Decision analysis.
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Decision Support Techniques↗
Biomedical subjects
D J Rouse
Publications and source records attributed to D J Rouse.
Chlorhexidine vaginal irrigation for the prevention of peripartal infection: a placebo-controlled randomized clinical trial.
OBJECTIVE: Our purpose was to determine whether chlorhexidine vaginal irrigation prevents maternal peripartal infection. STUDY DESIGN: A double-blinded, placebo-controlled, randomized trial was performed. Single 200 ml irrigations of either 0.2% chlorhexidine solution or sterile water placebo were given in active labor or before planned cesarean delivery. The primary outcome measure was the combined rate of chorioamnionitis and endometritis (which were mutually exclusive diagnoses). RESULTS: A total of 1024 patients were enrolled: 508 in the chlorhexidine group and 516 in the placebo group. The two groups were generally well balanced on important clinical factors but differed (p < 0.05) in rates of nulliparity (chlorhexidine 42%, placebo 52%), intrauterine pressure catheter usage (chlorhexidine 65%, placebo 72%), and presence of meconium (chlorhexidine 17%, placebo 22%). There were no recognized adverse maternal or neonatal reactions to irrigation. Rates of infection (chorioamnionitis + endometritis) did not differ significantly between the groups, chlorhexidine 10% versus placebo 13% (relative risk 0.8, 95% confidence interval 0.5 to 1.1). Stratified and logistic regression analyses supported the primary univariate analysis. Neonatal outcomes, including sepsis rates of 0.4%, were equivalent for the groups. CONCLUSION: As used in this trial, chlorhexidine lacked efficacy in the prevention of maternal peripartal infection.
Adult↗
The pediatric costs of strategies for minimizing the risk of early-onset group B streptococcal disease.
OBJECTIVE: To estimate the pediatric costs associated with the Centers for Disease Control and Prevention (CDC) guidelines for the management of infants born to mothers receiving intrapartum antimicrobial prophylaxis for prevention of early-onset group B streptococcal disease. METHODS: For an annual United States birth cohort of 3.95 million infants, we estimated the cost of pediatric care provided to full-term asymptomatic infants when pediatricians followed the CDC algorithm for the management of infants exposed to intrapartum antimicrobial prophylaxis under culture-based and risk factor-based maternal care approaches. We calculated the relative contribution of pediatric costs to the total costs of preventing a case of early-onset group B streptococcal sepsis. RESULTS: Total pediatric costs were $41 million for a culture-based approach and $33 million for a risk factor-based approach. Hospital and physician costs accounted for more than 78% of this total. The majority (over 95%) of the pediatric costs were associated with vaginal deliveries. Incorporating pediatric costs into previous cost-effectiveness analyses increased the cost per sepsis case averted by as much as 51% for culture-based strategies and by as much as 112% for risk factor-based strategies. Pediatric costs varied with the average length of stay for full-term infants and with the average cost of a hospital day. CONCLUSION: Substantial pediatric costs are associated with the implementation of an obstetric strategy for minimizing the risk of early-onset group B streptococcal disease. Such costs should be included in future cost-effectiveness analyses of different strategies for minimizing the risk of group B streptococcal disease in newborns.
Algorithms↗
Antenatal screening for factor V Leiden mutation: a critical appraisal.
Thromboembolic disease is a leading cause of maternal mortality in the United States. Recently, inherited resistance to activated protein C has been recognized as a major risk factor for thrombosis and has been demonstrated in 20-60% of patients with clinically evident thrombosis. The factor V Leiden mutation, which is readily detectable by molecular DNA techniques, is responsible for 90-95% of cases of activated protein C resistance. Because 5% of whites and 1% of blacks in the United States are heterozygous for the Leiden mutation, at least one group has suggested that screening of asymptomatic gravidas for the mutation should be considered. Therefore, we conducted a combined MEDLINE and bibliographic literature search for relevant data and evaluated screening for the factor V Leiden mutation in the context of well-elucidated desirable characteristics for a successful screening program. Based on this evaluation, we conclude that routine antenatal screening for the factor V Leiden mutation cannot be recommended at the present time.
Factor V↗
Preterm birth, cerebral palsy and magnesium.
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Cerebral Palsy↗
The effectiveness and costs of elective cesarean delivery for fetal macrosomia diagnosed by ultrasound.
OBJECTIVE: To quantitate the potential effectiveness and monetary costs of a policy of elective cesarean delivery for fetal macrosomia diagnosed by ultrasound. DESIGN: A decision analytic model was constructed to compare 3 policies: (1) management without ultrasound; (2) ultrasound and elective cesarean delivery for estimated fetal weight of 4000 g or more (4000-g policy); and (3) ultrasound and elective cesarean delivery for estimated fetal weight of 4500 g or more (4500-g policy). The impact of maternal diabetes was analyzed separately. Probability data used in the decision analytic model were summarized from the literature and supplemented with unpublished data from the Collaborative Trial of Preterm Birth Prevention. Costs were estimated from the literature, regional reimbursements, and clinical practice data. MAIN OUTCOME MEASURES: Rates of shoulder dystocia and permanent brachial plexus injury, and both the number of additional cesarean births and monetary costs per permanent brachial plexus injury averted. RESULTS: In the baseline analysis for nondiabetic women, the ultrasound policies increased both the cesarean delivery rate and costs, while decreasing the rate of shoulder dystocia and brachial plexus injury. For each permanent brachial plexus injury prevented by the 4500-g policy, 3695 cesarean deliveries were performed at an additional cost of $8.7 million, vs 2345 cesarean deliveries and $4.9 million with the 4000-g policy. In the baseline analysis for diabetic women, with all 3 policies, rates of cesarean delivery, shoulder dystocia and brachial plexus injury, and total costs were higher than for nondiabetic women. However, more favorable ratios for both cesarean deliveries and cost per permanent injury avoided were observed: 443 deliveries and $930 000, respectively, with the 4500-g policy, and 489 deliveries and $880 000, respectively, with the 4000-g policy. Sensitivity analysis confirmed the general robustness of these findings. CONCLUSIONS: For the 97% of pregnant women who are not diabetic, a policy of elective cesarean delivery for ultrasonographically diagnosed fetal macrosomia is medically and economically unsound. In pregnancies complicated by diabetes, such a policy appears to be more tenable, although the merits of such an approach are debatable.
Birth Injuries↗
Management of the presumed susceptible varicella (chickenpox)-exposed gravida: a cost-effectiveness/cost-benefit analysis.
OBJECTIVE: To compare the cost-effectiveness and cost-benefit of different strategies for managing the presumed susceptible varicella (chickenpox)-exposed gravida. METHODS: Three strategies were evaluated: 1) a do-nothing or observation strategy; 2) a testing strategy, in which immune status was assessed and varicella-zoster immune globulin was administered to those who tested nonimmune; and 3) a universal-administration strategy, in which varicella-zoster immune globulin was given to all exposed, presumed susceptible gravidas. Because precise data are unavailable about varicella mortality and hospitalization rates in pregnancy, a range of potential rates was evaluated, from one to greater than 20 times healthy nonpregnant adult rates. The potential efficacy of varicella-zoster immune globulin varied from 1 to 99%. A strategy was defined as cost-effective if it cost less than $50,000 per life-year gained. RESULTS: If the mortality rate from varicella infection in pregnancy was increased fivefold over the nonpregnant healthy adult rate (ie, from 31/100,000 to 155/100,000 cases), efficacy would have to be at least 49% for the immune-testing strategy to be cost-effective. If pregnancy only doubled the varicella mortality rate, then even with perfect efficacy, the immune-testing strategy would not be cost-effective. Under most assumptions, the universal-administration strategy was cost-ineffective when compared with the immune-testing strategy. Similar results were obtained in the parallel cost-benefit analysis, which considered hospitalization costs and rates. The analysis was sensitive to the varicella transmission rate and the discount rate. CONCLUSION: From a cost-effectiveness/cost-benefit standpoint, management based on immune testing is preferable to universal varicella-zoster immune globulin administration when caring for the varicella-exposed gravida with a negative or indeterminate infection history.
Adult↗
Treatment of the small unruptured ectopic pregnancy: a cost analysis of methotrexate versus laparoscopy.
OBJECTIVE: To compare the economic costs between two strategies for management of the small unruptured ectopic pregnancy: initial treatment with methotrexate versus initial treatment with laparoscopic salpingostomy. METHODS: We assumed that both treatment strategies would result in identical clinical outcomes: resolution of the ectopic pregnancy without maternal mortality or long-term morbidity. Based on a literature review, estimates were derived for the likely clinical outcomes of a single injection of methotrexate (50 mg/m2) and for the likely clinical outcomes of the laparoscopy strategy. A range of values was evaluated for the initial success rate of each strategy and varying assumptions made about the type of treatment modality used for initial treatment failures. Direct medical costs of each strategy were estimated based on actual reimbursement rates of a third-party payer for the components of each strategy. The treatment strategies were compared in best-case/worst-case scenarios to determine the potential range of differences in costs between the two strategies. RESULTS: The cost of the methotrexate strategy ranged from $438 to $1390, and the cost of laparoscopic salpingostomy ranged from $2506 to $2974; therefore, the methotrexate strategy was less costly than laparoscopy, with a cost difference ranging from $1124 (best-case laparoscopy-worst-case methotrexate scenario) to $2536 (worst-case laparoscopy-best-case methotrexate scenario). Sensitivity analyses demonstrated that initial therapy with methotrexate was less costly over a wide range of probability and cost estimates. CONCLUSION: Initial methotrexate is a cost-effective alternative to laparoscopic salpingostomy in the treatment of the small unruptured ectopic pregnancy.
Costs and Cost Analysis↗
The feasibility of a randomized clinical perinatal trial: maternal magnesium sulfate for the prevention of cerebral palsy.
OBJECTIVE: Because recent epidemiologic data suggest an association between maternal magnesium sulfate use and a decreased risk of cerebral palsy in infants who survive preterm birth, we investigated the feasibility of a randomized trial of intrapartum maternally administered magnesium sulfate to prevent cerebral palsy in children who were born before term. STUDY DESIGN: On the basis of a literature review, we calculated cumulative rates of delivery, neonatal survival, and cerebral palsy for progressively longer gestational age intervals beginning at 24 weeks' gestation. Sample size estimates with two-tailed chi 2 tests without Yates' correction (alpha = 0.05, beta = 0.2, 50% effect size) for a clinical trial were calculated for these rates. RESULTS: In the 4-week interval from 24 weeks 0 days to 27 weeks 6 days the minimum number of neonates required to conduct a randomized trial would be 1189. Loss to follow-up of neonates, maternal ineligibility, and failure of enrollment would substantially increase the number of necessary gravid women delivered in the 4-week interval to complete such a trial, such that 1 million pregnancies would be required to generate the necessary number of eligible gravid women. Shorter gestational age intervals (e.g., 24 weeks 0 days to 25 weeks 6 days) required fewer neonates (n = 729) but more pregnancies (n = 1.5 million). Because of the decreasing prevalence of cerebral palsy at higher gestational ages, extending the gestational age interval (e.g., to 29 weeks 6 days) markedly increased the minimum number of neonates to 1982 but only slightly decreased the necessary number of pregnancies, to 900,000. CONCLUSIONS: A randomized trial of maternally administered intrapartum magnesium sulfate to reduce the rate of cerebral palsy in surviving preterm neonates would be a formidable undertaking, requiring a concerted multicentered effort.
Cerebral Palsy↗
On the use of surrogate end points for the calculation of the false-positive rate of antenatal testing.
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False Positive Reactions↗
Zidovudine for the prevention of vertical HIV transmission: a decision analytic approach.
The purpose of this study was to quantify the benefits of maternal-neonatal zidovudine (ZDV) administration for the prevention of vertical human immunodeficiency virus (HIV) transmission against the potential risks of drug-induced complications in uninfected children. A decision analysis model was created with use of a Markov cohort simulation, for evaluating both survival and quality of life for two hypothetical cohorts of HIV-exposed neonates: one with in utero and neonatal exposure to preventive ZDV therapy and the other not exposed. The model included the probability of congenital HIV infection with and without ZDV treatment (estimates derived from AIDS Clinical Trials Group study 076), the yearly probability of death with and without congenital HIV infection, a range of probabilities of adverse effects from ZDV use, and a range of ages in life when any adverse effect would manifest. In a series of scenarios, the impact of different estimates for the quality-of-life decrement from any adverse ZDV effect in HIV-uninfected children was assessed, and threshold values for this estimate were established, i.e., critical values below which withholding ZDV would be the preferred choice. Across a wide range of estimates for multiple contingencies, ZDV use was associated with a greater number of quality-adjusted life years than was non-use. Only in implausible, pessimistic scenarios (i.e., a high incidence of profound adverse effects beginning early in life) would withholding ZDV be the rational choice for an asymptomatic HIV-infected pregnant woman.(ABSTRACT TRUNCATED AT 250 WORDS)
Decision Support Techniques↗
Determinants of the optimal time in gestation to initiate antenatal fetal testing: a decision-analytic approach.
To identify the most important determinants of the optimal timing for the initiation of antenatal fetal testing in a high-risk pregnancy (such as insulin-dependent diabetes mellitus), we performed a decision analysis based on a Markov model. The model incorporated several components: test sensitivity and specificity and week-specific probability estimates for fetal death, delivery, and neonatal morbidity and mortality. The analysis demonstrated that the optimal time in gestation to begin testing (from the combined standpoint of both maximizing neonatal survival and minimizing fetal death) was highly dependent on test specificity, the cumulative risk of fetal death (and its distribution throughout gestation), and the week-specific probabilities of neonatal death. For example, even with the increased risk of fetal death associated with insulin-dependent diabetes, very high test specificity (> 99%) is required to recommend testing before 30 weeks. If tests of lower specificity (higher false-positive rates) are used, neonatal deaths will increase and will not be offset by a corresponding decrease in fetal deaths. By performing sensitivity analyses, we demonstrated the effect and relative importance of the model components for determining the optimal gestational age to initiate fetal testing.
Decision Support Techniques↗
Screening and treatment of asymptomatic bacteriuria of pregnancy to prevent pyelonephritis: a cost-effectiveness and cost-benefit analysis.
OBJECTIVE: To compare the effectiveness, benefits, and costs of two asymptomatic bacteriuria screening and treatment strategies to prevent pyelonephritis in pregnancy. METHODS: A decision analytic model was created to compare strategies based on either 1) a leukocyte esterase-nitrite dipstick, or 2) on urine culture, with a policy of no screening or treatment. A literature search was conducted to generate probability estimates. Cost estimates were based on a local pharmacy and laboratory survey and supplemented by recent literature estimates. Sensitivity analyses were performed over wide ranges of probability and cost estimates. RESULTS: Under baseline assumptions, no screening resulted in 23.2 cases of pyelonephritis per 1000 pregnancies, versus 16.2 cases with the dipstick strategy and 11.2 with the culture strategy. The cost of screening and treatment of asymptomatic bacteriuria per 1000 pregnancies was $1968 with dipstick and $19,264 with culture. The cost of treating pyelonephritis with no screening was $57,562, versus $40,257 with dipstick and $27,832 with culture. Therefore, both the dipstick strategy and the culture strategy were cost-beneficial (based on a pyelonephritis cost of $2485) when compared with no screening. However, because it cost $3492 to prevent each additional case of pyelonephritis with culture that was not prevented by dipstick, the culture strategy was not cost-beneficial compared with the dipstick strategy. These results were sensitive to varying estimates for the prevalence of asymptomatic bacteriuria, the rate of progression of asymptomatic bacteriuria to pyelonephritis, the sensitivity of the dipstick, culture costs, and the cost of a case of pyelonephritis. CONCLUSION: When compared with a policy of no screening, screening for and treatment of asymptomatic bacteriuria to prevent pyelonephritis in pregnancy is cost-beneficial whether based on the leukocyte esterase-nitrite dipstick or on urine culture. However, the culture strategy is not cost-beneficial when compared with the dipstick strategy.
Bacteriological Techniques↗
Reductions in cost and cesarean rate by routine use of external cephalic version: a decision analysis.
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Breech Presentation↗
Strategies for the prevention of early-onset neonatal group B streptococcal sepsis: a decision analysis.
OBJECTIVE: To perform a decision analysis to understand better the implications of 19 potential group B streptococcus screening and treatment strategies. METHODS: We searched the literature to locate appropriate articles from which to derive probability estimates. Using decision analysis, we determined the likely outcomes of 19 group B streptococcus screening and treatment strategies and focused on three main outcomes: 1) number of expected cases of early-onset neonatal group B streptococcal sepsis, 2) percentage of gravidas treated with intrapartum antibiotics, and 3) total costs. RESULTS: The strategy recently recommended by two committees of the American Academy of Pediatrics (universal 28-week maternal rectovaginal group B streptococcal culture and treatment of culture-positive, high-risk patients in labor) is among the least effective at reducing neonatal sepsis and the most costly. Strategies based on the currently available rapid streptococcus identification tests are ineffective at reducing neonatal sepsis and are costly. Three strategies outperform the rest: 1) Universal intrapartum maternal antibiotic treatment is the most effective strategy in reducing early-onset neonatal group B streptococcal sepsis (6% of expected) and is also the least costly; 2) intrapartum treatment based solely on risk factors (recently endorsed by ACOG) lowers the rate of neonatal sepsis to 31% of expected with an 18% maternal treatment rate and low total costs; and 3) universal 36-week maternal culture, and treatment of all patients experiencing preterm birth and all culture-positive patients results in 14% of expected neonatal sepsis, with a 27% maternal treatment rate and low total costs. CONCLUSION: Given the present state of knowledge, three strategies emerge from this decision analysis as most optimal for the prevention of early-onset neonatal group B streptococcal sepsis: universal treatment, treatment based on risk factors, and treatment based on preterm delivery and 36-week culture status.
Anti-Bacterial Agents↗
Active-phase labor arrest: a randomized trial of chorioamnion management.
OBJECTIVE: To determine whether leaving the membranes intact in active-phase arrest would affect the cesarean delivery rate or the incidence of maternal morbidity secondary to infection. METHODS: We conducted a randomized trial of healthy, spontaneously laboring women at term with an intact chorioamnion and active-phase arrest (defined as 1 cm or less of cervical change over 2 hours in the active phase of labor). Patients were assigned to either oxytocin augmentation with intact chorioamnion or oxytocin augmentation with amniotomy and internal monitoring of the fetal heart rate and uterine contractions. RESULTS: The intact group (n = 58) and the amniotomy group (n = 60) were similar with respect to maternal age, race, parity, labor epidural usage, gestational age, cervical dilatation at randomization, number of vaginal examinations, and infant birth weight. Four patients in the intact group and five in the amniotomy group underwent cesarean delivery (P = 1.0). No patient in the intact group and three in the amniotomy group were diagnosed with chorioamnionitis (P = .24). Endometritis did not occur in the intact group, whereas four cases occurred in the amniotomy group (P = .12). There were no cases of maternal infection in the intact group, versus seven in the amniotomy group (P = .01). The interval between randomization and vaginal delivery was 44 minutes longer in the intact group than in the amniotomy group (P = .11). CONCLUSION: In women with active-phase arrest of labor and intact membranes, oxytocin augmentation with elective amniotomy and internal monitoring increases maternal infectious morbidity.
Adult↗
Midpregnancy serum thromboxane B2 determinations do not predict subsequent adverse pregnancy outcomes.
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Female↗
Effect of intravenous beta-sympathomimetic tocolysis on human fetal serum erythropoietin levels.
OBJECTIVE: The major stimulus for erythropoietin production is tissue hypoxia. We sought to investigate the relationship of beta-sympathomimetic administration for tocolysis and fetal serum erythropoietin. STUDY DESIGN: Umbilical cord blood was obtained from infants whose mothers received intravenous beta-sympathomimetic tocolysis and who were delivered at < or = 34 weeks' gestation. Serum erythropoietin was measured by radioimmunoassay. On the basis of the presumed 2- to 4-hour half-life of fetal erythropoietin, the infants were divided into two groups. In group 1 (n = 16) beta-sympathomimetic therapy was discontinued < 24 hours before delivery; in group 2 (n = 11) it was discontinued > or = 24 hours before delivery. RESULTS: Group 1 fetuses had significantly higher erythropoietin levels than did group 2 fetuses (37.3 vs 13.9 mU/ml, p = 0.02). The duration of beta-sympathomimetic tocolysis and the maximum infusion rate were not different. The two groups did not differ in gestational age, birth weight, route of delivery, presence of labor, or duration of first or second stage of labor. CONCLUSIONS: We speculate that intravenous beta-sympathomimetic tocolytic therapy stimulates fetal erythropoietin production by decreasing fetal oxygenation as a result of the reversible fetal metabolic effects of the tocolysis. These data suggest that beta-sympathomimetic tocolysis should be undertaken cautiously if fetal compromise is suspected, fetal well-being should be assessed carefully if tocolysis is undertaken, and treatment should be discontinued promptly if a clear benefit is not realized.
Erythropoietin↗