Evidence of telescoping in regular smoking onset age.

INTRODUCTION: We examined the evidence of telescoping bias in self-reports of regular smoking onset age. Since the exact year of the onset was not available, the discrepancy (termed shift) in self-reports was explored. The study was targeted at establishing the relationships between the prevalence and the magnitude of shifting and respondent and survey characteristics and identifying the key factors contributing to forward and backward shifting. METHODS: The 2002-2003 Tobacco Use Supplement to the Current Population Survey was administered using phone and in-person interviews to the same respondents in 2002 and 2003. The regular smoking onset age, reported by current and former smokers during both years, was used. All statistical analyses incorporated replicate weights to adjust for the complex survey design. RESULTS: In our sample, about 31.6% (31.8%) of respondents forwardly (backwardly) shifted the smoking onset age, with the mean magnitude of discrepancy about 2.7 years (both directions). The elapsed time since the onset was shown to be the most important considered predictor of prevalence of shifting. The prevalence of forward (backward) shifting tends to increase (decrease) as elapsed time increases. Furthermore, the discrepancy in forwardly shifted responses tends to increase, on average, with elapsed time. CONCLUSIONS: The findings indicate that both forward and backward shifting may be prevalent in reports on smoking onset age. The extent of shifting depends on elapsed time since the onset (and therefore, the respondent's age) and other respondent and survey characteristics. The findings are consistent with presence of both forward and backward telescoping biases.

Applications of asymptotic confidence intervals with continuity corrections for asymmetric comparisons in noninferiority trials.

A large-sample problem of illustrating noninferiority of an experimental treatment over a referent treatment for binary outcomes is considered. The methods of illustrating noninferiority involve constructing the lower two-sided confidence bound for the difference between binomial proportions corresponding to the experimental and referent treatments and comparing it with the negative value of the noninferiority margin. The three considered methods, Anbar, Falk-Koch, and Reduced Falk-Koch, handle the comparison in an asymmetric way, that is, only the referent proportion out of the two, experimental and referent, is directly involved in the expression for the variance of the difference between two sample proportions. Five continuity corrections (including zero) are considered with respect to each approach. The key properties of the corresponding methods are evaluated via simulations. First, the uncorrected two-sided confidence intervals can, potentially, have smaller coverage probability than the nominal level even for moderately large sample sizes, for example, 150 per group. Next, the 15 testing methods are discussed in terms of their Type I error rate and power. In the settings with a relatively small referent proportion (about 0.4 or smaller), the Anbar approach with Yates' continuity correction is recommended for balanced designs and the Falk-Koch method with Yates' correction is recommended for unbalanced designs. For relatively moderate (about 0.6) and large (about 0.8 or greater) referent proportion, the uncorrected Reduced Falk-Koch method is recommended, although in this case, all methods tend to be over-conservative. These results are expected to be used in the design stage of a noninferiority study when asymmetric comparisons are envisioned.

Low adherence to national guidelines for thyroid screening in Down syndrome.

PURPOSE: To determine adherence to the American Academy of Pediatrics guidelines for thyroid screening in children with Down syndrome among primary care providers in the states of Oklahoma and Nebraska. METHODS: We sought to identify all children with Down syndrome born in Oklahoma and Nebraska between 1994 and 2004 and review their medical records for evidence of thyroid screening. Patients were identified through a State Department of Health birth defects registry in Oklahoma and through participation in genetics clinics and laboratories in Nebraska and Oklahoma. Charts obtained from primary care providers were reviewed and the number of actual thyroid screens was compared with the number of recommended screens for each individual during the study period. RESULTS: In Oklahoma, 13% of participating children received all thyroid screens recommended in the guidelines. In Nebraska, 14% of children received all recommended thyroid screenings. Among participants in Oklahoma, a mean of 34% of recommended thyroid screenings were performed. In Nebraska, a mean of 45% of recommended thyroid screenings were performed. CONCLUSIONS: The level of adherence to the American Academy of Pediatrics guidelines for thyroid screening in children with Down syndrome is low. Factors contributing to this low level of adherence need to be identified and addressed.

Body mass index as a predictive value for complications associated with reconstructive surgery in patients with myelodysplasia.

PURPOSE: Patients with myelodysplasia often have urological pathology, with 25% to 40% requiring reconstructive procedures to achieve urinary and/or fecal continence. Complication rates from these major reconstructive procedures range between 10% and 50%. Additionally many of these patients have significant comorbidities, including a nonambulatory status that leads to an increased body mass index. It is currently unknown whether a high body mass index is associated with increased surgical complications. In this study we compare body mass index and postoperative complications. MATERIALS AND METHODS: We retrospectively reviewed the charts of all patients with myelodysplasia undergoing urinary or fecal reconstructive procedures. We analyzed data for body mass index and any documented complication occurring during hospitalization or at any time during followup. Patients were categorized based on body mass index as normal weight (less than 85th percentile), overweight (85th to 95th percentile) or obese (greater than 95th percentile). Statistical analyses using chi-square and Fisher's exact tests were then performed. RESULTS: Reconstructive procedures were carried out in 66 patients with myelodysplasia between 1997 and 2005. A total of 48 bladder augmentations were performed with a total of 101 stomas created. Mean followup was 39 months. Height and weight were available for body mass index calculation in 60 patients. Obesity was common in our patients with myelodysplasia, affecting 33% of the population (20 of 60 patients). We found a total of 53 complications in 31 patients (52%). There was a significant association between presence of complications and weight category, with complications occurring in 40% of normal weight, 40% of overweight and 75% of obese patients (p = 0.0380). An association between stomal stenosis and weight category was also found (p = 0.0373). In addition, multiple complications were more prevalent in obese patients. Of the 15 patients (25%) with 2 or more complications 10 (67%) were obese (p = 0.0066). CONCLUSIONS: Patients with myelodysplasia have a high incidence of obesity. Since obesity is associated with a higher complication rate, weight loss programs are highly recommended for obese patients with myelodysplasia before and after any reconstructive surgery.

Severe chronic refractory immune thrombocytopenic purpura during childhood: a survey of physician management.

BACKGROUND: Physician attitudes regarding management of children with severe chronic immune thrombocytopenic purpura (ITP) have not been recently characterized. PROCEDURE: We designed a survey of members of the American Society of Pediatric Hematology-Oncology (ASPHO) that described a 5-year-old female with ITP for 1 year who was unresponsive to steroids, IVIG, and anti-D immune globulin and having frequent epistaxis causing interference with her daily activities. A 13-item questionnaire evaluated physician decision-making in this setting. RESULTS: Two hundred and ninety-seven surveys (35% response rate) were returned, and 295 were evaluable. Thirty-three percent of respondents stated that they would recommend splenectomy for such a child. Of those who would not recommend splenectomy, 67% reported that they would instead treat with rituximab. If initial drug therapy failed, 47% would proceed with splenectomy. Those who reported treating with rituximab initially were more likely to recommend splenectomy following failure than those who preferred other drug therapy (P < 0.0001). CONCLUSIONS: Physician management of patients with chronic ITP is diverse. With the advent of new treatments such as rituximab and thrombopoetic agents it is critically important to compare their cost, adverse effects and efficacy with splenectomy in order to optimally guide treatment practices.

Evaluating the performance of simultaneous stepwise confidence intervals for the difference between two Poisson rates.

We consider the problem of simultaneously estimating Poisson rate differences via applications of the Hsu and Berger stepwise confidence interval method (termed HBM), where comparisons to a common reference group are performed. We discuss continuity-corrected confidence intervals and investigate the HBM performance with a moment-based confidence interval, and uncorrected and corrected for continuity Wald and Pooled confidence intervals. Using simulations, we compare nine individual confidence intervals in terms of coverage probability and the HBM with nine intervals in terms of family-wise error rate and overall and local power. The simulations show that these statistical properties depend highly on parameter settings.

Perception of Time Since Smoking Cessation: Time in Memory Can Elapse Faster.

Self-reports concerning smoking behaviors are subject to different types of response bias that may severely affect the data quality. This study examined the evidence and extent of backward telescoping bias in reports on time since completely quitting smoking among former smokers. The study goals were to determine whether the extent of bias differs, on average, across subpopulations with diverse sociodemographic characteristics, prior smoking habits and duration of smoking abstinence, and across the survey administration mode (phone, in-person, mixed). The sample included 1,611 subjects who responded to the 2002-2003 Tobacco Use Supplement to the Current Population Survey. Multiple regressions for subjects who quit smoking recently, some time ago, and a long time ago were fitted, where the variance was estimated via the Balanced Repeated Replications approach. The model-based estimates were used to compare the extent of response bias across diverse subpopulations of respondents. Analyses revealed a significantly smaller overall extent of response bias for respondents who were younger (p < 0.01), female (p < 0.01), Non-Hispanic White (p = 0.02), employed (p < 0.01), who were regular (rather than occasional) smokers in the past (p < 0.01), and who quit smoking recently or some time ago as opposed to a long time ago (p < 0.01); a significant overall effect of survey mode was also detected (p < 0.01). Male respondents who smoked occasionally in the past tended to provide the most disagreeing reports. The discrepancy in reports may be due to backward telescoping bias. Studies which use the national survey smoking cessation measures should be aware of not only possible forward telescoping (that has been addressed in the literature) but also backward telescoping. This will help correctly account for possible impaired perception of time elapsed since smoking cessation in former smokers.

On Consistency of Self- and Proxy-reported Regular Smoking Initiation Age.

Early onset of smoking is associated with heavier tobacco consumption and longer smoking careers. Consequently, obtaining accurate estimates of early smoking is a priority. The purpose of this study was to examine the utility of proxy reports of the age of smoking initiation, and specifically to explore whether there are differences in the consistency of proxy-reported and self-reported smoking behaviors. Data came from the 2002-2003 Tobacco Use Supplement to the Current Population Survey, where the current smoking behaviors and smoking history of participants were reported by self-and proxy-respondents on two occasions, one year apart. Sequential multiple-testing methods were used to assess significance of the differences in reported prevalence of consistent reports among specific sub-populations defined by age, gender and survey administration mode. Results indicated that self-reports are more reliable (more consistent over time) than proxy reports or mixed reports that include self-report at one time point and proxy reports at another. The rate of perfect agreement was also highest for self-reports. The impact of respondent type on the consistency of reports also depended on the target subjects' age and the survey administration mode (phone or in-person).

Dietary intake of participants with peripheral artery disease and claudication.

We compared the dietary intake of participants with peripheral artery disease (PAD) and claudication with diet recommendations of the National Cholesterol Education Program (NCEP) and dietary reference intake values recommended by the Institute of Medicine (IOM) of the National Academy of Sciences. Forty-six participants consumed a mean macronutrient composition of 17% protein, 51% carbohydrate, and 30% fat. Compared to the NCEP and IOM recommendations, few participants met the recommended daily intake for sodium (0%), vitamin E (0%), folate (13%), saturated fat (20%), fiber (26%), and cholesterol (39%). Participants with PAD and claudication have poor nutrition, with diets particularly high in saturated fat, sodium, and cholesterol, and low in fiber, vitamin E, and folate intakes. Participants should be encouraged to reduce consumption of dietary fat, saturated fat, cholesterol, and sodium and to increase fiber and vitamin intakes to meet recommendations of the NCEP and IOM.

Impact of type 1 diabetes and body weight status on cardiovascular risk factors in adolescent children.

Type 1 diabetes (T1D) is a risk factor for cardiovascular disease. However, it is unclear whether increased body weight amplifies that risk in T1D patients. This is a cross-sectional study examining the presence of cardiovascular risk factors in normal and overweight children, both with and without T1D. Sixty-six children (aged 16±2.2 years) were included in one of the following groups: (T1D and normal weight, T1D and overweight, healthy and normal weight, and healthy and overweight). A fasting blood sample was analyzed for lipid profile (triglyceride, cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol), apolipoprotein B (apoB), and apolipoprotein C-III (apoC-III) levels. Body composition was determined by dual energy x-ray absorptiometry and vascular elasticity by HDI/Pulsewave CR-2000 (Hypertension Diagnostics, Eagan, MN). Statistical analyses examined the effect of T1D and body weight status and their interactions on cardiovascular risk parameters. In this study, the authors were unable to demonstrate an additive effect of body weight status and T1D on cardiovascular risk profile. However, subgroup analysis of patients with T1D revealed higher apoC-III levels in overweight patients with T1D (P=.0453) compared with normal-weight diabetic children. Most notably, there was a direct relationship of small artery elasticity to body weight status. This seemingly paradoxical observation supports recent data and warrants further investigation.

Normal sex differences in prenatal growth and abnormal prenatal growth retardation associated with 46,XY disorders of sex development are absent in newborns with congenital adrenal hyperplasia due to 21-hydroxylase deficiency.

BACKGROUND: Congenital adrenal hyperplasia due to 21-hydroxylase deficiency is the most common presentation of a disorder of sex development (DSD) in genetic females. A report of prenatal growth retardation in cases of 46,XY DSD, coupled with observations of below-optimal final height in both males and females with congenital adrenal hyperplasia due to 21-hydroxylase deficiency, prompted us to investigate prenatal growth in the latter group. Additionally, because girls with congenital adrenal hyperplasia are exposed to increased levels of androgens in the absence of a male sex-chromosome complement, the presence or absence of typical sex differences in growth of newborns would support or refute a hormonal explanation for these differences. METHODS: In total, 105 newborns with congenital adrenal hyperplasia were identified in our database. Gestational age (weeks), birth weight (kg), birth length (cm) and parental heights (cm) were obtained. Mid-parental height was considered in the analyses. RESULTS: Mean birth weight percentile for congenital adrenal hyperplasia was 49.26%, indicating no evidence of a difference in birth weight from the expected standard population median of 50th percentile (P > 0.05). The expected sex difference in favor of heavier males was not seen (P > 0.05). Of the 105 subjects, 44 (27%; 34 females, 10 males) had birth length and gestational age recorded in their medical chart. Mean birth length for this subgroup was 50.90 cm (63rd percentile), which differed from the expected standard population median of 50th percentile (P = 0.0082). The expected sex difference in favor of longer males was also not seen (P > 0.05). CONCLUSION: The prenatal growth retardation patterns reported in cases of 46,XY disorders of sex development do not generalize to people with congenital adrenal hyperplasia due to 21-hydroxylase deficiency. Sex differences in body weight and length typically seen in young infants were not seen in the subjects who participated in this study. We speculate that these differences were ameliorated in this study because of increased levels of prenatal androgens experienced by the females infants.

Hepatitis C prevalence in patients with hepatocellular carcinoma without cirrhosis.

BACKGROUND: Hepatocellular carcinoma (HCC) occurring in "noncirrhotic" hepatitis C virus (HCV)-infected patients has been reported; but the exact prevalence or incidence has not been described before. METHODS: We conducted a systematic review of literature: Ovid was used to search the literature from January 1, 1990, to September 1, 2008. Articles containing "HCC" keywords (hepatocellular carcinoma, hepatoma, liver cancer) were combined with the word "cirrhosis" or "fibrosis" and with "absence" keywords [noncirrhotic, absence, without]. Two hundred articles were selected and screened according to predesigned exclusion and inclusion criteria. RESULTS: Nineteen articles met the inclusion criteria. The estimated prevalence of noncirrhotic HCC ranged from 6.7% to 50.1%. The pooled prevalence estimates for HCV in noncirrhotic HCC ranged from 0% and 68.4% according to the geographic location. Reports from Japan had the highest estimated pooled prevalence of HCV (55.01%) followed by Italy (29.95%). CONCLUSION: HCV can occur in patients with HCC without cirrhosis, but the true incidence and prevalence are very difficult to ascertain. Further studies are needed to define this group of patients.

Effect of decreasing target oxygen saturation on retinopathy of prematurity.

INTRODUCTION: The authors of previous studies suggest that the oxygenation status of premature infants contributes to the development of retinopathy of prematurity (ROP). In this study we compared the incidence and severity of ROP before and after institution of a new neonatal intensive care unit oxygen protocol. METHODS: A retrospective chart review was performed of all eligible inborn patients screened for ROP during the 2 years immediately before (Group 1) to and the 2 years after (Group 2) the initiation of a new oxygen protocol. In the new protocol, target oxygen saturation was adjusted from 90%-99% to 85%-93%. Treatment criteria adhered to Early Treatment for Retinopathy of Prematurity guidelines for the study's duration. RESULTS: There were 387 infants in Group 1 and 386 infants in Group 2 (descriptive statistics adjusted for correlation due to multiple births). Mean birth weights (BWs) and gestational ages were 1,194 g and 29.2 weeks (ranges, 525-2,085 g; 23 2/7-39 6/7 weeks) for Group 1 and 1,139 g and 28.9 weeks (ranges, 520-2,500 g; 22 6/7-35 3/7 weeks) for Group 2 (p = 0.02/0.10). ROP developed in 32.7% of infants in Group 1 and 27.8% in Group 2 (p = 0.17). The incidence of ROP requiring treatment was 19.9% in Group 1 and 20.5% in Group 2 (p = 0.91). Subanalysis of infants with BW ≤ 1,000g (Group 1, n = 119; Group 2, n = 141) revealed ROP incidence of 75.1% versus 57.1%, respectively (p < 0.01); treatable disease occurred in 37.5% and 21.9% of affected infants (p = 0.19). CONCLUSIONS: Lowering target oxygen saturation for inborn premature infants was associated with decreased incidence of ROP only in infants with BW ≤ 1,000 g. Severity of disease, including need for treatment, was similar in both groups.

Anthropometric models to predict appendicular lean soft tissue in adolescent athletes.

PURPOSE: Skeletal muscle (SM), which is found mainly within the appendicular lean soft tissue (ALST) compartment, is a biological important body compartment. Simple and accurate methods to estimate both SM and ALST remain difficult to obtain. We aimed to develop and to cross-validate anthropometric models for ALST in athletes, using dual-energy x-ray absorptiometry (DXA) as the reference method. METHODS: ALST equations were developed in 176 athletic boys (15.0 +/- 2.8 yr; 64.5 +/- 15.8 kg; 1.72 +/- 0.15 m) and 92 athletic girls (14.6 +/- 2.8 yr; 53.0 +/- 13.1 kg; 1.61 +/- 0.13 m). Skinfolds were measured at the triceps, the thigh, and medial calf, and circumferences were measured at the midupper arm, the midthigh, and the midcalf. ALST was assessed using DXA (QDR-4500; Hologic, Walthman, MA; fan-beam mode). Two models were developed: a body weight model (WHt model) and a corrected muscle girth model (CMG model, which included the parameters height x CAG, height x CTG, and height x CCG, where CAG is corrected arm girth, CTG is corrected thigh girth, and CCG is the corrected calf). Simple regression analysis was used to identify the best model fit. The equations were internally cross-validated using the predicted residual sum of squares method, and performance of new equations was analyzed by regression analysis and agreement between methods. RESULTS: The new WHt model generated the following equation: ALST = -20.338 + 0.199(W) + 3.294(gender) + 14.230(height) + 0.192(age), where gender = 1 for male and 0 for female. The CMG model produced the following equation: ALST = 3.260 + 0.002(height x CTG) + 0.007(height x CAG) + 0.003(height x CCG). WHt equation had an R = 0.91 and an SEE = 2.00 kg, whereas CMG equation presented an R = 0.93 and an SEE = 1.80 kg. In both equations, slopes and intercepts did not differ from the line of identity; no mean differences between predicted and measured values and no trend line were observed (P > 0.05). CONCLUSIONS: Both models accurately predict ALST in young athletes, affording a practical means to quantify this compartment.

Operative versus nonoperative management of ureteropelvic junction obstruction in children.

OBJECTIVES: To describe and validate our strategy for treating patients with ureteropelvic junction obstruction operatively or nonoperatively according to ultrasonography and nuclear renal scan findings. METHODS: A retrospective analysis of 243 patients from 1999 to 2006 with grade 3-4 hydronephrosis was performed. Depending on the grade of hydronephrosis with parenchymal thinning on ultrasonography and renal function on the nuclear renal scan, patients were treated with immediate pyeloplasty, pyeloplasty after a period of observation, or observation only. RESULTS: Of 243 patients, 116 were found to have UPJO as determined by a half-life >20 minutes. The mean follow-up was 24.0 months (range 3-69). Immediate pyeloplasty was performed in 32 children, and 84 were treated conservatively. Crossover from observation to surgery occurred in 47 children. In the immediate pyeloplasty group, the mean pre- and postoperative differential function was 30.4% and 38.8%, respectively (P < .0001). In the observation-only group (n = 37), the initial mean renal function was 41.4% and stayed stable throughout the follow-up period, at a mean of 43.2% (P = .2764). In the delayed pyeloplasty group (n = 47), the initial mean renal function was 35.9% and increased to a mean of 41.6% after intervention (P = .0003). The median improvement of hydronephrosis on ultrasonography for those who underwent immediate surgery from before to after the intervention was from grade 4 to grade 3 (P < .0001). For those not undergoing surgery, it improved from grade 4 to grade 2.25 (P = .0026) and for those who underwent delayed surgery, from grade 4 to 3 (P = .0003). CONCLUSIONS: According to our findings, the serial ultrasonography findings and initial renal function on nuclear renal scan are better indicators than the half-life alone for determining whether pyeloplasty is indicated.

Occurrence of urinary tract infection in children with significant upper urinary tract obstruction.

OBJECTIVES: Ureteropelvic junction obstruction and obstructive megaureter are common causes of upper urinary tract obstruction. Recent data have demonstrated that the rate of urinary tract infection (UTI) among children with upper tract obstruction not treated with prophylactic antibiotics is >36%. The aim of this study was to evaluate the occurrence of UTI in our patients with ureteropelvic junction obstruction and megaureter to better assess the role of prophylactic antibiotics. METHODS: A retrospective analysis was conducted. The inclusion criteria were grade 3 or 4 hydronephrosis secondary to obstructive megaureter or ureteropelvic junction obstruction in children not maintained on prophylactic antibiotics. UTI was defined as a culture-documented symptomatic infection. Fisher's exact tests were used to evaluate for an association between the occurrence of UTI with sex, level of obstruction, grade of hydronephrosis, and circumcision status. RESULTS: A total of 92 patients met the study criteria. The rate of UTI in all patients was 4.3% (95% confidence interval 0.2%-8.6%). No statistically significant difference in the infection rate was noted according to sex, obstruction level, hydronephrosis grade, or circumcision status. CONCLUSIONS: Our results have demonstrated a low occurrence of UTI in antenatally diagnosed patients not maintained on antibiotics. We have concluded that antibiotic prophylaxis is unlikely to benefit most children with grade 3 or 4 hydronephrosis secondary to upper tract obstruction.