The extent of intestinal failure-associated liver disease in patients referred for intestinal rehabilitation is associated with increased mortality: an analysis of the Pediatric Intestinal Failure Consortium database

BACKGROUND

The advent of regional multidisciplinary intestinal rehabilitation programs has been associated with improved survival in pediatric intestinal failure. Yet, the optimal timing of referral for intestinal rehabilitation remains unknown. We hypothesized that the degree of intestinal failure-associated liver disease (IFALD) at initiation of intestinal rehabilitation would be associated with overall outcome.

METHODS

The multicenter, retrospective Pediatric Intestinal Failure Consortium (PIFCon) database was used to identify all subjects with baseline bilirubin data. Conjugated bilirubin (CBili) was used as a marker for IFALD, and we stratified baseline bilirubin values as CBili<2 mg/dL, CBili 2-4 mg/dL, and CBili>4 mg/dL. The association between baseline CBili and mortality was examined using Cox proportional hazards regression.

RESULTS

Of 272 subjects in the database, 191 (70%) children had baseline bilirubin data collected. 38% and 28% of patients had CBili >4 mg/dL and CBili <2 mg/dL, respectively, at baseline. All-cause mortality was 23%. On univariate analysis, mortality was associated with CBili 2-4 mg/dL, CBili >4 mg/dL, prematurity, race, and small bowel atresia. On regression analysis controlling for age, prematurity, and diagnosis, the risk of mortality was increased by 3-fold for baseline CBili 2-4 mg/dL (HR 3.25 [1.07-9.92], p=0.04) and 4-fold for baseline CBili >4 mg/dL (HR 4.24 [1.51-11.92], p=0.006). On secondary analysis, CBili >4 mg/dL at baseline was associated with a lower chance of attaining enteral autonomy.

CONCLUSION

In children with intestinal failure treated at intestinal rehabilitation programs, more advanced IFALD at referral is associated with increased mortality and decreased prospect of attaining enteral autonomy. Early referral of children with intestinal failure to intestinal rehabilitation programs should be strongly encouraged.

LEVEL OF EVIDENCE

Treatment Study, Level III.

Flares of Disease in Children with Clinically Inactive Juvenile Idiopathic Arthritis Were Not Correlated with Ultrasound Findings

OBJECTIVE

The validity of our current definitions for clinically inactive disease (CID) in juvenile idiopathic arthritis (JIA) based on physical examination is challenged by the development of advanced musculoskeletal imaging tools. We aimed to prospectively determine the prevalence of abnormal ultrasound (US) findings in children with CID in JIA and their clinical significance.

METHODS

Children aged ≥ 4 years with CID and a history of arthritis from a single tertiary center were approached over 1 year. Standard US of knees, tibiotalar joints, subtalar joints, and wrists were performed at baseline and at a followup visit. US images were scored by 2 pediatric musculoskeletal radiologists.

RESULTS

Forty children with CID were enrolled and followed clinically. The median duration of inactive disease was 1 year. The most common International League of Associations for Rheumatology JIA categories were extended oligoarticular JIA (30%) and rheumatoid factor-negative polyarthritis (38%). At baseline, among a total of 289 joints scanned, 24 joints (8%) had at least 1 abnormal finding in 18 (45%) of 40 subjects. When evaluated at the individual joint level against flares identified during followup exams, these baseline US findings had a sensitivity of 15% and a positive predictive value of 12%. The predictive performance of the second US was even less.

CONCLUSION

Our study demonstrates that nearly half of children with CID had abnormal US findings in 1 of 8 commonly affected joints. These findings did not correlate with subsequent clinical flares in up to 2 years of followup.

Association of ambient pollution with inhaler use among patients with COPD: a panel study

BACKGROUND

Studies have linked ambient air pollution to chronic obstructive pulmonary disease (COPD) healthcare encounters. However, the association between air quality and rescue medication use is unknown.

OBJECTIVES

We assessed the role of air pollution exposure for increased short-acting beta-2-agonist (SABA) use in patients with COPD through use of remote monitoring technology.

METHODS

Participants received a portable electronic inhaler sensor to record the date, time and location for SABA use over a 3-month period. Ambient air pollution data and meteorological data were collected from a centrally located federal monitoring station. Mixed-effects Poisson regression was used to examine the association of daily inhaler use with pollutant levels. Four criteria pollutants (PM_2.5, PM₁₀, O₃ and NO₂), two particulate matter species (elemental carbon (EC) and organic carbon), estimated coarse fraction of PM₁₀ (PM_10-2.5) and four multipollutant air quality measures were each examined separately, adjusting for covariates that passed a false discovery rate (FDR) screening.

RESULTS

We enrolled 35 patients with COPD (94.3% male and mean age: 66.5±8.5) with a mean forced expiratory volume in 1 s (FEV₁) % predicted of 44.9+17.2. Participants had a median of 92 observation days (range 52-109). Participants' average SABA inhaler use ranged from 0.4 to 13.1 puffs/day (median 2.8). Controlling for supplemental oxygen use, long-acting anticholinergic use, modified Medical Research Council Dyspnoea Scale and influenza season, an IQR increase in PM₁₀ concentration (8.0 µg/m³) was associated with a 6.6% increase in daily puffs (95% CI 3.5% to 9.9%; FDR <0.001). NO₂ and EC concentration were also significantly associated with inhaler use (3.9% and 2.9% per IQR increase, respectively).

CONCLUSIONS

Exposure to increased ambient air pollution were associated with a significant increase in SABA use for patients with COPD residing in a low-pollution area.

Upper Airway Computed Tomography Measures and Receipt of Tracheotomy in Infants With Robin Sequence

IMPORTANCE

Airway management in infants with Robin sequence is challenging. Objective upper airway measures associated with severe airway compromise requiring tracheotomy are needed to guide decision making.

OBJECTIVES

To define objective upper airway measures in infants with Robin sequence from craniofacial computed tomography (CT) and to identify those measures in Robin sequence associated with tracheotomy.

DESIGN, SETTING, AND PARTICIPANTS

A cohort study (2003 to 2014, over 1-year follow-up) of 37 infants with Robin sequence evaluated for surgical management and 37 selected age- and sex-matched controls without a craniofacial condition conducted in a pediatric institution's craniofacial center.

MAIN OUTCOMES AND MEASURES

Define and compare CT-generated upper airway measures in these groups: infants with Robin sequence vs controls, and infants with Robin sequence with vs without tracheotomy. A negative difference signifies lower values for the Robin sequence and tracheotomy groups. Clinical data collected included age and height at time of CT scan, sex, tracheotomy presence, associated syndrome, and laboratory indicators of hypoventilation and hypoxemia. To evaluate interrater reliability, 2 raters performed each measurement in the Robin sequence group.

RESULTS

In 74 infants, 17 of 28 measures were different between infants with Robin sequence and those in the control group. Tracheotomy was performed in 14 of 37 (38%) infants with Robin sequence. Infants with tracheotomy more commonly had associated syndromes (12 of 14 [86%] vs 11 of 23 [48%]) and a history of hypoventilation and hypoxemia (13 of 14 [93%] vs 15 of 23 [65%]). Five of the 11 measures associated with tracheotomy were reliable and simpler to measure with the following mean differences (95% CIs) between groups: tongue length, 0.87 (0.26 to 1.48); tongue position relative to palate, 0.83 (0.22 to 1.45); mandibular total length, -0.8 (-1.42 to -0.19); gonial angle, 0.71 (0.08 to 1.34); and inferior pogonial angle, 0.66 (0.02 to 1.29). Using a receiver operating characteristic analysis, a composite score of these 5 measures for predicting tracheotomy risk yielded an area under the curve of 0.83 and achieved 86% sensitivity and 74% specificity.

CONCLUSIONS AND RELEVANCE

Computed tomography measures quantifying tongue position and mandibular configuration can identify infants with Robin sequence, and importantly, differentiate those who have severe upper airway compromise requiring tracheotomy. Following validation, these measures can be used for objective upper airway assessment and for expediting clinical decision-making in these challenging cases for which no such tools currently exist.

Precision, Sensitivity and Patient Preference of Non-Invasive Thermometers in a Pediatric Surgical Acute Care Setting

PURPOSE

The purpose of the project was to compare the temporal artery thermometer (TAT) to the digital probe thermometer readings at axillary or oral sites, to determine the relative precision and sensitivity of the three methods of thermometry, to compare their readings to core temperature when feasible, and to survey patient and family thermometer preferences.

DESIGN & METHODS

A randomized crossover design in a 70-bed surgical unit over eight months. Two sets of temperature measurements were obtained for each patient: TAT, axillary, oral (depending on patient ability) and a bladder temperature representing core body temperature (when available). Each method was used twice on each patient, to examine within-method precision. Following measurement, patients or caregivers provided their thermometer preference. For younger/nonverbal patients, a professional observer recorded a disruption score. N=298 patients were enrolled RESULTS: TAT was more precise than oral and axillary thermometers (p<0.001 vs. axillary, p=0.001 vs. oral). TAT measurements were higher on average than axillary and oral, by 0.7°C and 0.6°C respectively (p<0.001). TAT's disruption score for younger patients was 0.6 points lower on average than axillary (p<0.001). 84% of patients and families who indicated a clear thermometry preference chose TAT. Only 3 patients had bladder-temperature devices, and therefore accuracy could not be analyzed.

CONCLUSIONS

TAT is more precise, more fever sensitive, less disruptive to younger children, and more preferred by patients and families.

PRACTICE IMPLICATIONS

TAT is an acceptable temperature measure that could be substituted for oral or axillary temperature in acute care pediatric settings.

Characterization of Inpatient Cystic Fibrosis Pulmonary Exacerbations

BACKGROUND AND OBJECTIVES

Pulmonary exacerbations lead to significant morbidity and mortality in patients with cystic fibrosis (CF). National consensus guidelines exist, but few studies report current practice in the treatment and monitoring of pulmonary exacerbations. The goal of this study was to characterize consistency and variability in the inpatient management of CF-related pulmonary exacerbations. We focused on the use of guideline-recommended maintenance therapies, antibiotic selection and treatment regimens, use of systemic corticosteroids, and frequency of lung function testing. We hypothesized that significant variability in these treatment practices exists nationally.

METHODS

This trial was a retrospective cross-sectional study. It included patients with CF aged ≤18 years hospitalized for pulmonary exacerbations between July 1, 2010, and June 30, 2015, at hospitals within the US Pediatric Health Information System database that are also Cystic Fibrosis Foundation-accredited care centers. One exacerbation per patient was randomly selected over the 5-year study period.

RESULTS

From 38 hospitals, 4827 individual pulmonary exacerbations were examined. Median length of stay was 10.0 days (interquartile range, 6-14.0 days). Significant variation was seen among centers in the use of hypertonic saline (11%-100%), azithromycin (5%-83%), and systemic corticosteroids (3%-61%) and in the frequency of lung function testing. Four different admission antibiotic regimens were used >10% of the time, and the most commonly used admission antibiotic regimen comprised 2 intravenous antibiotics with no additional oral or inhaled antibiotics (29%).

CONCLUSIONS

Significant variation exists in the treatment and monitoring of pulmonary exacerbations across Pediatric Health Information System-participating, Cystic Fibrosis Foundation-accredited care centers. Results from this study can inform future research working toward standardized inpatient pulmonary exacerbation management to improve CF care for children and adolescents.

Perceptions on the Impact of a Just-in-Time Room on Trainees and Supervising Physicians in a Pediatric Emergency Department

BACKGROUND

Just-in-time (JIT) training refers to education occurring immediately prior to clinical encounters. An in situ JIT room in a pediatric emergency department (ED) was created for procedural education.

OBJECTIVE

We examined trainee self-reported JIT room use, its impact on trainee self-perception of procedural competence/confidence, and the effect its usage has on the need for intervention by supervising physicians during procedures.

METHODS

Cross-sectional survey study of a convenience sample of residents rotating through the ED and supervising pediatric emergency medicine physicians. Outcomes included JIT room use, trainee procedural confidence, and frequency of supervisor intervention during procedures.

RESULTS

Thirty-one of 32 supervising physicians (97%) and 122 of 186 residents (66%) completed the survey, with 71% of trainees reporting improved confidence, and 68% reporting improved procedural skills (P < .05, +1.4-point average skills improvement on a 5-point Likert scale). Trainees perceived no difference among supervising physicians intervening in procedures with or without JIT room use (P = .30, paired difference -0.0 points). Nearly all supervisors reported improved trainee procedural confidence, and 77% reported improved trainee procedural skills after JIT room use (P < .05, paired difference +1.8 points); 58% of supervisors stated they intervene in procedures without trainee JIT room use, compared with 42% with JIT room use (P < .05, paired difference -0.4 points).

CONCLUSIONS

Use of the JIT room led to improved trainee confidence and supervisor reports of less procedural intervention. Although it carries financial and time costs, an in situ JIT room may be important for convenient JIT training.

Extended- Versus Narrower-Spectrum Antibiotics for Appendicitis

BACKGROUND AND OBJECTIVES

Appendicitis guidelines recommend either narrower- or extended-spectrum antibiotics for treatment of complicated appendicitis. The goal of this study was to compare the effectiveness of extended-spectrum versus narrower-spectrum antibiotics for children with appendicitis.

METHODS

We performed a retrospective cohort study of children aged 3 to 18 years discharged between 2011 and 2013 from 23 freestanding children's hospitals with an appendicitis diagnosis and appendectomy performed. Subjects were classified as having complicated appendicitis if they had a postoperative length of stay ≥3 days, a central venous catheter placed, major or severe illness classification, or ICU admission. The exposure of interest was receipt of systemic extended-spectrum antibiotics (piperacillin ± tazobactam, ticarcillin ± clavulanate, ceftazidime, cefepime, or a carbapenem) on the day of appendectomy or the day after. The primary outcome was 30-day readmission for wound infection or repeat abdominal surgery. Multivariable logistic regression, propensity score weighting, and subgroup analyses were used to control for confounding by indication.

RESULTS

Of 24 984 patients, 17 654 (70.7%) had uncomplicated appendicitis and 7330 (29.3%) had complicated appendicitis. Overall, 664 (2.7%) patients experienced the primary outcome, 1.1% among uncomplicated cases and 6.4% among complicated cases (P < .001). Extended-spectrum antibiotic exposure was significantly associated with the primary outcome in complicated (adjusted odds ratio, 1.43 [95% confidence interval, 1.06 to 1.93]), but not uncomplicated, (adjusted odds ratio, 1.32 [95% confidence interval, 0.88 to 1.98]) appendicitis. These odds ratios remained consistent across additional analyses.

CONCLUSIONS

Extended-spectrum antibiotics seem to offer no advantage over narrower-spectrum agents for children with surgically managed acute uncomplicated or complicated appendicitis.

Emergency and Hospital Care for Food-Related Anaphylaxis in Children

OBJECTIVES

Among patients with food-related anaphylaxis, to describe trends in emergency and hospital care and determine the revisit rate.

METHODS

This retrospective cohort study included children 6 months to 18 years of age with food-related anaphylaxis from 37 children's hospitals between 2007 and 2012. Summary statistics and trends for patient characteristics were evaluated. Multivariable regression was used to identify predictors for hospital admission. Revisit rates to either the emergency department (ED) and/or inpatient unit were calculated.

RESULTS

7303 patients were evaluated in the ED; 3652 (50%) were admitted to the hospital. Hospital admission rates varied widely (range, 20%-98%). Food-related anaphylaxis increased from 41 per 100 000 ED visits to 72 per 100 000 while hospital admission rates did not change. Males (odds ratio [OR], 1.2 [95% confidence interval (CI), 1.0-1.4]), patients < 1 year old (OR, 1.8 [95% CI, 1.3-2.5]), those with anaphylaxis to either peanut (OR, 1.2 [95% CI, 1.0-1.5]) or tree nut (OR, 1.7 [95% CI, 1.3-2.1]), and patients with asthma (OR, 7.4 [95% CI, 5.8-9.3]) or a chronic complex condition (OR, 5.2 [95% CI, 3.0-9.0]) were more likely to be admitted to the hospital. The 3-day revisit rate was 3% for patients discharged from the ED and 0.6% for those admitted on the index visit.

CONCLUSIONS

The incidence of food-related anaphylaxis in pediatric EDs is increasing, but rates of hospital admission are stable. Hospital admission is common but widely variable. Further research is needed to identify optimal management practices for this potentially life-threatening problem.

Identifying Antimicrobial Stewardship Targets for Pediatric Surgical Patients

BACKGROUND

More than 80% of surgical inpatients at US children's hospitals receive antibiotics, accounting for >40% of all inpatient pediatric antibiotic use. We aimed to examine the collective pool of all systemic antibiotics prescribed to children hospitalized for surgical conditions and identify common surgical conditions with highly variable and potentially unnecessary antibiotic use, because these conditions may represent antimicrobial stewardship priorities.

METHODS

We conducted a retrospective cross-sectional study of surgical inpatients discharged in 2012 at 37 freestanding children's hospitals. We captured all systemic antibiotic use as days of therapy (DOT), and we reported surgical conditions by frequency and contribution to overall antibiotic use. We used multivariable logistic and Poisson regression with marginal standardization to estimate (1) the standardized proportion and (2) DOT of condition-specific targeted antibiotic use among top surgical condition patients.

RESULTS

Among 151 345 surgical inpatients, 82.9% received antimicrobials for a median 2 DOT per subject (interquartile range, 1-5; range, 1-958). The most commonly received antibiotics were cefazolin (16.7% of all DOT), vancomycin (12.5%), and piperacillin/tazobactam (6.9%). The top 10 conditions contributing most to antibiotic use accounted for 51.3% of all antibiotic use. Among these, adjusted use of postoperative and perioperative vancomycin varied across hospitals among craniotomy and cardiothoracic surgery subjects (all P < .001); adjusted use of broad-spectrum antipseudomonal agents varied across hospitals among gastrointestinal surgery subjects (all P < .001).

CONCLUSIONS

Use of (1) vancomycin for pediatric cardiothoracic and neurosurgical patients and (2) broad-spectrum antipseudomonal agents for gastrointestinal surgery patients represent potentially high-yield targets for stewardship efforts to reduce unnecessary antimicrobial use.

Neighborhood-Scale Spatial Models of Diesel Exhaust Concentration Profile Using 1-Nitropyrene and Other Nitroarenes

With emerging evidence that diesel exhaust exposure poses distinct risks to human health, the need for fine-scale models of diesel exhaust pollutants is growing. We modeled the spatial distribution of several nitrated polycyclic aromatic hydrocarbons (NPAHs) to identify fine-scale gradients in diesel exhaust pollution in two Seattle, WA neighborhoods. Our modeling approach fused land-use regression, meteorological dispersion modeling, and pollutant monitoring from both fixed and mobile platforms. We applied these modeling techniques to concentrations of 1-nitropyrene (1-NP), a highly specific diesel exhaust marker, at the neighborhood scale. We developed models of two additional nitroarenes present in secondary organic aerosol: 2-nitropyrene and 2-nitrofluoranthene. Summer predictors of 1-NP, including distance to railroad, truck emissions, and mobile black carbon measurements, showed a greater specificity to diesel sources than predictors of other NPAHs. Winter sampling results did not yield stable models, likely due to regional mixing of pollutants in turbulent weather conditions. The model of summer 1-NP had an R(2) of 0.87 and cross-validated R(2) of 0.73. The synthesis of high-density sampling and hybrid modeling was successful in predicting diesel exhaust pollution at a very fine scale and identifying clear gradients in NPAH concentrations within urban neighborhoods.

Variation in the use of procedural sedation for incision and drainage of skin and soft tissue infection in pediatric emergency departments

OBJECTIVES

Little is known about procedural sedation use for anxiety and pain associated with skin and soft tissue infections (SSTIs) requiring incision and drainage (I&D). Our objectives were therefore (1) to characterize the use of procedural sedation use for SSTI I&D procedures in pediatric emergency departments (EDs), (2) to compare the frequency of procedural sedation for I&D across hospitals, and (3) to determine factors associated with use of procedural sedation for I&D.

METHODS

We performed a retrospective cohort study of pediatric EDs contributing to the Pediatric Health Information Systems database in 2010. Cases were identified by primary International Classification of Diseases, 9th revision, Clinical Modification procedure codes for I&D. We used descriptive statistics to describe procedural sedation use across hospitals and logistic generalized linear mixed models to identify factors associated with use of procedural sedation.

RESULTS

There were 6322 I&D procedures, and procedural sedation was used in 24% of cases. Hospital-level use of procedural sedation varied widely, with a range of 2% to 94% (median 17%). Procedural sedation use was positively associated with sensitive body site, female gender, and employer-based insurance, and negatively associated with African American race and increasing age. Estimates of hospital-level use of procedural sedation for a referent case eliminating demographic differences exhibit similar variability with a range of 5% to 97% (median 34%).

CONCLUSIONS

Use of procedural sedation for SSTI I&D varies widely across pediatric EDs, and the majority of variation is independent of demographic differences. Additional work is needed to understand decision-making and to standardize delivery of procedural sedation in children requiring I&D.

Significance of C4d Immunostaining in Placental Chronic Intervillositis

Deposition of the complement split product C4d is a phenomenon studied extensively as a marker for complement activation in antibody-mediated transplant rejection. C4d also is observed in placental disease processes including spontaneous abortion, infarct, and villitis of unknown origins. Massive chronic intervillositis is a rare placental abnormality associated with increased risk of growth restriction, fetal death, and recurrent fetal loss. In this study, we evaluated C4d immunostaining in placentas with accumulation of intervillous monocytes with and without villitis. Archived placentas from Kosair Children's Hospital (Louisville, KY) and Seattle Children's Hospital (Seattle, WA) were selected and divided into 4 groups, 16 cases of intervillositis with complicated pregnancy, 15 cases of uncomplicated intervillositis, 20 cases of complicated villitis, and 13 cases of uncomplicated villitis, all with varying degrees of monocytic cells in the intervillous space. Representative specimen blocks were immunohistochemically stained for C4d. The percentage of positive staining of the microvillous surface of the syncytiotrophoblast was scored by five pathologists, and the following consensus score was determined: 0  =  0% to 5%; 1  =  5% to 25%; 2  =  25% to 75%; and 3 ≥ 75%. C4d immunostain localized to the microvillous border of syncytiotrophoblast in many of the placentas. C4d staining was more strongly associated with intervillositis than with villitis (odds ratio: 6.3; confidence interval: 2.1-18.7; P  =  0.001).

A unified spatiotemporal modeling approach for predicting concentrations of multiple air pollutants in the multi-ethnic study of atherosclerosis and air pollution

BACKGROUND

Cohort studies of the relationship between air pollution exposure and chronic health effects require predictions of exposure over long periods of time.

OBJECTIVES

We developed a unified modeling approach for predicting fine particulate matter, nitrogen dioxide, oxides of nitrogen, and black carbon (as measured by light absorption coefficient) in six U.S. metropolitan regions from 1999 through early 2012 as part of the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air).

METHODS

We obtained monitoring data from regulatory networks and supplemented those data with study-specific measurements collected from MESA Air community locations and participants' homes. In each region, we applied a spatiotemporal model that included a long-term spatial mean, time trends with spatially varying coefficients, and a spatiotemporal residual. The mean structure was derived from a large set of geographic covariates that was reduced using partial least-squares regression. We estimated time trends from observed time series and used spatial smoothing methods to borrow strength between observations.

RESULTS

Prediction accuracy was high for most models, with cross-validation R2 (R2CV) > 0.80 at regulatory and fixed sites for most regions and pollutants. At home sites, overall R2CV ranged from 0.45 to 0.92, and temporally adjusted R2CV ranged from 0.23 to 0.92.

CONCLUSIONS

This novel spatiotemporal modeling approach provides accurate fine-scale predictions in multiple regions for four pollutants. We have generated participant-specific predictions for MESA Air to investigate health effects of long-term air pollution exposures. These successes highlight modeling advances that can be adopted more widely in modern cohort studies.

Contemporary trends in the use of primary repair for gastroschisis in surgical infants

BACKGROUND

Gastroschisis is a newborn anomaly requiring emergent surgical intervention. We review our experience with gastroschisis to examine trends in contemporary surgical management.

METHODS

Infants who underwent initial surgical management of gastroschisis from 1996 to 2014 at a pediatric hospital were reviewed. Closure techniques included primary fascial repair using suture or sutureless umbilical closure, and staged repair using sutured or spring-loaded silo (SLS). Data were separated into 3 clinical eras: pre-SLS (1996 to 2004), SLS (2005 to 2008), and umbilical closure (2009 to 2014).

RESULTS

In the pre-SLS era, 60% (34/57) of infants with gastroschisis underwent primary repair. With the advent of SLS, there was a decrease in primary repair (15%, 10/68, P < .0001). Following introduction of sutureless umbilical closure, 61% (47/77) of infants have undergone primary repair. On multivariate regression, primary repair was associated with shorter intensive care unit stays (P < .001) and time to initiate enteral nutrition (P < .01).

CONCLUSIONS

Following introduction of a less invasive technique for gastroschisis repair, most infants with gastroschisis were able to be repaired primarily. Primary repair should be considered in all babies with gastroschisis and favorable anatomy.

Air pollution and percent emphysema identified by computed tomography in the Multi-Ethnic study of Atherosclerosis

BACKGROUND

Air pollution is linked to low lung function and to respiratory events, yet little is known of associations with lung structure.

OBJECTIVES

We examined associations of particulate matter (PM2.5, PM10) and nitrogen oxides (NOx) with percent emphysema-like lung on computed tomography (CT).

METHODS

The Multi-Ethnic Study of Atherosclerosis (MESA) recruited participants (45-84 years of age) in six U.S. states. Percent emphysema was defined as lung regions < -910 Hounsfield Units on cardiac CT scans acquired following a highly standardized protocol. Spirometry was also conducted on a subset. Individual-level 1- and 20-year average air pollution exposures were estimated using spatiotemporal models that included cohort-specific measurements. Multivariable regression was conducted to adjust for traditional risk factors and study location.

RESULTS

Among 6,515 participants, we found evidence of an association between percent emphysema and long-term pollution concentrations in an analysis leveraging between-city exposure contrasts. Higher concentrations of PM2.5 (5 μg/m3) and NOx (25 ppb) over the previous year were associated with 0.6 (95% CI: 0.1, 1.2%) and 0.5 (95% CI: 0.1, 0.9%) higher average percent emphysema, respectively. However, after adjustment for study site the associations were -0.6% (95% CI: -1.5, 0.3%) for PM2.5 and -0.5% (95% CI: -1.1, 0.02%) for NOx. Lower lung function measures (FEV1 and FVC) were associated with higher PM2.5 and NOx levels in 3,791 participants before and after adjustment for study site, though most associations were not statistically significant.

CONCLUSIONS

Associations between ambient air pollution and percentage of emphysema-like lung were inconclusive in this cross-sectional study, thus longitudinal analyses may better clarify these associations with percent emphysema.

Intestinal Neuronal Dysplasia-Like Submucosal Ganglion Cell Hyperplasia at the Proximal Margins of Hirschsprung Disease Resections

Intestinal neuronal dysplasia type B (IND) denotes an increased proportion of hyperplastic submucosal ganglia, as resolved histochemically in 15-μm-thick frozen sections. IND has been reported proximal to the aganglionic segment in patients with Hirschsprung disease (HSCR) and is putatively associated with a higher rate of postsurgical dysmotility. We developed and validated histological criteria to diagnose IND-like submucosal ganglion cell hyperplasia (IND-SH) in paraffin sections and used the approach to study the incidence and clinical and/or genetic associations of IND-SH at the proximal margins of HSCR pull-through resection specimens. Full-circumference paraffin sections from the proximal margins of 64 HSCR colonic pull-through specimens and 24 autopsy controls were immunostained for neuron-specific Hu antigen, and nucleated ganglion cells in each submucosal ganglion were counted. In controls, an age-related decline in the relative abundance of "giant" ganglia (≥7 nucleated Hu-positive [Hu+] ganglion cells) was observed. A conservative diagnostic threshold for IND-SH (control mean ± 3× standard deviation) was derived from 15 controls less than 25 weeks of age. No control exceeded this threshold, whereas in the same age range, IND-SH was observed at the proximal margins in 15% (7 of 46) of HSCR resections, up to 15 cm proximal to the aganglionic segment. No significant correlation was observed between IND-SH and length of or distance from the aganglionic segment, sex, trisomy 21, RET or SEMA3C/D polymorphisms, or clinical outcome, but analysis of more patients, with better long-term follow-up will be required to clarify the significance of this histological phenotype.

A Flexible Spatio-Temporal Model for Air Pollution with Spatial and Spatio-Temporal Covariates

The development of models that provide accurate spatio-temporal predictions of ambient air pollution at small spatial scales is of great importance for the assessment of potential health effects of air pollution. Here we present a spatio-temporal framework that predicts ambient air pollution by combining data from several different monitoring networks and deterministic air pollution model(s) with geographic information system (GIS) covariates. The model presented in this paper has been implemented in an R package, SpatioTemporal, available on CRAN. The model is used by the EPA funded Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air) to produce estimates of ambient air pollution; MESA Air uses the estimates to investigate the relationship between chronic exposure to air pollution and cardiovascular disease. In this paper we use the model to predict long-term average concentrations of NO_x in the Los Angeles area during a ten year period. Predictions are based on measurements from the EPA Air Quality System, MESA Air specific monitoring, and output from a source dispersion model for traffic related air pollution (Caline3QHCR). Accuracy in predicting long-term average concentrations is evaluated using an elaborate cross-validation setup that accounts for a sparse spatio-temporal sampling pattern in the data, and adjusts for temporal effects. The predictive ability of the model is good with cross-validated R² of approximately 0.7 at subject sites. Replacing four geographic covariate indicators of traffic density with the Caline3QHCR dispersion model output resulted in very similar prediction accuracy from a more parsimonious and more interpretable model. Adding traffic-related geographic covariates to the model that included Caline3QHCR did not further improve the prediction accuracy.

Pediatric nephrologists' beliefs regarding randomized controlled trials

BACKGROUND

Pediatrics and pediatric nephrology lag behind adult medicine in producing randomized controlled trials (RCTs). Physician attitudes have been shown to play a significant role in RCT enrollment.

METHODS

We surveyed members of the American Society of Pediatric Nephrology regarding beliefs about RCTs and factors influencing decisions to recommend RCT enrollment. Regression analyses were used to identify the effects of variables on an aggregate score summarizing attitudes toward RCTs.

RESULTS

One hundred thirty replies were received. Sixty-six percent had enrolled patients in RCTs. Respondents in practice for more than 15 years were more likely to have recruited a patient to an RCT than those in practice for less than 5 years. Respondents were more willing to recommend RCT enrollment if the study was multicenter, patients were sicker or had a poorer prognosis, or if the parent or participant received a financial incentive versus the provider. In multiple regression analysis, history of enrolling patients in an RCT was the only significant predictor of higher aggregate RCT-friendly attitude.

CONCLUSIONS

Many pediatric nephrologists have never enrolled a patient in an RCT, particularly those in practice for less than 5 years. Respondents who have not enrolled patients in RCTs have a less RCT-friendly attitude. Provision of improved training and resources might increase participation of junior providers in RCTs.

Pediatric nephrologists' beliefs regarding randomized controlled trials

BACKGROUND

Pediatrics and pediatric nephrology lag behind adult medicine in producing randomized controlled trials (RCTs). Physician attitudes have been shown to play a significant role in RCT enrollment.

METHODS

We surveyed members of the American Society of Pediatric Nephrology regarding beliefs about RCTs and factors influencing decisions to recommend RCT enrollment. Regression analyses were used to identify the effects of variables on an aggregate score summarizing attitudes toward RCTs.

RESULTS

One hundred thirty replies were received. Sixty-six percent had enrolled patients in RCTs. Respondents in practice for more than 15 years were more likely to have recruited a patient to an RCT than those in practice for less than 5 years. Respondents were more willing to recommend RCT enrollment if the study was multicenter, patients were sicker or had a poorer prognosis, or if the parent or participant received a financial incentive versus the provider. In multiple regression analysis, history of enrolling patients in an RCT was the only significant predictor of higher aggregate RCT-friendly attitude.

CONCLUSIONS

Many pediatric nephrologists have never enrolled a patient in an RCT, particularly those in practice for less than 5 years. Respondents who have not enrolled patients in RCTs have a less RCT-friendly attitude. Provision of improved training and resources might increase participation of junior providers in RCTs.

Small-sample behavior of novel phase I cancer trial designs

Background

Novel dose-finding designs for Phase I cancer clinical trials, using estimation to assign the best estimated Maximum Tolerated Dose (MTD) at each point in the experiment, most prominently via Bayesian techniques, have been widely discussed and promoted since 1990.

Purpose

To examine the small-sample behavior of these ‘Bayesian Phase I’ designs, and also of non-Bayesian designs sharing the same main ‘Long-Memory’ traits of using likelihood estimation and assigning the estimated MTD to the next patient.

Methods

Data from several recently published experiments are presented and discussed, and Long-Memory designs’ operating principles are explained. Simulation studies compare the small-sample behavior of Long-Memory designs with short-memory ‘Up-and-Down’ designs.

Results

In simulation, Long-Memory and Up-and-Down designs achieved similar success rates in finding the MTD. However, for all Long-Memory designs examined, the number n* of cohorts treated at the true MTD was highly variable between simulated experiments drawn from the same toxicity-threshold distribution. Further investigation using the same set of thresholds in permuted order indicates that this Long-Memory behavior is driven by sensitivity to the order in which participants enter the experiment. This sensitivity is related to Long-Memory designs’ ‘winner-takes-all’ dose-assignment rule, which grants the early cohorts a disproportionately large influence, and causes many experiments to settle early on a specific dose. Additionally for the Bayesian Long-Memory designs, the prior-predictive distribution over the dose levels has a substantial impact upon MTD-finding performance, long into the experiment.

Limitations

While the numerical evidence for Long-Memory designs’ order sensitivity is broad, and plausible explanations for it are provided, we do not present a theoretical proof of the phenomenon.

Conclusions

Method developers, analysts, and practitioners should be aware of Long-Memory designs’ order sensitivity and related phenomena. In particular, they should be informed that settling on a single dose does not guarantee that this dose is the MTD. Presently, Up-and-Down designs offer a simpler and more robust alternative for the sample sizes of 10–40 patients used in most Phase I trials. Future designs might benefit from combining the two approaches. We also suggest that the field’s paradigm change from dose-selection to dose-estimation.