Beyond Zar: the use and abuse of classification statistics for otolith chemistry

Classification method performance was evaluated using otolith chemistry of juvenile Atlantic menhaden Brevoortia tyrannus when assumptions of data normality were met and were violated. Four methods were tested [linear discriminant function analysis (LDFA), quadratic discriminant function analysis (QDFA), random forest (RF) and artificial neural networks (ANN)] using computer simulation to determine their performance when variable-group means ranged from small to large and their performance under conditions of typical skewness to double the amount of skewness typically observed. Using the kappa index, the parametric methods performed best after applying appropriate data transformation, gaining 2% better performance with LDFA performing slightly better than QDFA. RF performed as well as QDFA and showed no difference in performance between raw and transformed data while the performance of ANN was the poorest and worse with raw data. All methods performed well when group differences were large, but parametric methods outperformed machine-learning methods. When data were skewed the performance of all methods declined and worsened with greater skewness, but RF performed consistently as well or better than the other methods in the presence of skewness. The parametric methods were found to be more powerful when assumptions of normality can be met and can be used confidently when skewness and kurtosis are minimized. When these assumptions cannot be minimized, then machine-algorithm methods should also be tried.

Kidney Transplantation From a Donor With Sickle Cell Disease

In the United States, >100 000 patients are waiting for a kidney transplant. Given the paucity of organs available for transplant, expansion of eligibility criteria for deceased donation is of substantial interest. Sickle cell disease (SCD) is viewed as a contraindication to kidney donation, perhaps because SCD substantially alters renal structure and function and thus has the potential to adversely affect multiple physiological processes of the kidney. To our knowledge, transplantation from a donor with SCD has never been described in the literature. In this paper, we report the successful transplantation of two kidneys from a 37-year-old woman with SCD who died from an intracranial hemorrhage. Nearly 4 mo after transplant, both recipients are doing well and are off dialysis. The extent to which kidneys from donors with SCD can be safely transplanted with acceptable outcomes is unknown; however, this report should provide support for the careful expansion of kidneys from donors with SCD without evidence of renal dysfunction and with normal tissue architecture on preimplantation biopsies.

Interpretation of Post-operative Distal Humerus Radiographs After Internal Fixation: Prediction of Later Loss of Fixation

PURPOSE

Stable fixation of distal humerus fracture fragments is necessary for adequate healing and maintenance of reduction. The purpose of this study was to measure the reliability and accuracy of interpretation of postoperative radiographs to predict which implants will loosen or break after operative treatment of bicolumnar distal humerus fractures. We also addressed agreement among surgeons regarding which fracture fixation will loosen or break and the influence of years in independent practice, location of practice, and so forth.

METHODS

A total of 232 orthopedic residents and surgeons from around the world evaluated 24 anteroposterior and lateral radiographs of distal humerus fractures on a Web-based platform to predict which implants would loosen or break. Agreement among observers was measured using the multi-rater kappa measure.

RESULTS

The sensitivity of prediction of failure of fixation of distal humerus fracture on radiographs was 63%, specificity was 53%, positive predictive value was 36%, the negative predictive value was 78%, and accuracy was 56%. There was fair interobserver agreement (κ = 0.27) regarding predictions of failure of fixation of distal humerus fracture on radiographs. Interobserver variability did not change when assessed for the various subgroups.

CONCLUSIONS

When experienced and skilled surgeons perform fixation of type C distal humerus fracture, the immediate postoperative radiograph is not predictive of fixation failure. Reoperation based on the probability of failure might not be advisable.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic III.

Trends in the use of emergency contraception in Britain: evidence from the second and third National Surveys of Sexual Attitudes and Lifestyles

OBJECTIVE

To examine the changes in the prevalence of, and the factors associated with, the use of emergency contraception (EC) in Britain between 2000 and 2010, spanning the period of deregulation and increase in pharmacy supply.

DESIGN

Cross-sectional probability sample surveys.

SETTING AND POPULATION

British general population.

METHODS

Data were analysed from the second and third British National Surveys of Sexual Attitudes and Lifestyles (Natsal), undertaken in 1999-2001 and 2010-12. Univariate and logistic regression analyses were used to measure change in EC use amongst sexually active women aged 16-44 years not intending pregnancy.

MAIN OUTCOME MEASURES

Prevalence of EC use and factors associated with use.

RESULTS

Of the 5430 women surveyed in 1999-2001 and the 4825 women surveyed in 2010-12, 2.3 and 3.6%, respectively, reported using EC in the year prior to interview (P = 0.0019 for change over time). The prevalence of EC use increased amongst single women and those with higher educational attainment (adjusted odds ratio, aOR 1.51; 95% confidence interval, 95% CI 1.04-2.20; P = 0.0308). Increases in EC use were generally greater among women without behavioural risk factors, such as those with no history of abortion within 5 years (aOR 1.57; 95% CI 1.17-2.12; P = 0.0029), or those whose first heterosexual intercourse occurred after the age of 16 years (aOR 1.68; 95% CI 1.21-2.35; P = 0.0021). The increase in EC use was also more marked among women usually accessing contraception from retail sources than among those doing so from healthcare sources, which may reflect a use of condoms amongst EC users.

CONCLUSION

The increase in EC use among women in Britain in the first decade of the 21st century was associated with some, but not all, risk factors for unplanned pregnancy. Advice and provision may need to be targeted at those at highest risk of unplanned pregnancy.

TWEETABLE ABSTRACT

Despite pharmacy access, only a small rise in emergency contraception use has been seen in Britain over 10 years.

Reduction of the 28-Day Readmission Rate for Children with Sickle Cell Disease

BACKGROUND: Failure to provide coordinated care may lead to inefficiencies and negatively impact the quality of patient care provided. For children with sickle cell disease (SCD) at our tertiary care children’s hospital, traditionally hematology has provided ambulatory and consultative care, and general paediatrics has provided inpatient management. We fostered collaboration and used quality improvement (QI) methods to improve patient care, using hospital readmission rates as our primary QI measure.

OBJECTIVES: To reduce the 28-day readmission rate for pediatric patients with SCD from current levels (18.5%) to 14% over a 12-month period.

DESIGN/METHODS: An interdisciplinary team diagnosed and developed strategies to address gaps in care coordination. A chart audit was conducted and a process map of the hospital journey was created to identify opportunities for improvement. Based on impact and effort, the following strategies were prioritized and implemented: standardization of pain management, support for patients at highest risk of readmission, streamlining the discharge process, and increased use of hydroxyurea. Quarterly data were abstracted via Health Records from the Discharge Abstract Database (DAD). The measure of interest was the percentage of patients (0-18 years of age) with SCD and crisis readmitted with the same or related diagnosis within 28 days. Patients were identified using the ICD10 code D57.0; “crisis” includes vaso-occlusive crisis, acute chest syndrome, and splenic sequestration. Individual process measures reflecting our multiple improvement strategies were also collected.

RESULTS: From fiscal year 2013-14 to 2014-15, the total number of patient admissions for SCD decreased from 173 to 166. The readmission rate, as defined above, decreased from 18.5% to 10.8%. Other measures specifically reflecting our improvement strategies continue to be followed with ongoing process improvement.

CONCLUSION: A multi-modal strategy approach aimed at coordinating care has led to a decrease in rate of readmission for children with SCD below the established target. Ongoing monitoring will be required to ensure sustainability of this result. Further opportunities for standardization of care for this patient population include updating relevant clinical practice guidelines and order sets; implementing “pain plans” for transition home; and optimizing outpatient follow-up.

Leptospirosis acquisition following the reintroduction of wildlife

Potential risks posed to domestic animals and human beings by zoonotic diseases in reintroduced animals can reduce the acceptability of reintroductions. The authors investigated the role of endangered water voles, Arvicola amphibius, as a host for leptospirosis, a waterborne zoonosis affecting a range of mammals. Based on samples from 112 individuals from across the UK, a 6.2 per cent exposure rate was found (7 animals were microscopic agglutination test (MAT) positive for serum antibodies), with 4 of 11 sites having positive animals. No individual was actively excreting leptospires in urine (PCR urine test, 0 per cent positive). The acquisition of Leptospira species by a cohort of 'clean' captive-bred voles reintroduced to one site in the wild was then examined. By four months postrelease the maximum exposure prevalence (by either MAT or culture) was 42.9 per cent. Thirty-five per cent were actively excreting leptospires. The rapidity of leptospire acquisition and comparatively high prevalence of infectious individuals is notable, exceeding expectation based on wild voles. One possible explanation is a lack of immunocompetence in reintroduced voles. Analyses of haematological parameters from reintroduced voles suggest a link between prior condition and disease acquisition. There may be potential to select the fittest animals before release to maximise reintroduction success.

Aspects of protected mealtimes are associated with improved mealtime energy and protein intakes in hospitalized adult patients on medical and surgical wards over 2 years

BACKGROUND/OBJECTIVES

Protected mealtimes programs aim to improve inpatient intakes. Yet its efficacy has not yet been established. We aimed to determine which patient-related factors and aspects of protected mealtimes, for example, mealtime assistance and meal within reach, were associated with energy and protein intakes of adult inpatients on medical and surgical wards.

SUBJECTS/METHODS

Patient characteristics and dietary intake data were collected at main meals over 2 years. Proportions of individual foods and drinks consumed were visually estimated and converted to nutrients using averaged ready reckoner data. Mealtime factors associated with energy and protein intakes were determined using multivariate linear hierarchical regression analyses.

RESULTS

Over 2 years, mealtime nutrient intakes of 798 inpatients were calculated ((63 ± 19) years, 52% male). Average intakes at main meals were 1419 ± 614 kJ and 15 ± 7 g protein. Inpatient intakes were significantly associated with gender, age, season, stopping or refusing a meal, time until discharge and eating at dinner (B = -829-222 kJ, B = -8.8 to 2.2 g protein, P = 0.000-0.032). Protected mealtimes program implementation was not associated with inpatient intake (P=0.094-0.157). However, aspects of protected mealtimes were associated with intake. This included requiring and documenting the need for mealtime assistance, introduction of mealtime volunteers, time to eat and appropriate positioning during mealtimes (B = 177-296 kJ, B = 0.07-3.9 g protein, P=0.000-0.014, R(2) = 0.148-0.154). In those specifically requiring mealtime assistance, inpatient protein intake was associated with mealtime volunteers and appropriate positioning (B = 4.1-4.4 g protein, P = 0.013-0.026, R(2) = 0.197).

CONCLUSIONS

Aspects of protected mealtimes were associated with improved intake. Identifying these achievable aspects during planning and ensuring successful implementation of protected mealtimes may be critical for optimizing acute inpatient intake.

Agreement between student dietitians' identification of refeeding syndrome risk with refeeding guidelines, electrolytes and other dietitians: a pilot study

BACKGROUND

Limited research exists concerning how consistently and accurately student and newly-graduated dietitians are identifying refeeding syndrome risk in hospitalised patients. The present study aimed to determine the consistency of students' and newly-graduated dietitians' classification of refeeding syndrome risk, as well as agreement with the application of comparison tools such as the National Institute for Health and Care Excellence guidelines, patients' electrolytes and supplementation, and clinical dietitians previously surveyed.

METHODS

Recently-graduated and final-year Griffith University dietetics students were invited to complete an online survey. The survey questioned demographics and asked respondents to classify the level of refeeding syndrome risk (i.e. none, some, high, unsure) in 13 case studies. Electrolytes and supplementation data were sourced from electronic patient records. Chi-squared tests, t-tests and linear regression analyses were conducted.

RESULTS

Fifty-three eligible people responded [n = 53 of 112, mean (SD) age 26 (4) years, 89% female, 34% graduates]. Respondents' answers were generally more consistent and more likely to agree with comparison tools when two tools showed the same level of refeeding syndrome risk (49-98%, β = 0.626-1.0994, P < 0.001) than when they differed (11-49%). Respondents' level of agreement with refeeding identification guidelines, electrolyte levels, supplementation and dietitians previously surveyed did not differ by graduate status, degree level, clinical placement status or having read refeeding syndrome guidelines recently (P > 0.05).

CONCLUSIONS

Students' and new graduates' identification of refeeding syndrome risk improved when there was consistency between guidelines, electrolytes and dietitians' responses. More research is needed to improve the evidence behind refeeding guidelines, with the aim of enhancing the accuracy and consistency of assessment.

Adapting to the wild: the case of aquaculture-produced and released meagres Argyrosomus regius

The performance of juvenile Argyrosomus regius released off the coast of Mallorca Island (Balearic Islands, Spain) was assessed by comparing the body condition, stable isotope signature and stomach contents of aquaculture-produced A. regius that had been released, fished and returned by fishermen after spending from a few days to >1 year at liberty with A. regius reared under controlled conditions on two contrasting diets (well-fed and unfed). During the first 40 days of the experiment, the condition index (K(R)) of the returned A. regius and the unfed A. regius followed the same decreasing trend. Thereafter, the K(R) values of the returned A. regius were significantly higher than those of the unfed A. regius but never reached the values of well-fed A. regius. The δ¹³C signal of the returned A. regius clearly increased (in comparison with the well-fed A. regius) after they had spent a few months at liberty. The temporal pattern depicted by the stable isotopes and the most likely prey composition inferred from this pattern strongly suggest a shift in diet. The stomach contents of the returned A. regius that had spent <100 days at liberty consisted almost exclusively of decapods. The diet of the few returned A. regius that had spent >100 days at liberty consisted entirely of fishes. Wild A. regius from the remaining fishery on the Spanish coast exhibited the same ontogenetic diet shift from invertebrates to fishes, but at a smaller size threshold. Overall, the results demonstrated that culture-reared A. regius experience adverse conditions during the first days after release into the wild but that at least some A. regius are able to adapt to the natural environment after a few months at liberty.

Measurement of transmission efficiency for 400 MeV proton beam through collimator at Fermilab MuCool Test Area using Chromox-6 scintillation screen

The MuCool Test Area (MTA) at Fermilab is a facility to develop the technology required for ionization cooling for a future Muon Collider and∕or Neutrino Factory. As part of this research program, feasibility studies of various types of RF cavities in a high magnetic field environment are in progress. As a unique approach, we have tested a RF cavity filled with a high pressure hydrogen gas with a 400 MeV proton beam in an external magnetic field (B = 3 T). Quantitative information about the number of protons passing through this cavity is an essential requirement of the beam test. The MTA is a flammable gas (hydrogen) hazard zone. Due to safety reasons, no active (energized) beam diagnostic instrument can be used. Moreover, when the magnetic field is on, current transformers (toroids) used for beam intensity measurements do not work due to the saturation of the ferrite material of the transformer. Based on these requirements, we have developed a passive beam diagnostic instrumentation using a combination of a Chromox-6 scintillation screen and CCD camera. This paper describes details of the beam profile and position obtained from the CCD image with B = 0 T and B = 3 T, and for high and low intensity proton beams. A comparison is made with beam size obtained from multi-wires detector. Beam transmission efficiency through a collimator with a 4 mm diameter hole is measured by the toroids and CCD image of the scintillation screen. Results show that the transmission efficiency estimated from the CCD image is consistent with the toroid measurement, which enables us to monitor the beam transmission efficiency even in a high magnetic field environment.