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Biomedical subjects

David M Lawrence

Publications and source records attributed to David M Lawrence.

14 recordsLinked to original sources
PubMed2005

Optimal fetal growth for the Caucasian singleton and assessment of appropriateness of fetal growth: an analysis of a total population perinatal database.

BACKGROUND: The appropriateness of an individual's intra uterine growth is now considered an important determinant of both short and long term outcomes, yet currently used measures have several shortcomings. This study demonstrates a method of assessing appropriateness of intrauterine growth based on the estimation of each individual's optimal newborn dimensions from routinely available perinatal data. Appropriateness of growth can then be inferred from the ratio of the value of the observed dimension to that of the optimal dimension. METHODS: Fractional polynomial regression models including terms for non-pathological determinants of fetal size (gestational duration, fetal gender and maternal height, age and parity) were used to predict birth weight, birth length and head circumference from a population without any major risk factors for sub-optimal intra-uterine growth. This population was selected from a total population of all singleton, Caucasian births in Western Australia 1998-2002. Births were excluded if the pregnancy was exposed to factors known to influence fetal growth pathologically. The values predicted by these models were treated as the optimal values, given infant gender, gestational age, maternal height, parity, and age. RESULTS: The selected sample (N = 62,746) comprised 60.5% of the total Caucasian singleton birth cohort. Equations are presented that predict optimal birth weight, birth length and head circumference given gestational duration, fetal gender, maternal height, age and parity. The best fitting models explained 40.5% of variance for birth weight, 32.2% for birth length, and 25.2% for head circumference at birth. CONCLUSION: Proportion of optimal birth weight (length or head circumference) provides a method of assessing appropriateness of intrauterine growth that is less dependent on the health of the reference population or the quality of their morphometric data than is percentile position on a birth weight distribution.

Anthropometry↗
PubMed2004

Expanding developmental and behavioral services for newborns in primary care: implications of the findings.

BACKGROUND: In two other papers in this issue, the rationale, development, implementation, experimental design, approach to evaluation, and early results of a program to deliver developmental and behavioral services to all infants in primary care practice were described. Positive effects were seen for parental satisfaction, including decreased disenrollment, provider satisfaction, parenting practices, and health outcomes. METHODS: In the present article, the results are reviewed and implications of our findings for the delivery of care, families, healthcare systems, and further research are discussed. RESULTS: Findings that have broad implications are as follows: (1) developmental and behavioral services can be delivered successfully in practice using dedicated professionals to deliver and integrate services; (2) the "planned care model" was useful in program implementation for making "the right thing to do, the easy thing to do"; (3) the added focus on satisfaction and cost helps to develop the "business case" for broad scale implementation; (4) bonding of parents to organizations has marketing implications; (5) the program provides positive effects for all parents, not just high-risk parents; and (6) several research questions emerge, including persistence of effects on health outcomes, costs, and utilization. CONCLUSIONS: The authors conclude that study results have implications for preventive services, families, child healthcare in office practice, healthcare systems, and healthcare policy. In this ongoing study, examination of intervention effects at 30 months of age shoud be informative. Further research is warranted as it remains to be seen whether or not these interventions can become viable ongoing programs.

Child Development↗
PubMed2004

Hospital chart review provided more accurate comorbidity information than data from a general practitioner survey or an administrative database.

BACKGROUND AND OBJECTIVE: The accuracy of comorbidity data within the Western Australian Data Linkage System was evaluated by means of comparison with hospital charts and a general practitioner (GP) survey. METHODS: Patients (n=2,037) with a hospital admission from 1991 to 1996 were selected. Linked data were extracted for 100 comorbidities, categorized into 16 diagnostic chapters, for each hospital admission within a 5-year period. Clinical chart review and a GP survey were performed. Comorbidity occurrence in each data source and false-positive and false-negative diagnoses were ascertained. RESULTS: Administrative data contained 45.5% of comorbidity recorded in hospital charts and underascertained secondary conditions for all 16 diagnostic chapters. False-positive diagnoses were low for most conditions (range: 0-1.5%); however, a high occurrence of false negatives existed for all comorbidity chapters (range: 16.3-91.3%). GP-identified comorbidity was 20.0% greater than that found using administrative data but, with the exceptions of injury-poisoning and cutaneous-subcutaneous diseases, was less (42.0%) than that observed from hospital charts. CONCLUSION: Our results indicate that when accurate comorbidity data are crucial to health outcome research, hospital chart review (as opposed to using administrative data) may be required. Furthermore, surveying GPs, at least in Australia, appears an unsatisfactory alternative to hospital charts for obtaining retrospective comorbidity information.

Comorbidity↗
PubMed2004

Rapamycin suppresses experimental aortic aneurysm growth.

OBJECTIVE: Inflammatory modulators are important in the pathogenesis of aneurysmal disease. Gene expression profiling of experimental abdominal aortic aneurysm (AAA) tissue demonstrated upregulation of the FK506BP12 (rapamycin binding protein) gene product. Rapamycin is a potent immunosuppressor that prevents recurrent stenosis. However, its effect on aneurysm formation has not been studied. We therefore examined the effect of rapamycin in an experimental rat AAA model. METHODS: Adult male Wistar rats underwent elastase infusion into isolated infrarenal aortas to create experimental aneurysms. Rats were randomized to receive either rapamycin or placebo via gastric lavage daily starting on the day of surgery. On postoperative day 7 the aneurysm was measured, the infrarenal aorta was harvested, and the rats were euthanized. NF kappa B was measured with Western blotting as a marker of inflammation. Matrix metalloproteinase (MMP)-9 protein levels were measured. Hematoxylin-eosin and elastin staining were used to examine tissue inflammation and elastin preservation. RESULTS: Aneurysms were significantly smaller in diameter in the rapamycin-treated group (3.3 +/- 0.7 mm vs 4.5 +/- 0.5 mm; P <.0001). NF kappa B levels were significantly reduced by 64% +/- 14% in rapamycin-treated aortas (P =.023). MMP-9 was reduced in rapamycin-treated aortas by 54% +/- 22% (P =.043). Hematoxylin-eosin and elastin staining showed no changes in inflammatory infiltrate or degradation of elastin fibers in elastase-infused aortic segments in rapamycin-treated rats. CONCLUSION: Rapamycin significantly reduces the rate of aneurysm expansion in the experimental AAA rat model by 40%. Biochemical evidence suggests that this is related to suppression of inflammatory signaling and decreased MMP-9 levels. Rapamycin could provide a new treatment for small aneurysms. CLINICAL RELEVANCE: Human aortic aneurysms are characterized histologically by an inflammatory infiltrate with severe proteolytic destruction. Rapamycin is an immunosuppressive agent commonly used to control transplant rejection and intimal hyperplasia by modulating the inflammatory cascade. In this experimental model rapamycin suppressed aneurysm expansion, decreased NF kappa B activation (a marker of inflammation), and decreased matrix metalloproteinase-9 levels. It is hoped that rapamycin or other similar anti-inflammatory drugs will one day be able to control aneurysm expansion in patients

Animals↗
PubMed2003

Improved methods for estimating incidence from linked hospital morbidity data.

BACKGROUND: Linked hospital morbidity data can be used to estimate the incidence of serious chronic disease. However, incidence rates calculated from first-time hospital admissions tend to be overestimated as a result of the erroneous inclusion of prevalent cases that have had previous hospital admissions prior to the study observation period. To address this problem, we have developed the backcasting method. METHOD: A retrograde survival model was implemented to calculate the level of over-ascertainment of incidence according to the number of years of linked data on which the estimates were based and corresponding correction factors were calculated. The method is illustrated using the example of linked hospital morbidity data on diabetes mellitus and then acute myocardial infarction, which was validated against the Perth MONICA database for cardiovascular disease. RESULTS: Corrected estimates of the incidence of diabetes and acute myocardial infarction were produced. The incidence of diabetes was shown to be lower than in North America in accordance with prevalence estimates, whereas the incidence of acute myocardial infarction was overestimated by approximately 10%. CONCLUSION: A new method is presented for estimating incidence trends in disease from linked hospital morbidity data. The advantages of this method are its ease of use with routinely collected data and the relatively low cost of applying it in comparison with community surveys or maintaining formal disease registers. The method has other applications using linked data, such as the study of trends in first-time health care procedures and pharmaceutical prescriptions.

Databases, Factual↗
PubMed2003

Death rate from ischaemic heart disease in Western Australian psychiatric patients 1980-1998.

BACKGROUND: People with mental illness suffer excess mortality due to physical illnesses. AIMS: To investigate the association between mental illness and ischaemic heart disease (IHD) hospital admissions, revascularisation procedures and deaths. METHOD: A population-based record-linkage study of 210 129 users of mental health services in Western Australia during 1980-1998. IHD mortality rates, hospital admission rates and rates of revascularisation procedures were compared with those of the general population. RESULTS: IHD (not suicide) was the major cause of excess mortality in psychiatric patients. In contrast to the rate in the general population, the IHS mortality rate in psychiatric patients did not diminish over time. There was little difference in hospital admission rates for IHD between psychiatric patients and the general community, but much lower rates of revascularisation procedures with psychiatric patients, particularly in people with psychoses. CONCLUSIONS: People with mental illness do not receive an equitable level of intervention for IHD. More attention to their general medical care is needed.

Australia↗
PubMed2003

Laparoscopic versus open sigmoid colectomy for diverticulitis.

This study compared laparoscopic with open sigmoid colectomy for patients with a diagnosis of diverticulitis. Increased use of less invasive techniques makes it vitally important to evaluate outcomes of these techniques as compared with standard open procedures. Patients undergoing sigmoid colectomy for diverticulitis without hemorrhage (code 56211) between January 1997 and December 2001 were reviewed. Two groups were identified: those undergoing open sigmoid colectomy and those undergoing laparoscopic sigmoid colectomy; American Society of Anesthesiologists (ASA) scores, operative time, intensive care unit (ICU) and hospital length of stay, morbidity/mortality, and hospital charges were compared. During the study period 271 sigmoid colectomies were performed for diverticulitis without hemorrhage: 56 laparoscopically and 215 with the standard open technique. Four patients required conversion from laparoscopic to open colectomy. Mean ASA scores were: open group 2.4; laparoscopic group, 1.9 (P < 0.001). Mean operative times were: laparoscopic group, 170 +/- 45 minutes; open group, 140 +/- 49 minutes (P < 0.001). In the open group 39 patients required transfer to the ICU; one patient in the laparoscopic group required transfer to the ICU. Average hospital lengths of stay for the open and laparoscopic groups were 9.06 and 4.12 days, respectively (P < 0.001). Complications were recorded in 57 (27%) of 215 patients who underwent an open procedure versus 5 (9%) of 56 patients who underwent laparoscopic sigmoid colectomy (P < 0.01). There were three deaths in the open group and none in laparoscopic group. Average total hospital charges were 25,700 dollars for open sigmoid colectomy and 17,414 dollars for laparoscopic colectomy. Laparoscopic sigmoid colectomy compares favorably with open sigmoid colectomy for patients with a diagnosis of diverticulitis.

Colectomy↗
PubMed2002

Increasing 'active prevalence' of cancer in Western Australia and its implications for health services.

OBJECTIVE: To measure the active and total prevalence of cancer in Western Australia from 1990-98 and to examine trends in utilisation of hospital services by prevalent cancer patients. METHOD: Longitudinal analysis of linked cancer registrations, hospital separations and death registrations in Western Australia in 1990-98 using a population-based record linkage system. RESULTS: There was an estimated total of 53,450 patients ever-diagnosed with cancer in Western Australia at 30 June 1998 (29.7 per 1,000 population), an increase of 51% since mid-1990 (21.9/1,000). Patients with active disease accounted for 25% of the total prevalence, and the active prevalence of cancer increased from 5.1/1,000 in 1990 to 7.4/1,000 in 1998. In patients with active cancer, hospital admission rates for procedures other than chemotherapy and radiotherapy were stable or declining, but admission rates for chemotherapy and radiotherapy increased. The annual average cumulative length of stay decreased. CONCLUSIONS AND IMPLICATIONS: There has been a rapid increase in the number of prevalent patients requiring health care services for cancer during the 1990s. Most of the increase is due to improved survival, population growth and ageing. Further strain on Australian health care expenditure seems inevitable.

Female↗