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Biomedical subjects

W L Holcomb

Publications and source records attributed to W L Holcomb.

14 recordsLinked to original sources
PubMed2001

An odd measure of risk: use and misuse of the odds ratio.

OBJECTIVE: To determine how often the odds ratio, as used in clinical research of obstetrics and gynecology, differs substantially from the risk ratio estimate and to assess whether the difference in these measures leads to misinterpretation of research results. METHODS: Articles from 1998 through 1999 in Obstetrics & Gynecology and the American Journal of Obstetrics and Gynecology were searched for the term "odds ratio." The key odds ratio in each article was identified, and, when possible, an estimated risk ratio was calculated. The odds ratios and the estimated risk ratios were compared quantitatively and graphically. RESULTS: Of 151 studies using odds ratios, 107 were suitable to estimate a risk ratio. The difference between the odds ratio and the estimated risk ratio was greater than 20% in 47 (44%) of these articles. An odds ratio appears to magnify an effect compared with a risk ratio. In 39 (26%) articles the odds ratio was interpreted as a risk ratio without explicit justification. CONCLUSION: The odds ratio is frequently used, and often misinterpreted, in the current literature of obstetrics and gynecology.

Data Interpretation, Statistical↗
PubMed2001

African-American women have higher initial HbA1c levels in diabetic pregnancy.

OBJECTIVE: African-American women with diabetes are at greater risk for poor glycemic control outside of pregnancy. We evaluated the effect of race on glycemic control in a racially mixed population of women with diabetes entering prenatal care. RESEARCH DESIGN AND METHODS: HbA1c levels along with demographic data were collected at the first prenatal visit from a group of 234 women with preexisting diabetes. We applied logistic multivariate analysis to identify factors associated with HbA1c levels above the median for the group. RESULTS: The median HbA1c level for the group was 8%. HbA1c levels were 8.7 +/- 2.0% in African-Americans and 7.7 +/- 1.5% in Caucasians (P < 0.001). African-American racial designation was significantly and independently associated with high HbA1c when controlled for maternal age, parity, White classification, diabetes type, education, marital status, obesity, insurance type, and first trimester entry into care. The effect of race was confined to the nonobese patients, for whom the adjusted odds ratio for African-American race as a predictor of high HbA1c was 8.15 with a 95% CI of 2.41-27.58 (P = 0.001). CONCLUSIONS: We found a clear racial disparity in glycemic control among women entering prenatal care with preexisting diabetes. This study demonstrates that there generally is need for better glycemic control among reproductive-age women with diabetes, but especially among those who are African-American.

Adult↗
PubMed1998

Plasma leptin concentrations in newborns of diabetic and nondiabetic mothers.

Leptin plays an important role in regulating body composition through modulation of appetite and energy expenditure. We hypothesized that leptin levels in umbilical cord blood correlate with newborn body weight and habitus. We also hypothesized that infants of diabetic mothers would demonstrate altered leptin metabolism. Venous blood was sampled at birth from the umbilical cords of 105 infants (74 infants of nondiabetic mothers, and 31 infants of diabetic mothers). Thirty-nine mothers had plasma leptin concentrations measured. Analysis was done using Student's t-test, Pearson's correlation, and Spearman's correlation. Univariate/multivariate regression was used for analysis of factors associated with leptin concentration in umbilical cord plasma. Maternal and newborn characteristics were correlated with log leptin levels in umbilical venous plasma. Leptin concentration in umbilical cord plasma correlated best with birth weight for newborns of both nondiabetic and diabetic mothers (p < 0.01 for either). Umbilical cord plasma concentration of leptin was higher in infants of diabetic mothers than in infants of nondiabetic mothers (2.53 +/- 1.09 vs. 1.76 +/- 0.82; p < 0.001). Multiple regression analysis revealed a significant (p < 0.01) relationship between umbilical cord leptin level and newborn birth weight, as well as maternal DM, but not with gestational age. Similarly, there was no significant correlation with maternal plasma leptin concentration. The strong correlation of leptin concentration in umbilical cord plasma with newborn birth weight, and the lack of significant correlation with maternal leptin plasma levels, suggest that normal fetal leptin metabolism reflects fetal size and/or body habitus independent of maternal leptin metabolism. On the other hand, the higher umbilical plasma levels in infants of diabetic mothers may reflect an influence of altered fetal insulin homeostasis on fetal leptin metabolism, and suggests that maternal diabetes may influence fetal leptin metabolism.

Adolescent↗
PubMed1997

Transitivity and emergent sequence performances in young children.

Children taught to sequence pairs of visual stimuli also performed additional sequences without direct training. In Experiment 1, the children were trained to produce a six-stimulus sequence (A > B > C > D > E > F) with one set of forms, and five overlapping two-stimulus sequences (A > B, B > C, C > D, D > E, and E > F) with another set of forms. Few of the children succeeded on tests for the untrained two- (e.g., B > D and B > E) and six-stimulus sequences derivable from the two-stimulus training. The children in Experiments 2 and 3 received only the overlapping sequence training before testing with refined protocols: Nearly all succeeded on tests of emergent sequences involving two, three, four, five, and six stimuli. The results suggest methods for examining transitive relations between pairs of the stimuli used in training and the development of a relation of order among all six of the stimuli involved.

Chi-Square Distribution↗
PubMed1996

Screening for depression in pregnancy: characteristics of the Beck Depression Inventory.

OBJECTIVE: To determine the test characteristics of a self-report questionnaire, the Beck Depression Inventory, when used as a screening test for depression in a population of ambulatory pregnant women. METHODS: One hundred five pregnant women completed the Beck Depression Inventory and underwent a structured interview using the National Institute of Mental Health Diagnostic Interview Schedule-version III. Current depression was diagnosed according to the criteria of the Diagnostic and Statistical Manual of Mental Disorders-III-R. A receiver operating characteristic curve was constructed for the Beck Depression Inventory score as a predictor of current depression. A table of sensitivities, specificities, predictive values, and likelihood ratios was created for various cutoff values. RESULTS: For the 105 women enrolled, the median Beck Depression Inventory score was 8.0. Twelve women (11%) were diagnosed with current depression and had a median Beck Depression Inventory score of 25.5, compared with those without current depression, who had a median score of 8.0 (P = .001). The area under the receiver operating characteristic curve was 0.9940. Using a cutoff range of greater than 16, the sensitivity of the Beck Depression Inventory to detect current depression was 0.83, the specificity was 0.89, the positive predictive value was 0.50, and the negative predictive value was 0.98. CONCLUSIONS: The Beck Depression Inventory can serve as a rapid screening test for depression during pregnancy. A higher cutoff value is required for pregnant women than is customarily used outside of pregnancy.

Adult↗
PubMed1995

Renal transplantation one week after conception.

A successful 38-week pregnancy is reported following renal transplantation approximately 1 week after conception. The patient was treated with quadruple sequential induction therapy, maintenance immunosuppression, and routine posttransplantation care, including ganciclovir treatment for a symptomatic cytomegalovirus infection during the pregnancy and 3 months after delivery. No decline in renal function was noted. The mother and child remain healthy at 18 months. This case demonstrates the ability of renal transplant patients to maintain renal function throughout pregnancy and the lack of deleterious effects upon the child during gestation and at up to 18 months after birth, despite significant immunosuppression, including antithymocyte globulin induction therapy, and infectious complications of the mother's renal transplantation.

Adult↗
PubMed1994

Comparative diagnosis of neonatal chlamydial conjunctivitis by polymerase chain reaction and McCoy cell culture.

Cervical and ocular swabs from 100 mother/newborn pairs delivering on the clinic service were assayed for Chlamydia trachomatis with standard McCoy cell culture and with standard and biotinylated polymerase chain reaction techniques, using primers directed against the major outer membrane protein gene and C. trachomatis-specific cryptic plasmid, respectively. Using the polymerase chain reaction, 20 (20%) mothers and seven (7%) neonates were positive for Chlamydia. All neonates positive by polymerase chain reaction were from mothers positive by polymerase chain reaction, yielding a 35% transmission rate. Only five of 20 (25%) mothers and two of seven (28%) neonates positive by polymerase chain reaction were positive by cell culture. All cell culture samples were positive by polymerase chain reaction testing. Culture and polymerase chain reaction analysis two weeks after treatment with oral erythromycin were negative. The polymerase chain reaction assay appears to be equally specific and more sensitive than McCoy cell culture for the detection of C. trachomatis from ocular specimens.

Adolescent↗
PubMed1993

Fetal nonmuscular soft tissue: a prenatal assessment.

In this study, the fetal nonmuscular soft tissue is evaluated prenatally in 52 uncomplicated singleton pregnancies at 36 weeks of gestation or later. The means and standard deviations of the NMST at the midarm region and the ratio of NMST to HL are 6.0 +/- 1.0 mm and 0.08 +/- 0.02, respectively. No correlation was seen between the NMST and birth weight.

Anthropometry↗
PubMed1991

Magnesium tocolysis and neonatal bone abnormalities: a controlled study.

This study was conducted to investigate the relationship between maternal administration of intravenous (IV) magnesium sulfate and radiographic abnormality of neonatal long bones. Eleven neonates in the exposed group were born to mothers who had received IV magnesium tocolysis for more than 7 days. Two gestational age-matched unexposed neonates were selected for each member of the exposed group. Initial chest radiographs of exposed and unexposed neonates were reviewed in random sequence by a pediatric radiologist who was blinded to exposure status. On evaluation of the proximal humeri, six neonates had radiographic abnormalities consisting of transverse radiolucent and/or sclerotic bands; all six were in the exposed group. The difference in radiographic findings between the exposed and unexposed groups was statistically significant (P less than .001). These results support the existence of a causal relationship between prolonged IV magnesium tocolysis and abnormal fetal bone mineralization. Further study is needed to elucidate the mechanism and clinical significance of these bone changes.

Abnormalities, Drug-Induced↗
PubMed1991

Cervical effacement: variation in belief among clinicians.

Cervical effacement may be described as a percentage or as residual cervical length in centimeters. For effective communication among clinicians, the percentage method requires agreement about the length of the uneffaced cervix. Variation in beliefs regarding cervical effacement and length was assessed among practicing obstetricians at a single medical center. The mean estimate for the length of the uneffaced cervix at term was 2.47 +/- 0.64 cm, with a range of 1-4 cm and a coefficient of variation of 26%. The mean estimate of physicians in private practice was significantly shorter (P less than .001) than that of faculty and house staff combined. There is the potential for miscommunication among physicians based on variation in beliefs about effacement. Adoption of the metric system for description of the cervix would eliminate hidden assumptions about cervical length and the concept of effacement.

Cervix Uteri↗
PubMed1990

Clinical use of the Kleihauer-Betke test.

Results of all Kleihauer-Betke (KB) tests performed in 1988, at a center with 4,201 deliveries, were reviewed. Two hundred and twenty-seven tests were performed on maternal specimens from 205 patients. Eighteen (8.8%) of the 205 patients had positive test results. Medical records were available for 147 (71.7%) of the patients, including 17 of the 18 patients with a positive result. Indications for testing were: vaginal bleeding (33%), maternal trauma (31%), unexplained fetal death (5%), Rh incompatibility (3%), fetal distress (3%), and miscellaneous (24%). Most of the tests were performed antepartum. In only one case, and without clear benefit, did the KB test prompt a clinical intervention. At least two of the 18 patients with positive test results had probable false positive results due to maternal hemoglobin F. Such false positive KB test results may be misleading. Further evaluation of the role of the KB test in obstetrical management is needed.

Erythrocyte Count↗
PubMedDate not supplied

Abdominal circumference vs. estimated weight to predict large for gestational age birth weight in diabetic pregnancy.

Early third trimester fetal abdominal circumference and sonographic fetal weight estimates were compared to predict large for gestational age birth weight in diabetic pregnancy. Both parameters have similar sensitivity, specificity, and predictive values. However, the optimal percentile cutoff values differ. Choice of birth weight standard significantly influences test characteristics. Negative prediction of large birth weight is more accurate than positive prediction. At third trimester sonography with maternal diabetes, the abdominal circumference percentile is potentially useful and should be routinely reported.

Abdomen↗