Mass screening

About: Mass screening is a research topic. Over the lifetime, 34508 publications have been published within this topic receiving 1365148 citations.

Dynamics and control of the transmission of gonorrhea.

Abstract: Calculations revealed that approximately a third of the reported cases of gonorrhea in women during 1973-1975 were discoveries of the screening program. Theoretical models and epidemiologic data showed that the prevalence of gonorrhea adjusts rapidly to changes in social behavior, medical treatment, and control programs, that prevalence oscillates seasonally around an equilibrium state determined by the current social and medical conditions, and that this equilibrium moves as epidemiologic conditions change. The incidence of gonorrhea is theoretically limited by saturation in a sexually active core population, and this core causes gonorrhea to remain endemic.

Comparison of the Instructional Efficacy of Internet-Based CME With Live Interactive CME Workshops: A Randomized Controlled Trial

Abstract: ContextDespite evidence that a variety of continuing medical education (CME) techniques can foster physician behavioral change, there have been no randomized trials comparing performance outcomes for physicians participating in Internet-based CME with physicians participating in a live CME intervention using approaches documented to be effective.ObjectiveTo determine if Internet-based CME can produce changes comparable to those produced via live, small-group, interactive CME with respect to physician knowledge and behaviors that have an impact on patient care.Design, Setting, and ParticipantsRandomized controlled trial conducted from August 2001 to July 2002. Participants were 97 primary care physicians drawn from 21 practice sites in Houston, Tex, including 7 community health centers and 14 private group practices. A control group of 18 physicians from these same sites received no intervention.InterventionsPhysicians were randomly assigned to an Internet-based CME intervention that could be completed in multiple sessions over 2 weeks, or to a single live, small-group, interactive CME workshop. Both incorporated similar multifaceted instructional approaches demonstrated to be effective in live settings. Content was based on the National Institutes of Health National Cholesterol Education Program—Adult Treatment Panel III guidelines.Main Outcome MeasuresKnowledge was assessed immediately before the intervention, immediately after the intervention, and 12 weeks later. The percentage of high-risk patients who had appropriate lipid panel screening and pharmacotherapeutic treatment according to guidelines was documented with chart audits conducted over a 5-month period before intervention and a 5-month period after intervention.ResultsBoth interventions produced similar and significant immediate and 12-week knowledge gains, representing large increases in percentage of items correct (pretest to posttest: 31.0% [95% confidence interval {CI}, 27.0%-35.0%]; pretest to 12 weeks: 36.4% [95% CI, 32.2%-40.6%]; P<.001 for all comparisons). Chart audits revealed high baseline screening rates in all study groups (≥93%) with no significant postintervention change. However, the Internet-based intervention was associated with a significant increase in the percentage of high-risk patients treated with pharmacotherapeutics according to guidelines (preintervention, 85.3%; postintervention, 90.3%; P = .04).ConclusionsAppropriately designed, evidence-based online CME can produce objectively measured changes in behavior as well as sustained gains in knowledge that are comparable or superior to those realized from effective live activities.

Effect of NHS breast screening programme on mortality from breast cancer in England and Wales, 1990-8: comparison of observed with predicted mortality.

Abstract: Objective: To assess the impact of the NHS breast screening programme on mortality from breast cancer in women aged 55-69 years over the period 1990-8. Design: Age cohort model with data for 1971-89 used to predict mortality for 1990-8 with assumption of no major effect from screening or improvements in treatment until after 1989. Effect of screening and other factors on mortality estimated by comparing three year moving averages of observed mortality with those predicted (by five year age groups from 50-54 to 75-79), the effect of screening being restricted to certain age groups. Setting: England and Wales. Subjects: Women aged 40 to 79 years. Results: Compared with predicted mortality in the absence of screening or other effects the total reduction in mortality from breast cancer in 1998 in women aged 55-69 was estimated as 21.3%. Direct effect of screening was estimated as 6.4% (range of estimates from 5.4-11.8%). Effect of all other factors (improved treatment with tamoxifen and chemotherapy, and earlier presentation outside the screening programme) was estimated as 14.9% (range 12.2-14.9%). Conclusions: By 1998 both screening and other factors, including improvements in treatment, had resulted in substantial reductions in mortality from breast cancer. Many deaths in the 1990s will be of women diagnosed in the 1980s and early 1990s, before invitation to screening. Further major effects from screening and treatment are expected, which together with cohort effects should result in further substantial reductions in mortality from breast cancer, particularly for women aged 55-69, over the next 10 years.

The benefits and hazards of antioxidants: controlling apoptosis and other protective mechanisms in cancer patients and the human population.

Abstract: Cellular oxidants, called reactive oxygen species (ROS), are constantly produced in animal and human cells. Excessive ROS can induce oxidative damage in cell constituents and promote a number of degenerative diseases and aging. Cellular antioxidants protect against the damaging effects of ROS. However, in moderate concentrations, ROS are necessary for a number of protective reactions. Thus, ROS are essential mediators of antimicrobial phagocytosis, detoxification reactions carried out by the cytochrome P-450 complex, and apoptosis which eliminates cancerous and other life-threatening cells. Excessive antioxidants could dangerously interfere with these protective functions, while temporary depletion of antioxidants can enhance anti-cancer effects of apoptosis. Experimental data are presented supporting these notions. The human population is heterogeneous regarding ROS levels. Intake of exogenous antioxidants (vitamins E, C, beta-carotene and others) could protect against cancer and other degenerative diseases in people with innate or acquired high levels of ROS. However, abundant antioxidants might suppress these protective functions, particularly in people with a low innate baseline level of ROS. Screening human populations for ROS levels could help identify groups with a high level of ROS that are at a risk of developing cancer and other degenerative diseases. It also could identify groups with a low level of ROS that are at a risk of down-regulating ROS-dependent anti-cancer and other protective reactions. Screening populations could provide a scientifically grounded application of antioxidant supplements, which could significantly contribute to the nation's health.

How to read a paper. Papers that report diagnostic or screening tests.

Abstract: If you are new to the concept of validating diagnostic tests, the following example may help you. Ten men are awaiting trial for murder. Only three of them actually committed a murder; the seven others are innocent of any crime. A jury hears each case and finds six of the men guilty of murder. Two of the convicted are true murderers. Four men are wrongly imprisoned. One murderer walks free. PETER BROWN This information can be expressed in what is known as a two by two table (table 1). Note that the “truth” (whether or not the men really committed a murder) is expressed along the horizontal title row, whereas the jury's verdict (which may or may not reflect the truth) is expressed down the vertical row. View this table: Table 1 Two by two table showing outcome of trial for 10 men accused of murder These figures, if they are typical, reflect several features of this particular jury: These five features constitute, respectively, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of this jury's performance. The rest of this article considers these five features applied to diagnostic (or screening) tests when compared with a “true” diagnosis or gold standard. A sixth feature—the likelihood ratio—is introduced at the end of the article. Our window cleaner told me that he had been feeling thirsty recently and had …