Universal Screening Strategy Research Articles

Institution of universal screening for Group B streptococcus (GBS) from a risk management protocol results in reduction of early‐onset GBS disease in a tertiary obstetric unit

To determine the effect of institution of a universal screening protocol as per CDC 2002 guidelines had on the incidence of early-onset Group B streptococcal (GBS) and non-GBS disease in a tertiary obstetric unit. A prospective study with historical control data reporting the incidence of early-onset GBS and non-GBS disease following institution of a universal screening strategy at John Hunter Hospital, Newcastle, Australia. We compared the incidence of early-onset GBS and non-GBS disease during prescreening (1994-2002) with screening period (2004 to June 2006). The outcome measure was the incidence of early-onset GBS disease. We specifically reported the number of women needed to treat (NNT) with antibiotics and the number of women needed to screen. The incidence of early-onset GBS and non-GBS during the prescreening period was 0.84/1000 and 0.94/1000 live births, respectively. After institution of universal screening, the incidence was 0.00/1000 and 0.72/1000 live births, respectively. This is a statistically significant reduction in early-onset GBS disease by 84% (chi(2) = 5.75; P = 0.016). There was no difference in non-GBS disease (chi2 = 0.14; P = 0.71). The NNT is 1191 and we needed to screen 5704 women to prevent one case of early-onset GBS disease. Screening for GBS rather than by assessing risk factors has significantly reduced the incidence of early-onset GBS disease in our unit. Despite low incidence of early-onset GBS prior to screening period, we still found a significant decrease in early-onset GBS disease after institution of universal screening protocol. These results support the screening-based approach at 34-37 weeks gestation.

Two-tiered universal newborn screening strategy for severe combined immunodeficiency

Outcomes for infants with severe combined immunodeficiency (SCID) would be improved by universal newborn screening, but there are not yet screening tests of sufficient accuracy for the disorder. In a pilot study, we assessed the ability of a two-tiered strategy to improve accuracy. Dried blood samples from patients were assessed with two tests for lymphopenia: interleukin-7, a T-cell growth cytokine, and TRECs, a byproduct of T-cell receptor recombination. IL-7 screening has a specificity of 96.1% and TRECs have a specificity of 92.3%. Combining these tests in a two-tiered strategy increases specificity to 100% (97–100% CI). Sensitivity was 85% for IL-7 screening and 100% for TREC screening. A two-tiered strategy may be of sufficient accuracy to enable universal SCID screening, and should be assessed in a prospective trial.

Cost effectiveness of human papillomavirus testing to augment cervical cancer screening in women infected with the human immunodeficiency virus

Purpose To determine the cost effectiveness of incorporating molecular testing for high-risk types of human papillomavirus into a cervical cancer screening program for women infected with the human immunodeficiency virus (HIV). Subjects and methods We developed a Markov model to simulate the natural history of cervical cancer precursor lesions in HIV-infected women. Probabilities of progression and regression of cervical lesions were conditional on transient or persistent infection with human papillomavirus, as well as stage of HIV and effectiveness of antiretroviral therapy. Incorporating data from prospective cohort studies, national databases, and published literature, the model was used to calculate quality-adjusted life expectancy, life expectancy, lifetime costs, and incremental cost-effectiveness ratios for two main strategies: targeted screening—human papillomavirus testing is added to the initial two cervical cytology smears obtained after an HIV diagnosis and subsequent screening intervals are modified based on the test results; and universal screening—no testing for human papillomavirus is performed, and a single cytology screening interval is applied to all women. Results In HIV-infected women on anti-retroviral therapy, a targeted screening strategy in which cervical cytology screening was conducted every 6 months for women with detected human papillomavirus DNA, and annually for all others, cost $10,000 to $14,000 per quality-adjusted life year gained compared with no screening. A universal screening strategy consisting of annual cervical cytology for all women was 15% less effective and had a less attractive cost-effectiveness ratio. Targeted screening remained economically attractive in multiple sensitivity analyses, although when the overall incidence of cervical cancer precursor lesions was lowered by 75%, the screening interval for women with detected human papillomavirus DNA could be widened to 1 year. Conclusions Adding human papillomavirus testing to the two cervical cytology smears obtained in the year after an HIV diagnosis, and modifying subsequent cytology screening intervals based on the results, appears to be an effective and cost-effective modification to current recommendations for annual cytology screening in HIV-infected women.

Maternal and neonatal infection rates with three different protocols for prevention of group B streptococcal disease

Objectives: We compared maternal and neonatal infection rates under 3 different group B streptococcal prevention strategies and also evaluated reasons for each protocol’s failures in preventing neonatal disease. Study Design: Women who were delivered at our center from August 1, 1991, through April 30, 1998, were managed by 1 of 3 protocols for prevention of early-onset neonatal group B streptococcal infection: a selective screening protocol, The American College of Obstetricians and Gynecologists protocol, and the Centers for Disease Control and Prevention–recommended universal screening strategy. We compared maternal infection rates and neonatal group B streptococcal infection rates under each protocol. We also compared reasons for each protocol’s failures in preventing neonatal infection. Results: Clinical chorioamnionitis rates were 7.4% with selective screening, 7.7% under The American College of Obstetricians and Gynecologists’ protocol, and 5.2% with universal screening (relative risk 0.7, 95% confidence interval 0.6-0.8). Endometritis rates were 4.0% with selective screening, 4.6% with The American College of Obstetricians and Gynecologists protocol, and 2.8% with universal screening (relative risk 0.7, 95% confidence interval 0.6-0.8). Overall neonatal group B streptococcal infection rates were lower under the 2 more recent strategies, but not significantly so. Despite the ability of universal screening to find more women at risk for group B streptococcal transmission, half of the neonatal infections under this protocol occurred when the mothers were not considered candidates for prophylaxis. Conclusions: The Centers for Disease Control and Prevention–endorsed universal screening strategy for group B streptococcal infection prevention was associated with significantly lower rates of clinical chorioamnionitis and endometritis than were the other strategies. We were unable to document statistically significant improvement in neonatal outcome under the universal screening protocol. (Am J Obstet Gynecol 1999;180:416-22.)

Selective versus universal antenatal HIV testing: epidemiological and implementational factors in policy choice.

To develop an epidemiological basis for economic analyses of selective and universal antenatal screening strategies, and to apply it to the UK. The prevalence of higher-risk women and the prevalence of undiagnosed infection within groups of high-risk and low-risk women was estimated from surveillance and survey data. The numbers of women tested and the numbers of infected women who would be identified by universal and selective strategies were then calculated under a range of assumptions about the identification of higher-risk women and acceptance of testing. In higher-risk women estimated prevalence of undiagnosed infection was between 0.06% and 2.8%, comparing well with independent estimates. In low-risk women, estimates ranged from 0.014% in London to 0.002% in the rest of the UK. If uptake among the high-risk women was the same in selective and universal strategies, universal testing would entail testing between 7100 (London) and 50000 (rest of England) additional women to detect an additional case. However, if selective screening identified only 60% of those at high risk and achieved only 60% acceptance compared with a universal programme, then universal screening would require only 1150 additional women to identify one additional case in London, compared to 6470 in Scotland and 13140 in the rest of the UK. Overall prevalence does not form an adequate basis for determining screening strategy. Instead, universal screening can be justified either because the prevalence of HIV in the low-risk group is sufficiently high, or because it achieves sufficiently higher uptake relative to selective screening among those at higher risk.

Strategies for reducing coronary risk factors in primary care: which is most cost effective?

To examine the relative cost effectiveness of a range of screening and intervention strategies for preventing coronary heart disease in primary care. 7840 patients aged 35-64 years who were participants in a trial of modifying coronary heart disease risk factors in primary care. Effectiveness of interventions assumed and the potential years of life gained estimated from a risk equation calculated from Framingham study data. The cost per year of life gained. The most cost effective strategy was minimal screening of blood pressure and personal history of vascular disease, which cost 310 pounds-930 pounds per year of life gained for men and 1100 pounds-3460 pounds for women excluding treatment of raised blood pressure. The extra cost per life year gained by adding smoking history to the screening was 400 pounds-6300 pounds in men. All strategies were more cost effective in men than in women and more cost effective in older age groups. Lipid lowering drugs accounted for at least 70% of the estimated costs of all strategies. Cost effectiveness was greatest when drug treatment was limited to those with cholesterol concentrations above 9.5 mmol/l. Universal screening and intervention strategies are an inefficient approach to reducing the coronary heart disease burden. A basic strategy for screening and intervention, targeted at older men with raised blood pressure and limiting the use of cholesterol lowering drugs to those with very high cholesterol concentrations would be most cost effective.

Should children or young adults be screened for serum lipid levels to prevent adult coronary heart disease? Experience from the Cardiovascular Risk in Young Finns Study

Coronary heart disease (CHD) has its origin in childhood. High cholesterol levels measured in children and adolescents are indicative of concurrent atherosclerotic changes and probably predict adult coronary heart disease. We review here the relevance of screening children, adolescents or young adults for serum lipid levels in order to efficiently prevent premature adult coronary heart disease. Data is presented in the light of the large Cardiovascular Risk in Young Finns study and other studies. The authors do not recommend universal screening strategies because of (i) the limited predictive power of serum lipid levels on an individual level, (ii) the limited knowledge on the safety of interventive measures on the growing child, and (iii) the limited knowledge on the ethical aspects of screening (labelling). However, the importance of measuring serum lipids to detect familial dyslipidaemic disorders such as familial hypercholesterolaemia, is stressed. The selection of children or adolescents for serum lipid measurements should be made on the basis of family history of early CHD or dyslipidaemia.