Discover the most talked about and latest scientific content & concepts.

Concept: Rates


Complications of surgical mesh procedures have led to legal cases against manufacturers worldwide and to national inquiries about their safety. The aim of this study was to investigate the rate of adverse events of these procedures for stress urinary incontinence in England over 8 years. This was a retrospective cohort study of first-time tension-free vaginal tape (TVT), trans-obturator tape (TOT) or suprapubic sling (SS) surgical mesh procedures between April 2007 and March 2015. Cases were identified from the Hospital Episode Statistics database. Outcomes included number and type of procedures, including those potentially confounded by concomitant procedures, and frequency, nature and timing of complications. 92,246 first-time surgical mesh procedures (56,648 TVT, 34,704 TOT, 834 SS and 60 combinations) were identified, including 68,002 unconfounded procedures. Peri-procedural and 30-day complication rates in the unconfounded cohort were 2.4 [2.3-2.5]% and 1.7 [1.6-1.8]% respectively; 5.9 [5.7-6.1]% were readmitted at least once within 5 years for further mesh intervention or symptoms of complications, the highest risk being within the first 2 years. Complication rates were higher in the potentially confounded cohort. The complication rate within 5 years of the mesh procedure was 9.8 [9.6:10.0]% This evidence can inform future decision-making on this procedure.

Concepts: Cohort study, Cohort, Clinical trial, Urinary incontinence, Retrospective, Rates, Reaction rate


The primary objective was to calculate the rate of return to sport (RTS) following anterior cruciate ligament (ACL) reconstruction in elite athletes. Secondary objectives were to estimate the time taken to RTS, calculate rates of ACL graft rupture, evaluate postsurgical athletic performance and identify determinants of RTS.

Concepts: Rates, Knee, Anterior cruciate ligament, Ligament, Anterior cruciate ligament reconstruction, Cruciate ligament, Ligaments, Rate of return


BACKGROUND:High school athletes are at risk for concussions. Although a previously published study showed an increase in concussion rates for a single school district, it remains unknown if the rate of concussions among high school athletes is increasing nationally. PURPOSE:To investigate national high school athlete concussion rates over time. STUDY DESIGN:Descriptive epidemiologic study. METHODS:The rate of concussions per 1000 athlete-exposures was calculated for academic years 2005-2006 through 2011-2012 using the High School Reporting Information Online sports injury surveillance system. RESULTS:During the 7-year period of this study, High School Reporting Information Online captured 4024 concussions with overall concussion diagnosis rates increasing significantly from 0.23 to 0.51 (P = .004). Concussion diagnosis rates increased for each of the 9 sports studied, with 5 sports having statistically significant increases over this 7-year period. CONCLUSION:The study analysis indicates that national concussion diagnosis rates for high school sports have increased significantly over time.

Concepts: Time, Epidemiology, Statistics, Rates, High school, College, Biostatistics, Concussion


Objectives. We studied state-adopted bicycle guidelines to determine whether cycle tracks (physically separated, bicycle-exclusive paths adjacent to sidewalks) were recommended, whether they were built, and their crash rate. Methods. We analyzed and compared US bicycle facility guidelines published between 1972 and 1999. We identified 19 cycle tracks in the United States and collected extensive data on cycle track design, usage, and crash history from local communities. We used bicycle counts and crash data to estimate crash rates. Results. A bicycle facility guideline written in 1972 endorsed cycle tracks but American Association of State Highway and Transportation Officials (AASHTO) guidelines (1974-1999) discouraged or did not include cycle tracks and did not cite research about crash rates on cycle tracks. For the 19 US cycle tracks we examined, the overall crash rate was 2.3 (95% confidence interval = 1.7, 3.0) per 1 million bicycle kilometers. Conclusions. AASHTO bicycle guidelines are not explicitly based on rigorous or up-to-date research. Our results show that the risk of bicycle-vehicle crashes is lower on US cycle tracks than published crashes rates on roadways. This study and previous investigations support building cycle tracks. (Am J Public Health. Published online ahead of print May 16, 2013: e1-e9. doi:10.2105/AJPH.2012.301043).

Concepts: Statistics, Estimator, United States, Million, Rates, U.S. state, Crash, American Association of State Highway and Transportation Officials


Screening colonoscopy (SC) outcome quality is best determined by the adenoma detection rate (ADR). The substantial variability in the ADRs between endoscopists may reflect different skills, experience and/or equipment.

Concepts: Rates, Determinacy, Endoscopy, American Depositary Receipt, Reaction rate


Acute mesenteric ischemia (AMI) is an emergency with a high mortality rate; survivors have high rates of intestinal failure. We performed a prospective study to assess a multidisciplinary and multimodal management approach, focused on intestinal viability.

Concepts: Mortality rate, Rates, Management, Project management, Planning, Mortality displacement, Plan, Mesenteric ischemia


BACKGROUND:: Mesh cages have commonly been used for reconstruction after corpectomy. Recently, expandable cages have become a popular alternative. Regardless of cage type, subsidence is a concern following cage placement. OBJECTIVE:: To assess whether subsidence rates differ between static and expandable cages, and identify independent risk factors for subsidence and extent of subsidence when present. METHODS:: A consecutive population of patients who underwent corpectomy between 2006 and 2009 was identified. Subsidence was assessed via x-ray at 1-month and 1-year follow-ups. In addition to cage type, demographic, medical, and cage-related covariates were recorded. Multivariate models were employed to assess independent associations with rate, odds, and extent of subsidence. RESULTS:: Of 91 patients, 44.0% had expandable and 56.0% had static cage. One-month subsidence rate was 36.3%, and 51.6% at 1 year. Expandable cages were independently associated with higher rates and odds of subsidence compared to static cages. Infection, trauma, and footplate-to-vertebral body endplate ratio of less than 0.5 were independent risk factors for subsidence. Presence of prongs on cages and posterior fusion 2 or more levels above and below corpectomy level had lower rates and odds of subsidence. Infection and cage placement in the thoracic or lumbar region had greater extent of subsidence when subsidence was present. CONCLUSION:: Expandable cages had higher rates and risk of subsidence compared to static cages. When subsidence was present, expandable cages had greater magnitudes of subsidence. Other factors including footplate-to-vertebral body endplate ratio, prongs, extent of supplemental posterior fusion, spinal region, and diagnosis also impacted subsidence.

Concepts: Cohort study, Cohort, Retrospective, Rates, Assessment, Cage, Lumbar, Multivariate


OBJECTIVE: Graduated Driver Licensing (GDL) has been implemented in Australia, Canada, New Zealand, USA and Israel. We conducted an exploratory summary of available data to estimate whether GDL effects varied with age. METHODS: We searched MEDLINE and other sources from 1991-2011. GDL evaluation studies with crashes resulting in injuries or deaths were eligible. They had to provide age-specific incidence rate ratios with CI or information for calculating these quantities. We included studies from individual states or provinces, but excluded national studies. We examined rates based on person-years, not license-years. RESULTS: Of 1397 papers, 144 were screened by abstract and 47 were reviewed. Twelve studies from 11 US states and one Canadian province were selected for meta-analysis for age 16, eight were selected for age 17, and four for age 18. Adjusted rate ratios were pooled using random effects models. The pooled adjusted rate ratios for the association of GDL presence with crash rates was 0.78 (95% CI 0.72 to 0.84) for age 16 years, 0.94 (95% CI 0.93 to 0.96) for 17 and 1.00 (95% CI 0.95 to 1.04) for 18. The difference between these three rate ratios was statistically significant: p<0.001. CONCLUSIONS: GDL policies were associated with a 22% reduction in crash rates among 16-year-old drivers, but only a 6% reduction for 17-year-old drivers. GDL showed no association with crashes among 18-year-old drivers. Because we had few studies to summarise, particularly for older adolescents, our findings should be considered exploratory.

Concepts: Epidemiology, Statistics, Mathematics, Rates, Provinces and territories of Canada, Driving, Crash, Driver's license


Rates of hydride transfer from several hydride donors to benzhydrylium ions have been measured at 20 °C and used for the determination of empirical nucleophilicity parameters N and s(N) according to the linear free energy relationship log k(20 °C) =s(N) (N+E). Comparison of the rate constants of hydride abstraction by tritylium ions with those calculated from the reactivity parameters s(N) , N, and E showed fair agreement. Therefore, it was possible to convert the large number of literature data on hydride abstraction by tritylium ions into N and s(N) parameters for the corresponding hydride donors, and construct a reactivity scale for hydride donors covering more than 20 orders of magnitude.

Concepts: Hydrogen, Rates, Hydride, Gibbs free energy, Free-energy relationship, Large numbers, Logarithmic scale, Order of magnitude


OBJECTIVE: To explore the applicability of a syndromic surveillance method to the early detection of health information technology (HIT) system failures. METHODS: A syndromic surveillance system was developed to monitor a laboratory information system at a tertiary hospital. Four indices were monitored: (1) total laboratory records being created; (2) total records with missing results; (3) average serum potassium results; and (4) total duplicated tests on a patient. The goal was to detect HIT system failures causing: data loss at the record level; data loss at the field level; erroneous data; and unintended duplication of data. Time-series models of the indices were constructed, and statistical process control charts were used to detect unexpected behaviors. The ability of the models to detect HIT system failures was evaluated using simulated failures, each lasting for 24 h, with error rates ranging from 1% to 35%. RESULTS: In detecting data loss at the record level, the model achieved a sensitivity of 0.26 when the simulated error rate was 1%, while maintaining a specificity of 0.98. Detection performance improved with increasing error rates, achieving a perfect sensitivity when the error rate was 35%. In the detection of missing results, erroneous serum potassium results and unintended repetition of tests, perfect sensitivity was attained when the error rate was as small as 5%. Decreasing the error rate to 1% resulted in a drop in sensitivity to 0.65-0.85. CONCLUSIONS: Syndromic surveillance methods can potentially be applied to monitor HIT systems, to facilitate the early detection of failures.

Concepts: Monotonic function, Type I and type II errors, Rates, Time series, Order theory, Health informatics, Baseball statistics, Control chart