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Biomedical subjects

W K Poole

Publications and source records attributed to W K Poole.

At least 19 recordsLinked to original sources
PubMed2005

Changes in mortality and morbidities among infants born at less than 25 weeks during the post-surfactant era.

OBJECTIVES: To compare mortality and death or major morbidity (DOMM) among infants <25 weeks estimated gestational age (EGA) born during two post-surfactant era time periods. STUDY DESIGN AND PATIENTS: Comparative cohort study of very low birthweight (501-1500 g) infants <25 weeks EGA in the NICHD Neonatal Research Network born during two post-surfactant era time periods (group I, 1991-1994, n=1408; group II, 1995-1998, n=1348). Perinatal and neonatal factors were compared, and group related mortality and DOMM risk were evaluated. RESULTS: Mortality was higher for group I (63.1% v 56.7%; p=0.0006). Antenatal steroids (ANS) and antenatal antibiotics (AABX), surfactant (p<0.0001), and bronchopulmonary dysplasia (p=0.0008) were more prevalent in group II. In a regression model that controlled for basic and delivery factors only, mortality risk was greater for group I than for group II (odds ratio (OR) 1.4, 95% confidence interval (CI) 1.2 to 1.7); the addition of AABX and surfactant, or ANS (OR 0.97, 95% CI 0.79 to 1.2) to the model appeared to account for this difference. There was no difference in DOMM (86.8% v 88.4%; p=0.2), but risk was lower for group I in regression models that included ANS (OR 0.70, 95% CI 0.52 to 0.94). CONCLUSION: Survival to discharge was more likely during the more recent period because of group differences in ANS, AABX, and surfactant. However, this treatment shift may reflect an overall more aggressive management approach. More consistent application of treatment has led to improving survival of <25 week EGA infants during the post-surfactant era, but possibly at the cost of greater risk of major in-hospital morbidities.

Analysis of Variance↗
PubMed2001

Adverse effects of early dexamethasone treatment in extremely-low-birth-weight infants. National Institute of Child Health and Human Development Neonatal Research Network.

BACKGROUND: Early administration of high doses of dexamethasone may reduce the risk of chronic lung disease in premature infants but can cause complications. Whether moderate doses would be as effective but safer is not known. METHODS: We randomly assigned 220 infants with a birth weight of 501 to 1000 g who were treated with mechanical ventilation within 12 hours after birth to receive dexamethasone or placebo with either routine ventilatory support or permissive hypercapnia. The dexamethasone was administered within 24 hours after birth at a dose of 0.15 mg per kilogram of body weight per day for three days, followed by a tapering of the dose over a period of seven days. The primary outcome was death or chronic lung disease at 36 weeks' postmenstrual age. RESULTS: The relative risk of death or chronic lung disease in the dexamethasone-treated infants, as compared with those who received placebo, was 0.9 (95 percent confidence interval, 0.8 to 1.1). Since the effect of dexamethasone treatment did not vary according to the ventilatory approach, the two dexamethasone groups and the two placebo groups were combined. The infants in the dexamethasone group were less likely than those in the placebo group to be receiving oxygen supplementation 28 days after birth (P=0.004) or open-label dexamethasone (P=0.01), were more likely to have hypertension (P<0.001), and were more likely to be receiving insulin treatment for hyperglycemia (P=0.02). During the first 14 days, spontaneous gastrointestinal perforation occurred in a larger proportion of infants in the dexamethasone group (13 percent, vs. 4 percent in the placebo group; P=0.02). The dexamethasone-treated infants had a lower weight (P=0.02) and a smaller head circumference (P=0.04) at 36 weeks' postmenstrual age. CONCLUSIONS: In preterm infants, early administration of dexamethasone at a moderate dose has no effect on death or chronic lung disease and is associated with gastrointestinal perforation and decreased growth.

Anti-Inflammatory Agents↗
PubMed1999

When throughout the year is coronary death most likely to occur? A 12-year population-based analysis of more than 220 000 cases.

BACKGROUND: Previous studies have suggested that there is an increase in cardiac events in the morning. Fewer data relate cardiac events to months of the year and season. METHODS AND RESULTS: We analyzed all monthly death certificate data from Los Angeles County, California, for death caused by coronary artery disease from 1985 through 1996 (n=222 265). The mean number of deaths was highest in December at 1808 and January at 1925; the lowest rates were in June, July, August, and September at 1402, 1424, 1418, and 1371, respectively. December and January had significantly higher rates than would be expected from a uniform distribution of monthly deaths (P=0.00001). The percent of yearly coronary deaths was defined by the quadratic U-shaped equation [percent=13.1198-1.5238(month)+0. 0952(month(2)), where January=1, February=2, etc]. When monthly deaths were plotted by year, there was a decrease from 1985 through 1996. Monthly mortality correlated inversely with temperature. During the months with the highest frequency of death (December, January), however, there was an increase in deaths that peaked around the holiday season and then fell, which could not be explained solely on the basis of the daily temperature change. CONCLUSIONS: Even in the mild climate of Los Angeles County, there are seasonal variations in the development of coronary artery death, with approximately 33% more deaths occurring in December and January than in June through September. Although cooler temperatures may play a role, other factors such as overindulgence or the stress of the holidays might also contribute to excess deaths during these peak times.

Climate↗
PubMed1999

Impact of bacterial pneumonia and Pneumocystis carinii pneumonia on human immunodeficiency virus disease progression. Pulmonary Complications of HIV Study Group.

The course of pneumonia caused by pyogenic bacteria and Pneumocystis carinii was examined in a multicity cohort study of HIV infection. The median duration of survival among 150 individuals following initial bacterial pneumonia was 24 months, compared with 37 months among 299 human immunodeficiency virus (HIV)-infected control subjects matched by study site and CD4 lymphocyte count (P<.001). For 152 subjects with P. carinii pneumonia, median survival was 23 months, compared with 30 months for 280 matched control subjects (P = .002). Median durations of survival associated with the two types of pneumonia differed by only 47 days, despite a higher median CD4 lymphocyte count associated with bacterial pneumonia. These results suggest that both P. carinii pneumonia and bacterial pneumonia are associated with a significantly worse subsequent HIV disease course. The similarity of prognosis after one episode of bacterial pneumonia vs. an AIDS-defining opportunistic infection and the proportion of cases occurring in association with a CD4 lymphocyte count of >200 suggest that measures to prevent bacterial pneumonia should be emphasized.

AIDS-Related Opportunistic Infections↗
PubMed1997

Population-based analysis of the effect of the Northridge Earthquake on cardiac death in Los Angeles County, California.

OBJECTIVES: We sought to determine whether a natural disaster affected total cardiovascular mortality and coronary mortality in an entire population. BACKGROUND: The effect of the January 17, 1994 Northridge Earthquake (NEQ) on all deaths and causes of deaths within the entire population of Los Angeles County is unknown. The purposes of our study were to analyze all deaths in this entire population before, during and after the NEQ and to determine whether the NEQ temporally and spatially altered death due to cardiovascular disease. METHODS: We analyzed all death certificate data (n = 19,617) from Los Angeles County during January of 1992, 1993 (control periods) and 1994, using International Classification of Diseases, 9th Revision codes for ischemic heart disease (IHD) and atherosclerotic cardiovascular disease (ASCVD), as well as other causes of death. RESULTS: There was an average of 73 deaths per day due to IHD and ASCVD during January 1 to 16, 1994; this increased to 125 on the day of the NEQ, and then decreased to 57 deaths per day from January 18 to 31 (p < 0.00001, before NEQ vs. day of NEQ; after NEQ vs. day of NEQ; and before NEQ vs. after NEQ). The NEQ was associated with an increase in deaths due to myocardial infarction and trauma but not cardiomyopathy, hypertensive heart disease, valvular heart disease, cerebrovascular disease or noncardiovascular causes. Based on plots of daily deaths due to IHD and ASCVD, the decrease in deaths during the 14 days after the NEQ (-144) overcompensated for the increase on the day of the NEQ (+55). Geographic analysis revealed a redistribution of deaths due to IHD and ASCVD toward the epicenter on the day of the NEQ. CONCLUSIONS: When an entire population simultaneously experiences a major environmental stress, there is an increase in death due to coronary artery disease (but not other cardiac causes), followed by a decrease that overcompensates for the excess of death. The overcompensation may represent a residual population that is more resistant to stress or a possible preconditioning effect of the stress, or both. This study supports the concept that cardiovascular events within an entire population can be triggered by a shared stress.

Aged↗
PubMed1997

Prospective validation of a composite end point in thrombolytic trials of acute myocardial infarction (TIMI 4 and 5). Thrombosis In Myocardial Infarction.

Although the use of composite end points in clinical trials has increased in recent years, few data are available on the validity of such an approach. In the Thrombolysis In Myocardial Infarction (TIMI) 4 and 5 trials, we set out to validate prospectively the nonfatal components of the "unsatisfactory outcome" end point. This end point consisted of the in-hospital occurrence or observation of new-onset severe congestive heart failure/shock, left ventricular ejection fraction <40% (or <30% for patients with prior myocardial infarction), reinfarction, reocclusion by sestamibi perfusion imaging, TIMI flow grade <2 at 90 minutes or 18 to 36 hours, intracranial hemorrhage, major spontaneous hemorrhage, or anaphylaxis. Among 576 patients in TIMI 4 and 5 with 1-year follow-up, a nonfatal unsatisfactory outcome end point was reached in hospital in 45% of patients. Compared with patients without such an end point, patients with an end point had a relative risk of 1-year mortality of 2.5 (95% confidence interval 1.4 to 5.6, p = 0.001). For individual components, new-onset severe congestive heart failure/shock had a relative risk of 4.6 (p = 0.001), left ventricular ejection fraction <40% had a relative risk of 3.5 (p = 0.006), recurrent myocardial infarction had a relative risk of 2.2 (p = 0.047), and TIMI flow grade <2 at 90 minutes had a relative risk of 2.2 (p = 0.005). Our findings show that these nonfatal in-hospital end points and the composite end point are associated with an increased risk of 1-year mortality and as such are valid predictive survival markers for use in clinical trials.

Aged↗
PubMed1996

Estimating the prevalence of drug use from self-reports in a cohort for which biologic data are available for a subsample.

Diagnostic procedures, used singly or in combination, are crucial in the determination of the presence and prevalence of medical and other conditions. In the absence of a "gold standard," two or more measures or diagnostic tests are often available that may be used to estimate true prevalence. The authors have developed a statistical method with which to calculate more precise estimates of a condition in the presence of two diagnostic measures, one measurement being performed on the entire study sample and a second, more precise one being made in a random sample of the study sample. This method uses the well-known equations which express the probabilities of the four possible outcomes of the two measures in terms of the sensitivities and specificities of the measures and the prevalence of the condition and some properties of maximum likelihood estimates to obtain an expression for the estimated true prevalence and its precision. The method is illustrated by applying it to data collected by urinalysis and self-report in 1992-1993 in a national multisite study-the Cocaine Treatment Outcome Study. Through application of this methodology, a more precise estimate of the true prevalence of substance use can be obtained from two measures, one biologic and the other self-reported. Detailed equations and expressions are provided so that the method can be applied in other situations where diagnostic data from two different sources or procedures are available.

Bias↗
PubMed1996

TIMI frame count: a quantitative method of assessing coronary artery flow.

BACKGROUND: Although the Thrombolysis in Myocardial Infarction (TIMI) flow grade is valuable and widely used qualitative measure in angiographic trials, it is limited by its subjective and categorical nature. METHODS AND RESULTS: In normal patients and patients with acute myocardial infarction (MI) (TIMI 4), the number of cineframes needed for dye to reach standardized distal landmarks was counted to objectively assess an index of coronary blood flow as a continuous variable. The TIMI frame-counting method was reproducible (mean absolute difference between two injections, 4.7 +/- 3.9 frames, n=85). In 78 consecutive normal arteries, the left anterior descending coronary artery (LAD) TIMI frame count (36.2 +/- 2.6 frames) was 1.7 times longer than the mean of the right coronary artery (20.4 +/- 3.0) and circumflex counts (22.2 +/- 4.1, P < .001 for either versus LAD). Therefore, the longer LAD frame counts were corrected by dividing by 1.7 to derive the corrected TIMI frame count (CTFC). The mean CTFC in culprit arteries 90 minutes after thrombolytic administration followed a continuous unimodal distribution (there were not subpopulations of slow and fast flow) with a mean value of 39.2 +/- 20.0 frames, which improved to 31.7 +/- 12.9 frames by 18 to 36 hours (P < .001). No correlation existed between improvements in CTFCs and changes in minimum lumen diameter (r=-.05, P=.59). The mean 90-minute CTFC among nonculprit arteries (25.5 +/- 9.8) was significantly higher (flow was slower) compared with arteries with normal flow in the absence of acute MI (21.0 +/- 3.1, P < .001) but improved to that of normal arteries by 1 day after thrombolysis (21.7 +/- 7.1, P=NS). CONCLUSIONS: The CTFC is a simple, reproducible, objective and quantitative index of coronary flow that allows standardization of TIMI flow grades and facilitates comparisons of angiographic end points between trials. Disordered resistance vessel function may account in part for reductions in flow in the early hours after thrombolysis.

Blood Flow Velocity↗
PubMed1996

Sudden cardiac death triggered by an earthquake.

BACKGROUND: The earthquake that struck the Los Angeles area at 4:31 a.m. on January 17, 1994, was one of the strongest earthquakes ever recorded in a major city in North America. Once the life-threatening situation was over, the Northridge earthquake, so called because its epicenter was near Northridge, California, just north of Los Angeles, provided investigators an unusual opportunity to examine the relation between emotional stress and sudden cardiac death. METHODS: We reviewed the records of the Department of Coroner of Los Angeles County for the week before the earthquake, the day of the earthquake, the six days after the earthquake, and corresponding control periods in 1991, 1992, and 1993. RESULTS: On the day of the earthquake, there was a sharp increase in the number of sudden deaths from cardiac causes that were related to atherosclerotic cardiovascular disease, from a daily average (+/- SD) of 4.6 +/- 2.1 in the preceding week to 24 on the day of the earthquake (z = 4.41, P < 0.001). Sixteen victims of sudden death had symptoms, usually chest pain, or died within the first hour after the initial tremor. Only three sudden deaths occurred during or immediately after unusual physical exertion. During the six days after the earthquake, the number of sudden deaths declined to below the base-line value, to an average of 2.7 +/- 1.2 per day. CONCLUSIONS: The Northridge earthquake was a significant trigger of sudden death due to cardiac causes, independently of physical exertion. This finding, along with the unusually low incidence of such deaths in the week after the earthquake, suggests that emotional stress may precipitate cardiac events in people who are predisposed to such events.

Adult↗
PubMed1996

Overall and cause-specific mortality in a cohort of homo-/bisexual men, injecting drug users, and female partners of HIV-infected men. Pulmonary Complications of Human Immunodeficiency Virus Infection Study Group.

OBJECTIVE: To study the overall and cause-specific HIV-related mortality in a cohort of HIV-seropositive subjects according to transmission category, race/ethnicity, sex and severity of immunosuppression. DESIGN: A cohort of 1129 HIV-seropositive homo-/bisexual men, injecting drug users, and female partners of HIV-infected men were enrolled at six centers in San Francisco, Los Angeles, Chicago, Newark, Detroit and New York between 1 November 1988 and 1 November 1989. Subjects were evaluated every 6 months at least until 31 March 1994. METHODS: The analyses of overall mortality for the subgroups of interest were performed with Kaplan-Meier plots and Cox proportional hazards models. Cause-specific analyses were performed on the primary cause of death using rates per 100 person-years of exposure. RESULTS AND CONCLUSIONS: Baseline severity of immunosuppression is the strongest predictor of mortality. There were no statistically significant differences in overall HIV-related mortality among transmission categories, race/ethnicity groups or sexes. There were differences, however, in cause-specific mortality among the different risk groups.

AIDS-Related Opportunistic Infections↗
PubMed1996

Reliability of anergy skin testing in persons with HIV infection. The pulmonary Complications of HIV Infection Study Group.

Testing with antigens that elicit delayed-type cutaneous hypersensitivity reactions is commonly used to evaluate immune competence in persons infected with the human immunodeficiency virus; however, the reliability of such testing has not been determined. We performed serial testing with tuberculin, mumps, and Candida antigens in 491 HIV-infected persons and found that 30% of persons who initially had no reaction (0 mm) to any of the three antigens, and, thus, were considered to be anergic, had reaction to the mumps or Candida antigen when they were retested 12 months later. We also examined the results of mumps antigen tests in 50 subjects who had a negative tuberculin tests after an initial positive test. The mumps antigen test was positive in 39% of the subjects when the tuberculin test was falsely negative. We conclude that tests commonly used to define anergy cannot reliably identify the anergic state. Moreover, using the mumps antigen to aid in the interpretation of the tuberculin test will often lead to erroneous conclusions. These data indicate that the results of anergy testing should not be used to make individual patient decisions concerning preventive therapy for tuberculosis.

Administration, Cutaneous↗
PubMed1995

Previous angina alters in-hospital outcome in TIMI 4. A clinical correlate to preconditioning?

BACKGROUND: Ischemic preconditioning has been shown to reduce myocardial infarct size in experimental models, but its role in patients remains unclear. Angina before myocardial infarction reflects brief episodes of ischemia and may be a marker of preconditioning. As part of the Thrombolysis in Myocardial Infarction (TIMI) 4 study, we performed an analysis on the effect of a history of previous angina on in-hospital outcomes for patients with acute myocardial infarction. METHODS AND RESULTS: Patients eligible for thrombolytic therapy were enrolled into the study. Data were collected from case report forms regarding previous history of angina, in-hospital outcome and 6-week follow-up. Two hundred eighteen patients had a history of previous angina at any time before acute myocardial infarction, and 198 patients did not have previous angina. Patients with any previous history of angina were less likely than with those without angina to experience in-hospital death (3% versus 8%) (P = .03), severe congestive heart failure (CHF) or shock (1% versus 7%, P = .006), or the combined end point of in-hospital death, severe CHF, or shock (4% versus 12%, P = .004). Moreover, patients with any history of angina were more likely to have a smaller creatine kinase (CK)-determined infarct size (119 versus 154 CK integrated units; P = .01) and were less likely to have Q waves on their ECG (57% versus 69%; P = .01). In the subset of patients who experienced angina within the 48 hours before infarction (compared with those who did not), there was a trend toward less likely in-hospital death (3% versus 6%; P = .09), a lower incidence of severe CHF or shock (1% versus 6% P = .008), a lower combined end point of death, CHF, or shock (3% versus 10%; P = .006), smaller infarct size assessed by CK (115 versus 151 CK units; P = .03), and a trend toward fewer Q-wave infarcts. However, patients with a history of previous angina did have a trend toward more recurrent ischemic pain. Of importance is that the beneficial in-hospital effects of previous angina were not dependent on angiographically visible coronary collaterals. CONCLUSIONS: Previous angina confers a beneficial effect on in-hospital outcome after acute myocardial infarction. The reasons for this benefit are uncertain, but one potential mechanism for this observation may be ischemic preconditioning.

Angina Pectoris↗
PubMed1995

Incidence of neonatal circumcision in Atlanta, 1985-1986.

We reviewed Atlanta area hospital records to determine the following regarding neonatal circumcision: incidence in July 1985; incidence after publicized serious complications of circumcision in August 1985; medical record documentation; and the complication rate. After stratified sampling from hospital birth logs, we abstracted information from medical charts and calculated weighted estimates and P values. The circumcision incidence was 89.3% in July 1985, 87.5% in September 1985, and 84.3% in September 1986. Circumcision was recorded on the medical record face sheet for 84.3% of circumcised boys. The complication rate was 3.1%; no serious complications were recorded. We conclude the following: circumcision incidence was high during the study period; publicity regarding adverse outcomes may have decreased the subsequent incidence of the procedure; hospital discharge data, which rely on medical record face sheet information, underestimate the true incidence of neonatal circumcision; and neonatal circumcision is usually safe, but serious complications may occur.

Adult↗
PubMed1989

Pericarditis in acute myocardial infarction: characterization and clinical significance.

To determine the significance of pericarditis following acute myocardial infarction, the hospital course and 12-month follow-up were analyzed in 703 patients enrolled in the Multicenter Investigation of the Limitation of Infarct Size (MILIS). Pericarditis, defined by the detection of a pericardial rub, occurred in 20% of the patients (n = 141) and was more likely to follow Q wave than non-Q wave infarction (25% vs 9%, p less than 0.001). Patients with pericarditis experienced more serious myocardial damage compared to those without pericarditis, as evidenced by a larger infarct size (25 +/- 1 vs 17 +/- 1 MB-CK gm-Eq/m2, p less than 0.001), a lower admission left ventricular ejection fraction (42 +/- 1% vs 48 +/- 1%, p less than 0.001), and a higher incidence of congestive heart failure (47% vs 26%, p less than 0.001) and atrial tachyarrhythmias (16% vs 10%, p less than 0.05). When patients were classified by the presence of Q or non-Q wave infarction, these differences persisted although statistical significance was not always achieved due to smaller sample size. Mortality at 12-month follow-up for patients with pericarditis was 18% compared with 12% for patients without pericarditis (p = 0.055). This mortality difference could be accounted for in part by the lower ventricular ejection fraction in patients with pericarditis (p = 0.20 after adjustment).

Electrocardiography↗
PubMed1989

Effects of fetal sex and dexamethasone on preterm maternal serum concentrations of human chorionic gonadotropin, progesterone, estrone, estradiol, and estriol.

The serum human chorionic gonadotropin concentration for the 43 female-bearing gestations was significantly higher (geometric mean 15,603 mIU/ml; 95% confidence interval 12,337 to 19,733) than that for 26 male-bearing pregnancies (geometric mean 8902 mIU/ml; 95% confidence interval 6288 to 12,596), p = 0.0087. The mean gestational age was 32 +/- 2.4 weeks (mean +/- SD). There was no significant difference between male- and female-bearing pregnancies for progesterone, cortisol, estrone, estradiol, estriol, or gestational age. In 19 placebo-treated pregnancies and 14 dexamethasone-treated pregnancies with a mean gestational age of 31.5 +/- 2.7 weeks, there was no significant change from the baseline value observed for either maternal serum human chorionic gonadotropin level or maternal serum progesterone level at 42 hours after institution of treatment. In the dexamethasone-treated subjects the geometric mean was reduced to 20% of baseline for cortisol; 42% of baseline for estrone; 30% of baseline for estradiol; and 41% of baseline for estriol (all p less than 0.001).

Chorionic Gonadotropin↗
PubMed1988

Factors leading to shorter survival after acute myocardial infarction in patients ages 65 to 75 years compared with younger patients.

Although the number of elderly patients with acute myocardial infarction (AMI) has steadily increased and these patients are known to have a higher early subsequent mortality than younger patients, the reasons for this adverse prognosis are poorly understood. We compared the clinical courses of 217 patients, ages 65 to 75 years, with 631 patients younger than 65 years of age enrolled in the Multicenter Investigation of the Limitation of Infarct Size (MILIS). The older group had a higher prevalence of adverse baseline risk factors, including history of congestive heart failure (14 vs 7%, p less than 0.001), previous AMI (28 vs 22%, p less than 0.05), angina pectoris (42 vs 34%, p less than 0.05), systemic hypertension (64 vs 52%, p less than 0.01), diabetes mellitus (24 vs 17%, p less than 0.05) and female gender (37 vs 24%, p less than 0.001). Despite having a smaller infarct size index than younger patients (15 +/- 1 vs 18 +/- 1 CK-MB g-Eq/m2, p less than 0.002), the elderly patients had a lower admission left ventricular ejection fraction (43 +/- 1 vs 47 +/- 1%, p less than 0.01) and a higher frequency of clinical congestive heart failure (44 vs 28%, p less than 0.001) and in-hospital death (14 vs 7%, p less than 0.01). The 1-year mortality for elderly hospital survivors was also markedly greater (19 vs 5%, p less than 0.001) as was the 4-year mortality (35 vs 13%, p less than 0.001). Adjustment for 7 adverse baseline characteristics in the elderly could account for their increased in-hospital mortality. However, these and 12 additional in-hospital characteristics did not account for the increased 1- and 4-year mortalities of the elderly hospital survivors, which are presumably affected by variables not included in the present age-associated study.

Age Factors↗