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J D Dawson

Publications and source records attributed to J D Dawson.

At least 19 recordsLinked to original sources

Increased carotid intimal-medial thickness and coronary calcification are related in young and middle-aged adults. The Muscatine study.

BACKGROUND: Increased carotid intimal-medial thickness (IMT) and coronary artery calcification (CAC) are used as 2 markers of early atherosclerosis. Our objectives were to assess whether increased IMT and CAC are related and to determine the relationship between cardiovascular risk factors and carotid IMT in young adults. METHODS AND RESULTS: A sample of 182 men and 136 women aged 33 to 42 years living in Muscatine, Iowa, underwent B-mode carotid ultrasound to determine the mean of 12 measurements of maximal carotid IMT. CAC was defined as calcification in the proximal coronary arteries in >/=3 contiguous pixels with a density of >/=130 HU. The mean IMT was 0.788 mm (SD 0.127) for men and 0.720 mm (SD 0.105) for women. CAC was present in 27% of men and 14% of women and was significantly associated with IMT in men (P<0.025) and women (P<0.005). With multivariate analysis, after adjustment for age, significant risk factors for carotid IMT were LDL cholesterol (P<0.001) and pack-years of smoking (P<0.05) in men and LDL cholesterol (P<0.001) and systolic blood pressure (P<0.01) in women. These risk factors remained significant after CAC was included in the multivariate model. CONCLUSIONS: There is an association between increased carotid IMT and CAC and between cardiovascular risk factors and increased IMT in young adults. Carotid IMT may provide information in addition to CAC that can be used to identify young adults with premature atherosclerosis.

Adult

Cytomegalovirus transmission in child care homes.

BACKGROUND: Children attending child care centers have high rates of cytomegalovirus (CMV) excretion. Women exposed to such children have an increased risk of acquiring CMV infection, and primary infection places the offspring of such women at risk of congenital CMV infection. We studied family child care homes to determine if this child care alternative might represent a safe haven from CMV. METHODS: One hundred thirty-two women providing care in their homes were studied using a latex agglutination method to determine the rate of CMV seropositivity at baseline. Women who were seronegative for CMV were then sampled prospectively at 6-month intervals between March 1991 and August 1994 to determine the annual rate of CMV acquisition. A point prevalence of CMV excretion in family homes was determined by sampling 106 children from 25 randomly selected homes. Cytomegalovirus isolates were compared by molecular analysis using polymerase chain reaction-based methods to identify transmission. RESULTS: At baseline, 57.6% of the 132 providers were seropositive for CMV. Seropositive providers were more likely to be caring for toddlers (aged 1-2 years) (67% vs 46%; P=.02) and had worked in child care somewhat longer (median of 28.5 vs 21.5 months; P=.11). Using stepwise logistic regression, the strongest predictors of seropositivity at baseline were caring for children aged 1 to 2 years (odds ratio [OR] =2.37; P=.02) and number of months as a child care provider (OR= 1.17 for an increase of 24 months as provider; P=.08). Six or more years as a provider was highly associated with seropositivity (OR=3.27; P=.02). During follow-up, 5 of 51 seronegative providers seroconverted, yielding an annual infection rate of 6.8%. The point prevalence survey of children from the 25 homes (14 had seropositive providers) identified 8 CMV-excreting children. Three children in 1 home had indistinguishable isolates by polymerase chain reaction mapping. The provider seroconverted and excreted an isolate with a molecular profile indistinguishable from that of the children. CONCLUSIONS: The prevalence of CMV excretion is low among children attending child care homes (8% vs 15% in prior studies of child care centers; P=.07), and only 1 (20%) in 5 of the homes had CMV-excreting children. However, the overall CMV seroconversion rate of home child care providers was comparable to the rate observed among providers in child care centers. Families who use family home child care as an alternative to large child care centers are exposed to a low and unpredictable risk of CMV infection.

Adult

Ovarian volume may predict assisted reproductive outcomes better than follicle stimulating hormone concentration on day 3.

This study was undertaken to compare ovarian volume with other factors which are important for the success of assisted reproduction. The first treatment cycle for 261 patients meeting all entry criteria between September 1993 and June 1995 was considered. All cycles employed the same stimulation protocol and no interventions were based upon pre-treatment indicators. Pre-treatment ovarian volumes, cycle day 3 follicle stimulating hormone (FSH) and oestradiol concentrations, smoking status and age were compared to subsequent peak oestradiol concentrations, numbers of oocytes retrieved, cycle cancellation and occurrence of clinical pregnancy. Statistical evaluation was performed using simple and multiple logistic regression analysis to determine odds ratios. The resultant odds ratios suggest that age and small ovarian volume may predict retrieval of fewer mature oocytes, while the failure to achieve clinical pregnancy was predicted by current smoking and small ovarian volume. Day 3 FSH values failed to be a significant predictor when maternal age, smoking status and ovarian volume were known. It can be concluded that, like maternal age and smoking status, ovarian volume may be a clinically important predictor of reproductive success, being superior to cycle day 3 FSH or oestradiol concentrations as an assessment of ovarian reserve.

Adult

Malpractice claims against family physicians are the best doctors sued more?

BACKGROUND: Physicians who have been sued multiple times for malpractice are assumed to be less competent than those who have never been sued. However, there is a lack of data to support this assumption. Competence includes both knowledge and performance, and there are theoretical reasons to suspect that the most knowledgeable physicians may be sued the most. METHODS: We conducted a retrospective cohort study of family physicians who were included in the Florida section of the 1996 American Medical Association's Physician Masterfile and who practiced in Florida at any time between 1971 and 1994 (N = 3686). The main outcome was the number of malpractice claims per physician adjusted for time in practice. Using regression methods, we analyzed associations between malpractice claims and measures of physician knowledge. RESULTS: Risk factors for malpractice claims included graduation from a medical school in the United States or Canada (incidence rate ratio [IRR] 1.8; 95% confidence interval [CI], 1.6-2.1), specialty board certification (IRR 1.8; 95% CI, 1.6-2.1), holding the American Medical Association Physician's Recognition Award (IRR 1.4; 95% CI, 1.2-1.7), and Alpha Omega Alpha Honor Society membership (IRR 1.8; 95% CI, 1.1-3.0). Among board-certified family physicians, sued physicians who made no payments to a plaintiff had higher certification examination scores than nonsued physicians (53.48 vs 51.38, P < .01). The scores of sued physicians who made payments were similar to those of nonsued physicians (51.05 vs 51.38, P = .93). CONCLUSIONS: Among Florida family physicians, the frequency of malpractice claims increased with evidence of greater medical knowledge.

Family Practice

Variability in the learning experiences of family practice residents during an obstetrics rotation.

BACKGROUND AND OBJECTIVES: Residency rotations do not necessarily provide the same clinical experience to each resident. This study quantified and explained the variability in participation in deliveries by family practice residents during an obstetrics rotation at a community hospital. METHODS: We collected prospectively completed resident experience logs from 17 residents and information from the hospital Summary of Delivery forms for 1,166 deliveries. The data were analyzed using methods to account for within-supervisor correlation. RESULTS: Participation and delivery rates varied markedly. In stepwise conditional regression analysis, resident participation in deliveries was positively associated with prior resident involvement during the labor and negatively associated with occurrence of the delivery on the night shift and with male gender of the resident. Resident performance of delivery was positively associated with non-instrumented vaginal delivery, prior resident involvement during the labor, and patient multiparity and negatively associated with male resident gender. CONCLUSIONS: We found substantial variability in resident experience and identified several factors associated with increased resident experience. Variability of experience among residents in clinical rotations should be assessed to ensure that all residents receive adequate training.

Adult

Epidemiology of congenital cytomegalovirus infection: maternal risk factors and molecular analysis of cytomegalovirus strains.

To determine factors that influence the occurrence of congenital cytomegalovirus (CMV) infection, the authors surveyed prospectively 8,254 infants born in eastern Iowa between October 1989 and June 1994. The authors conducted a case-control study to identify maternal risk factors, matching each CMV-infected infant with three uninfected infants according to hospital and date of birth. CMV strains were compared by using the polymerase chain reaction (PCR) to identify common sources of infection. Of the 7,229 infants cultured successfully for CMV, 35 (0.48%) were congenitally infected. Mothers of CMV-infected infants were more likely to be single (odds ratio (OR) = 3.05, p = 0.016), to work in sales (OR = 4.93, p = 0.008), or to be students (OR = 5.01, p = 0.017). Conversely, women who worked in health-care professions were less likely to have a congenitally infected infant (OR = 0.14, p = 0.049). PCR analysis indicated 27 distinct strains of CMV, but two groups of infants (two infants per group) excreted strains with indistinguishable molecular patterns. One of these pairs of infants had older siblings who attended the same child-care center during their mothers' pregnancies. The authors concluded that demographic and occupational factors influenced the risk of giving birth to an infant with congenital CMV infection. Many distinct CMV strains were identified, suggesting that major point source outbreaks had not occurred. Nonetheless, point source acquisition of CMV from child-care environments did account for some cases of congenital CMV infection in eastern Iowa.

Adult

Predictors of neonatal resuscitation, low Apgar scores, and umbilical artery pH among growth-restricted neonates.

OBJECTIVE: To identify risk factors associated with poorer immediate neonatal outcomes among growth-restricted neonates. METHODS: Records of all 530 growth-restricted neonates born between January 1989 and February 1995 were reviewed. Outcomes included resuscitation measures, Apgar scores, and umbilical blood gas values. Neonates were assigned to one of six anesthetic groups, and outcomes were compared. Predictors of poorer outcomes were examined using logistic and linear regression. RESULTS: Neonates exposed to general anesthesia were more likely to be intubated (37.9% versus 4.1%, P < .001, Pearson chi2) and had lower mean 1- (4.0 versus 7.0) and 5-minute (6.5 versus 8.4) Apgar scores (P < .01, Scheffé) than those in all other anesthetic groups. They also had significantly lower umbilical artery (UA) pH values than neonates who received nalbuphine, epidural, or no anesthesia (7.21 versus 7.28, 7.26, 7.29, respectively; P < .01, Scheffé). Factors that significantly and independently predicted intubation among all neonates included exposure to general anesthesia (odds ratio [OR] 4.1; 95% confidence interval [CI] 1.9, 8.9) and lower infant weight (OR 10.1 per kg decrease; CI 5.1, 20). Factors predicting UA pH at most 7.15 included preeclampsia (OR 3.0; CI 1.5, 5.9) and older maternal age (OR 1.3 per 5 years; CI 1.02, 1.64); vertex delivery (OR 0.5; CI 0.2, 0.9) was protective. Factors predicting a 5-minute Apgar less than 7 were meconium (OR 1.5 per category going from none to terminal to light to heavy; CI 1.04, 2.3), general anesthesia (OR 6.9; CI 2.6, 18.2), lower infant weight (OR 16.5 per kg decrease; CI 7.8, 34.5), and vaginal breech delivery (OR 7.0; CI 1.8, 28.6); cesarean delivery (OR 0.2; CI 0.08, 0.66) was protective. Spontaneous vertex delivery raised the UA pH, and preeclampsia, amnioinfusion, breech delivery, and general anesthesia significantly and independently lowered the UA pH among all neonates. For infants delivered by cesarean, "fetal distress," preeclampsia, previous spontaneous abortion, failed forceps use, and nalbuphine significantly and independently predicted lower UA pH. CONCLUSION: Risk factors for poorer immediate neonatal outcomes among growth-restricted neonates include preeclampsia, fetal distress, breech delivery, forceps use, nalbuphine during labor, lower infant weight, and general anesthesia.

Analgesics, Opioid

The effect of physician characteristics on compliance with adult preventive care guidelines.

BACKGROUND AND OBJECTIVES: This study identified physician characteristics and attitudes related to self-reported compliance with adult prevention guidelines. METHODS: A questionnaire was mailed to family practice and internal medicine residents and faculty at the University of Iowa (n = 209). The questionnaire's 78 items fell into seven categories, including physician demographics, history-taking practices, counseling practices, self-perceived effectiveness in changing patient behavior, beliefs about preventive care, knowledge about preventive care, and perceived barriers to the delivery of preventive care. RESULTS: Compliance with history-taking recommendations was independently associated with high knowledge scores, female physician gender, and high self-perceived effectiveness in changing patient behavior. The only factor that was independently associated with counseling efforts was self-perceived effectiveness in changing patient behavior. CONCLUSIONS: Factors that were independently associated with self-reported preventive care efforts include female physician gender, knowledge about preventive care guidelines, and perceived effectiveness in changing patient behavior. After controlling for these factors, other variables such as lack of time, lack of reminder systems, attitudes about preventive care, and amount of formal preventive care education were not related to self-reported compliance with counseling and history-taking recommendations.

Adult

Sample size calculations based on slopes and other summary statistics.

Sample size calculations based on two-sample comparisons of slopes have been reported by many. This paper extends such discussions to include summary statistics other than slopes, such as post-baseline means, change scores, and final observations. Specifically, sample size formulas for analyses based on a broad class of summary statistics are presented, with modifications proposed to allow for missing data caused by staggered entry and random dropouts. The formulas developed are used to illustrate how required sample size is affected by summary statistic choice, variance parameters, the type of treatment difference of interest, and the manner in which incomplete observations are used in the analysis. An example based on longitudinal data from the Muscatine Study is presented.

Adolescent

Anal incontinence after anal sphincter disruption: a 30-year retrospective cohort study.

OBJECTIVE: To compare the prevalence of anal incontinence remote from delivery (approximately 30 years postpartum) in 29 women whose index delivery was complicated by anal sphincter disruption versus a matched control group of 89 women who had an episiotomy without extension to the anal sphincter and versus a group of 33 women who delivered via cesarean. METHODS: In this retrospective cohort study, a structured questionnaire was sent to women in the above categories who delivered at a university hospital between 1961 and 1965 and for whom we could obtain current addresses. Outcome measures included frequent fecal and flatus incontinence and bothersome fecal and flatus incontinence. RESULTS: The three groups did not differ significantly in age, weight, age at delivery, parity, weight of largest baby, postmenopausal status, estrogen replacement usage, most medical conditions, or rectocoele, rectovaginal fistula, or incontinence surgeries. Frequent flatus incontinence was reported by nine (31.0%), 38 (42.7%), and 12 (36.4%) women in the anal sphincter disruption, episiotomy, and cesarean groups, respectively (not significant). The number of women with bothersome flatus incontinence was higher in the anal sphincter disruption group: 17 (58.6%) versus 27 (30.3%) in the episiotomy only group and versus five (15.2%) in the cesarean group (P = .001). Frequent fecal incontinence was reported by two (6.9%), 16 (18.0%), and 0 women (P = .008 between cesarean and episiotomy only groups), whereas bothersome fecal incontinence was reported by eight (27.6%), 23 (25.8%), and five (15.2%) women (not significant) in the anal sphincter disruption, episiotomy only, and cesarean groups, respectively. CONCLUSION: Regardless of the type of delivery, anal incontinence occurs in a surprisingly large number of middle-aged women.

Anal Canal

Value of preoperative CA 125 level in the management of uterine cancer and prediction of clinical outcome.

OBJECTIVE: To enhance cost-effective management of uterine cancer by predicting the likelihood of extrauterine disease and survival on the basis of preoperative parameters. METHODS: A retrospective review of preoperative CA 125 levels from 210 women with endometrial carcinoma was performed. The relationship of preoperative CA 125 levels to various preoperative and postoperative histopathologic factors was investigated. RESULTS: Elevated CA 125 (greater than 35 U/mL) correlated (P < .05) with higher stage, higher grade, increased depth of myometrial invasion, positive cytology, pelvic or para-aortic lymph node metastases, and reduced actuarial survival (P < .001). Multivariate analysis of preoperative factors showed that an elevated CA 125 level was the most important predictor for poor survival (P < .001). Moreover, a preoperative CA 125 level greater than 65 U/mL was the most significant predictor of extrauterine disease and carried a 6.5-fold higher risk (95% confidence interval 2.5, 17.1). A logistic model to predict extrauterine disease was developed. The model has a sensitivity of 62%, specificity of 91%, positive predictive value of 69%, and negative predictive value of 88%. CONCLUSION: A CA 125 level should be included as part of the preoperative workup for all patients with uterine cancer. Patients with a preoperative CA 125 level less than or equal to 20 U/mL should be considered as candidates for vaginal hysterectomy unless unfavorable histology or a high-grade (grade II or III) tumor is present. In our series, this approach would have eliminated 24% of the abdominal staging procedures, with a risk of less than 3% for extrauterine disease, while lowering treatment-related morbidity and cutting costs in the treatment of this common female cancer.

Adult

An introduction to time-trend analysis.

Healthcare professionals often are presented with data that appear to indicate an upward or downward trend over time. For example, admissions of acquired immunodeficiency syndrome (AIDS) patients appear to be increasing, cesarean section rates appear to be decreasing, or nosocomial pneumonia rates appear to be increasing. Critical decisions sometimes are based on such trends, which often are presented without a statistical analysis. Those responsible for decision making may be left wondering whether these apparent trends represent only chance variation. Graphs showing trends over time generally present one of three kinds of outcome data: counts (eg, three AIDS admissions), proportions (eg, 10 cesarean sections per 100 total deliveries), or person-time data (eg, 13 cases of nosocomial pneumonia per 10,000 patient days). Using familiar examples and a minimum of technical language, we illustrate the analysis of time trends.

Data Interpretation, Statistical

Skills that Iowa family physicians desire in a new physician partner.

BACKGROUND AND OBJECTIVES: The importance of specific skills in primary care continues to be debated. As a result, there is not consensus on which skills need to be stressed during residency training. Our project asked community-based family physicians to rate the importance of specific skills in a new family physician partner. METHODS: Data were collected through a cross-sectional survey of all active members of the Iowa Academy of Family Physicians. Participants were surveyed by mail, using a list of 83 skills pertinent to primary care. Physicians were asked to rate the importance of a new member of their practice having the individual skills on this list. RESULTS: A total of 546 family physicians (67%) completed questionnaires. Fourteen skills (seven cognitive and seven psychomotor) were reported to be "essential" or "very important" by at least 80% of the physicians. A total of 43 skills were rated as "essential" or "very important" by at least 50% of responding family physicians. Many of the hospital-based procedural skills, particularly those used in an intensive care setting, were rated as less important. The importance ratings of many skills were associated with the physicians' ages, size of their primary hospitals, and availability of other medical specialties. CONCLUSIONS: Family physicians tended to rate office-based procedural skills, counseling skills, and management skills as "essential or very important" to their practices. These rating might be used to guide residency training in family practice.

Clinical Competence

The effects of smoking on ovarian function and fertility during assisted reproduction cycles.

OBJECTIVE: To investigate the effects of cigarette smoking on ovarian function and fertility in women undergoing assisted reproduction cycles. METHODS: We assessed the effects of smoking on ovarian function and fertility in a cohort of 499 women. Questionnaires were designed to quantify past smoking exposure and to determine whether the woman was smoking during the treatment cycle. Ovarian function characteristics and pregnancy rates were compared among current smokers, past smokers, and nonsmokers. RESULTS: Compared with nonsmokers, both current and past smokers have reduced gonadotropin-stimulated ovarian function. A history of increasing tobacco exposure was associated with decreasing serum estradiol concentrations, numbers of retrieved oocytes, and numbers of embryos. On average, for every 10 pack-years of cigarette smoking, 2.5 fewer mature oocytes and 2.0 fewer embryos were obtained. Women who smoked during their treatment cycle had approximately a 50% reduction in implantation rate and ongoing pregnancy rate compared with women who had never smoked. Women who quit smoking before their treatment cycle had the same pregnancy rate as nonsmokers. CONCLUSION: Cigarette smoking is associated with a prolonged and dose-dependent adverse effect on ovarian function. Smoking appears to have a more transient toxic effect on fertility, because current smokers, but not past smokers, had a markedly reduced pregnancy rate after treatment cycles compared with nonsmokers. Women should quit smoking before assisted reproduction cycles.

Adult

Vancomycin-resistant enterococcal bacteremia: natural history and attributable mortality.

Previous studies have shown that bacteremia due to vancomycin-resistant Enterococcus species (VRE) is associated with mortality of 17%-100%, but comorbid conditions may have confounded the estimates. We designed a historical cohort study to determine the mortality attributable to VRE bacteremia. Twenty-seven patients with VRE bacteremia were identified as cases. Within 7 days of the onset of bacteremia, severe sepsis developed in 12 patients (44%) and septic shock developed in 10 (37%). Case patients were closely matched to control patients without VRE bacteremia (1:1) by time of hospitalization, duration of exposure, underlying disease, age, gender, and surgical procedure. The mortality was 67% among cases and 30% among matched controls (P = 0.1). Thus, the mortality attributable to VRE bacteremia was 37% (95% confidence interval [CI], 10%-64%) and the risk ratio for death was 2.3 [CI, 1.2-4.1). We conclude that VRE bacteremia is associated with high rates of severe sepsis and septic shock. The attributable mortality approaches 40%, and patients who have VRE bacteremia are twice as likely to die than closely matched controls.

Adult

Interinnominate motion and symmetry: comparison between gymnasts and nongymnasts.

Some clinical approaches to the treatment of low back pain evaluate and treat observed asymmetries of pelvic posture and motion. Scientific evidence suggests the motion available between the innominate bones is small and variable in nature. The purposes of this investigation were 1) to determine if interinnominate motion of subjects without low back pain was symmetrical in reciprocal test posture combinations, 2) to assess innominate bone symmetry in standing, and 3) to determine if a difference in the magnitude of interinnominate motion was present between a subject group which performs more frequent flexibility activities compared with a subject group representing the general population. Thirty-four subjects (eight male gymnasts, nine female gymnasts, eight male nongymnasts, and nine female nongymnasts) were evaluated in standing and three other reciprocal postures (modified standing, modified sitting, and half-kneeling). In each posture, the Metrecom Skeletal Analysis System was used to obtain coordinates for the anterior and posterior iliac spines. Projection angles were used to determine the relative positions of the right and left innominate bones. Results suggest that stand to right modified standing and stand to left modified standing oblique sagittal interinnominate composite motions were symmetrical, stand to right modified sitting and stand to left modified sitting oblique sagittal interinnominate composite motions were asymmetrical, and stand to right half-kneel and stand to left half-kneel oblique sagittal interinnominate composite motions' symmetrical properties were mixed depending on the group. Gymnasts as a group were found to have asymmetrically positioned innominate bones while nongymnasts as a group had symmetrically positioned innominate bones.

Adolescent

Benign fever following vaginal delivery.

BACKGROUND: In patients with fever following vaginal delivery, physicians must differentiate benign self-resolving fevers from fevers with more serious causes, especially endometritis. To help differentiate these clinical entities, we explored the characteristics and risk factors for benign "single-day" postpartum fever. METHODS: We conducted a retrospective cohort study of 2137 vaginal deliveries. Patients were randomly selected from the 25,687 vaginal deliveries that took place between 1979 and 1992 at The University of Iowa Hospitals and Clinics. The data were analyzed using odds ratios and multiple logistic regression. RESULTS: Benign fevers occurred in 3.3% of patients, while endometritis was diagnosed in 1.6%. After controlling for confounding variables, two clinical factors were independently associated with single-day fever: primiparity (odds ratio [OR], 3.4; 95% confidence interval [CI], 2.0 to 5.7) and use of a uterine pressure catheter (OR, 2.4; 95% CI, 1.5 to 3.7). These factors were not associated with endometritis. The first postpartum temperature elevation ( > or = 38.0 degrees C) occurred earlier in patients with single-day fever than in patients with endometritis (4.0 +/- 4.6 hours postpartum vs 30.2 +/- 27.0 hours postpartum, P < .001). The maximum temperature elevation was lower, on average, in patients with single-day fever than in patients with endometritis (38.2 degrees +/- 0.2 degrees C vs 38.9 degrees +/- 0.6 degrees C, P < .001). CONCLUSIONS: Single-day fever was more likely to occur in primiparous women and in women who were monitored with a uterine pressure catheter. Most women with benign single-day fevers had early low-grade fevers, whereas women with endometritis had higher fevers that occurred later in the postpartum period.

Adult

Understanding logistic regression analysis through example.

Logistic regression is a valuable statistical tool that is often used in primary care research. When researchers explore the association between a possible risk factor and a disease, they attempt to control the effects of extraneous factors (confounders) that can obscure the true association. Using logistic regression, researchers can simultaneously control for the effects of multiple confounders. When investigators use logistic regression, they make subjective decisions about which factors to include in the analysis and in the final predictive model. Critical readers must understand basic concepts of logistic regression and potential problems with its use before they can accurately interpret study results. This article uses a familiar example to explain the principles of logistic regression to make it understandable to nonstatisticians.

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