Tyler Hartwell

RTI International, Durham, North Carolina, United States

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Publications (13)176.3 Total impact

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    ABSTRACT: BACKGROUND: Oral clefts are one of the most common birth defects with significant medical, psychosocial, and economic ramifications. Oral clefts have a complex etiology with genetic and environmental risk factors. There are suggestive results for decreased risks of cleft occurrence and recurrence with folic acid supplements taken at preconception and during pregnancy with a stronger evidence for higher than lower doses in preventing recurrence. Yet previous studies have suffered from considerable design limitations particularly non-randomization into treatment. There is also well-documented effectiveness for folic acid in preventing neural tube defect occurrence at 0.4 mg and recurrence with 4 mg. Given the substantial burden of clefting on the individual and the family and the supportive data for the effectiveness of folic acid supplementation as well as its low cost, a randomized clinical trial of the effectiveness of high versus low dose folic acid for prevention of cleft recurrence is warranted.Methods/designThis study will assess the effect of 4 mg and 0.4 mg doses of folic acid, taken on a daily basis during preconception and up to 3 months of pregnancy by women who are at risk of having a child with nonsyndromic cleft lip with/without palate (NSCL/P), on the recurrence of NSCL/P. The total sample will include about 6,000 women (that either have NSCL/P or that have at least one child with NSCL/P) randomly assigned to the 4 mg and the 0.4 mg folic acid study groups. The study will also compare the recurrence rates of NSCL/P in the total sample of subjects, as well as the two study groups (4mg, 0.4 mg) to that of a historical control group.The study has been approved by IRBs (ethics committees) of all involved sites. Results will be disseminated through publications and presentations at scientific meetings. DISCUSSION: The costs related to oral clefts are high, including long term psychological and socio-economic effects. This study provides an opportunity for huge savings in not only money but the overall quality of life. This may help establish more specific clinical guidelines for oral cleft prevention so that the intervention can be better tailored for at-risk women.ClinicalTrials.gov IdentifierNCT00397917.
    BMC Pediatrics 11/2012; 12(1):184. · 1.98 Impact Factor
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    ABSTRACT: Improved complementary feeding is cited as a critical factor for reducing stunting. Consumption of meats has been advocated, but its efficacy in low-resource settings has not been tested. The objective was to test the hypothesis that daily intake of 30 to 45 g meat from 6 to 18 mo of age would result in greater linear growth velocity and improved micronutrient status in comparison with an equicaloric multimicronutrient-fortified cereal. This was a cluster randomized efficacy trial conducted in the Democratic Republic of Congo, Zambia, Guatemala, and Pakistan. Individual daily portions of study foods and education messages to enhance complementary feeding were delivered to participants. Blood tests were obtained at trial completion. A total of 532 (86.1%) and 530 (85.8%) participants from the meat and cereal arms, respectively, completed the study. Linear growth velocity did not differ between treatment groups: 1.00 (95% CI: 0.99, 1.02) and 1.02 (95% CI: 1.00, 1.04) cm/mo for the meat and cereal groups, respectively (P = 0.39). From baseline to 18 mo, stunting [length-for-age z score (LAZ) <-2.0] rates increased from ∼33% to nearly 50%. Years of maternal education and maternal height were positively associated with linear growth velocity (P = 0.0006 and 0.003, respectively); LAZ at 6 mo was negatively associated (P < 0.0001). Anemia rates did not differ by group; iron deficiency was significantly lower in the cereal group. The high rate of stunting at baseline and the lack of effect of either the meat or multiple micronutrient-fortified cereal intervention to reverse its progression argue for multifaceted interventions beginning in the pre- and early postnatal periods. This trial was registered at clinicaltrials.gov as NCT01084109.
    American Journal of Clinical Nutrition 09/2012; 96(4):840-7. · 6.50 Impact Factor
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    ABSTRACT: This study was designed to test the hypothesis that 2 training programs would reduce incrementally 7-day neonatal mortality rates for low-risk institutional deliveries. Using a train-the-trainer model, certified research midwives sequentially trained the midwives who performed deliveries in low-risk, first-level, urban, community health clinics in 2 cities in Zambia in the protocol and data collection, in the World Health Organization Essential Newborn Care (ENC) course (universal precautions and cleanliness, routine neonatal care, resuscitation, thermoregulation, breastfeeding, kangaroo care, care of small infants, and common illnesses), and in the American Academy of Pediatrics Neonatal Resuscitation Program (in-depth basic resuscitation). Data were collected during 3 periods, after implementation of each training course. A total of 71 689 neonates were enrolled in the 3 study periods. All-cause, 7-day neonatal mortality rates decreased from 11.5 deaths per 1000 live births to 6.8 deaths per 1000 live births after ENC training (relative risk: 0.59 [95% confidence interval: 0.48-0.77]; P < .001), because of decreases in rates of deaths attributable to birth asphyxia and infection. Perinatal mortality rates but not stillbirth rates decreased. The 7-day neonatal mortality rate was decreased further after Neonatal Resuscitation Program training, after correction for loss to follow-up monitoring. ENC training for midwives reduced 7-day neonatal mortality rates in low-risk clinics. Additional in-depth basic training in neonatal resuscitation may reduce mortality rates further.
    PEDIATRICS 10/2010; 126(5):e1064-71. · 4.47 Impact Factor
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    ABSTRACT: The goal was to determine the effect of training in newborn care and resuscitation on 7-day (early) neonatal mortality rates for very low birth weight (VLBW) infants. The study was designed to test the hypothesis that these training programs would reduce neonatal mortality rates for VLBW infants. Local instructors trained birth attendants from 96 rural communities in 6 developing countries in protocol and data collection, the World Health Organization Essential Newborn Care (ENC) course, and a modified version of the American Academy of Pediatrics Neonatal Resuscitation Program (NRP), by using a train-the-trainer model. To test the impact of ENC training, data on infants of 500 to 1499 g were collected by using a before/after, active baseline, controlled study design. A cluster-randomized, controlled trial design was used to test the impact of the NRP. A total of 1096 VLBW (500-1499 g) infants were enrolled, and 98.5% of live-born infants were monitored to 7 days. All-cause, 7-day neonatal mortality, stillbirth, and perinatal mortality rates were not affected by ENC or NRP training. Neither ENC nor NRP training of birth attendants decreased 7-day neonatal, stillbirth, or perinatal mortality rates for VLBW infants born at home or at first-level facilities. Encouragement of delivery in a facility where a higher level of care is available may be preferable when delivery of a VLBW infant is expected.
    PEDIATRICS 10/2010; 126(5):e1072-80. · 4.47 Impact Factor
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    ABSTRACT: Of the 3.7 million neonatal deaths and 3.3 million stillbirths each year, 98% occur in developing countries. An evaluation of community-based interventions designed to reduce the number of these deaths is needed. With the use of a train-the-trainer model, local instructors trained birth attendants from rural communities in six countries (Argentina, Democratic Republic of Congo, Guatemala, India, Pakistan, and Zambia) in the World Health Organization Essential Newborn Care course (which focuses on routine neonatal care, resuscitation, thermoregulation, breast-feeding, "kangaroo" [skin-to-skin] care, care of the small baby, and common illnesses) and (except in Argentina) in a modified version of the American Academy of Pediatrics Neonatal Resuscitation Program (which teaches basic resuscitation in depth). The Essential Newborn Care intervention was assessed among 57,643 infants with the use of a before-and-after design. The Neonatal Resuscitation Program intervention was assessed as a cluster-randomized, controlled trial involving 62,366 infants. The primary outcome was neonatal death in the first 7 days after birth. The 7-day follow-up rate was 99.2%. After birth attendants were trained in the Essential Newborn Care course, there was no significant reduction from baseline in the rate of neonatal death from all causes in the 7 days after birth (relative risk with training, 0.99; 95% confidence interval [CI], 0.81 to 1.22) or in the rate of perinatal death; there was a significant reduction in the rate of stillbirth (relative risk with training, 0.69; 95% CI, 0.54 to 0.88; P=0.003). In clusters of births in which attendants had been randomly assigned to receive training in the Neonatal Resuscitation Program, as compared with control clusters, there was no reduction in the rates of neonatal death in the 7 days after birth, stillbirth, or perinatal death. The rate of neonatal death in the 7 days after birth did not decrease after the introduction of Essential Newborn Care training of community-based birth attendants, although the rate of stillbirths was reduced. Subsequent training in the Neonatal Resuscitation Program did not significantly reduce the mortality rates. (ClinicalTrials.gov number, NCT00136708.)
    New England Journal of Medicine 02/2010; 362(7):614-23. · 54.42 Impact Factor
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    Hrishikesh Chakraborty, Janet Moore, Tyler D Hartwell
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    ABSTRACT: Adequately powered sample size calculations for cluster randomized trials primarily depend on the event rate variability, effect size, average cluster size, and intracluster correlation (ICC). Furthermore, an ICC estimate depends on event rate variability among clusters, cluster size, and number of clusters. We evaluated the impact on ICC estimates of event rates, event rate variations, cluster size, and cluster size variations for different numbers of clusters. We also evaluated how the event rate changes at the end of the trial affect ICC estimates. We created one simulation exercise to investigate how different event rates, event rate variations, cluster size, and cluster size variations impact ICC estimates and 95% confidence intervals. A separate simulation exercise in four different trial scenarios examined the impact of an intervention or drug effect in the intervention group on ICC estimates, 95% confidence intervals, and on sample size. The first simulation results suggest that the ICC value depends upon the event rate and event rate variations in addition to the cluster size, cluster size variations, and number of clusters. The second simulation exercise suggested that adjusting the sample size will help to preserve the appropriate power at the end of the trial.
    Contemporary clinical trials 05/2009; 30(5):473-80. · 1.51 Impact Factor
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    ABSTRACT: Cluster randomized trials have become the design of choice for evaluating the effect of selected interventions on well-known health indicators such as neonatal mortality rate, episiotomy rate, and postpartum hemorrhage rate in a community setting. Determining the sample size of a cluster randomized trial requires a reliable estimate of cluster size and the intracluster correlation (ICC), because sample size can be substantially impacted by these parameters. During the design phase of a trial, the investigators may have estimates of the valid range of the health indicator which is the primary outcome variable. Furthermore, investigators often have an estimate of the average cluster size or range of cluster sizes that exist among the proposed samples they are planning to include in the trial. We present in this article a simulation technique to estimate the ICC value and its distribution for known binary outcome variables and a varying number of clusters and cluster sizes. We applied this technique to estimate ICC values and confidence intervals for a multi-country trial assessing the effect of neonatal resuscitation to decrease seven-day neonatal mortality, where communities within a country were clusters. This simulation technique can be used to estimate the possible ranges of the ICC values and to help to design an appropriately powered trial.
    Contemporary clinical trials 01/2009; · 1.51 Impact Factor
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    ABSTRACT: The main objective of this study was to identify factors associated with variation in the rate of acute postpartum hemorrhage (PPH), defined as blood loss >or= 500 mL within 2 hours of delivery, observed in a randomized clinical trial of misoprostol for the prevention of PPH, conducted in rural India. Although the women in the misoprostol group had a significantly lower probability of having a PPH, we also noted a reduction in the rate of PPH in the placebo group over the course of the study. We hypothesized that this was due to the changing skills of the auxiliary nurse midwives (ANMs) over the course of the study. We conducted a post-hoc analysis examining variation in PPH rates over the duration of the trial among the women randomized to the placebo arm (n = 808). Descriptive, correlation analysis and generalized estimating equations (GEE) were used to predict PPH rates. With no direct measure of ANM skills, we used proxy measures, including: (1) the ANM's point of entry into the study (original ANMs at the initiation of the trial were less skilled than replacement ANMs); (2) the study duration, representing exposure of the ANM to ongoing training and monitoring; and (3) duration of the second stage of labor as a measure of improved delivery practices. As the study duration increased, the duration of the second stage of labor decreased (-0.12, p = 0.001) and as the duration of the second stage of labor decreased, the rate of PPH decreased (0.0282; 95% CI 0.0201-0.0363). For each 10-minute increase in the duration of second stage labor increased PPH odds by 7.1% and each 30-day duration of the trial decreased PPH odds by 3.4%. Additionally, a patient delivered by an original ANM was 3.14 times more likely to have a PPH compared to a patient delivered by a replacement ANM. Declining PPH rates were associated with improved skills and delivery practices that decreased duration of the second stage of labor. These improvements appeared to be consistent with the introduction of the more skilled replacement ANMs as well as ongoing training and monitoring for all ANMs over the duration of the trial.
    The journal of maternal-fetal & neonatal medicine: the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians 07/2008; 21(8):559-64. · 1.36 Impact Factor
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    ABSTRACT: Implementation of evidence-based obstetrical practices remains a significant challenge. Effective strategies to disseminate and implement such practices are needed. We randomly assigned 19 hospitals in Argentina and Uruguay to receive a multifaceted behavioral intervention (including selection of opinion leaders, interactive workshops, training of manual skills, one-on-one academic detailing visits with hospital birth attendants, reminders, and feedback) to develop and implement guidelines for the use of episiotomy and management of the third stage of labor or to receive no intervention. The primary outcomes were the rates of prophylactic use of oxytocin during the third stage of labor and of episiotomy. The main secondary outcomes were postpartum hemorrhage and birth attendants' readiness to change their behavior with regard to episiotomies and management of the third stage of labor. The outcomes were measured at baseline, at the end of the 18-month intervention, and 12 months after the end of the intervention. The rate of use of prophylactic oxytocin increased from 2.1% at baseline to 83.6% after the end of the intervention at hospitals that received the intervention and from 2.6% to 12.3% at control hospitals (P=0.01 for the difference in changes). The rate of use of episiotomy decreased from 41.1% to 29.9% at hospitals receiving the intervention but remained stable at control hospitals, with preintervention and postintervention values of 43.5% and 44.5%, respectively (P<0.001 for the difference in changes). The intervention was also associated with reductions in the rate of postpartum hemorrhage of 500 ml or more (relative rate reduction, 45%; 95% confidence interval [CI], 9 to 71) and of 1000 ml or more (relative rate reduction, 70%; 95% CI, 16 to 78). Birth attendants' readiness to change also increased in the hospitals receiving the intervention. The effects on the use of episiotomy and prophylactic oxytocin were sustained 12 months after the end of the intervention. A multifaceted behavioral intervention increased the prophylactic use of oxytocin during the third stage of labor and reduced the use of episiotomy. (ClinicalTrials.gov number, NCT00070720 [ClinicalTrials.gov]; Current Controlled Trials number, ISRCTN82417627 [controlled-trials.com].).
    New England Journal of Medicine 05/2008; 358(18):1929-40. · 54.42 Impact Factor
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    ABSTRACT: We examined pregnant women's use of cigarettes and other tobacco products and the exposure of pregnant women and their young children to secondhand smoke (SHS) in 9 nations in Latin America, Asia, and Africa. Face-to-face surveys were administered to 7961 pregnant women (more than 700 per site) between October 2004 and September 2005. At all Latin American sites, pregnant women commonly reported that they had ever tried cigarette smoking (range: 78.3% [Uruguay] to 35.0% [Guatemala]). The highest levels of current smoking were found in Uruguay (18.3%), Argentina (10.3%), and Brazil (6.1%). Experimentation with smokeless tobacco occurred in the Democratic Republic of the Congo and India; one third of all respondents in Orissa, India, were current smokeless tobacco users. SHS exposure was common: between 91.6% (Pakistan) and 17.1% (Democratic Republic of the Congo) of pregnant women reported that smoking was permitted in their home. Pregnant women's tobacco use and SHS exposure are current or emerging problems in several low- and middle-income nations, jeopardizing ongoing efforts to improve maternal and child health.
    American Journal of Public Health 03/2008; 98(10):1833-40. · 3.93 Impact Factor
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    ABSTRACT: Background: Data on tobacco use by pregnant women in developing countries is sparse. The Global Network for Women's and Children's Health Research implemented a Tobacco Use Survey of Pregnant Women in nine developing countries in Africa, Asia and Latin America to document the prevalence of tobacco use during pregnancy and information on the knowledge and attitudes regarding tobacco, health hazards of tobacco use, and environmental tobacco smoke (ETS) exposure. Objective: To assess having ever tried and having ever been a regular user of tobacco products prior to pregnancy and to evaluate factors associated with these categories of use. Understanding these factors may help the development of tobacco use prevention and control efforts for vulnerable populations. Methods: A cross-sectional survey of pregnant women was conducted using a convenience sample in each of 10 study sites. Logistic regression was performed separately for each site to examine associations with tobacco use prior to pregnancy. Odds ratios and confidence intervals were calculated. Results: Among the study sites, the proportion of respondents that ever tried tobacco products ranged from 9.0% to 78% and that reported regular use from <1% to 53%. Tobacco use in the home, ETS exposure, women's acceptability of tobacco use, and education were found to be significantly associated with having ever tried and having ever been a regular tobacco user at more than half of the study sites. Conclusion: Results may be used to guide the development and testing of customized interventions to reduce the vulnerability of women and children to ETS.
    135st APHA Annual Meeting and Exposition 2007; 11/2007
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    ABSTRACT: The commonest cause of maternal deaths worldwide is postpartum bleeding, and the great majority of such deaths take place in developing countries such as India where women frequently do not deliver their children in a hospital setting. The major cause is uterine atony, which can be prevented by administering a uterotonic agent such as oxytocin. Such treatment remains impractical for much of the developing world, where women giving birth are cared for by untrained attendants. In addition, injected uterotonic agents must be stored in the cold and require active management of the third stage of labor. Orally administered misoprostol, a prostaglandin E1 analogue, is a comparatively inexpensive alternative to oxytocin that has proved to be effective and safe, does not need to be refrigerated, and has a long shelf life. The investigators report a trial, conducted in rural India, which compared a single oral dose of 600 μg of misoprostol (n = 812) with placebo (n = 808) for preventing acute postpartum hemorrhage, defined as 500 mL or more within 2 hours after delivery. Medication was administered within 5 minutes of cutting the umbilical cord. The rate of acute severe bleeding (1000 mL or more within 2 hours) also was estimated. The actively treated women and placebo recipients were similar with respect to demographic, clinical, and perinatal features. The overall incidence of acute postpartum hemorrhage was 9.2%, occurring in 6.4% of misoprostol-treated women compared to 12% of placebo recipients, a highly significant difference (P < 0.0001). The relative risk for actively treated women compared with the placebo group was 0.53 (95% confidence interval, 0.39-0.74). All but 2 of 10 women with acute severe postpartum bleeding had received the placebo. Overall mean blood loss was lessened by misoprostol (214 versus 262 mL; P < 0.0001). Actively treated women were less likely to require transfer to a higher-level facility, blood transfusion, and surgical interventions. There were no group differences in delayed postpartum bleeding or infection. Rates of neonatal fever, vomiting, and diarrhea did not differ in the two groups. Oral administration of the prostaglandin analogue misoprostol is an effective, safe, inexpensive, and easily administered means of limiting the risk of postpartum bleeding in areas where medical resources may be scarce.
    Obstetrical and Gynecological Survey 01/2007; 62(2):95-96. · 2.51 Impact Factor
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    ABSTRACT: Postpartum haemorrhage is a major cause of maternal mortality in the developing world. Although effective methods for prevention and treatment of such haemorrhage exist--such as the uterotonic drug oxytocin--most are not feasible in resource-poor settings where many births occur at home. We aimed to investigate whether oral misoprostol, a potential alternative to oxytocin, could prevent postpartum haemorrhage in a community home-birth setting. In a placebo-controlled trial undertaken between September, 2002, and December, 2005, 1620 women in rural India were randomised to receive oral misoprostol (n=812) or placebo (n=808) after delivery. 25 auxiliary nurse midwives undertook the deliveries, administered the study drug, and measured blood loss. The primary outcome was the incidence of acute postpartum haemorrhage (defined as > or =500 mL bleeding) within 2 h of delivery. Analysis was by intention-to-treat. The trial was registered with the US clinical trials database (http://www. clinicaltrials.gov) as number NCT00097123. Oral misoprostol was associated with a significant reduction in the rate of acute postpartum haemorrhage (12.0% to 6.4%, p<0.0001; relative risk 0.53 [95% CI 0.39-0.74]) and acute severe postpartum haemorrhage (1.2% to 0.2%, p<0.0001; 0.20 [0.04-0.91]. One case of postpartum haemorrhage was prevented for every 18 women treated. Misoprostol was also associated with a decrease in mean postpartum blood loss (262.3 mL to 214.3 mL, p<0.0001). Postpartum haemorrhage rates fell over time in both groups but remained significantly higher in the placebo group. Women taking misoprostol had a higher rate of transitory symptoms of chills and fever than the control. Oral misoprostol was associated with significant decreases in the rate of acute postpartum haemorrhage and mean blood loss. The drug's low cost, ease of administration, stability, and a positive safety profile make it a good option in resource-poor settings.
    The Lancet 10/2006; 368(9543):1248-53. · 39.21 Impact Factor

Publication Stats

383 Citations
176.30 Total Impact Points

Institutions

  • 2006–2012
    • RTI International
      • Division of Statistics and Epidemiology
      Durham, North Carolina, United States
  • 2009–2010
    • University of Alabama at Birmingham
      • Department of Pediatrics
      Birmingham, Alabama, United States
  • 2008
    • Institute for Clinical Effectiveness and Health Policy
      Buenos Aires, Buenos Aires F.D., Argentina