Biomedical subjects

Margaret Burgess

Publications and source records attributed to Margaret Burgess.

15 recordsLinked to original sources

PubMed2007

Risk factors for statin-associated rhabdomyolysis.

PURPOSE: To identify and characterize risk factors for rhabdomyolysis in patients prescribed statin monotherapy or statin plus fibrate therapy. METHODS: A nested case-control study was conducted within a cohort of 252,460 new users of lipid-lowering medications across 11 geographically dispersed U.S. health plans. Twenty-one cases of rhabdomyolysis confirmed by medical record review were compared to 200 individually matched controls without rhabdomyolysis. A conditional logistic regression model was applied to evaluate the effects of age, gender, comorbidities, concurrent medication use, dosage, and duration of statin use on the development of rhabdomyolysis. RESULTS: Statin users 65 years of age and older have four times the risk of hospitalization for rhabdomyolysis than those under age 65 (odds ratio (OR) = 4.36, 95% confidence interval (CI): 1.5,14.1). We also observed a joint effect of high statin dosage and renal disease (p = 0.022). When these two variables were added to the model with age, we obtained an OR of 5.73 for dosage (95%CI: 0.63, 52.6) and 6.26 for renal disease (95%CI: 0.46, 63.38). Although not statistically significant, we did observe a greater than twofold increase in risk for rhabdomyolysis among females (OR = 2.53, 95%CI: 0.91, 7.32). CONCLUSIONS: Findings of this study indicate that older age is a risk factor for rhabdomyolysis among statin users. Although the evidence is not as strong, high statin dosage, renal disease, and female gender may be additional risk factors. Patients at higher risk of developing rhabdomyolysis should be closely monitored for signs and symptoms of the disease.

Adult↗

PubMed2006

What maintains parental support for vaccination when challenged by anti-vaccination messages? A qualitative study.

This study sought to explore how parents respond to competing media messages about vaccine safety. Six focus groups with mothers of infants were shown television vignettes of typical pro- and anti-vaccination claims. Thematic analysis of transcripts was undertaken. Mothers expressed surprise and concern about alleged vaccine risks but quickly reinstated their support for vaccination by deference to authority figures; type-casting immunisation opponents; and notions of anticipatory regret, good parenting and social responsibility. We conclude that personal experiences, value systems and level of trust in health professionals are fundamental to parental decision making about vaccination. Vaccination advocacy should increase the focus on matters of process such as maintaining trust and public confidence, particularly in health professionals. Stories about people affected by vaccine-preventable diseases need to re-enter the public discourse.

Adult↗

PubMed2006

New-onset and idiopathic thrombotic thrombocytopenic purpura: incidence, diagnostic validity, and potential risk factors.

OBJECTIVE: The aim of this study was to determine the incidence rate for new-onset and idiopathic thrombotic thrombocytopenic purpura (TTP) among adults 20-64 years old, the validity of diagnostic criteria, and potential risk factors for TTP. METHODS: This retrospective observational study analyzed automated administrative data from 11 geographically dispersed U.S. health plans. Cases of TTP were identified based on the presence of an inpatient hospital claim for TTP (ICD-9-CM 446.6) between 1/1/97 and 12/31/01 and confirmed by medical record review. Pharmacy and medical claims were used to evaluate outpatient drug exposure and comorbidities preceding hospitalization for TTP. Cases and the base population were screened so as to result in an incidence rate for idiopathic TTP. RESULTS: We confirmed new-onset and idiopathic TTP in 9 of 15 presumptive cases for an incidence density of 1.4 per million person-years (95% CI: 0.6-2.6). The rate increased to 1.8 per million person-years after projection and age-standardization. The highest incidence rate of TTP was found in patients 50-64 years old (2.8 per million person-years; 95% CI: 0.8-7.1). These 9 patients had no apparent risk factors for TTP based on claims and medical record data. CONCLUSIONS: In a general U.S. population, the incidence rate of confirmed new-onset and idiopathic TTP was lower than previously reported, but appears to be on the rise. Our findings suggest that administrative claims data are useful for identifying outpatient drug exposures and comorbidities potentially associated with TTP.

Adult↗

PubMed2004

Anti-diphtheria antibody seroprotection rates are similar 10 years after vaccination with dTpa or DTPa using a mathematical model.

The reduced antigen content diphtheria, tetanus and pertussis (dTpa) vaccine (Boostrixtrade mark) has been shown to induce a strong booster response to all the vaccine components in 4-6 year olds. However, anti-diphtheria antibody levels were observed to be lower when compared to the "full strength" paediatric DTPa vaccine. To assess the impact of this difference on long-term protection, a mathematical model was developed to predict diphtheria antibody decay over time. The model was based on a linear decrease in log-transformed antibody concentrations after the first year post-vaccination. When applied to data collected 3.5 years after vaccination of 4-6 year olds with either DTPa or dTpa, the model predicted that 10 years post-vaccination, 98.6% of subjects vaccinated with dTpa were likely to remain seroprotected against diphtheria, compared to 99.6% vaccinated with DTPa. Therefore, the difference observed in diphtheria antibody geometric mean concentrations 1 month after booster vaccination at 4-6 years with dTpa or DTPa is unlikely to be of clinical relevance 10 years later at the time of the adolescent booster.

Adult↗

PubMed2004

Immunogenicity of a combined diphtheria-tetanus-acellular pertussis vaccine in adults.

Two clinical studies were undertaken to evaluate the immunogenicity of an adult-type dTpa booster vaccine (Boostrix by GlaxoSmithKline Biologicals). Blood samples taken prior to vaccination showed that 24.4 and 13.0% of subjects were seronegative for diphtheria and tetanus antibodies, respectively. Moreover, about one-third of the vaccinees had no detectable levels of antibodies to pertussis toxoid (PT) or pertactin (PRN). One month post-vaccination, more than 93% of all individuals, regardless of age or type of vaccine received, had seroprotective antibody levels for diphtheria and tetanus (> or = 0.1IU/ml). In those individuals vaccinated with the adult-type dTpa vaccine (Boostrix), more than 98% were found to be seropositive for antibodies to all three pertussis antigens (PT, filamentous haemogluttin (FHA), and PRN). These data suggest that immunity to diphtheria, tetanus and pertussis (DTP) in adults wanes and that booster vaccination with an adult-type combined dTpa vaccine would boost the serological response to diphtheria antitoxin, tetanus antitoxin and antibodies to Bordetella pertussis PT, FHA and PRN.

Adolescent↗

PubMed2004

Hepatitis C prevalence--a nationwide serosurvey.

Hepatitis C is the most commonly notified disease in Australia. In 1998 the Hepatitis C Virus Projections Working Group (HCPWG) estimated that there were approximately 210,000 people who had been infected by hepatitis C virus (HCV) in Australia by 2001. Population-based serosurveys are required to validate this estimate. Here we estimate HCV prevalence on the basis of HCV antibody seroprevalence in the Australian national serosurvey. Between 1996 and 1998, 2,800 sera opportunistically collected from pathology laboratories throughout Australia were tested for HCV antibody. National HCV notifications reported from 1991 through 1998 were also assessed. Eighty-one sera were HCV antibody positive, giving an age standardised prevalence of 2.3 per cent (95% CI 1.8%-2.9%). The 20-24 year age group had the highest HCV prevalence, 5.3 per cent (95% CI 3.3%-8.1%) and the male to female ratio was 1.8:1.0. Approximately 111,000 HCV notifications were received from 1991 through 1998. HCV prevalence estimated by the serosurvey is approximately three times higher than cumulative HCV notifications. Age and sex distributions of seroprevalence are broadly consistent with cumulative notification data. These distributions are consistent with the majority of HCV infections in Australia being transmitted by injecting drug use. Very low age specific seroprevalence estimates in the over 50 years age group indicate that there is not a large pool of undiagnosed infection in this age group. The serosurvey provides an estimate of Australian HCV prevalence and baseline data to determine incidence trends, both of which are required for health-care planning.

Adolescent↗

PubMed2003

Surveillance of adverse events following immunisation: Australia, 2000-2002.

The Adverse Drug Reactions Advisory Committee (ADRAC) database collates notifications of adverse events following immunisation (AEFI) from across Australia. The data were analysed for vaccines received between 1 January 2000 and 30 September 2002. Dose-based AEFI reporting rates were calculated using denominator data from the Australian Childhood Immunisation Register and annual national influenza vaccination coverage surveys. The majority of the 2,409 AEFI records analysed described non-serious events, principally injection site reactions; 10.5 per cent (n = 253) described AEFIs with outcomes defined as 'serious'. Ten deaths were recorded but only one, following yellow fever vaccine, was causally related to immunisation. The average annual population-based reporting rate was 4.5 per 100,000 population. Vaccine dose-based AEFI reporting rates were 2.2 per 100,000 doses of influenza vaccine for adults aged 40 years and over and 14.6 per 100,000 doses of all scheduled vaccines for children aged less than 7 years. The most frequently reported type of adverse event was injection site reaction following receipt of an acellular pertussis-containing vaccine, particularly among children in the age groups scheduled to receive their fourth or fifth doses of the vaccine (overall reporting rate 67 per 100,000 doses). The data highlight the safety of vaccines in Australia, and illustrate both the utility of available immunisation coverage data to estimate dose-based AEFI reporting rates and the value of the ADRAC database as a surveillance tool for monitoring AEFIs nationally.

Adolescent↗

PubMed2003

A resurgence of congenital rubella in Australia?

Two infants with congenital rubella defects (congenital rubella syndrome) have been reported from Queensland in 2003, after an increase in rubella in that State in 2001-2002. The national Measles Control Campaign in 1998 aimed to give measles-mumps-rubella (MMR) vaccine to all unvaccinated preschoolers and a second dose to primary schoolchildren. Following the Campaign no children with congenital rubella defects were born to Australian-born mothers during the five years 1998 to 2002, according to reports to the Australian Paediatric Surveillance Unit. However, three imported cases occurred. Broad immunisation coverage and detection and vaccination of susceptible women of child-bearing age before they become pregnant are necessary to prevent further cases.

Adult↗

PubMed2003

Rubella in Australia: can we explain two recent cases of congenital rubella syndrome?

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Adolescent↗

PubMed2003

Varicella and varicella vaccination. An update.

BACKGROUND: Although varicella is generally mild in children, it is often more severe in adults and overall is responsible for approximately 2000 hospital admissions each year in Australia. Live attenuated varicella vaccines have been available in Australia since 2000. They are safe and effective. OBJECTIVE: This article discusses the role of varicella vaccination and management of varicella in pregnancy. DISCUSSION: The National Health and Medical Research Council recommends vaccination of all children at the age of 18 months and a catch up program for nonimmune adolescents and adults. The program is not yet funded by the commonwealth government. Varicella vaccine may be used for postexposure prophylaxis and is most effective if given within three days after exposure, but can be used up to five days from exposure. Varicella in pregnancy may cause congenital malformations; the highest risk (2%) being when maternal infection occurs between 13-20 weeks gestation. Offer varicella zoster immunoglobulin to nonimmune pregnant women, neonates and other high risk subjects with significant exposure to varicella or zoster.

Australia↗

PubMed2002