W. Meade Morgan

Pseudomonas cepacia colonization in patients with cystic fibrosis: Risk factors and clinical outcome†

During the period of 1979 to 1983, 38 patients with cystic fibrosis (CF) at the CF center of St. Christophers Hospital for Children in Pennsylvania developed respiratory tract colonization with Pseudomonas cepacia. Seventeen (45%) of the patients with colonization died. Yearly incidence rates of P. cepacia colonization fluctuated between 1.3% and 6.1%, suggesting an endemic phenomenon. Case-control studies showed that severe underlying CF, use of aminoglycosides, and having a sibling with CF and P. cepacia colonization were significant risk factors for P. cepacia colonization. Once colonized with P. cepacia, patients with CF were likely to be hospitalized longer (P = 0.008) and to die sooner (P = 0.0001) than control patients with CF. Environmental and microbiologic studies did not identify a common source or mode of transmission of P. cepacia among patients. The results of this investigation suggest that P. cepacia colonization of patients with CF was endemic in the hospital, occurred more frequently in those with severe disease, and was associated with adverse clinical outcome.

Update from the SENIC project: Hospital infection control: Recent progress and opportunities under prospective payment

From a survey of all U.S. hospitals in 1976 and of a random sample in 1983, we found that the intensity of infection surveillance and control activities greatly increased, and the percentage of hospitals with an infection control nurse per 250 beds increased from 22% to 57%. The percentage with a physician trained in infection control remained low (15%), and there was a drop in the percentages of hospitals doing surgical wound infection surveillance (from 90% down to 79%) and reporting surgeon-specific rates to surgeons (from 19% down to 13%). There was an increase in the percentage of hospitals with programs shown to be effective in preventing urinary tract infections, bacteremias, and pneumonias, but not surgical wound infections. The percentage of nosocomial infections being prevented nationwide appears to have increased from 6% to only 9%, whereas 32% could be prevented if all hospitals adopted the most effective programs.

The changing incidence of Kaposi's sarcoma among patients with AIDS

Kaposis sarcoma (KS), the most common cancer in patients with acquired immunodeficiency syndrome (AIDS), occurs predominantly in homosexual men. However, the percentage of homosexual AIDS patients with KS has declined during the past 6 years. This and other findings suggest that one or more cofactors associated with the homosexual lifestyle, rather than a special viral strain, probably influence the development of KS in patients infected with the human immunodeficiency virus (HIV). Possible reasons for the decline include changes in homosexual behaviors, leading to the practice of safer sexual techniques, and a decrease in use of nitrite inhalants. Identification of the KS-AIDS cofactor(s) could be invaluable to developing prevention and treatment strategies.

Prevalence, incidence, and risks for HIV-1 infection in female sex workers in Miami, Florida.

Annual cross-sectional prevalence, incidence of new infection, and risks for human immunodeficiency virus type 1 (HIV-1) infection were studied in 607 women convicted of prostitution between October 1987 and December 1990 and tested for HIV under court order. Cross-sectional prevalence was stable for 4 years (23-24% positivity in 1987-1991, p = 0.6). However, the incidence of new infections (rate of seroconversion) in 264 women tested more than once increased significantly each year from 12 per 100 person-years in 1987-1988 to 19 per 100 person-years in 1991 (p < 0.03). Seroconverters were more likely to be young black women with a prior history of syphilis or gonorrhea. A new episode of syphilis or rectal gonorrhea during the follow-up period predicted HIV seroconversion in a survival analysis model. Female sex workers are at great risk of acquiring HIV infection. Although HIV prevalence in cross-sectional samples was stable, incidence was increasing. Interpretation of prevalence trends from convenience samples, such as screening programs, may be difficult because changes in incidence may not be detected.

Predicting AIDS incidence by extrapolating from recent trends

Projections of future acquired immunodeficiency syndrome (AIDS) cases are important for public health planning. This report provides a detailed description of the extrapolation method that the Centers for Disease Control has used to make 5-year projections. Reported incidence is first adjusted for reporting delays. The prediction model extrapolates recent trends in incidence by fitting a Box-Cox model to adjusted incidence by maximum likelihood. Prediction intervals can be computed from least squares regression prediction intervals conditional on the Box-Cox transformation parameter or from a bootstrap procedure. Projections for subgroups can also be made by modeling the time series of proportions of AIDS cases in the subgroups. Projections made in early 1986 were quite accurate for 1986 and 1987, but improved methods for adjusting for reporting delays could yield better projections. Our experience indicates that the form of the extrapolation model must be chosen carefully, using both statistical criteria and substantive knowledge.