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Biomedical subjects

J M Mann

Publications and source records attributed to J M Mann.

At least 55 records · Page 3Linked to original sources

Measures of hospital market structure: a review of the alternatives and a proposed approach.

Efforts to evaluate the plethora of recent programs adopted by public and private payers to promote hospital price competition critically depend on the availability of measures of local market structure. To gauge the effects of these policies, researchers must be able to delineate hospital market areas and measure the intensity of competition within these markets. This article reviews alternative methods that have been used to define hospital market areas and measure market structure. We propose an empirical patient origin-based method for measuring hospital market structure. The results of sensitivity analyses using data on California hospitals demonstrate the robustness of our measures over a broad range of parameter values.

California↗

Human T cell lymphotropic virus type I (HTLV-I) among female prostitutes in Kinshasa, Zaire.

Three hundred seventy-seven prostitutes from Kinshasa, Zaire, were enrolled in a study to determine associated risk factors for human immunodeficiency virus type 1 (HIV-1) and human T cell lymphotropic virus type I (HTLV-I) infection. Twelve samples (3.2%) were seropositive for HTLV-I; results for HIV-1 (101 [26.8%]) are reported elsewhere. HTLV-I prevalence increased with age, and seven of the seropositive women originated from the Equateur region, a remote area in northwestern Zaire. The prevalence among women from Equateur (7.2%) was higher than that of women from all other regions (1.8%, P = .02). Presence of HTLV-I antibodies was not associated with frequency or type of sex practice. In a subsequent study, 350 serum samples were obtained from a variety of subjects in the Equateur region in 1986. Nineteen (5.4%) showed antibodies to HTLV-I. These data and a recent report of a cluster of patients with tropical spastic paraparesis from this region suggest that HTLV-I is endemic in the Equateur region of Zaire.

Adult↗

Cerebrovascular accidents in infective endocarditis: role of anticoagulation.

Anticoagulation is still a matter of debate in infective endocarditis, since it can increase the risk of complications, mostly neurological. In our series of 269 patients with native valve endocarditis studied between 1970 and 1982, 35 were anticoagulated. We observed 14 patients with brain infarcts, of whom five died, and 12 patients with cerebromeningeal or brain haemorrhage of whom six died. In a similar series of 63 patients with prosthetic valve endocarditis, all of whom were on anticoagulation and were studied between 1972 and 1987, we observed five patients with brain infarcts, three of whom died, and two patients with brain haemorrhage, one of whom died. The frequency of cerebrovascular accident (CVA) was similar for both groups (11.1% in prosthetic endocarditis vs 11.5% in native valve endocarditis, P = ns), as was mortality rate (57% vs 48.4%, P = ns). CVA are significantly more frequent among anticoagulated patients (19/94 vs 19/238: P less than 0.01), but the mortality rate in CVA is similar for anticoagulated and non-anticoagulated patients (11/19 vs 8/19: P = ns). The indications for anticoagulation in infective endocarditis remain similar to those in valvular heart disease. In patients with infective endocarditis, anticoagulation with heparin should be maintained whenever a brain infarct is present, unless it is large and/or haemorrhagic.

Adolescent↗

Projections of HIV infections and AIDS cases to the year 2000.

After the recognition of AIDS (acquired immunodeficiency syndrome) in the early 1980s, uncertainty about the present and future dimensions of HIV (human immunodeficiency virus) infection led to the development of many models to estimate current and future numbers of HIV infections and AIDS cases. The Global Programme on AIDS (GPA) of the World Health Organization (WHO) has developed an AIDS projection model which relies on available HIV seroprevalence data and on the annual rate of progression from HIV infection to AIDS for use in areas where reporting of AIDS cases is incomplete, and where scant data are available to quantify biological and human behavioural variables. Virtually all models, including the WHO model, have projected large increases in the number of AIDS cases by the early 1990s. Such short-term projections are considered relatively reliable since most of the new AIDS cases will develop in persons already infected with HIV. Longer-term prediction (10 years or longer) is less reliable because HIV prevalence and future trends are determined by many variables, most of which are still not well understood. WHO has now applied the Delphi method to project HIV prevalence from the year 1988 to mid-2000. This method attempts to improve the quality of the judgements and estimates for relatively uncertain issues by the systematic use of knowledgeable "experts". The mean value of the Delphi projections for HIV prevalence in the year 2000 is between 3 and 4 times the 1988 base estimate of 5.1 million; these projections have been used to obtain annual estimates of adult AIDS cases up to the year 2000. Coordinated HIV/AIDS prevention and control programmes are considered by the Delphi participants to be potentially capable of preventing almost half of the new HIV infections that would otherwise occur between 1988 and the year 2000. However, more than half of the approximately 5 million AIDS cases which are projected for the next decade will occur despite the most rigorous and effective HIV/AIDS prevention efforts since these AIDS cases will develop in persons whose HIV infection was acquired prior to 1989. The Delphi projections of HIV infection and AIDS cases derived from the WHO projection model need to be periodically reviewed and modified as additional data become available. These projections should be viewed as the first of many attempts to develop estimates for planning strategies to combat the HIV/AIDS pandemic in the 1990s.

Adult↗

International travel and HIV infection.

Although human immunodeficiency virus (HIV) infection is a worldwide problem, its prevalence and pattern vary from country to country. Accordingly, the risk to international travellers of acquiring HIV infection also varies widely in different parts of the world, and depends principally on their behaviour. The risk of sexual acquisition of HIV infection can be virtually eliminated by avoiding penetrative sexual intercourse with intravenous drug users and persons who have had multiple sexual partners (such as prostitutes) or reduced by the use of condoms. The risk of parenteral exposure to HIV can be reduced by avoiding parenteral drug use and behaviour that is likely to lead to injury (with its attendant risk of requiring blood transfusion) and by seeking medical facilities with adequate capabilities to screen blood donors for HIV and to sterilize instruments. HIV screening of international travellers is an ineffective, costly, and impractical public health strategy for limiting the worldwide spread of HIV infection. Travellers infected with HIV require specialized advice regarding health precautions, prophylactic medications, and immunization.

Acquired Immunodeficiency Syndrome↗

Prospective payments to hospitals: should emergency admissions have higher rates?

Systematic variation in patient resource use can be a significant problem for a system based on diagnosis-related groups (DRG's) if this variation is not evenly distributed across hospitals. If certain hospitals routinely treat patients who require more services than average under DRG's, the long-run financial viability of these hospitals will be threatened. In this study, the authors examine whether patients who are admitted on an emergency or urgent basis represent an identifiable group of patients whose costs are systematically higher than those of electively admitted patients, controlling for DRG. Alternative approaches for incorporating admission status into a DRG payment system are developed and tested.

Costs and Cost Analysis↗

The global epidemiology and projected short-term demographic impact of AIDS.

This paper summarizes the natural history, surveillance, and global patterns of infections with the human immunodeficiency virus (HIV), the etiologic agent of AIDS The focus is primarily on HIV-1 because surveillance of HIV-2, which has recently been recognized as a separate type of the virus, is only just beginning. The natural progress of the disease is described, from acute infection through asymptomatic phase to the clinical illness phase. Available evidence on the speed of progression from infection to AIDS and possible co-factors in that progression are reviewed. The 3 patterns of AIDS which are described characterize the experience of different regions according to the types of transmission ( i.e., homosexual versus heterosexual, contaminated blood, drug use) and demographic characteristics of the affected persons. An epidemiologically based short-term forecasting model for AIDS cases is presented and used to project the demographic impact of AIDS in a hypothetical central African country. In that hypothetical setting, the impact of AIDS is shown to be disproportionately felt in urban areas, where the projected increase in population will decrease by 30% due to AIDS deaths by 1997; the growth rate of the rural population will be only slightly affected. In conclusion, the global prevalence of the disease, and prospects and implications for the future are discussed. Without effective drugs for treatment and no vaccine for prevention of HIV infections, the short-term outlook is not good. HIV/AIDS is expected to be an increasing public-health problem in the next 2 decades.

Acquired Immunodeficiency Syndrome↗

Transmission of human immunodeficiency virus (HIV) in health-care settings worldwide.

Based on the information available, transmission of human immunodeficiency virus (HIV) can and does occur in health-care settings. No cases of such transmission have been reported from an infected health-care worker to a patient. Transmission of HIV from an infected patient to a health-care worker has been documented after parenteral or mucous-membrane exposure to blood. However, this risk is less than 1%, is limited to exposure to blood, and can be further minimized through adherence to routine infection control measures. Patient-to-patient transmission through invasive equipment or through HIV-infected blood, blood products, organs, tissues, or semen also occurs but can be prevented by proper sterilization of instruments and through donor-deferral, donor screening, and heat treatment of Factors VIII or IX to inactivate the HIV. In health-care settings, prevention of HIV transmission requires education of all health-care workers and ancillary staff, provision of necessary equipment, and strict adherence to general infection control practices.

Acquired Immunodeficiency Syndrome↗