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Biomedical subjects

Michael S Schechter

Publications and source records attributed to Michael S Schechter.

11 recordsLinked to original sources

Impact of pregnancy on women with cystic fibrosis.

BACKGROUND: Improvements in the health and survival of patients with cystic fibrosis (CF) have led to increasingly normal lifestyles, including successful pregnancies in women with CF. Concern exists among care providers about the impact of pregnancy on the health of women with CF. STUDY OBJECTIVES: We examined data from a large longitudinal observational study, the Epidemiologic Study of Cystic Fibrosis (ESCF), to characterize health outcomes and CF-related therapies in women who became pregnant. DESIGN: This analysis was conducted using ESCF data from 1995 to 2003. PATIENTS: A total of 216 women, aged 15 to 38 years, who met the criteria for a qualifying pregnancy, were compared with a matched group of never-pregnant women during three time periods (ie, baseline, during pregnancy, and follow-up). INTERVENTIONS: None. RESULTS: The baseline pulmonary function (FEV(1)) values were 74.5% and 66.4% predicted, respectively, in the pregnant and nonpregnant women. Declines in FEV(1) values of 6.8% and 4.7%, respectively, were observed from baseline to follow-up in the pregnant and nonpregnant women (p = 0.61). During pregnancy, outpatient visits were 33% more frequent compared to baseline and 62% more frequent than in the nonpregnant group (7.19 vs 4.45, respectively, visits annually). Annual rates of respiratory exacerbation and hospitalization were similar at baseline but increased during pregnancy. The prevalence of treatment for diabetes more than doubled, from 9.3% at baseline to 20.6% during pregnancy, and was 14.4% at follow-up. In contrast, 18.7% of the never-pregnant women were being treated for diabetes at baseline, rising to 25.2% at follow-up. CONCLUSIONS: These findings suggest that, over the same time period, women with CF who become pregnant experienced similar respiratory and health trends as nonpregnant women. However, pregnant women use a greater number of therapies and receive more intense monitoring of their health. These findings have implications for clinicians providing prepregnancy counseling for women with CF.

Adolescent↗

Effect of macrolides on in vivo ion transport across cystic fibrosis nasal epithelium.

Fourteen- and 15-member macrolide antibiotics are under investigation as potential therapeutic agents for cystic fibrosis (CF). The nonantibiotic mechanisms of action of these compounds in CF are not understood. We used nasal potential difference (NPD) measurements to test the effect of macrolides on airway epithelial ion (chloride, sodium) transport of CF mice and humans. We tested clarithromycin and azithromycin in mice, and clarithromycin in patients with CF. Baseline and post-treatment NPD was measured in two strains (C57Bl6 and BalbC) of CF transmembrane regulator "knockout" and littermate control mice, and in DeltaF508/DeltaF508 mice. In addition, NPD was measured in 18 human subjects with CF (17 DeltaF-508/DeltaF-508 and 1 DeltaF-508/other) who were undergoing a 12-month, randomized, double-blind crossover study of the effects of clarithromycin on pulmonary outcome in CF. Neither clarithromycin nor azithromycin affected ion transport characteristics of normal or CF nasal epithelium in either mouse or humans. We conclude that the apparent beneficial effects of macrolides on pulmonary outcome in CF are not mediated by their modulation of ion transport.

Adolescent↗

Sweat-testing in preterm and full-term infants less than 6 weeks of age.

Our objective was to examine the characteristics of preterm and full-term infants < or = 6 weeks old that influence the success of obtaining sufficient sweat for diagnosis of CF, and corresponding sweat chloride concentrations. A retrospective chart review of 119 sweat tests was performed on 103 preterm and full-term infants < or = 6 weeks of age. Bivariate and multivariate regression analyses were used to determine the predictors of successful sweat testing and characteristics influencing sweat chloride concentrations. Adequate amounts of sweat (> or = 75 mg) were obtained for analysis in 73.8% of initial attempts in the infant group. The following characteristics were associated with increased odds of obtaining a quantity not sufficient (QNS) for sweat chloride concentration measurement: African-American race, infant weight < 2,000 g, preterm birth, and postmenstrual age (PMA) < 36 weeks. With a multivariable logistic model, the only significant predictors were African-American race (7.3, 2.4-21.7) and PMA < 36 weeks (17.9, 4.2-75.9). Sweat chloride concentration in non-CF individuals is inversely related to both gestational age and age at testing, and this effect is additive in a linear regression model. In conclusion, sweat collection can be reliably performed in infants > or = 36 weeks postmenstrual age, > 2,000 g, and > 3 days postnatal age. Maturational factors have a mild impact on sweat chloride concentration.

Black or African American↗

Outcomes associated with initiation of different controller therapies in a Medicaid asthmatic population: a retrospective data analysis.

BACKGROUND: Outcomes in asthmatic patients may vary depending on the controller medication used. Observational studies of outcomes of asthma therapy are needed to understand the implications of choice of controller in different populations. OBJECTIVES: To determine whether there are differences in health care use and costs of asthma treatment in asthma patients treated with montelukast compared with fluticasone proponiate 44 microg. METHOD: Using data from the North Carolina Medicaid program, we compared continuously enrolled asthmatic patients starting either fluticasone propionate 44 microg (FP44), an inhaled corticosteroid (ICS) (n = 312), or montelukast 5 and 10 mg, an oral leukotriene modifier (LM) (n = 398) between the years 1998 and 1999. A secondary analysis compared continuously enrolled asthmatic patients already using ICS as controller therapy initiating either salmeterol (long-acting beta-agonist) (n = 97) or montelukast (n = 101) in the year 1998. Patients were followed for 1 year pre- and postcontroller or additional controller initiation for health care service use, medication refill patterns, and costs. RESULTS: There were no significant differences in the adjusted asthma-related health care costs between the montelukast and FP44 groups. In both groups, physician visits were significantly higher in year 2 (p < 0.01) than in year 1. We found montelukast users to be more adherent with prescription refills (using measures of medication possession) even after allowing for a wider adherence range for FP (RR = 2.53; 95% CI = 1.50-4.26), although patients using montelukast were more likely than patients with fluticasone to switch controller pharmacotherapy (RR = 1.53; 95% CI = 1.12-2.09). Similarly, there were no differences in health care service use and costs between the montelukast and salmeterol groups, with the exception of a 33% reduction (p < 0.01) in number of inhaled corticosteroid refills in the second year in the salmeterol group. CONCLUSION: There were no cost and major health care use differences between the two primary or secondary controller therapies in the postinitiation year. Although FP was associated with lower rate of controller switch, montelukast use was associated with significantly better treatment adherence in patients with treatment persistence in this population of Medicaid-enrolled asthmatic patients. The addition of salmeterol as additional controller was associated with a significant decrease in inhaled corticosteroid use, suggesting decreased adherence in patients on the two-drug regimen.

Acetates↗

Non-genetic influences on cystic fibrosis lung disease: the role of sociodemographic characteristics, environmental exposures, and healthcare interventions.

Patients with cystic fibrosis (CF) exhibit significant variability in the course and severity of the disease, and this variability is best interpreted in the context of an interaction between genetic and nongenetic determinants. While a small number of patients with "mild" mutations in the CF transmembrane conductance regulator gene clearly have less severe disease, for the general population of patients with CF the strongest predictor of severity of clinical course appears to be socioeconomic status (SES). Low SES probably exerts an influence via the convergence of detrimental environmental influences on outcome such as environmental tobacco smoke, poor nutrition, and stress. Other important predictors that appear to be independent of SES include gender and acquisition of airway pathogens such as Pseudomonas aeruginosa and Burkholderia cepacia complex. Finally, effective provision of medical interventions is an important determinant of outcome, and this is affected primarily by patient adherence (which bears a poorly defined relationship to SES), and attendance at a CF care center that utilizes a system of care that allows optimal delivery of evidence-based interventions.

Journal Article↗

Nontuberculous mycobacteria. I: multicenter prevalence study in cystic fibrosis.

Nontuberculous mycobacteria (NTM) are potential respiratory pathogens in cystic fibrosis (CF). To assess the species-specific prevalence and risk factors for acquisition, we conducted a prospective, cross-sectional study of the prevalence of NTM and clinical features of patients at 21 U.S. centers. Almost 10% of patients with CF who were 10 years or older were included (n = 986). The overall prevalence of NTM in sputum was 13.0% (range by center, 7-24%). Mycobacterium avium complex (72%) and Mycobacterium abscessus (16%) were the most common species. When compared with patients with CF without NTM, culture-positive subjects were older (26 vs. 22 years, p < 0.001), had a higher FEV1 (60 vs. 54%, p < 0.01), higher frequency of Staphylococcus aureus (43 vs. 31%, p < 0.01), and lower frequency of Pseudomonas aeruginosa (71 vs. 82%, p < 0.01). Molecular typing revealed that almost all patients within each center had unique NTM strains. In summary, NTM are common in patients with CF, but neither person-to-person nor nosocomial acquisition explained the high prevalence. Older age was the most significant predictor for isolation of NTM. The clinical significance of NTM in CF is incompletely defined, but patients with these organisms should be monitored with repeat cultures.

Adolescent↗

Acute renal failure in cystic fibrosis: association with inhaled tobramycin therapy.

We describe a 20-year-old patient with cystic fibrosis who developed acute nonoliguric renal failure associated with inhaled tobramycin. Clinical evaluation and renal biopsy findings were consistent with aminoglycoside-induced changes. Renal failure due to inhaled aminoglycosides has not been previously reported. The incidence may rise, however, with the increased use of this treatment modality. Measurable tobramycin levels due to inhalational therapy with conventional dosing in the reported patient indicate that the drug can be systemically absorbed, and renal tubular toxicity may occur.

Acute Kidney Injury↗

Technical report: diagnosis and management of childhood obstructive sleep apnea syndrome.

OBJECTIVE: This technical report describes the procedures involved in developing the recommendations of the Subcommittee on Obstructive Sleep Apnea Syndrome in children. The group of primary interest for this report was otherwise healthy children older than 1 year who might have adenotonsillar hypertrophy or obesity as underlying risk factors of obstructive sleep apnea syndrome (OSAS). The goals of the committee were to enhance the primary care clinician's ability to recognize OSAS, identify the most appropriate procedure for diagnosis of OSAS, identify risks associated with pediatric OSAS, and evaluate management options for OSAS. METHODS: A literature search was initially conducted for the years 1966-1999 and then updated to include 2000. The search was limited to English language literature concerning children older than 2 and younger than 18 years. Titles and abstracts were reviewed for relevance, and committee members reviewed in detail any possibly appropriate articles to determine eligibility for inclusion. Additional articles were obtained by a review of literature and committee members' files. Committee members compiled evidence tables and met to review and discuss the literature that was collected. RESULTS: A total of 2115 titles were reviewed, of which 113 provided relevant original data for analysis. These articles were mainly case series and cross-sectional studies; overall, very few methodologically strong cohort studies or randomized, controlled trials concerning OSAS have been published. In addition, a minority of studies satisfactorily differentiated primary snoring from true OSAS. Reports of the prevalence of habitual snoring in children ranged from 3.2% to 12.1%, and estimates of OSAS ranged from 0.7% to 10.3%; these studies were too heterogeneous for data pooling. Children with sleep-disordered breathing are at increased risk for hyperactivity and learning problems. The combined odds ratio for neurobehavioral abnormalities in snoring children compared with controls is 2.93 (95% confidence interval: 2.23-3.83). A number of case series have documented decreased somatic growth in children with OSAS; right ventricular dysfunction and systemic hypertension also have been reported in children with OSAS. However, the risk growth and cardiovascular problems cannot be quantified from the published literature. Overnight polysomnography (PSG) is recognized as the gold standard for diagnosis of OSAS, and there are currently no satisfactory alternatives. The diagnostic accuracy of symptom questionnaires and other purely clinical approaches is low. Pulse oximetry appears to be specific but insensitive. Other methods, including audiotaping or videotaping and nap or home overnight PSG, remain investigational. Adenotonsillectomy is curative in 75% to 100% of children with OSAS, including those who are obese. Up to 27% of children undergoing adenotonsillectomy for OSAS have postoperative respiratory complications, but estimates are varied. Risk factors for persistent OSAS after adenotonsillectomy include continued snoring and a high apnea-hypopnea index on the preoperative PSG. CONCLUSIONS: OSAS is common in children and is associated with significant sequelae. Overnight PSG is currently the only reliable diagnostic modality that can differentiate OSAS from primary snoring. However, the PSG criteria for OSAS have not been definitively validated, and it is not clear that primary snoring without PSG-defined OSAS is benign. Adenotonsillectomy is the first-line treatment for OSAS but requires careful postoperative monitoring because of the high risk of respiratory complications. Adenotonsillectomy is usually curative, but children with persistent snoring (and perhaps with severely abnormal preoperative PSG results) should have PSG repeated postoperatively.

Adenoidectomy↗