Development of an index of maternal transport.

The authors used a decision-analytic approach to develop a Maternal Transport Index (MTI) from ACOG guidelines for maternal transport. Data were obtained from three questionnaires administered to five perinatologists, practicing in facilities with various casemixes. Each questionnaire was based on a given level of hospital and contained scenarios describing indications for maternal transport.

Does workplace health promotion decrease medical claims?

We examined the relationship between workplace health promotion and medical claims in 38 textile plants, considering also the effects of demographic and contextual variables (i.e., average worker age, sex ratio, racial composition, plant product, and access to medical services).

A method for constructing case-mix indexes, with application to hospital length of stay.

This article presents the methodological development of an index for case-mix adjustment of hospital data exemplified by our construction of an index for studying length of stay. We describe the development and evaluation of this index, including internal and external validation procedures, and show an example of its use in a policy-relevant context by applying it to the analysis of length-of-stay differences between investor-owned and voluntary hospitals. Some advantages of this approach to adjusting for case mix are applicability to many hospital or patient output measurements/diagnostic scheme situations; usefulness in reducing heterogeneity in other case-mix adjustments, e.

Analysis of length-of-stay differences between investor-owned and voluntary hospitals.

In contrast to assertions that investor-owned (I-O) hospitals are more efficient than voluntary hospitals, this study finds no significant difference between I-Os and voluntaries where the efficiency measure is length of hospitalization (LOH). The data base used is a national probability sample of hospitals and patients. The analysis accounts for variation in LOH by controlling for hospital characteristics other than ownership, and in particular it utilizes a new case-mix index to control for the case-mix portion of heretofore suggested differences.

A method to determine a non-economic personal value of life.

This paper presents a method for estimating a non-monetary personal value for death in the context of a decision problem. The method evolved from a case study of a personal decision strategy for choosing whether to receive the swine influenza vaccine, based on the predicted epidemic in the United States in the fall of 1976. Rather than dealing with the decision-maker's assessments of utilities associated with extreme outcomes such as one's own death, the basic approach considers probabilities representing marginal reductions in the probability of death.

A stochastic model to measure patient effects stemming from hospital-acquired infections.

We introduce a Markov chain model to represent a patient's path in terms of the number and type of infections s/he may have acquired during a hospitalization period. The model allows for categories of patient diagnosis, surgery, the four major types of nosocomial (hospital-acquired) infections, and discharge or death. Data from a national medical records survey including 58,647 patients enable us to estimate transition probabilities and, ultimately, perform statistical tests of fit, including a validation test.

Conditional rate derivation in the presence of intervening variables using a Markov chain.

When conducting inferential and epidemiologic studies, researchers are often interested in the distribution of time until the occurrence of some specified event, a form of incidence calculation. Furthermore, this interest often extends to the effects of intervening factors on this distribution. In this paper we impose the assumption that the phenomena being investigated are governed by a stationary Markov chain and review how one may estimate the above distribution.

Nosocomial infections in U.S. hospitals, 1975-1976: estimated frequency by selected characteristics of patients.

To obtain estimates of the frequency of nosocomial infections nationwide, those occurring at the four major sites--urinary tract, surgical wound, lower respiratory tract and bloodstream--were diagnosed in a stratified random sample of 169,526 adult, general medical and surgical patients selected from 338 hospitals representative of the "mainstream" of U.S. hospitals.

The accuracy of retrospective chart review in measuring nosocomial infection rates. Results of validation studies in pilot hospitals.

To measure the accuracy and consistency of a standardized method--retrospective chart review (RCR)--for estimating nosocomial infection rates (NIRs) in individual hospitals, the authors performed a series of pilot studies in four hospitals of different types. In comparison with a standard based on diagnoses made by physician-epidemiologists supervising intensive prospective data collection teams, the RCR method was found to have an average sensitivity of 0.74 (+/- 0.

The SENIC sampling process: design for choosing hospitals and patients and results of sample selection.

To achieve its primary objectives, the Study on the Efficacy of Nosocomial Infection Control (SENIC Project) focused its attention on a target population of patients referred to as SENIC-eligible admissions in a target population of hospitals referred to as the "SENIC Universe." SENIC thus required a design for sampling hospitals and patients within these hospitals and a valid procedure for projecting sample results to the target population. This paper presents the details of the sampling design used, describes the actual process of selecting hospitals and patients for the surveys, explains the procedure used to project sample results to the target population, and examines the possibility of bias in the design and hospital selection process.

The emergence of infection surveillance and control programs in US hospitals: an assessment, 1976.

To assess the current state of hospitals' infection surveillance and control programs (ISCPs) nationwide and to provide a sampling frame for selecting hospitals for later phases of the SENIC Project, the authors mailed a screening questionnaire in March, 1976, to virtually all US hospitals; 86% of those in the SENIC target universe responded. Of these, 64% (2299) reported that their ISCPs were being supervised by a physician or a microbiologist with special interest in infection control, and 42% had an infection control nurse (ICN), or equivalent, working at least half time. In contrast to the supervisors, most of the ICN's had recieved special training in hospital infection epidemiology and spent the majority of their time doing surveillance.

The interactive effects of induced abortion, inter-pregnancy interval and contraceptive use on subsequent pregnancy outcome.

Prior induced abortion and outcome of the next pregnancy are investigated, allowing for two intervening and potentially confounding variables: 1) length of interval between the termination of the first pregnancy and the conception of the next (inter-pregnancy interval) and 2) the utilization of contraception during this interval. Results show that non-contracepting (susceptibility) intervals which immediately precede a subsequent pregnancy are significantly shorter following an induced abortion than those following a spontaneous abortion or delivery. A life table analysis of all susceptibility intervals confirmed this finding.