of the fertile window and that static algorithms are more likely to fail during the most fertile days.

Inferior vena cava filters for prevention of venous thromboembolism in obese patients undergoing bariatric surgery: a systematic review.

OBJECTIVE: The use of inferior vena cava (IVC) filters for prevention of venous thromboembolism (VTE) in bariatric surgery is a contentious issue. We aim to review the evidence for the use of IVC filters in bariatric surgical patients, describe trends in practice, and discuss challenges in developing evidence-based guidelines. BACKGROUND: The incidence of VTE in modern bariatric procedures with traditional methods of thromboprophylaxis, such as sequential calf compression devices and perioperative low molecular weight heparin, is approximately 2%. METHODS: A systematic review of the literature was conducted according to PRISMA guidelines. We searched Medline up until July 2013 with the terms "bariatric filter" and "gastric bypass filter." Two investigators independently screened search results according to an agreed list of eligibility criteria. RESULTS: Eighteen studies were included. There were no randomized controlled trials. Data from controlled cohort studies suggest that those who undergo IVC filter insertion preoperatively may be at higher risk of developing deep vein thrombosis (DVT) and pulmonary embolism (PE). A small cohort of patients with multiple risk factors for VTE benefitted from reduced PE-related mortality after preoperative IVC filter insertion. Data from 12 case series reporting VTE outcomes from a total of 497 patients who underwent preoperative IVC filter insertion demonstrated DVT rates of 0% to 20.8% and PE rates ranging from 0% to 6.4%. CONCLUSIONS: Published data reporting the safety and efficacy of IVC filter use in bariatric surgical patients is highly heterogeneous. There is no evidence to suggest that the potential benefits of IVC filters outweigh the significant risks of therapy.

Metabolic surgery and obstructive sleep apnoea: the protective effects of bariatric procedures.

The global epidemic of obesity and the worldwide prevalence of obstructive sleep apnoea (OSA) are both increasing. Epidemiological studies reveal an association between obesity, weight gain and OSA. Metabolic or bariatric operations provide sustained weight loss and resolve or improve the symptoms of OSA in the majority of morbidly obese individuals. These operations also modulate the metabolic profile to improve glycaemic control, to decrease cardiovascular risk and obesity-related mortality. The beneficial effects of metabolic operations on OSA include mechanical weight-dependent and metabolic weight-independent effects that are achieved through the BRAVE effects: (Bile flow alteration; Reduction of gastric size; Anatomical gut rearrangement and altered flow of nutrients; Vagal manipulation; and Enteric gut hormone modulation). These result in an improvement in insulin resistance, adipokines, cytokines and systemic inflammation. A literature analysis was performed with statistical pooling of available surgical and medical studies to determine whether the weighted mean decrease in body mass index and sleep apnoea severity (measured by the apnoea-hypopnoea index) are larger in metabolic surgical studies than in non-surgical weight loss studies (diet, exercise and medication). However, heterogeneity across available trials, poor follow-up measures and a deficiency in comparative studies between surgical and non-surgical therapy precludes definitive statements regarding the relative benefits of surgical therapy. Further research is required to quantify robustly the effects and mechanisms of sleep apnoea resolution by metabolic surgery, which may reveal novel non-surgical treatments or enhanced surgical strategies in the management of this multisystem sleep disorder.

Body mass index category as a risk factor for colorectal adenomas: a systematic review and meta-analysis.

OBJECTIVES: The association between increasing body weight and colorectal adenoma prevalence has been suggested to follow a similar pattern to excess weight and colorectal cancer, although the magnitude of this relationship has not been validated. The objective of this study was to quantify the association and dose-response relationship between body mass index (BMI) and colorectal adenoma prevalence in clinical trials. METHODS: We systematically reviewed 23 studies (168,201 participants), which compared the prevalence of colorectal adenomas according to World Health Organization BMI categories. We assessed the effects of each BMI category on colorectal adenomas where odds ratio (OR) was used as a surrogate for effect size, and applied multivariate meta-analysis as a method of sensitivity analysis to evaluate the robustness of our findings and to analyze adenoma prevalence by multiple BMI categories simultaneously to assess for a dose-response relationship. Heterogeneity and publication bias were assessed. RESULTS: Subjects with a BMI of ≥25 had a significantly higher prevalence of colorectal adenomas (OR=1.24 (95% confidence interval (CI): 1.16-1.33), P<0.01) when compared with those with BMI<25. Multivariate meta-analysis also confirmed a positive association between higher BMI categories and the prevalence of colorectal adenoma (BMI: 25-30 vs. BMI<25; OR=1.21 (95% CI: 1.07-1.38), P<0.01; BMI≥30 vs. BMI<25; OR=1.32 (95% CI: 1.18-1.48), P<0.01) and revealed a dose-response relationship. CONCLUSIONS: The positive association between obesity and colorectal adenoma prevalence demonstrates an underlying dose-response relationship according to BMI. Colorectal centers may benefit from the timely screening of obese patients for colorectal adenomas in addition to clarifying the biological role of adiposity on colorectal tumor initiation and progression.

Digital health technology-specific risks for medical malpractice liability.

Medical professionals are increasingly required to use digital technologies as part of care delivery and this may represent a risk for medical error and subsequent malpractice liability. For example, if there is a medical error, should the error be attributed to the clinician or the artificial intelligence-based clinical decision-making system? In this article, we identify and discuss digital health technology-specific risks for malpractice liability and offer practical advice for the mitigation of malpractice risk.

What is the current status of revalidation in urology?

The aim of revalidation (or maintenance of certification) is to reassure patients, the general public, employers and other healthcare professionals that an individual is fit to practice. It may lead to a reduction in near misses or adverse events. The process of revalidation entails a commitment to the provision of lifelong learning and assessment of clinical practice that ultimately ensure patient safety. Lifelong learning addresses knowledge and skills, whereas assessment of clinical practice ensures quality of care. Various learning and assessment tools are available in clinical practice; however, the tools for revalidation are not validated at specialist level. Further research is needed to develop and implement evidence-based structured programmes of revalidation that consider the holistic needs of modern urologists.

Specialist anatomy: Is the structure of teaching adequate?

BACKGROUND: A knowledge and understanding of specialist anatomy, which includes radiological, laparoscopic, endoscopic and endovascular anatomy is essential for interpretation of imaging and development of procedural skills. METHODS AND MATERIALS: Medical students, specialist trainees and specialists from the London (England, UK) area were surveyed to investigate individual experiences and recommendations for: (1) timing of the introduction of specialist anatomy teaching, and (2) pedagogical methods used. Opinions relating to radiological, laparoscopic, endoscopic and endovascular anatomy were collected. Non-parametric tests were used to investigate differences in recommendations between specialist trainees and specialists. RESULTS: Two hundred and twenty-eight (53%) individuals responded to the survey. Imaging was most commonly used to learn radiological anatomy (94.5%). Procedural observation was most commonly used to learn laparoscopic (89.0%), endoscopic (87.3%) and endovascular anatomy (66.2%). Imaging was the most recommended method to learn radiological anatomy (92.1%). Procedural observation was the most recommended method for learning laparoscopic (80.0%), endoscopic (81.2%) and endovascular anatomy (42.5%). Specialist trainees and specialists recommended introduction of specialist anatomy during undergraduate training. CONCLUSION: Although the methods for specialist anatomy learning are in practice, there is no consensus on timing and structure within the anatomy curriculum. Recommendations from trainees and specialists should be considered so that the existing curriculum can be refined to maximise learning outcomes.

Assessment of anatomical knowledge for clinical practice: perceptions of clinicians and students.

PURPOSE: In anatomy education, assessment may be done by written, practical or oral methods. These are used to varying degrees in UK medical schools with no consensus on the preferred approach. The purpose of this article is to highlight changes to methods of anatomical knowledge assessment utilised in medical schools since the early 1990s and to present recommended methods of assessment according to the level of medical training. METHODS: Medical students, trainees and specialists in the London (UK) area were surveyed to: (1) identify methods experienced in anatomy education at medical school and (2) gather recommendations. Medical student, trainee and specialist responses were compared using non-parametric tests. RESULTS: Two hundred and twenty-eight individuals responded to the survey giving a response rate of 53%. Subjects who graduated before 2005 were assessed significantly more frequently by practical (94.2 vs. 33.3%) and oral (84.5 vs. 13.1%) methods than those whose graduation year was 2005 or later. Subjects whose graduation year was 2005 or later were assessed significantly more frequently by written methods, such as EMQs than those whose graduation was before 2005 (68.7 vs. 25.2%). Practical examination was identified as the most recommended method of assessment in anatomy education by medical students (59.1%), trainees (all stages combined; 54.2%) and specialists (51.7%). CONCLUSION: Practical assessment is recommended over written and oral methods for the assessment of anatomical knowledge. A formal evaluation of the relative benefits and limitations of available assessment tools is required.

Time to Pregnancy for Women Using a Fertility Awareness Based Mobile Application to Plan a Pregnancy.

Background: Time to pregnancy (TTP) is a biomarker of fecundability and has been associated with behavioral and environmental characteristics; however, these associations have not been examined in a large population-based sample of application (app) users. Materials and Methods: This observational study followed 5,376 women with an age range of 18 to 45 years who used an app to identify their fertile window. We included women who started trying to conceive between September 30, 2017 and August 31, 2018. TTP was calculated as the number of menstrual cycles from when the user switched to "Plan" mode up to and including the cycle in which they logged a positive pregnancy test. We examined associations with several characteristics, including age, gravidity, body mass index, cycle length and cycle length variation, frequency of sexual intercourse, and temperature measuring frequency. Discrete time fecundability models were used to estimate fecundability odds ratios. Results: For the complete cohort the 6-cycle and 12-cycle cumulative pregnancy probabilities were found to be 61% (95% confidence interval [CI]: 59-62) and 74% (95% CI: 73-76), respectively. The median TTP was four cycles. The highest fecundability was associated with an age of less than 35 years, with cycle length variation <5 days and logging sexual intercourse on at least 20% of days added (the proportion of days in which intercourse was logged) (11.5% [n = 613] of entire sample). This group achieved a 6- and 12-cycle cumulative pregnancy probability of 88% (95% CI: 85-91) and 95% (95% CI: 94-97), respectively, and a TTP of 2 cycles. Conclusions: Natural Cycles was an effective method of identifying the fertile window and a noninvasive educational option for women planning a pregnancy. Women under age 35 with regular cycles showed a high pregnancy rate.

Contraceptive Effectiveness of an FDA-Cleared Birth Control App: Results from the Natural Cycles U.S. Cohort.

Background: Digital fertility awareness-based methods of birth control are an attractive alternative to hormonal or invasive birth control for modern women. They are also popular among women who may be planning a pregnancy over the coming years and wish to learn about their individual menstrual cycle. The aim of this study was to assess the effectiveness of the Natural Cycles app at preventing pregnancy for a cohort of women from the United States and to describe the key demographics of current users of the app in such a cohort. Materials and Methods: This prospective real-world cohort study included users who purchased an annual subscription to prevent pregnancy. Demographics were assessed through answers to in-app questionnaires. Birth control effectiveness estimates for the entire cohort were calculated using 1-year pearl index (PI) and 13-cycle cumulative pregnancy probability (Kaplan-Meier life table analysis). Results: The study included 5879 women who contributed an average of 10.5 months of data for a total of 5125 woman-years of exposure. The average user was 30 years old with a body mass index of 24 and reported being in a stable relationship. With typical use, the app had a 13-cycle cumulative pregnancy probability of 7.2% and a 1-year typical use PI of 6.2. When the app was used under perfect use, the PI was 2.0. Conclusions: The data presented in this study give insights into the cohort of women using this app in the United States, and provide country-specific effectiveness estimates. The contraceptive effectiveness of the app was in line with previously published figures from Natural Cycles (PI of seven for typical use and two for perfect use).

Is the structure of anatomy curriculum adequate for safe medical practice?

INTRODUCTION: Anatomy has been considered a core subject within the medical education curriculum. In the current setting of ever-changing diagnostic and treatment modalities, the opinion of both students and trainers is crucial for the design of an anatomy curriculum which fulfils the criteria required for safe medical practice. METHODS: Medical students, trainees and specialist trainee doctors and specialists from the London (England) area were surveyed to investigate the how curriculum changes have affected the relevance of anatomical knowledge to clinical practice and to identify recommendations for optimum teaching methods. The survey employed 5-point Likert scales and multiple-choice questions. Where the effect of training level was statistically significant (p < 0.05), post-hoc analysis was carried out using Mann-Whitney U tests. Significance levels were modified according to the Bonferroni method. RESULTS: Two hundred and twenty-eight individuals completed the survey giving a response rate of 53%. Medical students, trainees and specialists all agreed (mean Likert score 4.51, 4.79, 4.69 respectively) that knowledge of anatomy is important for medical practice. Most of the trainees (88.4%) and specialists (81.3%) used dissection to learn anatomy, but only 61.4% of medical students used this approach. Dissection was the most commonly recommended approach for learning anatomy across all the groups (41.7%-69.3%). CONCLUSIONS: Knowledge of anatomy is perceived to be important for safe clinical practice. Anatomy should be taught with other relevant system or clinical modules. Newer tools for anatomy teaching need further validation before incorporation into the curriculum.

What is the clinical value of mHealth for patients?

Despite growing interest from both patients and healthcare providers, there is little clinical guidance on how mobile apps should be utilized to add value to patient care. We categorize apps according to their functionality (e.g. preventative behavior change, digital self-management of a specific condition, diagnostic) and discuss evidence for effectiveness from published systematic reviews and meta-analyses and the relevance to patient care. We discuss the limitations of the current literature describing clinical outcomes from mHealth apps, what FDA clearance means now (510(k)/de novo FDA clearance) and in the future. We discuss data security and privacy as a major concern for patients when using mHealth apps. Patients are often not involved in the development of mobile health guidelines, and professionals' views regarding high-quality health apps may not reflect patients' views. We discuss efforts to develop guidelines for the development of safe and effective mHealth apps in the US and elsewhere and the role of independent app reviews sites in identifying mHealth apps for patient care. There are only a small number of clinical scenarios where published evidence suggests that mHealth apps may improve patient outcomes.

Typical use effectiveness of Natural Cycles: postmarket surveillance study investigating the impact of previous contraceptive choice on the risk of unintended pregnancy.

OBJECTIVE: To investigate the association between contraceptive effectiveness of Natural Cycles and users' previous choice of contraceptive, and to evaluate the impact of shifting from other methods to Natural Cycles on the risk of unintended pregnancy. SETTING: Natural Cycles mobile application. PARTICIPANTS: 16 331 Natural Cycles users in Sweden for the prevention of pregnancy. OUTCOME MEASURES: Risk of unintended pregnancy. STUDY DESIGN: Real world evidence was collected from Natural Cycles users regarding contraceptive use prior to using Natural Cycles and sexual activity while using Natural Cycles. We calculated the typical use 1-year Pearl Index (PI) and 13-cycle failure rate of Natural Cycles for each cohort. The PI was compared with the population PI of their stated previous methods. RESULTS: For women who had used condoms before, the PI of Natural Cycles was the lowest at 3.5±0.5. For women who had used the pill before, the PI of Natural Cycles was the highest at 8.1±0.6. The frequency of unprotected sex on fertile days partially explained some of the observed variation in PI between cohorts. 89% of users switched to Natural Cycles from methods with higher or similar reported PIs. CONCLUSION: The effectiveness of Natural Cycles is influenced by previous contraceptive choice and this should be considered when evaluating the suitability of the method for the individual. We estimate that Natural Cycles usage can reduce the overall likelihood of having an unintended pregnancy by shifting usage from less effective methods.

Real-world menstrual cycle characteristics of more than 600,000 menstrual cycles.

The use of apps that record detailed menstrual cycle data presents a new opportunity to study the menstrual cycle. The aim of this study is to describe menstrual cycle characteristics observed from a large database of cycles collected through an app and investigate associations of menstrual cycle characteristics with cycle length, age and body mass index (BMI). Menstrual cycle parameters, including menstruation, basal body temperature (BBT) and luteinising hormone (LH) tests as well as age and BMI were collected anonymously from real-world users of the Natural Cycles app. We analysed 612,613 ovulatory cycles with a mean length of 29.3 days from 124,648 users. The mean follicular phase length was 16.9 days (95% CI: 10-30) and mean luteal phase length was 12.4 days (95% CI: 7-17). Mean cycle length decreased by 0.18 days (95% CI: 0.17-0.18, R 2 = 0.99) and mean follicular phase length decreased by 0.19 days (95% CI: 0.19-0.20, R 2 = 0.99) per year of age from 25 to 45 years. Mean variation of cycle length per woman was 0.4 days or 14% higher in women with a BMI of over 35 relative to women with a BMI of 18.5-25. This analysis details variations in menstrual cycle characteristics that are not widely known yet have significant implications for health and well-being. Clinically, women who wish to plan a pregnancy need to have intercourse on their fertile days. In order to identify the fertile period it is important to track physiological parameters such as basal body temperature and not just cycle length.

The learning curve of robot-assisted laparoscopic fundoplication in children: a prospective evaluation and CUSUM analysis.

BACKGROUND: Fundoplication is a leading application of robotic surgery in children, yet the learning curve for this procedure (RF) remains ill-defined. This study aims to identify various learning curve transition points, using cumulative summation (CUSUM) analysis. METHODS: A prospective database was examined to identify RF cases undertaken during 2006-2014. Time-based surgical process outcomes were evaluated, as well as clinical outcomes. RESULTS: A total of 57 RF cases were included. Statistically significant transitions beyond the learning phase were observed at cases 42, 34 and 37 for docking, console and total operating room times, respectively. A steep early learning phase for docking time was overcome after 12 cases. There were three Clavien-Dindo grade ≥ 3 complications, with two patients requiring redo fundoplication. CONCLUSIONS: We identified numerous well-defined learning curve trends to affirm that experience confers significant temporal improvements. Our findings highlight the value of the CUSUM method for learning curve evaluation.