Association of necrotizing enterocolitis with anemia and packed red blood cell transfusions in preterm infants.

OBJECTIVE: To determine association of anemia and red blood cell (RBC) transfusions with necrotizing enterocolitis (NEC) in preterm infants. STUDY DESIGN: A total of 111 preterm infants with NEC ≥ stage 2a were compared with 222 matched controls. In all, 28 clinical variables, including hematocrit (Hct) and RBC transfusions were recorded. Propensity scores and multivariate logistic regression models were created to examine effects on the risk of NEC. RESULT: Controlling for other factors, lower Hct was associated with increased odds of NEC (odds ratio (OR)=1.10, P=0.01). RBC transfusion has a temporal relationship with NEC onset. Transfusion within 24 h (OR=7.60, P=0.001) and 48 h (OR=5.55, P=0.001) has a higher odds of developing NEC but this association is not significant by 96 h (OR=2.13, P=0.07), post-transfusion. CONCLUSION: Anemia may increase the risk of developing NEC in preterm infants. RBC transfusions are temporally related to NEC. Prospective studies are needed to better evaluate the potential influence of transfusions on the development of NEC.

X-irradiation of the contusion site improves locomotor and histological outcomes in spinal cord-injured rats.

We have determined whether X-irradiation of the injury site can oppose tissue loss and improve recovery of locomotor function following contusion injury of the spinal cord. Contusion injury was produced in rats at the level of T10 with a weight drop device. Localized X-irradiation (20 Gy) of the injury site was performed at 20 min and 1, 2, 4, 7, and 17 days postinjury. Locomotor recovery was then determined with the 21-point Basso, Beattie, and Bresnahan (BBB) scale. X-irradiation enhanced recovery of locomotor function during a subsequent 6-week observation period when administered 20 min and 1 or 2 days following contusion injury (final BBB score approximately 7-8). X-irradiation at 4-17 days postinjury did not significantly affect final locomotor scores compared with unirradiated rats (final BBB score approximately 2), in marked contrast to previous studies where X-irradiation applied only at 17-18 days benefitted transection injury. The extent of recovery was directly related to measurements of sparing of spinal cord tissue at the contusion center. Because the treatment time window occurred earlier in contusion than reported for transection injury, the results suggest that contusion injury rapidly initiates underlying radiation-sensitive processes that occur only following a delay of several weeks after transection injury. Further optimization of X-ray treatment may lead to a useful therapeutic modality for use in spinal cord contusion injury.

Antenatal steroids and neonatal periventricular leukomalacia.

OBJECTIVE: To evaluate the effect of antenatal steroid treatment on the development of neonatal periventricular leukomalacia. METHODS: This retrospective cohort study included 1161 neonates with gestational ages of 24-34 weeks and birth weights of 500-1750 g, divided into two groups on the basis of antenatal steroid treatment. Neonatal neurosonograms were done on days 3 and 7 of life and labeled normal or abnormal. The abnormal outcomes evaluated were periventricular leukomalacia or intraventricular hemorrhage, periventricular leukomalacia with intraventricular hemorrhage, and isolated periventricular leukomalacia. The group treated with antenatal steroids was compared with the untreated group for these outcomes. RESULTS: Antenatal steroids were associated with significantly less periventricular leukomalacia or intraventricular hemorrhage (23% versus 31%, P =.005), periventricular leukomalacia with intraventricular hemorrhage (5% versus 11%, P =.001), and isolated periventricular leukomalacia (3% versus 7%, P =.009). Logistic regression analysis of antenatal steroid treatment, controlling for confounding maternal and neonatal characteristics, indicated that neonates treated with antenatal steroids had a 56% lower likelihood of periventricular leukomalacia with intraventricular hemorrhage (adjusted odds ratio [OR] 0.44, 95% confidence interval [CI] 0.25, 0.77) and a 58% lower likelihood of isolated periventricular leukomalacia (adjusted OR 0.42, 95% CI 0.20, 0.88). CONCLUSION: Antenatal steroid treatment was associated with over 50% reduction in the incidence of periventricular leukomalacia in preterm neonates. Increased use of antenatal steroid therapy might improve long-term neonatal neurologic outcomes.

Survey of the extent and nature of care for adults and older adults by allergy/immunology practitioners.

BACKGROUND: The proportion of older adults in the US population will increase dramatically in the near future, yet the frequency and nature of care furnished to older adults by Allergy/Immunology practitioners has not been described. OBJECTIVE: To determine the extent and nature of care being provided to adults and older adults by Allergy/Immunology practitioners. METHODS: ACAAI members and fellows were surveyed to obtain information regarding certification and training as well as their practice patterns. RESULTS: The distribution of diagnoses among patients aged 40 to 54 years were very similar to distributions found among adults age 55 to 69 years and > or = 70 years of age. Virtually all respondents indicated they provide inhalant allergen immunotherapy for patients age 40 to 54 years with asthma and/or allergic rhinitis; administration of inhalant allergen immunotherapy for asthma and allergic rhinitis was also frequently reported for adults > or = 55 years. The proportions of respondents providing venom immunotherapy for adults aged 40 to 54, 55 to 69, and > or = 70 years were 82%, 70%, and 39%, respectively. CONCLUSION: ACAAI members and fellows commonly provide care to older adults. Our survey findings highlight the need to develop strategies for successful management of Allergy/Immunology conditions specifically pertaining to older adults, including studies to determine the therapeutic utility of inhalant allergen and venom immunotherapy in this age group.

Reduced risk of low weight births among indigent women receiving care from nurse-midwives.

STUDY OBJECTIVE: To examine the effect of a comprehensive prenatal and delivery programme administered by nurse-midwives on the risk of low weight births among indigent women. STUDY DESIGN: Historical prospective study. Birth outcomes among the cohort were compared with all county births during the same period, adjusting for maternal age and race. Results are expressed as relative risks with 95% confidence intervals. SETTING: An enhanced Medicaid funded pre-natal programme administered by nurse-midwives from 1992 to 1994 in Westchester County, New York. PARTICIPANTS: Indigent mothers (n = 1443), between the ages of 15 and 44, who were residents of Westchester County and indicated having Medicaid or no health care coverage. RESULTS: There were 1474 live births among cohort mothers. Mean (SD) gestational age was 39.4 (1.9) weeks. Less than 6% of births occurred before 37 weeks gestation. The mean birth weight of cohort infants was 3365.6 (518.6) g. Only 4.1% of the cohort births were less than 2500 g. Compared with all county births, the cohort showed a 41% reduction in the risk of low weight births (RRlbw = 0.59, 95% CI: 0.46 to 0.73, p < .001) and a 56% reduction when compared with county Medicaid births only (RR = 0.44, 95% CI: 0.34 to 0.57, p < .005) adjusting for maternal age and race. Larger reductions were found for very low weight births. CONCLUSIONS: Mothers need not be considered at high risk for adverse pregnancy outcomes based on their socioeconomic status alone. Moreover, a comprehensive prenatal programme administered by nurse-midwives may promote a reduction in adverse pregnancy outcomes among indigent mothers.

Maternal magnesium sulfate and the development of neonatal periventricular leucomalacia and intraventricular hemorrhage.

OBJECTIVE: Neonatal periventricular leucomalacia and intraventricular hemorrhage are strong correlates of cerebral palsy. Our objective was to evaluate the effect of maternal magnesium sulfate exposure on the incidence and severity of periventricular leucomalacia and intraventricular hemorrhage in preterm neonates. METHODS: Nine hundred eighteen consecutive inborn neonates with birth weights from 500 to 1750 g were divided primarily into two groups on the basis of maternal exposure to magnesium sulfate. The groups were divided secondarily into two clinical groups, a physician-initiated group, which consisted of neonates delivered for maternal or fetal indications, and a preterm delivery group, which included neonates delivered as a result of preterm labor or preterm premature rupture of membranes. These clinical groups were stratified further into magnesium sulfate-exposed and -unexposed subgroups. Neonatal neurosonograms were performed on days 3 and 7 of life and described as normal or abnormal. Abnormal sonograms included any periventricular leucomalacia or intraventricular hemorrhage. Severe lesions included periventricular leucomalacia, periventricular leucomalacia with intraventricular hemorrhage, or grades 3 or 4 intraventricular hemorrhage. The magnesium sulfate groups and the clinical groups with their magnesium sulfate strata were compared for the incidence and severity of abnormal sonograms. They also were compared for maternal and neonatal characteristics. RESULTS: Maternal magnesium sulfate exposure was not associated with reduction in the incidence of abnormal sonograms when compared with the unexposed group (27% compared with 33%, P = .06). However, fewer severe lesions were observed in the exposed group (14% compared with 21%, P = .004). When clinical groups were examined, magnesium sulfate was not associated with a decrease in abnormal sonograms (adjusted odds ratio [OR] 1.09, 95% confidence interval [CI] 0.78, 1.52, P = .40) or severe lesions (adjusted OR 1.11, 95% CI 0.73, 1.68, P = .42). Logistic regression analyses of magnesium sulfate exposure within clinical groups controlling for the confounding effects of maternal and neonatal characteristics revealed no protective effect of magnesium sulfate exposure on the incidence of abnormal sonograms (adjusted OR 1.01, 95% CI 0.70, 1.44, P = .97) or severe lesions (adjusted OR 1.01, 95% CI 0.70, 1.74, P = .69). Within clinical groups, the preterm delivery group exhibited an increased risk for abnormal sonograms (adjusted OR 1.63, 95% CI 1.01, 2.67, P = .05) and severe lesions (adjusted OR 9.79, 95% CI 3.27, 29.29, P = .001) when compared with the physician-initiated delivery group, independent of maternal magnesium sulfate exposure. CONCLUSION: Maternal magnesium sulfate exposure had no protective effect on the incidence or severity of periventricular leucomalacia and intraventricular hemorrhage in preterm neonates. The prevalence of these lesions was correlated better with the clinical group of origin and indication for its use.

Understanding and using confidence intervals in clinical research.

Confidence intervals contain a wealth of clinically relevant information that is not available in the P value and usual significance testing. Numerous articles discuss the hazards of interpreting study results based solely on the P value, raising both practical and philosophical concerns. The general recommendation is that clinical research should not just test hypotheses, but also describe magnitudes of clinical effect. To this end, the confidence interval is a crucial tool in interpreting clinical studies. In this report, we show how one may use confidence intervals to gain further insight into clinical research. For example, by using confidence intervals, one can identify statistically significant results that are clinically imprecise, or conversely, statistically nonsignificant results that are quite precise. In addition, confidence intervals, like the P value, are influenced by sample size. We show how sample sizes that are sufficiently large to test hypotheses may be too small to generate precise estimates of the magnitude of effect. The application and interpretation of confidence intervals are demonstrated through the use of several examples.

Transcranial Doppler analysis of cerebral hemodynamics in primary craniosynostosis: study in progress.

BACKGROUND: Regional elevations in intracranial pressure (ICP) have been monitored adjacent to areas of cranial stenosis by some authors [9,19,20]; however, noninvasive techniques such as transcranial Doppler (TCD) would be preferable if increased ICP could be detected just as reliably. METHODS: TCD examinations of basal cerebral arteries were performed in 31 children with skull deformities. Skull X rays and computed tomography (CT) scans or magnetic resonance imaging (MRI) were analyzed for degree of cranial vault abnormality, as well as for presence or absence of intracranial pathology. Neurodevelopmental examination and clinical signs of increased ICP, if any, were recorded. RESULTS: The overall incidence of increased resistivity indices (RI) was 70%. Patients with asymmetric skull deformities (plagiocephaly) or sagittal synostosis (scaphocephaly) were statistically more prone to exhibit increased RI compared to previously reported prevalences. CONCLUSIONS: Because TCD is a convenient, rapid, accurate, and noninvasive method by which to gauge ICP, it should be considered in the preliminary work-up of a patient with craniosynostosis.

Gender risk for anaphylactoid reaction to radiographic contrast media.

BACKGROUND: Female predominance has been reported previously in series of anaphylaxis cases; however, no definite precedent has been established for greater risk of anaphylactoid reaction caused by contrast media infusion on the basis of gender. OBJECTIVE: This study was designed to determine whether greater risk for anaphylactoid reaction caused by intravenous contrast media infusion exists in association with female gender. METHODS: Rates of anaphylactoid and severe anaphylactoid reaction, according to gender, were determined in a sample of 5264 consecutive patients receiving conventional radiocontrast media during performance of computed tomography. RESULTS: Of 80 adverse reactions caused by contrast media infusion, 73 (1.39%) were classified as anaphylactoid in nature. Among 5191 patients who received intravenous contrast media without experiencing an anaphylactoid reaction, there were 2642 male patients (51%) and 2549 female patients (49%); reactors included 22 male patients and 51 female patients (odds ratio = 2.40, 95% confidence interval = 1.42-4.10, p < 0.0005). Female patients also comprised 21 of 22 cases of severe anaphylactoid reaction (odds ratio = 21.77, 95% confidence interval = 3.13-435.12, p < 0.0005). CONCLUSION: Greater risk for anaphylactoid and severe anaphylactoid reaction exists in association with female gender. Further studies are needed to identify mechanisms that can explain this risk. The importance of these findings for cost-effective use of lower osmolality contrast media need to be determined.

Proportionate mortality study of Vietnam-era veterans of Michigan.

This study examines the proportion of deaths from major diseases among Michigan Vietnam veterans. The distribution of deaths among Michigan Vietnam veterans was compared to deaths among veterans serving elsewhere for 1974-1989 to generate a proportionate mortality ratio (PMR). PMRs were estimated overall and for Black versus non-Black veterans. Overall, Vietnam veterans had significantly elevated PMRs for infectious and parasitic diseases and endocrine disease and lower PMRs for all malignant neoplasms combined. Vietnam veterans overall and non-Black specifically had elevated PMRs for non-Hodgkin's lymphoma. Black Vietnam veterans had elevated PMRs for cancer of the digestive organs, peritoneum, and pancreas. The elevated PMR for non-Hodgkin's lymphoma is consistent with results of individuals exposed to phenoxy herbicides. Results suggest that future studies should examine risks among racial groups separately.

Elevated risk of anaphylactoid reaction from radiographic contrast media is associated with both beta-blocker exposure and cardiovascular disorders.

BACKGROUND: A case-control study, with both retrospective and concurrent subject selection, was performed (1) to determine whether greater risk for anaphylactoid reaction from contrast media associated with beta-blocker exposure reflects presence, or is independent of underlying cardiovascular disorder; and (2) to characterize further the risk of anaphylactoid reaction from contrast media in patients with cardiovascular disorders and patients with asthma. METHODS: Adverse reactions from intravenous contrast media were recorded in accordance with quality assurance guidelines. Anaphylactoid reactions were classified as mild to moderate (urticaria/angioedema), severe (stridor, bronchospasm, or hypotension), or major and life-threatening (hypotension with or without the need for subsequent hospitalization). Medical records from reactors were compared with those from matched (gender, age, date, and type of contrast study) controls who received conventional contrast media without adverse reaction. RESULTS: Of 34,371 intravenous contrast media procedures performed, 122 anaphylactoid reactions were recorded. The risk of anaphylactoid reaction was significantly associated with asthma (odds ratio [OR], 8.74; 95% confidence interval [CI], 2.36 to 32.35; P = .0012). The risk of bronchospasm was associated with beta-blocker exposure (OR, 3.73; 95% CI, 1.18 to 11.75; P = .025) and with asthma (OR, 16.39; 95% CI, 4.30 to 62.46; P = .0001). The risk of major and life-threatening reaction was associated with the presence of cardiovascular disorder (OR, 7.71; 95% CI, 1.04 to 57.23; P = .046). Among patients with severe reactions, the risk of hospitalization was elevated by the presence of cardiovascular disorder (P = .001), exposure to beta-blockers (OR, 7.67; 95% CI, 1.79 to 32.85; P = .029), or asthma (OR, 20.7; 95% CI, 1.21 to 355.55; P = .065). Although beta-blocker exposure and the presence of cardiovascular disorder were highly associated (chi 2 = 49, P < .001), a greater risk of bronchospasm with severe reaction was observed in nonasthmatic patients with cardiovascular disorders receiving beta-blockers (OR, 15.75; P = .023). Among reactors with asthma, receiving beta-blockers, or with a cardiovascular disorder, 60.8% (31/51) experienced severe anaphylactoid reactions, compared with 35.2% (25/71) of patients without these risk factors (OR, 3.62; P = .005). CONCLUSIONS: beta-Blocker exposure and cardiovascular disorder are both statistically significant risk factors for severe anaphylactoid reaction from contrast media. Thus, patients receiving beta-adrenergic blockers and patients with asthma, on the basis of greater risk for bronchospasm, and patients with cardiovascular disorders, on the basis of elevated risk of major and life-threatening reaction, are appropriate target populations for risk reduction measures before receiving intravenous infusion of contrast media.

Interpretation of the pattern in rate ratios across strata.

The pattern in the ratio of disease rates over strata is a summary statistic used to describe the changing risk of disease in one group relative to another. While patterns of the ratios of disease rates over strata appear to correspond to specific changes in disease rates, plots of the disease rates over strata seem to contradict the information yielded by the ratios. For example, if disease rates from populations A and B have identical rates of decline (parallel lines), the difference in the rates (A-B) at each strata remains constant, while the ratio of the rates (A/B) increases over strata. Through simple algebraic manipulation, one can show that the pattern of the rate ratio is a function of the rate difference relative to the endemic disease rate. Thus, rather than describing the behavior of the disease rates, ratio patterns reflect the importance of exposure relative to the disease rate in the unexposed population.

Increased risk for anaphylactoid reaction from contrast media in patients on beta-adrenergic blockers or with asthma.

OBJECTIVE: To determine whether greater risk for anaphylactoid reaction from intravenous urographic contrast media exists in patients receiving beta-adrenergic blockers or in asthmatic patients. DESIGN: Case-control study. SETTING: Tertiary care, referral-based medical center. PATIENTS: Of 28,978 intravenous urographic contrast media procedures done from July 1987 to June 1988, 49 patients experienced moderate to severe anaphylactoid reaction. Medical records from these 49 reactors were compared with those from a control group matched for gender, age, and date and type of contrast study who received intravenous urographic contrast media without adverse reaction. MAIN RESULTS: Patients exposed to beta-adrenergic blockers or with asthma comprised 39% (19 of 49) of reactors, compared to 16% (13 of 83) of matched controls (odds ratio, 3.43; 95% CI, 1.45 to 8.15; P = 0.005). Exposure to beta-blockers was 27% among reactors and 12% in matched controls (odds ratio, 2.67; CI, 1.01 to 7.05; P = 0.036). Asthma was found in 12% of reactors and 4% of controls; after correction for beta-blocker use, asthma was also associated with increased risk for anaphylactoid reaction (odds ratio, 4.54; CI, 1.03 to 20.05; P = 0.046). Compared with nonasthmatic patients not taking beta-blockers, asthmatic patients were at greater risk for anaphylactoid reaction with bronchospasm (P = 0.02). Five of 13 reactors receiving beta-blockers became hypotensive, and three needed hospitalization. Compared with nonasthmatic patients not taking beta-blockers, patients exposed to beta-blocking drugs were almost nine times (odds ratio, 8.7; CI, 0.81 to 93.5; P = 0.075) more likely to be hospitalized after an anaphylactoid reaction. CONCLUSION: Increased risk for moderate to severe anaphylactoid reaction from intravenous urographic contrast media exists in patients receiving beta-adrenergic blockers or with asthma. These patients are appropriate target populations for efforts to reduce risk before intravenous urographic contrast media are administered.

Reliable assessment of cognitive impairment in dementia patients by family caregivers.

Caregivers (n = 53) of patients with mild to moderate dementia administered a modified version of a cognitive examination at home to their patients. Comparisons between caregiver-administered examinations and the associated clinical examinations revealed a high degree of interrater reliability that was not affected by age or level of education of the caregiver. Reliable assessment of cognitive functioning by caregivers can provide clinicians with an alternative method for monitoring cognitive function of dementia patients.

Familial aggregation of blood pressure and heart rate responses during behavioral stress.

Parent-offspring and sibling resemblances in blood pressure and heart rate responses to behavioral stress were evaluated in a sample of 142 families residing in an upper-middle-class community in the Pittsburgh metropolitan area between 1983 and 1985. The sample consisted of 121 daughters and 96 sons ranging in age from 7 to 18 years, and 141 mothers and 119 fathers ranging in age from 31 to 62 years. Three stressors were presented to all participants: serial subtraction, mirror image tracing, and isometric handgrip exercise. Multivariate analyses of the stress responses were based on maximum likelihood estimations of the magnitude of association, which provided collective significance tests, and were adjusted for familial resemblance of resting pressure and heart rate as well as body mass index. These analyses showed significant parent-offspring and sibling associations in resting blood pressure and body mass index, which replicate those found in previous epidemiological investigations. The novel findings in this study were the sibling similarities in heart rate responses to mirror image tracing and in systolic blood pressure responses to isometric handgrip exercise. An analysis of a subset of the sample--only those nonmedicated parents compliant with instructions not to smoke or drink caffeinated or alcoholic beverages for 3 hr prior to testing and their children--showed a parent-offspring resemblance in systolic blood pressure responses to isometric exercise. This analysis, along with the significant sibling association from the full sample, suggests that systolic blood pressure responses to static exercise might aggregate in the family. The results are discussed in light of previous twin data. The relative paucity of significant parent-offspring associations of physiological parameters during serial subtraction and mirror image tracing tasks implies that non-familial influences are most important in determining cardiovascular responses to psychological stress.

Stability of overt type A behaviors in children: results from a two- and five-year longitudinal study.

The stability of Type A behaviors in children was evaluated in a 2- and 5-year longitudinal study. Type A behaviors were rated by the children's classroom teachers using the Matthews Youth Test for Health (MYTH). MYTH ratings were obtained annually for 3 years on children from 3 inner-city parochial schools (initial N = 317) and for 6 years on children from 3 suburban public schools (initial N = 434). Participants were predominantly Caucasian and in grades K, 2, 4, and 6 when the project began in 1979. Correlations for total Type A scores for the 2-year follow-up period were .38 and .45 in the suburban and urban samples, respectively, collapsing across grade and sex. There were no significant differences in the magnitude of correlations between the samples or between sex or grade subgroups within each sample. The correlation for total Type A score for the 5-year follow-up period was .39 in the suburban sample, and no differences in the magnitude of the correlations between sex or grade subgroups were found. The stability of children's Type A behaviors across 2 and 5 years compares favorably to the stability of other cardiovascular risk factors in children.