Pre-transplant identification of risk factors that adversely affect length of stay and charges for renal transplantation

BACKGROUND

In the current era of renal transplantation, increasing attention is being focused on resource utilization. The purpose of this study was to identify demographic, medical and immunologic risk factors that are associated with changes in length of stay (LOS) and charges for renal transplantation.

METHOD

The study was a retrospective analysis of 311 consecutive renal transplants performed at a single institution. Univariate and multivariate analyses were used to examine relationships between risk factors, LOS, charges and post-operative complications.

RESULTS

The following pre-transplant variables were found to be independently significant in predicting increased LOS and/or charges: African-American race, obesity for women, chronic obstructive pulmonary disease (COPD), presence of cardiac disease or previous stroke, pre-transplant dialysis time > or = 1 yr, a 10% increase in panel reactive antibody (PRA), cadaver donor and retransplantation. The analyses were performed with and without adjustment for key outcome variables such as delayed graft function (DGF) and use of induction antibody therapy. Increased LOS or charges for specific risk factors could be attributed to increased complication rates, including delayed graft function seen with various co-morbidities, or increased immunologic risk and more frequent use of induction antibody therapy.

CONCLUSION

Analysis of linked financial and clinical databases can reveal demographic, medical and immunologic risk factors that correlate with LOS, charges and complications for renal transplantation. Efforts to establish quantitative relationships for various risk factors relative to resource utilization will become important in managed care and/or capitated healthcare delivery systems.

Immunohistochemical studies of productive rhesus cytomegalovirus infection in rhesus monkeys (Macaca mulatta) infected with simian immunodeficiency virus

In humans infected with the human immunodeficiency virus (HIV), clinical disease due to human cytomegalovirus (HCMV) infection is one of the AIDS-defining diseases; HCMV is the most common opportunistic infection found postmortem. Histologically, the typical lesions are characterized by "owl's eye cells." In rhesus monkeys infected with simian immunodeficiency virus (SIV), comparable lesions are caused by an infection with the rhesus CMV (RhCMV). The aim of this study was to investigate the incidence of productive and latent RhCMV infection in monkeys infected with SIV macaques (SIVmac). Eleven SIVmac-infected rhesus monkeys, which were euthanatized after developing AIDS-like disease, and 11 clinically healthy and uninfected animals comprised the study. The monkeys were screened serologically for RhCMV by western-blot analysis. Immunohistochemistry was performed by an indirect immunoperoxidase technique with a polyclonal rabbit RhCMV-antiserum. Lesions characteristic of RhCMV-associated diseases were detected histologically. All animals were latently RhCMV-infected. Seven of eleven (63.6%) SIV-infected macaques were productively RhCMV infected according to immunohistochemistry. RhCMV antigen was identified in the gastrointestinal tract, the hepatobiliary system, the lungs, and the testicles. Two of these seven animals showed characteristic inflammatory lesions associated with productive infection. Consequently, the CMV prevalence in SIVmac-infected rhesus monkeys and human AIDS patients is comparable.

Prestige of training programs and experience of bypass surgeons as factors in adjusted patient mortality rates

OBJECTIVES

The relation of physician performance to physician training and experience is not well understood. The aim of this study was to examine whether indicators of physician background and experience were associated with an objective measure of physician performance.

METHODS

Physician background information obtained from the Directory of Board-Certified Medical Specialists was linked to physician risk-adjusted mortality rates obtained from three statewide data bases of coronary artery bypass surgeons. Subjects were 275 surgeons who performed CABG surgery on 83,547 patients during the years 1989 to 1992. Surgical performance was measured by the mortality ratio (MR), the ratio of the observed to the predicted patient mortality rate as determined by detailed clinical information. Training institutions and physicians were characterized as prestigious if they were listed as outstanding in published articles.

RESULTS

Surgical performance was not associated with graduation from an American medical school; attendance at a prestigious medical school, residency, or fellowship program; or an academic appointment. Mortality ratios decreased with increased volume and increased with years of experience, age, and academic rank. Surgeons were more likely to be considered a "best doctor" if they had more years experience and trained at a prestigious residency or fellowship program.

CONCLUSIONS

Training at a prestigious institution was associated with identification as a "best" doctor but not with lower mortality ratios.

Charges for childhood asthma by hospital characteristics

BACKGROUND

The ownership, location, and teaching status of hospitals affect their missions, policies, finances, and operations.

OBJECTIVE

This study assesses the relationship of hospital ownership, location, and teaching status with charges and length of stay for children with asthma, the most common reason for pediatric admission after birth.

METHODS

All 28 545 complete records of patients </=18 years of age with the principal diagnosis asthma in 1994 were extracted from the Healthcare Cost and Utilization Project Nationwide Inpatient Sample, providing a stratified sample of 735 nonfederal, acute-care hospitals in 17 states. Multiple regression analysis on log transformed data was used to calculate mean total charges and average length of stay (ALOS) after adjusting for illness severity and mortality risk (four All Patient Refined-Diagnosis Related Group classes based on secondary diagnoses and procedures); payer (Medicaid, private, uninsured, other); patient age, sex, income (four categories based on ZIP code of residence); state; bed size (three categories varying by location); hospital ownership; location; teaching status; and admission month.

RESULTS

Asthma severity did not differ significantly by hospital location or teaching status. Nonprofit hospitals treated a slightly higher proportion of children with major or extreme severity asthma than either public or for-profit hospitals. Urban teaching hospitals treated more children with asthma who lived in low-income neighborhoods, were uninsured, or received Medicaid coverage than urban nonteaching hospitals. For-profit hospitals admitted fewer children with asthma from low-income areas than did public hospitals. The ALOS was 2.5 days and did not differ significantly by hospital ownership, location, or teaching status. However, the mean total charges, after adjusting for all other significant covariates, was higher at for-profit ($4203) than at nonprofit ($3640) or public hospitals ($3620). Average charges also were higher at urban teaching ($4230) and lower at rural institutions ($2910) compared with urban nonteaching hospitals ($3424).

CONCLUSIONS

Despite similar ALOS, mean charges for childhood asthma varied significantly by hospital ownership, location, and teaching status. Implications. Additional clinical and outpatient data are needed to study variations in quality of care by hospital characteristics. With the proliferation of investor-owned hospitals, both the reasons for and the impact of higher average charges at for-profit institutions require additional investigation. With the expanding needs of the medically underserved, socially just policies are required for financing hospitals that care for a disproportionate share of economically disadvantaged children.

Complete withdrawal of immunosuppression in kidney allograft recipients: a prospective study in rhesus monkeys

BACKGROUND

We previously reported the successful withdrawal of immunosuppression in kidney-allografted rhesus monkeys. Recipients had received pretransplant blood transfusions and cyclosporine (CsA) immunosuppression for 6 to 12 months. One animal is still alive at more than 15 years after transplantation. Our hypothesis was that the sharing of a single DR antigen between blood donor and recipient, and the sharing of the same DR antigen with the kidney donor, may be beneficial to allograft survival. We now report on the results from a prospective study.

METHODS

The animals received three pretransplant blood transfusions from a single donor sharing one DR antigen with the recipient. Subsequently, a life-supporting kidney from a donor sharing the same DR antigen was transplanted. CsA was given for at least 6 months after transplantation.

RESULTS

Two animals rejected their graft at 5-8 weeks after cessation of CsA treatment. One animal is still alive at 700 days after transplantation. This animal showed MLR nonreactivity to its kidney donor, similar to the animal at more than 15 years after transplantation.

CONCLUSION

These results demonstrate that withdrawal of immunosuppression may be a realistic option in kidney graft patients under careful immunological monitoring of donor-specific immunity.

The interleukin-17 gene of herpesvirus saimiri

In comparison to wild-type herpesvirus saimiri, viral interleukin-17 gene knockout mutants have unaltered behavior regarding viral replication, T-cell transformation in vitro, and pathogenicity in cottontop tamarins. Thus, this gene is not required for T-cell lymphoma induction but may contribute to apathogenic viral persistence in the natural host, the squirrel monkey.

Platynosomum fastosum in ex-captive orangutans from Indonesia

The liver fluke Platynosomum fastosum was identified upon necropsy of three ex-captive orangutans (Pongo pygmaeus) which had been part of a rehabilitation program for reintroduction to the wild. This trematode has not been reported in orangutans previously and is commonly found in cats in Southeast Asia. Cross infection from cats via intermediate hosts, to orangutans kept in captivity as pets, could explain their presence in the latter. Although P. fastosum caused intrahepatic and bile duct damage, death of the hosts could not be attributed solely to the presence of the liver fluke infection.

Hospitalization costs associated with homelessness in New York City

BACKGROUND

Homelessness is believed to be a cause of health problems and high medical costs, but data supporting this association have been difficult to obtain. We compared lengths of stay and reasons for hospital admission among homeless and other low-income persons in New York City to estimate the hospitalization costs associated with homelessness.

METHODS

We obtained hospital-discharge data on 18,864 admissions of homeless adults to New York City's public general hospitals (excluding admissions for childbirth) and 383,986 nonmaternity admissions of other low-income adults to all general hospitals in New York City during 1992 and 1993. The differences in length of stay were adjusted for diagnosis-related group, principal diagnosis, selected coexisting illnesses, and demographic characteristics.

RESULTS

Of the admissions of homeless people, 51.5 percent were for treatment of substance abuse or mental illness, as compared with 22.8 percent for the other low-income patients, and another 19.7 percent of the admissions of homeless people were for trauma, respiratory disorders, skin disorders, and infectious diseases (excluding the acquired immunodeficiency syndrome [AIDS]), many of which are potentially preventable medical conditions. For the homeless, 80.6 percent of the admissions involved either a principal or a secondary diagnosis of substance abuse or mental illness -- roughly twice the rates for the other patients. The homeless patients stayed 4.1 days, or 36 percent, longer per admission on average than the other patients, even after adjustments were made for differences in the rates of substance abuse and mental illness and other clinical and demographic characteristics. The costs of the additional days per discharge averaged $4,094 for psychiatric patients, $3,370 for patients with AIDS, and $2,414 for all types of patients.

CONCLUSIONS

Homelessness is associated with substantial excess costs per hospital stay in New York City. Decisions to fund housing and supportive services for the homeless should take into account the potential of these services to reduce the high costs of hospitalization in this population.

T-cell lymphoma caused by herpesvirus saimiri C488 independently of ie14/vsag, a viral gene with superantigen homology

The immediate-early gene ie14/vsag of herpesvirus saimiri has homology with murine superantigens. We compared the pathogenesis of infection with either ie14/vsag deletion mutants or wild-type virus C488 in cottontop tamarin monkeys (Saguinus oedipus). Two weeks after infection, all animals developed acute T-cell lymphomas independently of the presence of the viral ie14/vsag gene.

Cytokine gene transcription in simian immunodeficiency virus and human immunodeficiency virus-associated non-Hodgkin lymphomas

Infection of rhesus monkeys with SIV leads to AIDS-like symptoms. Similar to human AIDS patients, some monkeys develop B cell non-Hodgkin lymphoma (NHL). We determined transcription of cytokine genes regulating the activation of B and T cells, which play a role in intratumoral immune surveillance. Therefore, we compared the transcription of the cytokine genes encoding IL-2, IL-4, IL-6, IL-10, IFN-gamma, TNF-alpha, and TGF-beta1, and the Epstein-Barr virus-encoded BCRF 1 gene, in cells from five monkey and two human tumor specimens. The immune-suppressive IL-10 and TGF-beta1 genes were predominantly transcribed in all tumor specimens analyzed. Cytokine gene transcription patterns appeared to be similar in human and animal tumor cells. The transcription patterns corresponded to their histological classification as diffuse large-cell lymphoma according to the REAL classification and as immunoblastic or centroblastic tumors according to the Kiel classification. The determination of cytokine gene transcription pattern in the NHL may improve our understanding of pathogenesis and immune surveillance in this heterogeneous group of tumors. Our data show that SIV-associated NHLs of rhesus monkeys are comparable to human HIV-1-associated EBV-positive non-Hodgkin lymphoma.

Intestinal manifestations of experimental SIV-infection in rhesus monkeys (Macaca mulatta): a histological and ultrastructural study

Intestinal lesions were studied in 32 rhesus monkeys experimentally infected with different strains of simian immunodeficiency virus SIVmac (251/32H, 251/32H-SPL and 251/MPBL) by light microscopy, transmission and scanning electron microscopy. A spectrum of primary and secondary manifestations of SIV-infection were detected. Primary changes included 'SIV-enteropathy' in 12 monkeys and virus-induced syncytial giant cell formation (GCF) of the intestine in two animals. A primary virus-induced enteropathy occurred both as only histologically visible 'SIV-enteropathy' and as 'AIDS-enteropathy' accompanied by clinical signs of enteritis. Secondary opportunistic infections (Balantidium coli, Cryptosporidium, Trichuris, Trichomonas, Spironucleus, Mycobacteria and Cytomegalovirus) were identified in 27 animals and three monkeys developed malignant lymphomas involving the intestinal tract. Compared to intestinal lesions in HIV-infected patients, differences were found concerning the incidence of GCF and the range of opportunistic infections, with cryptosporidium, cytomegalovirus and mycobacteria occurring in both SIV-infected macaques and AIDS patients. The present observations revealed that SIV-infected rhesus monkeys provide an excellent model both for studies on the pathogenesis of HIV-enteropathy and opportunistic infections and for the development of therapies against cryptosporidial, cytomegalovirus and mycobacteria infection. Comparison of three SIV-strains revealed differences in primary and secondary lesions observed: SIVmac251/MPBL was correlated with severe primary SIV-induced pathologic changes and SIVmac251-SPL-infected animals showed a higher incidence of malignant lymphomas.

Are the best coronary artery bypass surgeons identified by physician surveys?

OBJECTIVES

This study assessed the validity of surveys for identifying the best coronary artery bypass surgeons.

METHODS

Data on physicians who performed coronary artery bypass surgery were available from New York, Pennsylvania, and Wisconsin. Data on physicians' reputation were obtained from one national and five city surveys. The measure of surgical performance was the mortality ratio (MR), that is, the ratio of the observed to the predicted patient mortality rate.

RESULTS

Mortality ratios were very similar for the 10,722 patients treated by the 31 surgeons defined as "best" doctors in the surveys (MR = 98) and for the 74,854 patients treated by 243 other surgeons who had more than a minimal number of cases (MR = .96). The mortality ratio was 1.34 for the patients treated by surgeons with the lowest volumes and .87 for the surgeons who performed more than 400 coronary artery bypass surgeries in 3 years.

CONCLUSIONS

These results suggest that the quality of a coronary artery bypass surgeon may be more closely associated with patient volume than with the surgeon's reputation among peers.

The relationship of the value of outcome comparisons to the number of patients per provider

PURPOSE

Monte Carlo methods were used to assess how the value of outcome comparisons depends on the number of patients per provider.

METHODS

We simulated two patient data sets that have been used for well-known studies of outcome comparisons: mortality rates for coronary artery bypass surgeons from New York and Pennsylvania, and 30-day hospital mortality rates of Medicare patient from a national data set. In the simulated data sets, each surgeon or hospital provider was assigned a true or underlying probability of mortality.

RESULTS

For the simulated CABG surgery data set, the underlying probability of mortality explained 30% of the variation in the observed mortality rate when there were 100 patients per physician, and 63% when there were 400 patients. The positive predictive value of using an observed mortality rate in the bottom 10% to identify a surgeon whose underlying probability of mortality was in the bottom 10% was 31% for 100 patients and 59% for 400 patients. The relationship between underlying and observed rates was weaker in the simulated Medicare data set with the same number of patients per provider. For a given data set, the amount of random variation in the observed rates of adverse outcomes among providers can be estimated with a simple equation.

CONCLUSION

The results show that the assessment of provider outcomes may be greatly affected by random variation. An indication of the amount of random variation in a given data set can be obtained from the examples in this study and an equation for estimating random variation.

Association of simian immunodeficiency virus Nef with cellular serine/threonine kinases is dispensable for the development of AIDS in rhesus macaques

The nef gene of simian immunodeficiency virus (SIV) is essential for high viral load and induction of AIDS in rhesus monkeys. A mutant form of the SIVmac239 Nef, which contains changes in a putative SH3-binding domain (amino acids 104 and 107 have been changed from PxxP to AxxA), does not associate with cellular serine/threonine kinases, but is fully active in CD4 downregulation and associates with the cellular tyrosine kinase Src. Infection of two rhesus macaques with SIVmac239 containing the mutant AxxA-Nef caused AIDS and rapid death in both animals. No reversions were observed in the majority of nef sequences analyzed from different time points during infection and from lymphatic tissues at the time of death. Our findings indicate that the putative SH3-ligand domain in SIVmac Nef and the association with cellular serine/threonine kinases are not important for efficient replication and pathogenicity of SIVmac in rhesus macaques.

Live attenuated SIV vaccines are not effective in a postexposure vaccination model

Live attenuated simian immunodeficiency virus (SIV) vaccines, like nef deletion mutants, have been the most effective vaccines tested in the SIV/macaque model so far. The efficacy of live attenuated SIV vaccines in therapeutic vaccination and postexposure prophylaxis has not been determined. Inoculation of macaques with a pathogenic challenge virus and an attenuated SIV vaccine at the same time mimics postexposure vaccination, whereby vaccination with the attenuated virus is performed as rapidly as possible after exposure to pathogenic SIV. In the study presented here, four rhesus macaques were coinfected with pathogenic SIV and a nearly 3000-fold excess of a nef deletion mutant of SIV. Four macaques received pathogenic SIV and an approximately 200-fold excess of a nef deletion mutant expressing interleukin 2 (IL-2). The IL-2-expressing SIV had been previously constructed to enhance the immunogenicity of live attenuated SIV vaccines. All coinfected macaques had a high viral load, and some of them developed AIDS-like symptoms and pathological alterations rapidly. In the presence of pathogenic SIV, both live attenuated SIV vaccines did not protect from disease in this postexposure vaccination model.

Rapid development of vaccine protection in macaques by live-attenuated simian immunodeficiency virus

Convincing data on experimental vaccines against AIDS have been obtained in the simian immunodeficiency virus (SIV) macaque model by preinfection with a virus attenuated by a nef deletion. To investigate the efficacy of a nef deletion mutant of SIVmac32H called pC8 as a live-attenuated vaccine after shorter preinfection periods and to learn more about the nature of the immune protection induced, eight rhesus monkeys were infected intravenously with the pC8 virus. All monkeys became persistently infected, exhibiting low cell-associated viral loads, but strong cellular and, in terms of binding antibodies, strong humoral antiviral responses. Two of eight pC8-infected monkeys developed an immunodeficiency and were not challenged. Sequence analysis of their nef revealed complete replenishment of the deletion. The other six monkeys, two preinfected for 42 weeks and four for 22 weeks, were challenged with pathogenic spleen-derived SIV. Complete protection was achieved in four vaccinees. Virus was consistently detected in two vaccinees from the 22-week-group challenge, however, they remained clinically healthy over a prolonged period. Protection from challenge virus infection or a delayed disease development seemed to be associated with a sustained SIV-specific T helper cell response after challenge. Thus, a sterilizing immunity against superinfection with pathogenic SIV can be induced even after a relatively short waiting period of 22 weeks. Nevertheless, such a vaccine raises severe safety concerns because of its potential to revert to virulence.

Morphological characteristics of the ileal Peyer's patches in the rhesus macaque: a histological and ultrastructural study

Ileal Peyer's patches of rhesus macaques were investigated by light and electron microscopy (scanning-electron microscopy, transmission-electron microscopy). The results were compared with findings in other species. Differences were found concerning the shape of the dome area, the composition of the dome epithelium and the apical membrane of M cells: in the rhesus monkey, hemispherical domes bulge into the intestinal lumen. The dome epithelium is composed of three populations of gut epithelial cells; absorptive enterocytes as the predominant cell type; goblet cells; and M cells ("microfold bearing' or "membraneous' gut epithelial cells). The apical membrane of M cells forms irregular protrusions.

Test of the acute cardiac ischemia time-insensitive predictive instrument (ACI-TIPI) for prehospital use

STUDY OBJECTIVES

To test diagnostic performance for acute cardiac ischemia (ACI) in a manually calculated and in a computerized, ECG-calculated ACI time-insensitive predictive instrument (ACI-TIPI) in prehospital chest pain patients.

METHODS

We carried out prospective inclusion and data acquisition with retrospective analysis. Over a 6-month period, 439 adult emergency medical services patients with chest pain underwent prehospital electrocardiography. Because of incomplete data, 77 cases were excluded, leaving a study sample of 362 patients. Excluded patients did not differ significantly with respect to age, sex, final diagnosis, or history of myocardial infarction, heart surgery, diabetes, or stroke. ACI-TIPI probabilities of ACI were computed on the basis of the prehospital ECGs as interpreted retrospectively and independently by two study investigators blinded to patient outcome, with a specially programmed electrocardiograph, and with a computer algorithm further modified by logistic-regression analysis.

RESULTS

Diagnostic performance on the basis of receiver operating characteristic (ROC) curve areas of the ACI-TIPI was scored, by the two physician readers, .73 and .74; and by ECG, .75. Patients with low ACI-TIPI probability (0% to 9%) had no acute myocardial infarctions, a 2.3% incidence of angina, and no prehospital life-threatening events.

CONCLUSION

ACI-TIPI probabilities of ACI as generated by a specially programmed electrocardiograph are comparable to those based on physician ECG interpretations and may be useful in the prehospital evaluation of chest pain.

Correlation of rates of coronary artery bypass surgery, angioplasty, and cardiac catheterization in 305 large communities for persons age 65 and older

OBJECTIVE

The rate of coronary artery bypass surgery (CABG) has been shown to vary greatly across geographic regions. This study examined whether these rates were associated with the rate of coronary artery angioplasty (PTCA) and with other community characteristics.

DATA SOURCES/STUDY SETTING

The health care financing administration provided the number of Medicare hospitalizations in 1988 for conditions and procedures related to coronary artery disease. Information on physicians and hospitals was obtained from the Area Resource File, and the number of persons in each age, sex, and race category was obtained from US. census data.

STATISTICAL METHODS

Age-and sex-adjusted hospitalization rates based on the patient's zip code of residence were calculated at the level of the Metropolitan Statistical Area (MSA) for white patients age 65 or older. Rates were obtained for 305 MSAs for CABG, PTCA, cardiac catheterization, angina, and myocardial infarction.

PRINCIPAL FINDINGS

The rate of cardiac catheterization had a correlation of .72 with the CABG rate and .64 with the PTCA rate. The correlation of the PTCA and CABG rates with each other was .49. This correlation was not charged by adjusting for the rates of hospitalization for angina or myocardial infection, but it was reduced to only .05 (ns) after adjusting for the rate of cardiac catheterization. The rates of all three procedures had rank correlations of about .15 with the density of thoracic surgeons and about .30 with the density of hospitals with cardiac catheterization and open heart surgery units.

CONCLUSIONS

Community CABG and PTCA rates tend to move in the same direction due to community factors that also affect the rates of cardiac catheterization. These community factors do not appear to include the rate of coronary artery disease, but may include resources or attitudes toward aggressive treatment of coronary artery disease.

BUN as a risk factor for mortality after coronary artery bypass grafting

BACKGROUND

Although information on blood urea nitrogen (BUN) is universally available for patients who undergo coronary artery bypass grafting, BUN has not often been considered as a risk factor for mortality. This study assessed BUN as a risk factor for CABG patients.

METHODS

Four data sets were evaluated that differed with respect to the types of patients and available patient information. In each of these data sets logistic regression analysis was used to examine the relationship between BUN and mortality after adjusting for other risk factors.

RESULTS

Blood urea nitrogen level was strongly associated with mortality in each of the data sets. After adjustment for the available risk factors other than creatinine level, patients with BUN levels greater than 30 mg/dL had a relative odds of mortality ranging between 1.86 and 2.49 (p < 0.0001 in three of the data sets). Even after adjustment for creatinine level as well as the other variables, BUN was statistically significant at the p less than 0.01 level for three of the data sets.

CONCLUSIONS

The results suggest that BUN provides additional information on cardiac function that supplements the information provided by other risk factors.