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1.
BMC Emerg Med ; 24(1): 95, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38824546

RESUMO

OBJECTIVE: This study assesses the influence of hyperkalemia on both disease severity and the risk of mortality among patients admitted to the emergency room. METHODS: This retrospective observational study utilized data from the Chinese Emergency Triage Assessment and Treatment database (CETAT, version 2.0), which was designed to evaluate and optimize management strategies for emergency room (ER) patients. Patients were systematically categorized based on serum potassium levels. Relationships between serum potassium levels, risk of mortality, and the severity of illness were then analyzed using multifactorial logistic regression and through Receiver Operating Characteristic (ROC) analysis. The effectiveness of various treatments at lowering potassium levels was also investigated. RESULTS: 12,799 emergency patients were enrolled, of whom 20.1% (n = 2,577) were hypokalemic and 2.98% (n = 381) were hyperkalemic. Among hyperkalemic patients, the leading reasons for visiting the ER were altered consciousness 23.88% (n = 91), cardiovascular symptoms 22.31% (n = 85), and gastrointestinal symptoms 20.47% (n = 78). Comparative analysis with patients exhibiting normal potassium levels revealed hyperkalemia as an independent factor associated with mortality in the ER. Mortality risk appears to positively correlate with increasing potassium levels, reaching peaks when blood potassium levels ranged between 6.5 and 7.0. Hyperkalemia emerged as a strong predictor of death in the ER, with an Area Under the Curve (AUC) of 0.89. The most frequently prescribed treatment for hyperkalemia patients was diuretics (57.32%, n = 188), followed by intravenous sodium bicarbonate (50.91%, n = 167), IV calcium (37.2%, n = 122), insulin combined with high glucose (27.74%, n = 91), and Continuous Renal Replacement Therapy (CRRT) for 19.82% (n = 65). Among these, CRRT appeared to be the most efficacious at reducing potassium levels. Diuretics appeared relatively ineffective, while high-glucose insulin, sodium bicarbonate, and calcium preparations having no significant effect on the rate of potassium decline. CONCLUSION: Hyperkalemia is common in emergency situations, especially among patients with altered consciousness. There is a strong positive correlation between the severity of hyperkalemia and mortality risk. CRRT appears to be the most effective potassium reducting strategy, while the use of diuretics should be approached with caution.


Assuntos
Serviço Hospitalar de Emergência , Hiperpotassemia , Unidades de Terapia Intensiva , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , China/epidemiologia , Mortalidade Hospitalar , Hiperpotassemia/mortalidade , Hiperpotassemia/terapia , Potássio/sangue , Estudos Retrospectivos , Curva ROC , Índice de Gravidade de Doença , Admissão do Paciente
2.
J Theor Biol ; 574: 111611, 2023 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-37640233

RESUMO

XBB, an Omicron subvariant of SARS-CoV-2 that began to circulate in late 2022, has been dominant in the US since early 2023. To quantify the impact of XBB on the progression of COVID-19, we propose a new mathematical model which describes the interplay between XBB and other SARS-CoV-2 variants at the population level and which incorporates the effects of reinfection. We apply the model to COVID-19 data in the US that include surveillance data on the cases and variant proportions from the New York City, the State of New York, and the State of Washington. Our fitting and simulation results show that the transmission rate of XBB is significantly higher than that of other variants and the reinfection from XBB may play an important role in shaping the pandemic/epidemic pattern in the US.

3.
Neuroimage ; 255: 119166, 2022 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-35398282

RESUMO

Magnetic Resonance Imaging (MRI) technology has been increasingly used in neuroscience studies. Reproducibility of statistically significant findings generated by MRI-based studies, especially association studies (phenotype vs. MRI metric) and task-induced brain activation, has been recently heavily debated. However, most currently available reproducibility measures depend on thresholds for the test statistics and cannot be use to evaluate overall study reproducibility. It is also crucial to elucidate the relationship between overall study reproducibility and sample size in an experimental design. In this study, we proposed a model-based reproducibility index to quantify reproducibility which could be used in large-scale high-throughput MRI-based studies including both association studies and task-induced brain activation. We performed the model-based reproducibility assessments for a few association studies and task-induced brain activation by using several recent large sMRI/fMRI databases. For large sample size association studies between brain structure/function features and some basic physiological phenotypes (i.e. Sex, BMI), we demonstrated that the model-based reproducibility of these studies is more than 0.99. For MID task activation, similar results could be observed. Furthermore, we proposed a model-based analytical tool to evaluate minimal sample size for the purpose of achieving a desirable model-based reproducibility. Additionally, we evaluated the model-based reproducibility of gray matter volume (GMV) changes for UK Biobank (UKB) vs. Parkinson Progression Marker Initiative (PPMI) and UK Biobank (UKB) vs. Human Connectome Project (HCP). We demonstrated that both sample size and study-specific experimental factors play important roles in the model-based reproducibility assessments for different experiments. In summary, a systematic assessment of reproducibility is fundamental and important in the current large-scale high-throughput MRI-based studies.


Assuntos
Conectoma , Imageamento por Ressonância Magnética , Encéfalo/diagnóstico por imagem , Substância Cinzenta , Humanos , Imageamento por Ressonância Magnética/métodos , Reprodutibilidade dos Testes
4.
Am J Perinatol ; 37(5): 503-510, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-30895577

RESUMO

OBJECTIVE: This study aimed to evaluate whether the number of vacuum pop-offs, the number of forceps pulls, or the duration of operative vaginal delivery (OVD) is associated with adverse maternal and perinatal outcomes. STUDY DESIGN: This is a secondary analysis of a multicenter observational cohort of women who underwent an attempted OVD. Women were stratified by the duration of OVD and the number of pop-offs (vacuum) or pulls (forceps) attempted. Severe perineal lacerations, failed OVD, and a composite adverse neonatal outcome were compared by the duration of OVD and number of pop-offs or pulls. RESULTS: Of the 115,502 women in the primary cohort, 5,325 (4.6%) underwent an attempt at OVD: 3,594 (67.5%) with vacuum and 1,731 (32.5%) with forceps. After adjusting for potential confounders, an increasing number of pop-offs was associated with an increased odds of the composite adverse neonatal outcome. However, an increasing duration of vacuum exhibited a stronger association with the composite adverse neonatal outcome. Similarly, the number of forceps pulls was less strongly associated with the composite adverse neonatal outcome compared with the duration of forceps application. CONCLUSION: The duration of OVD may be more associated with adverse neonatal outcomes than the number of pop-offs or pulls.


Assuntos
Extração Obstétrica/efeitos adversos , Complicações do Trabalho de Parto/cirurgia , Duração da Cirurgia , Adulto , Extração Obstétrica/instrumentação , Feminino , Humanos , Recém-Nascido , Doenças do Recém-Nascido/etiologia , Lacerações/etiologia , Forceps Obstétrico/efeitos adversos , Gravidez , Falha de Tratamento , Vácuo-Extração/efeitos adversos
5.
BMC Genomics ; 20(Suppl 2): 195, 2019 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-30967117

RESUMO

BACKGROUND: The next generation sequencing technology allows us to obtain a large amount of short DNA sequence (DNA-seq) reads at a genome-wide level. DNA-seq data have been increasingly collected during the recent years. Count-type data analysis is a widely used approach for DNA-seq data. However, the related data pre-processing is based on the moving window method, in which a window size need to be defined in order to obtain count-type data. Furthermore, useful information can be reduced after data pre-processing for count-type data. RESULTS: In this study, we propose to analyze DNA-seq data based on the related distance-type measure. Distances are measured in base pairs (bps) between two adjacent alignments of short reads mapped to a reference genome. Our experimental data based simulation study confirms the advantages of distance-type measure approach in both detection power and detection accuracy. Furthermore, we propose artificial censoring for the distance data so that distances larger than a given value are considered potential outliers. Our purpose is to simplify the pre-processing of DNA-seq data. Statistically, we consider a mixture of right censored geometric distributions to model the distance data. Additionally, to reduce the GC-content bias, we extend the mixture model to a mixture of generalized linear models (GLMs). The estimation of model can be achieved by the Newton-Raphson algorithm as well as the Expectation-Maximization (E-M) algorithm. We have conducted simulations to evaluate the performance of our approach. Based on the rank based inverse normal transformation of distance data, we can obtain the related z-values for a follow-up analysis. For an illustration, an application to the DNA-seq data from a pair of normal and tumor cell lines is presented with a change-point analysis of z-values to detect DNA copy number alterations. CONCLUSION: Our distance-type measure approach is novel. It does not require either a fixed or a sliding window procedure for generating count-type data. Its advantages have been demonstrated by our simulation studies and its practical usefulness has been illustrated by an experimental data application.


Assuntos
Algoritmos , Variações do Número de Cópias de DNA , Genoma Humano , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Neoplasias/genética , Análise de Sequência de DNA/métodos , Estudos de Casos e Controles , Humanos
6.
Bioinformatics ; 33(23): 3852-3860, 2017 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-28174897

RESUMO

MOTIVATION: We have proposed a mixture model based approach to the concordant integrative analysis of multiple large-scale two-sample expression datasets. Since the mixture model is based on the transformed differential expression test P-values (z-scores), it is generally applicable to the expression data generated by either microarray or RNA-seq platforms. The mixture model is simple with three normal distribution components for each dataset to represent down-regulation, up-regulation and no differential expression. However, when the number of datasets increases, the model parameter space increases exponentially due to the component combination from different datasets. RESULTS: In this study, motivated by the well-known generalized estimating equations (GEEs) for longitudinal data analysis, we focus on the concordant components and assume that the proportions of non-concordant components follow a special structure. We discuss the exchangeable, multiset coefficient and autoregressive structures for model reduction, and their related expectation-maximization (EM) algorithms. Then, the parameter space is linear with the number of datasets. In our previous study, we have applied the general mixture model to three microarray datasets for lung cancer studies. We show that more gene sets (or pathways) can be detected by the reduced mixture model with the exchangeable structure. Furthermore, we show that more genes can also be detected by the reduced model. The Cancer Genome Atlas (TCGA) data have been increasingly collected. The advantage of incorporating the concordance feature has also been clearly demonstrated based on TCGA RNA sequencing data for studying two closely related types of cancer. AVAILABILITY AND IMPLEMENTATION: Additional results are included in a supplemental file. Computer program R-functions are freely available at http://home.gwu.edu/∼ylai/research/Concordance. CONTACT: ylai@gwu.edu. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Assuntos
Algoritmos , Perfilação da Expressão Gênica/métodos , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Análise de Sequência de RNA/métodos , Bases de Dados Genéticas , Estudos de Associação Genética , Genoma Humano , Humanos , Neoplasias Pulmonares/genética , Modelos Estatísticos
7.
Am J Obstet Gynecol ; 218(1): 122.e1-122.e8, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29138035

RESUMO

BACKGROUND: While there are well-accepted standards for the diagnosis of arrested active-phase labor, the definition of a "failed" induction of labor remains less certain. One approach to diagnosing a failed induction is based on the duration of the latent phase. However, a standard for the minimum duration that the latent phase of a labor induction should continue, absent acute maternal or fetal indications for cesarean delivery, remains lacking. OBJECTIVE: The objective of this study was to determine the frequency of adverse maternal and perinatal outcomes as a function of the duration of the latent phase among nulliparous women undergoing labor induction. STUDY DESIGN: This study is based on data from an obstetric cohort of women delivering at 25 US hospitals from 2008 through 2011. Nulliparous women who had a term singleton gestation in the cephalic presentation were eligible for this analysis if they underwent a labor induction. Consistent with prior studies, the latent phase was determined to begin once cervical ripening had ended, oxytocin was initiated, and rupture of membranes had occurred, and was determined to end once 5-cm dilation was achieved. The frequencies of cesarean delivery, as well as of adverse maternal (eg, postpartum hemorrhage, chorioamnionitis) and perinatal (eg, a composite frequency of seizures, sepsis, bone or nerve injury, encephalopathy, or death) outcomes, were compared as a function of the duration of the latent phase (analyzed with time both as a continuous measure and categorized in 3-hour increments). RESULTS: A total of 10,677 women were available for analysis. In the vast majority (96.4%) of women, the active phase had been reached by 15 hours. The longer the duration of a woman's latent phase, the greater her chance of ultimately undergoing a cesarean delivery (P < .001, for time both as a continuous and categorical independent variable), although >40% of women whose latent phase lasted ≥18 hours still had a vaginal delivery. Several maternal morbidities, such as postpartum hemorrhage (P < .001) and chorioamnionitis (P < .001), increased in frequency as the length of latent phase increased. Conversely, the frequencies of most adverse perinatal outcomes were statistically stable over time. CONCLUSION: The large majority of women undergoing labor induction will have entered the active phase by 15 hours after oxytocin has started and rupture of membranes has occurred. Maternal adverse outcomes become statistically more frequent with greater time in the latent phase, although the absolute increase in frequency is relatively small. These data suggest that cesarean delivery should not be undertaken during the latent phase prior to at least 15 hours after oxytocin and rupture of membranes have occurred. The decision to continue labor beyond this point should be individualized, and may take into account factors such as other evidence of labor progress.


Assuntos
Trabalho de Parto Induzido/efeitos adversos , Adulto , Maturidade Cervical , Cesárea/estatística & dados numéricos , Corioamnionite/epidemiologia , Estudos de Coortes , Feminino , Humanos , Ocitócicos/uso terapêutico , Ocitocina/uso terapêutico , Hemorragia Pós-Parto/epidemiologia , Gravidez , Fatores de Tempo , Estados Unidos/epidemiologia
8.
BMC Bioinformatics ; 18(Suppl 3): 69, 2017 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-28361675

RESUMO

BACKGROUND: q-value is a widely used statistical method for estimating false discovery rate (FDR), which is a conventional significance measure in the analysis of genome-wide expression data. q-value is a random variable and it may underestimate FDR in practice. An underestimated FDR can lead to unexpected false discoveries in the follow-up validation experiments. This issue has not been well addressed in literature, especially in the situation when the permutation procedure is necessary for p-value calculation. RESULTS: We proposed a statistical method for the conservative adjustment of q-value. In practice, it is usually necessary to calculate p-value by a permutation procedure. This was also considered in our adjustment method. We used simulation data as well as experimental microarray or sequencing data to illustrate the usefulness of our method. CONCLUSIONS: The conservativeness of our approach has been mathematically confirmed in this study. We have demonstrated the importance of conservative adjustment of q-value, particularly in the situation that the proportion of differentially expressed genes is small or the overall differential expression signal is weak.


Assuntos
Biologia Computacional , Genoma Humano , Modelos Estatísticos , Algoritmos , Interpretação Estatística de Dados , Diabetes Mellitus Tipo 2/genética , Reações Falso-Positivas , Estudos de Associação Genética , Humanos , Ilhotas Pancreáticas/metabolismo , Masculino , Neoplasias da Próstata/genética , Reprodutibilidade dos Testes , Análise de Sequência de RNA
9.
BMC Genomics ; 18(Suppl 1): 1050, 2017 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-28198679

RESUMO

BACKGROUND: With the current microarray and RNA-seq technologies, two-sample genome-wide expression data have been widely collected in biological and medical studies. The related differential expression analysis and gene set enrichment analysis have been frequently conducted. Integrative analysis can be conducted when multiple data sets are available. In practice, discordant molecular behaviors among a series of data sets can be of biological and clinical interest. METHODS: In this study, a statistical method is proposed for detecting discordance gene set enrichment. Our method is based on a two-level multivariate normal mixture model. It is statistically efficient with linearly increased parameter space when the number of data sets is increased. The model-based probability of discordance enrichment can be calculated for gene set detection. RESULTS: We apply our method to a microarray expression data set collected from forty-five matched tumor/non-tumor pairs of tissues for studying pancreatic cancer. We divided the data set into a series of non-overlapping subsets according to the tumor/non-tumor paired expression ratio of gene PNLIP (pancreatic lipase, recently shown it association with pancreatic cancer). The log-ratio ranges from a negative value (e.g. more expressed in non-tumor tissue) to a positive value (e.g. more expressed in tumor tissue). Our purpose is to understand whether any gene sets are enriched in discordant behaviors among these subsets (when the log-ratio is increased from negative to positive). We focus on KEGG pathways. The detected pathways will be useful for our further understanding of the role of gene PNLIP in pancreatic cancer research. Among the top list of detected pathways, the neuroactive ligand receptor interaction and olfactory transduction pathways are the most significant two. Then, we consider gene TP53 that is well-known for its role as tumor suppressor in cancer research. The log-ratio also ranges from a negative value (e.g. more expressed in non-tumor tissue) to a positive value (e.g. more expressed in tumor tissue). We divided the microarray data set again according to the expression ratio of gene TP53. After the discordance enrichment analysis, we observed overall similar results and the above two pathways are still the most significant detections. More interestingly, only these two pathways have been identified for their association with pancreatic cancer in a pathway analysis of genome-wide association study (GWAS) data. CONCLUSIONS: This study illustrates that some disease-related pathways can be enriched in discordant molecular behaviors when an important disease-related gene changes its expression. Our proposed statistical method is useful in the detection of these pathways. Furthermore, our method can also be applied to genome-wide expression data collected by the recent RNA-seq technology.


Assuntos
Perfilação da Expressão Gênica , Estudo de Associação Genômica Ampla , Transcriptoma , Algoritmos , Biologia Computacional/métodos , Biologia Computacional/normas , Bases de Dados Genéticas , Estudo de Associação Genômica Ampla/métodos , Estudo de Associação Genômica Ampla/normas , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Modelos Estatísticos , Neoplasias/genética , Neoplasias/metabolismo , Reprodutibilidade dos Testes , Transdução de Sinais
10.
Stat Appl Genet Mol Biol ; 14(4): 333-45, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26087068

RESUMO

Copy number alteration (CNA) data have been collected to study disease related chromosomal amplifications and deletions. The CUSUM procedure and related plots have been used to explore CNA data. In practice, it is possible to observe outliers. Then, modifications of the CUSUM procedure may be required. An outlier reset modification of the CUSUM (ORCUSUM) procedure is developed in this paper. The threshold value for detecting outliers or significant CUSUMs can be derived using results for sums of independent truncated normal random variables. Bartel's non-parametric test for autocorrelation is also introduced to the analysis of copy number variation data. Our simulation results indicate that the ORCUSUM procedure can still be used even in the situation where the degree of autocorrelation level is low. Furthermore, the results show the outlier's impact on the traditional CUSUM's performance and illustrate the advantage of the ORCUSUM's outlier reset feature. Additionally, we discuss how the ORCUSUM can be applied to examine CNA data with a simulated data set. To illustrate the procedure, recently collected single nucleotide polymorphism (SNP) based CNA data from The Cancer Genome Atlas (TCGA) Research Network is analyzed. The method is applied to a data set collected in an ovarian cancer study. Three cytogenetic bands (cytobands) are considered to illustrate the method. The cytobands 11q13 and 9p21 have been shown to be related to ovarian cancer. They are presented as positive examples. The cytoband 3q22, which is less likely to be disease related, is presented as a negative example. These results illustrate the usefulness of the ORCUSUM procedure as an exploratory tool for the analysis of SNP based CNA data.


Assuntos
Biologia Computacional/métodos , Variações do Número de Cópias de DNA , Genômica/métodos , Modelos Genéticos , Algoritmos , Simulação por Computador , Humanos , Neoplasias/genética
11.
J Ultrasound Med ; 35(6): 1293-7, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27151903

RESUMO

OBJECTIVES: The purpose of this study was to evaluate whether demographic and sonographic factors associated with spontaneous preterm birth among nulliparous women with a cervical length of less than 30 mm could be combined into an accurate prediction model for spontaneous preterm birth. METHODS: We conducted a secondary analysis of a trial of nulliparous women with a singleton gestation and a cervical length of less than 30 mm on transvaginal sonography between 16 and 22 weeks who lacked other risk factors for spontaneous (eg, prior cervical excisional procedure) or medically indicated (eg, chronic hypertension) preterm birth, who were randomized to either 17α-hydroxyprogesterone caproate treatment or a placebo. Risk factors associated with spontaneous preterm birth within the entire cohort were identified by univariable analysis. Factors significantly associated (P < .05) with spontaneous preterm birth were included in a multivariable logistic regression analysis to determine whether an accurate prediction model could be developed. RESULTS: Of the 657 randomized patients, 109 (16.6%) had spontaneous preterm birth before 37 weeks' gestation. Logistic regression analysis revealed only cervical length (odds ratio, 1.06 per 1-mm decrease; 95% confidence interval, 1.02-1.10) to be associated with spontaneous preterm birth. The area under the receiver operating characteristic curve based on this regression was low (0.63; 95% confidence interval, 0.58-0.69). Results were similar for the outcome of spontaneous preterm birth before 34 weeks. CONCLUSIONS: An accurate prediction model for spontaneous preterm birth among nulliparous women with a short cervix could not be developed.


Assuntos
Pesos e Medidas Corporais/métodos , Colo do Útero/diagnóstico por imagem , Colo do Útero/fisiopatologia , Nascimento Prematuro/diagnóstico , Ultrassonografia Pré-Natal/métodos , Adulto , Feminino , Humanos , Valor Preditivo dos Testes , Gravidez , Reprodutibilidade dos Testes , Fatores de Risco , Adulto Jovem
12.
Am J Perinatol ; 32(9): 833-8, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25594222

RESUMO

OBJECTIVE: This study aims to determine whether there is a threshold 3-hour oral glucose tolerance test (OGTT) value associated with accelerated risk of adverse pregnancy outcomes. STUDY DESIGN: In a secondary analysis of a cohort of women with untreated mild gestational glucose intolerance, we used generalized additive models with smoothing splines to explore nonlinear associations between each of the 3-hour OGTT values (fasting, 1-hour, 2-hour, and 3-hour) and adverse pregnancy outcomes, including the study's composite outcome (perinatal mortality, hypoglycemia, hyperbilirubinemia, neonatal hyperinsulinemia, and/or birth trauma), large for gestational age birth weight, small for gestational age birth weight, shoulder dystocia, neonatal hypoglycemia, gestational hypertension (gHTN), and preeclampsia. RESULTS: Among the 1,360 eligible women, each timed OGTT value was linearly associated with increased odds of composite adverse outcome. We found evidence of a departure from linearity only for the association between fasting glucose and gHTN/preeclampsia, with a stronger association for values of 85 to 94 mg/dL (p = 0.03). We found no evidence of departure from linearity for any other OGTT values and measured outcomes (all chi-square test p-values ≥ 0.05). CONCLUSION: In a population of untreated women with mild gestational glucose intolerance and fasting OGTT < 95 mg/dL, we found an increasing risk of gHTN with a fasting glucose between 85 and 94 mg/dL.


Assuntos
Distocia/epidemiologia , Intolerância à Glucose/sangue , Teste de Tolerância a Glucose/normas , Hipertensão Induzida pela Gravidez/epidemiologia , Hipoglicemia/epidemiologia , Pré-Eclâmpsia/epidemiologia , Resultado da Gravidez , Adulto , Peso ao Nascer , Estudos de Coortes , Feminino , Macrossomia Fetal , Idade Gestacional , Humanos , Recém-Nascido , Gravidez , Adulto Jovem
13.
Am J Perinatol ; 32(1): 57-62, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24819145

RESUMO

OBJECTIVE: The objective of the article is to describe latency for patients with preterm premature membrane rupture (PPROM) between 24(0/7) and 31(6/7) weeks' gestation. STUDY DESIGN: Secondary analysis of data collected prospectively in a multicenter clinical trial of magnesium sulfate for cerebral palsy prevention. Women with PPROM and fewer than six contractions per hour at enrollment who were candidates for expectant management (n = 1,377) were included in this analysis. Length of latency was calculated in days by subtracting the time of delivery from the time of membrane rupture. RESULTS: At each week of gestation, median latency between 24 and 28 weeks was similar at approximately 9 days, but it was significantly shorter with PPROM at 29, 30, and 31 weeks (p < 0.001). In addition, the percentage of patients remaining undelivered at 7 days and 14 days was similar for PPROM between 24 and 28 weeks, but it decreased significantly after that. For each gestational age, the proportion of patients remaining pregnant declined in a fashion similar to an exponential pattern. CONCLUSION: Median latency after PPROM is similar from 24 to 28 weeks' gestation, but it shortens with PPROM at and after 29 weeks.


Assuntos
Parto Obstétrico , Ruptura Prematura de Membranas Fetais , Segundo Trimestre da Gravidez , Terceiro Trimestre da Gravidez , Adulto , Estudos de Coortes , Feminino , Humanos , Modelos Logísticos , Análise Multivariada , Paridade , Gravidez , Gravidez de Gêmeos/estatística & dados numéricos , Modelos de Riscos Proporcionais , Estudos Prospectivos , Fumar/epidemiologia , Fatores de Tempo , Adulto Jovem
14.
Am J Perinatol ; 32(4): 387-92, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25241107

RESUMO

OBJECTIVE: This study aims to evaluate whether magnesium sulfate administration for neuroprotection prolongs latency in women with preterm premature rupture of membranes (PPROM) between 24 and 31(6/7) weeks' gestation. STUDY DESIGN: This is a secondary analysis of a randomized controlled trial of magnesium sulfate for prevention of cerebral palsy. Gravid women with a singleton pregnancy between 24 and 31(6/7) weeks' gestation with PPROM without evidence of labor were randomized to receive magnesium sulfate, administered intravenously as a 6-g bolus followed by a constant infusion of 2 g per hour up to 12 hours, or placebo. Maternal outcomes for this analysis were delivery in less than 48 hours and in less than 7 days from randomization. Neonatal outcomes included a composite of respiratory distress syndrome, interventricular hemorrhage grades 3 or 4, periventricular leukomalacia, sepsis, necrotizing enterocolitis, retinopathy of prematurity, or death. RESULTS: A total of 1,259 women were included. The rate of delivery < 48 hours was not different in the magnesium sulfate and the placebo groups (22.2 and 20.7%, p = 0.51). Delivery < 7 days was similar between groups (55.4 and 51.4%, p = 0.16). Median latency was also similar between groups (median [interquartile range], 6.0 days [range, 2.4-13.8 days] and 6.6 days [range, 2.4-15.1 days], p = 0.29). Composite neonatal outcomes did not differ between groups. CONCLUSION: Magnesium sulfate administration given for neuroprotection in women with a singleton gestation with PPROM and without labor before 32 weeks does not impact latency.


Assuntos
Ruptura Prematura de Membranas Fetais/tratamento farmacológico , Sulfato de Magnésio/uso terapêutico , Fármacos Neuroprotetores/uso terapêutico , Tocolíticos/uso terapêutico , Adulto , Paralisia Cerebral/prevenção & controle , Parto Obstétrico , Feminino , Idade Gestacional , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Doenças do Prematuro/prevenção & controle , Trabalho de Parto Prematuro/prevenção & controle , Gravidez , Resultado do Tratamento , Adulto Jovem
15.
BMC Genomics ; 15 Suppl 1: S6, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24564564

RESUMO

BACKGROUND: Gene set enrichment analysis (GSEA) is an important approach to the analysis of coordinate expression changes at a pathway level. Although many statistical and computational methods have been proposed for GSEA, the issue of a concordant integrative GSEA of multiple expression data sets has not been well addressed. Among different related data sets collected for the same or similar study purposes, it is important to identify pathways or gene sets with concordant enrichment. METHODS: We categorize the underlying true states of differential expression into three representative categories: no change, positive change and negative change. Due to data noise, what we observe from experiments may not indicate the underlying truth. Although these categories are not observed in practice, they can be considered in a mixture model framework. Then, we define the mathematical concept of concordant gene set enrichment and calculate its related probability based on a three-component multivariate normal mixture model. The related false discovery rate can be calculated and used to rank different gene sets. RESULTS: We used three published lung cancer microarray gene expression data sets to illustrate our proposed method. One analysis based on the first two data sets was conducted to compare our result with a previous published result based on a GSEA conducted separately for each individual data set. This comparison illustrates the advantage of our proposed concordant integrative gene set enrichment analysis. Then, with a relatively new and larger pathway collection, we used our method to conduct an integrative analysis of the first two data sets and also all three data sets. Both results showed that many gene sets could be identified with low false discovery rates. A consistency between both results was also observed. A further exploration based on the KEGG cancer pathway collection showed that a majority of these pathways could be identified by our proposed method. CONCLUSIONS: This study illustrates that we can improve detection power and discovery consistency through a concordant integrative analysis of multiple large-scale two-sample gene expression data sets.


Assuntos
Perfilação da Expressão Gênica/métodos , Neoplasias Pulmonares/genética , Algoritmos , Biologia Computacional/métodos , Bases de Dados Genéticas , Genoma Humano , Humanos , Modelos Estatísticos , Análise de Sequência com Séries de Oligonucleotídeos/métodos
16.
Stat Med ; 33(6): 1015-28, 2014 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-24114935

RESUMO

Although change-point analysis methods for longitudinal data have been developed, it is often of interest to detect multiple change points in longitudinal data. In this paper, we propose a linear mixed effects modeling framework for identifying multiple change points in longitudinal Gaussian data. Specifically, we develop a novel statistical and computational framework that integrates the expectation-maximization and the dynamic programming algorithms. We conduct a comprehensive simulation study to demonstrate the performance of our method. We illustrate our method with an analysis of data from a trial evaluating a behavioral intervention for the control of type I diabetes in adolescents with HbA1c as the longitudinal response variable.


Assuntos
Modelos Lineares , Adolescente , Algoritmos , Terapia Comportamental , Bioestatística , Criança , Simulação por Computador , Intervalos de Confiança , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 1/psicologia , Diabetes Mellitus Tipo 1/terapia , Hemoglobinas Glicadas/metabolismo , Humanos , Funções Verossimilhança , Estudos Longitudinais , Modelos Estatísticos , Ensaios Clínicos Controlados Aleatórios como Assunto/estatística & dados numéricos
17.
Am J Obstet Gynecol ; 209(4): 340.e1-5, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23770470

RESUMO

OBJECTIVE: The objective of the study was to determine whether an individualized growth standard (IS) improves the identification of preterm small-for-gestational-age (SGA) neonates at risk of developing moderate/severe cerebral palsy (CP) or death. STUDY DESIGN: This study was a secondary analysis of data from a randomized trial of MgSO4 for the prevention of CP or death among anticipated preterm births. Singleton nonanomalous liveborns delivered before 34 weeks' were classified as SGA (less than the 10th percentile for their gestational age) by a population standard (PS) or an IS (incorporating maternal age, height, weight, parity, race/ethnicity, and neonatal sex). The primary outcome was the prediction of moderate or severe CP or death by age 2 years. RESULTS: Of 1588 eligible newborns, 143 (9.4%) experienced CP (n = 33) or death (n = 110). Forty-four (2.8%) were SGA by the PS and 364 (22.9%) by the IS. All PS-SGA newborns also were identified as IS-SGA. SGA newborns by either standard had a similarly increased risk of CP or death (PS: relative risk [RR], 2.4, 95% confidence interval [CI], 1.3-4.3 vs IS: RR, 1.8, 95% CI, 1.3-2.5, respectively). The similarity of RRs remained after stratification by the MgSO4 treatment group. The IS was more sensitive (36% vs 6%, P < .001) but less specific (78% vs 98%, P < .001) for CP or death. The receiver operating characteristic curve analysis revealed a statistically lower area under the curve for the PS, although the ability of either method to predict which neonates would subsequently develop CP or death was poor (PS: 0.55, 95% CI, 0.49-0.60 vs IS: 0.59, 95% CI, 0.54-0.64, P < .001). CONCLUSION: An individualized SGA growth standard does not improve the association with, or prediction of, CP or death by age 2 years.


Assuntos
Peso ao Nascer , Paralisia Cerebral/epidemiologia , Idade Gestacional , Mortalidade Infantil , Adulto , Feminino , Retardo do Crescimento Fetal/epidemiologia , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Recém-Nascido Pequeno para a Idade Gestacional , Masculino , Gravidez , Nascimento Prematuro , Curva ROC , Medição de Risco , Adulto Jovem
18.
Am J Perinatol ; 30(4): 335-41, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22893556

RESUMO

OBJECTIVE: To compare population versus customized fetal growth norms in identifying neonates at risk for adverse outcomes (APO) associated with small for gestational age (SGA). STUDY DESIGN: Secondary analysis of an intrapartum fetal pulse oximetry trial in nulliparous women at term. Birth weight percentiles were calculated using ethnicity- and gender-specific population norms and customized norms (Gardosi). RESULTS: Of the studied neonates, 508 (9.9%) and 584 (11.3%) were SGA by population (SGApop) and customized (SGAcust) norms, respectively. SGApop infants were significantly associated with a composite adverse neonatal outcome, neonatal intensive care admission, low fetal oxygen saturation, and reduced risk of cesarean delivery; both SGApop and SGAcust infants were associated with a 5-minute Apgar score < 4. The ability of customized and population birth weight percentiles in predicting APO was poor (12 of 14 APOs had area under the curve of <0.6). CONCLUSION: In this intrapartum cohort, neither customized nor normalized population norms adequately identified neonates at risk of APO related to SGA.


Assuntos
Índice de Apgar , Retardo do Crescimento Fetal/fisiopatologia , Recém-Nascido Pequeno para a Idade Gestacional , Complicações na Gravidez/fisiopatologia , Resultado da Gravidez , Peso ao Nascer , Intervalos de Confiança , Feminino , Desenvolvimento Fetal/fisiologia , Idade Gestacional , Humanos , Recém-Nascido , Unidades de Terapia Intensiva Neonatal , Masculino , Oximetria/métodos , Gravidez , Diagnóstico Pré-Natal/métodos , Curva ROC , Valores de Referência
19.
N Engl J Med ; 360(2): 111-20, 2009 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-19129525

RESUMO

BACKGROUND: Because of increased rates of respiratory complications, elective cesarean delivery is discouraged before 39 weeks of gestation unless there is evidence of fetal lung maturity. We assessed associations between elective cesarean delivery at term (37 weeks of gestation or longer) but before 39 weeks of gestation and neonatal outcomes. METHODS: We studied a cohort of consecutive patients undergoing repeat cesarean sections performed at 19 centers of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network from 1999 through 2002. Women with viable singleton pregnancies delivered electively (i.e., before the onset of labor and without any recognized indications for delivery before 39 weeks of gestation) were included. The primary outcome was the composite of neonatal death and any of several adverse events, including respiratory complications, treated hypoglycemia, newborn sepsis, and admission to the neonatal intensive care unit (ICU). RESULTS: Of 24,077 repeat cesarean deliveries at term, 13,258 were performed electively; of these, 35.8% were performed before 39 completed weeks of gestation (6.3% at 37 weeks and 29.5% at 38 weeks) and 49.1% at 39 weeks of gestation. One neonatal death occurred. As compared with births at 39 weeks, births at 37 weeks and at 38 weeks were associated with an increased risk of the primary outcome (adjusted odds ratio for births at 37 weeks, 2.1; 95% confidence interval [CI], 1.7 to 2.5; adjusted odds ratio for births at 38 weeks, 1.5; 95% CI, 1.3 to 1.7; P for trend <0.001). The rates of adverse respiratory outcomes, mechanical ventilation, newborn sepsis, hypoglycemia, admission to the neonatal ICU, and hospitalization for 5 days or more were increased by a factor of 1.8 to 4.2 for births at 37 weeks and 1.3 to 2.1 for births at 38 weeks. CONCLUSIONS: Elective repeat cesarean delivery before 39 weeks of gestation is common and is associated with respiratory and other adverse neonatal outcomes.


Assuntos
Recesariana/efeitos adversos , Procedimentos Cirúrgicos Eletivos/efeitos adversos , Idade Gestacional , Doenças do Recém-Nascido/etiologia , Resultado da Gravidez , Adolescente , Adulto , Estudos de Coortes , Feminino , Hospitalização , Humanos , Hipoglicemia/epidemiologia , Recém-Nascido , Doenças do Recém-Nascido/epidemiologia , Recém-Nascido Pequeno para a Idade Gestacional , Tempo de Internação , Idade Materna , Gravidez , Grupos Raciais , Respiração Artificial/estatística & dados numéricos , Síndrome do Desconforto Respiratório do Recém-Nascido/epidemiologia , Sepse/epidemiologia , Estados Unidos , Adulto Jovem
20.
Am J Obstet Gynecol ; 206(3): 239.e1-8, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22244471

RESUMO

OBJECTIVE: The objective of the study was to compare pregnancy outcomes by completed week of gestation after 39 weeks with outcomes at 39 weeks. STUDY DESIGN: Secondary analysis of a multicenter trial of fetal pulse oximetry in spontaneously laboring or induced nulliparous women at a gestation of 36 weeks or longer. Maternal outcomes included a composite (treated uterine atony, blood transfusion, and peripartum infections) and cesarean delivery. Neonatal outcomes included a composite of death, neonatal respiratory and other morbidities, and neonatal intensive care unit admission. RESULTS: Among the 4086 women studied, the risks of the composite maternal outcome (P value for trend < .001), cesarean delivery (P < .001), and composite neonatal outcome (P = .047) increased with increasing gestational age from 39 to 41 or more completed weeks. Adjusted odds ratios (95% confidence interval) for 40 and 41 or more weeks, respectively, compared with 39 weeks were 1.29 (1.03-1.64) and 2.05 (1.60-2.64) for composite maternal outcome, 1.28 (1.05-1.57) and 1.75 (1.41-2.16) for cesarean delivery, and 1.25 (0.86-1.83) and 1.37 (0.90-2.09) for composite neonatal outcome. CONCLUSION: Risks of maternal morbidity and cesarean delivery but not neonatal morbidity increased significantly beyond 39 weeks.


Assuntos
Parto Obstétrico , Paridade , Resultado da Gravidez , Adolescente , Adulto , Feminino , Humanos , Mortalidade Infantil , Recém-Nascido , Masculino , Estudos Multicêntricos como Assunto , Oximetria , Gravidez , Risco , Fatores de Tempo , Adulto Jovem
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