Hyponatraemia and Moduretic-Grand Mal Seizures: A Review

Three cases are presented which emphasize the importance of hyponatraemia as a cause of grand mal seizures. The combination of hydrochlorothiazide and amiloride appears to increase the risk of hyponatraemia. We discuss the aetiology and treatment of hyponatraemia and review the necessity for such combination therapy. We recommend caution in prescribing diuretics and preparations such as Moduretic should be used only in those few patients shown to need potassium supplementation.

Inhibition of DNA2 nuclease as a therapeutic strategy targeting replication stress in cancer cells

Replication stress is a characteristic feature of cancer cells, which is resulted from sustained proliferative signaling induced by activation of oncogenes or loss of tumor suppressors. In cancer cells, oncogene-induced replication stress manifests as replication-associated lesions, predominantly double-strand DNA breaks (DSBs). An essential mechanism utilized by cells to repair replication-associated DSBs is homologous recombination (HR). In order to overcome replication stress and survive, cancer cells often require enhanced HR repair capacity. Therefore, the key link between HR repair and cellular tolerance to replication-associated DSBs provides us with a mechanistic rationale for exploiting synthetic lethality between HR repair inhibition and replication stress. DNA2 nuclease is an evolutionarily conserved essential enzyme in replication and HR repair. Here we demonstrate that DNA2 is overexpressed in pancreatic cancers, one of the deadliest and more aggressive forms of human cancers, where mutations in the KRAS are present in 90–95% of cases. In addition, depletion of DNA2 significantly reduces pancreatic cancer cell survival and xenograft tumor growth, suggesting the therapeutic potential of DNA2 inhibition. Finally, we develop a robust high-throughput biochemistry assay to screen for inhibitors of the DNA2 nuclease activity. The top inhibitors were shown to be efficacious against both yeast Dna2 and human DNA2. Treatment of cancer cells with DNA2 inhibitors recapitulates phenotypes observed upon DNA2 depletion, including decreased DNA double strand break end resection and attenuation of HR repair. Similar to genetic ablation of DNA2, chemical inhibition of DNA2 selectively attenuates the growth of various cancer cells with oncogene-induced replication stress. Taken together, our findings open a new avenue to develop a new class of anticancer drugs by targeting druggable nuclease DNA2. We propose DNA2 inhibition as new strategy in cancer therapy by targeting replication stress, a molecular property of cancer cells that is acquired as a result of oncogene activation instead of targeting currently undruggable oncoprotein itself such as KRAS.

Engineering polarization rotation in a ferroelectric superlattice

A key property that drives research in ferroelectric perovskite oxides is their strong piezoelectric response in which an electric field is induced by an applied strain, and vice versa for the converse piezoelectric effect. We have achieved an experimental enhancement of the piezoelectric response and dielectric tunability in artificially layered epitaxial PbTiO(3)/CaTiO(3) superlattices through an engineered rotation of the polarization direction. As the relative layer thicknesses within the superlattice were changed from sample to sample we found evidence for polarization rotation in multiple x-ray diffraction measurements. Associated changes in functional properties were seen in electrical measurements and piezoforce microscopy. The results demonstrate a new approach to inducing polarization rotation under ambient conditions in an artificially layered thin film.

Nuclear import strategies of high-risk HPV18 L2 minor capsid protein

We have investigated the nuclear import strategies of high-risk HPV18 L2 minor capsid protein. HPV18 L2 interacts with Kap alpha2 adapter, and Kap beta2 and Kap beta3 nuclear import receptors. Moreover, binding of RanGTP to either Kap beta2 or Kap beta3 inhibits their interaction with L2, suggesting that these Kap beta/L2 complexes are import competent. Mapping studies show that HPV18 L2 contains two NLSs: in the N-terminus (nNLS) and in the C-terminus (cNLS), both of which can independently mediate nuclear import. Both nNLS and cNLS form a complex with Kap alpha2beta1 heterodimer and mediate nuclear import via a classical pathway. The nNLS is also essential for the interaction of HPV18 L2 with Kap beta2 and Kap beta3. Interestingly, both nNLS and cNLS interact with the viral DNA and this DNA binding occurs without nucleotide sequence specificity. Together, the data suggest that HPV18 L2 can interact via its NLSs with several Kaps and the viral DNA and may enter the nucleus via multiple import pathways mediated by Kap alpha2beta1 heterodimers, Kap beta2 and Kap beta3.

Predictive Modelling of Post-onset Xenoma Growth During Microsporidial Gill Disease (Loma salmonae) of Salmonids

Loma salmonae, an obligate intracellular microsporidian parasite, is the causal agent of microsporidial gill disease of salmon (MGDS), characterized by the production, growth and eventual rupture of spore-filled xenomas. MGDS in farmed chinook salmon remains occult until xenoma rupture, at which time the infected fish respond with intense branchitis and high rates of mortality. The present study showed that in experimentally infected fish the rate of change of xenoma diameter could be modelled through regression analysis, particularly through the period of 4-9 weeks post-infection, yielding the predictive equation: xenoma diameter=-42.9 microns +15.3 microns x (number of weeks post-infection). This provides a tool for diagnosticians to predict the time to xenoma rupture and hence to the initiation of the clinical phase of MGDS.

Development and validation of a multifactorial risk index for predicting postoperative pneumonia after major noncardiac surgery

BACKGROUND

Pneumonia is a common postoperative complication associated with substantial morbidity and mortality.

OBJECTIVE

To develop and validate a preoperative risk index for predicting postoperative pneumonia.

DESIGN

Prospective cohort study with outcome assessment based on chart review.

SETTING

100 Veterans Affairs Medical Centers performing major surgery.

PATIENTS

The risk index was developed by using data on 160 805 patients undergoing major noncardiac surgery between 1 September 1997 and 31 August 1999 and was validated by using data on 155 266 patients undergoing surgery between 1 September 1995 and 31 August 1997. Patients with preoperative pneumonia, ventilator dependence, and pneumonia that developed after postoperative respiratory failure were excluded.

MEASUREMENTS

Postoperative pneumonia was defined by using the Centers for Disease Control and Prevention definition of nosocomial pneumonia.

RESULTS

A total of 2466 patients (1.5%) developed pneumonia, and the 30-day postoperative mortality rate was 21%. A postoperative pneumonia risk index was developed that included type of surgery (abdominal aortic aneurysm repair, thoracic, upper abdominal, neck, vascular, and neurosurgery), age, functional status, weight loss, chronic obstructive pulmonary disease, general anesthesia, impaired sensorium, cerebral vascular accident, blood urea nitrogen level, transfusion, emergency surgery, long-term steroid use, smoking, and alcohol use. Patients were divided into five risk classes by using risk index scores. Pneumonia rates were 0.2% among those with 0 to 15 risk points, 1.2% for those with 16 to 25 risk points, 4.0% for those with 26 to 40 risk points, 9.4% for those with 41 to 55 risk points, and 15.3% for those with more than 55 risk points. The C-statistic was 0.805 for the development cohort and 0.817 for the validation cohort.

CONCLUSIONS

The postoperative pneumonia risk index identifies patients at risk for postoperative pneumonia and may be useful in guiding perioperative respiratory care.

Guidelines for the management of patients with chronic stable angina: treatment

The dual aims of treating patients with chronic stable angina are 1) to reduce morbidity and mortality and 2) to eliminate angina with minimal adverse effects and allow the patient to return to normal activities. In the absence of contraindications, beta-blockers are recommended as initial therapy. All beta-blockers seem to be equally effective. If the patient has serious contraindications to beta-blockers, unacceptable side effects, or persistent angina, calcium antagonists should be administered. Long-acting dihydropyridine and nondihydropyridine agents are generally as effective as beta-blockers in relieving angina. Long-acting nitrates are considered third-line therapy because a nitrate-free interval is required to avoid developing tolerance. All long-acting nitrates seem to be equally effective. Patients with angina should take 75 to 325 mg of aspirin daily unless they have contraindications. Such risk factors as smoking, elevated low-density lipoprotein cholesterol level, diabetes, and hypertension should be treated appropriately. Coronary revascularization has not been shown to improve survival for most patients with chronic angina but may be required to control symptoms. However, coronary artery bypass grafting (CABG) is often indicated for symptomatic patients with left-main disease, three-vessel disease, or two-vessel disease including proximal stenosis of the left anterior descending coronary artery; it improves their survival. Percutaneous transluminal coronary angioplasty is an alternative to CABG for patients with normal left ventricular function and favorable angiographic features. Coronary artery bypass grafting is initially more effective in relieving angina than medical therapy, but the two procedures yield similar results after 5 to 10 years. Eighty percent of patients who undergo CABG remain angina-free 5 years after surgery. In low-risk patients, percutaneous transluminal coronary angioplasty seems to control angina better than medical therapy, but recurrent angina and repeated procedures are more likely than with CABG. Patient education is an important component of management. Long-term follow-up should be individualized to ascertain clinical stability at regular intervals and to reassess prognosis when warranted.

Preoperative risk factors for 30-day mortality after elective surgery for vascular disease in Department of Veterans Affairs hospitals: is race important?

PURPOSE

Racial variation in health care outcomes is an important topic. Risk-adjustment models have not been developed for elective abdominal aortic aneurysm repair (AAA), lower extremity bypass revascularization (LEB), or lower extremity amputation (AMP). Earlier studies examining racial variation in mortality and morbidity from AAA, LEB, or AMP were limited to administrative data. This study determined risk factors for mortality after surgery for vascular disease and determined whether race is an important risk factor.

METHODS

Data in this prospective observational study were obtained from the Department of Veterans Affairs (VA) National Surgical Quality Improvement Program. Detailed demographic and clinical data were collected prospectively from patients' medical records by trained nurse reviewers. Eligible patients were those 18 years and older who underwent elective AAA, LEB, or AMP at one of 44 VA medical centers performing both vascular and cardiac surgery (phase I; October 1991 to December 1993) and at one of these 44 or 79 additional VA medical centers performing vascular but not cardiac surgery (phase II; January 1994 to August 1995). The independent association of several preoperative factors with the 30-day postoperative mortality rate was examined with stepwise logistic regression analysis for AAA, LEB, and AMP. Models were developed in the combined 44 VA medical centers and validated in the 79 VA medical centers. The independent association of race with the 30-day postoperative mortality rate was examined after controlling for important preoperative risk factors for each operation.

RESULTS

More than 10,000 surgical operations were examined, and 5, 3, and 10 independent preoperative predictors of 30-day mortality rate were identified for AAA, LEB, and AMP, respectively. The observed mortality rate for patients undergoing AAA was higher (7.2% vs 3.2%; P =.02) in African American patients than in white patients in the 44 VA medical centers, although the differences were not significant in LEB and AMP or at the additional 79 hospitals. After important preoperative risk factors were controlled, there was no difference in 30-day mortality rates between African American patients and white patients.

CONCLUSION

We identified several important preoperative risk factors for 30-day mortality rate in three vascular operations. From the results of this study, race was determined not to be an independent predictor of mortality.

Nigrostriatal collaterals to thalamus degenerate in parkinsonian animal models

Movement, cognition, emotion, and positive reinforcement are influenced by mesostriatal, mesocortical, and mesolimbic dopamine systems. We describe a fourth major pathway originating from mesencephalic dopamine neurons: a mesothalamic system. The dopamine transporter, specific to dopamine containing axons, was histochemically visualized in thalamic motor and limbic-related nuclei and regions that modulate behavioral state as opposed to sensory nuclei in rats, nonhuman primates, and humans. Anatomical tracing established this innervation's origin via axon collaterals from the mesostriatal pathway. These findings implicate the thalamus as a novel site for disease specific alterations in dopamine neurotransmission, such as exist with nigral degeneration attending Parkinson's disease. This was confirmed in hemiparkinsonian animals where reduction of thalamic dopamine innervation occurred coincident with signs of active axonal degeneration. Individual mesencephalic dopamine neurons therefore have the potential to modulate normal and pathologic behavior not only through traditional nigrostriatal pathways but also by way of axon collaterals that innervate the thalamus.

Comparison of surgical outcomes between teaching and nonteaching hospitals in the Department of Veterans Affairs

OBJECTIVE

To determine whether the investment in postgraduate education and training places patients at risk for worse outcomes and higher costs than if medical and surgical care was delivered in nonteaching settings.

SUMMARY BACKGROUND DATA

The Veterans Health Administration (VA) plays a major role in the training of medical students, residents, and fellows.

METHODS

The database of the VA National Surgical Quality Improvement Program was analyzed for all major noncardiac operations performed during fiscal years 1997, 1998, and 1999. Teaching status of a hospital was determined on the basis of a background and structure questionnaire that was independently verified by a research fellow. Stepwise logistic regression was used to construct separate models predictive of 30-day mortality and morbidity for each of seven surgical specialties and eight operations. Based on these models, a severity index for each patient was calculated. Hierarchical logistic regression models were then created to examine the relationship between teaching versus nonteaching hospitals and 30-day postoperative mortality and morbidity, after adjusting for patient severity.

RESULTS

Teaching hospitals performed 81% of the total surgical workload and 90% of the major surgery workload. In most specialties in teaching hospitals, the residents were the primary surgeons in more than 90% of the operations. Compared with nonteaching hospitals, the patient populations in teaching hospitals had a higher prevalence of risk factors, underwent more complex operations, and had longer operation times. Risk-adjusted mortality rates were not different between the teaching and nonteaching hospitals in the specialties and operations studied. The unadjusted complication rate was higher in teaching hospitals in six of seven specialties and four of eight operations. Risk adjustment did not eliminate completely these differences, probably reflecting the relatively poor predictive validity of some of the risk adjustment models for morbidity. Length of stay after major operations was not consistently different between teaching and nonteaching hospitals.

CONCLUSION

Compared with nonteaching hospitals, teaching hospitals in the VA perform the majority of complex and high-risk major procedures, with comparable risk-adjusted 30-day mortality rates. Risk-adjusted 30-day morbidity rates in teaching hospitals are higher in some specialties and operations than in nonteaching hospitals. Although this may reflect the weak predictive validity of some of the risk adjustment models for morbidity, it may also represent suboptimal processes and structures of care that are unique to teaching hospitals. Despite good quality of care in teaching hospitals, as evidenced by the 30-day mortality data, efforts should be made to examine further the structures and processes of surgical care prevailing in these hospitals.

Postoperative and amputation-free survival outcomes after femorodistal bypass grafting surgery: findings from the Department of Veterans Affairs National Surgical Quality Improvement Program

PURPOSE

A noncardiac surgery risk model was used as a means of analyzing variations in postoperative mortality and amputation-free survival for older veterans undergoing femorodistal bypass grafting surgery.

METHODS

A prospective cohort study was undertaken in 105 Veterans Affairs (VA) hospitals at the time of index operation from 1991 to 1995. Each patient was linked to subsequent hospitalizations, major amputation surgery, and survival through 1999. Logistic regression and proportional hazards models were used as a means of developing risk indices on the basis of risk factors from the VA National Surgical Quality Improvement Program. A total of 4288 male veterans 40 years or older underwent artificial, vein, or in situ bypass grafting surgery at the femoral to tibial level. The main outcome measures were 30-day postoperative mortality and amputation-free survival.

RESULTS

Approximately half of all patients had undergone an earlier revascularization or amputation at any level for vascular disease. The 30-day postoperative mortality rate was 2.1% and varied greatly between mortality risk index quartiles (0.6%-5.2%). In a median 44.3 months of follow-up, surviving patients had 17,694 subsequent VA hospitalizations, 1147 patients (26.7%) underwent subsequent major amputation, and 1913 patients (44.6%) died. The overall survival probability was 88% at 1 year and 63% at 5 years; 1- and 5-year (any sided) limb salvage rates were 87% and 74%, respectively, for patients who underwent a femoropopliteal bypass grafting procedure, compared with 77% and 63%, respectively, for patients who underwent a tibial bypass grafting procedure. When amputation and death were combined as end points, amputation-free survival probability rates at 1, 3, and 7.5 years were 74%, 56%, and 29%, respectively. Patients with the best 20% survival risk scores had observed mean survival probability rates 30% higher than patients in the poorest 20% of survival risk.

CONCLUSION

Risk indices derived from the preoperative workup may be of use to clinicians in assessing and communicating risk and prognosis. Risk-adjustment of outcomes is critical for evaluating future disease management initiatives for patients with advanced peripheral arterial disease.

Postoperative and late survival outcomes after major amputation: findings from the Department of Veterans Affairs National Surgical Quality Improvement Program

BACKGROUND

A surgical risk model is used to analyze postoperative mortality and late survival for older veterans who underwent above- or below-knee amputations in 119 Veterans Affairs (VA) hospitals from 1991 to 1995.

METHODS

Preoperative medical conditions and laboratory values abstracted by the VA National Surgical Quality Improvement Program were linked to subsequent hospitalization and survival through 1999. Logistic regression and proportional hazards models were used to develop risk indexes for postoperative mortality and long-term survival.

RESULTS

Thirty-day postoperative mortality was 6.3% for 1909 below-knee and 13.3% for 2152 above-knee amputees. Mortality varied greatly between the lowest-highest risk index quartiles (0.8%-18.4% for below-knee amputation and 2.3%-31.1% for above-knee amputation). Surviving patients had 10,827 subsequent VA hospitalizations during a median 32-month follow-up. Survival probabilities for below- and above-knee amputees were 77% and 59% at 1 year, 57% and 39% at 3 years, and 28% and 20% at 7.5 years. The lowest quartile of survival risk had a 61% five-year survival compared with 14% for the highest-risk quartile.

CONCLUSION

A generic surgical risk model can be of use in stratifying prognosis after major amputation. The heavy burden of hospital use by these patients suggests the need for better disease management for this high-risk, high-cost patient population.

Hysterectomy in Veterans Affairs Medical Centers

OBJECTIVE

To examine the indications and surgical morbidity for women veterans who underwent hysterectomies in Department of Veterans Affairs Medical Centers (VAs).

METHODS

Data on hysterectomies performed in VAs from 1991 to 1997 were abstracted from a surgical quality improvement program.

RESULTS

Records of 1722 women who had hysterectomies in VAs over 6 years were examined. Women were predominately white (62%) and their average age was 42.5 years. Operations included abdominal (74%), vaginal (22%), and laparoscopic-assisted (4%) methods. The most common indications for surgery included uterine leiomyomas (31%), abnormal uterine bleeding (14%), and endometriosis (11%). Indications differed by race (P <.01); nonwhite women were most likely to have surgery for leiomyoma (51%), whereas white women had hysterectomies for leiomyomas (19%), abnormal bleeding (15%), endometriosis (13%), and genital prolapse (11%). The mean postoperative stay was significantly longer for abdominal hysterectomies (4.51 days) than either vaginal or laparoscopic-assisted hysterectomies (2.92 and 2.21 days, respectively; P <.001). The overall complication rate within 30 days was 9%, and the most frequent complication was urinary tract infection (3.3%).

CONCLUSION

Women who underwent hysterectomies in VAs had low complication rates, comparable to hysterectomy complication rates in the United States generally.

Validating risk-adjusted surgical outcomes: chart review of process of care

OBJECTIVE

The primary purpose of this study was to validate risk-adjusted surgical outcomes as indicators of the quality of surgical care at US Department of Veterans Affairs (VA) hospitals. The secondary purpose was to validate the risk-adjustment models for screening cases for quality review.

DESIGN

We compared quality of care, determined by structured implicit chart review, for patients from hospitals with higher and lower than expected operative mortality and morbidity (hospital-level tests) and between patients with high and low predicted risk of mortality and morbidity who died or developed complications (patient-level tests).

SUBJECTS

739 general, peripheral vascular and orthopedic surgery cases sampled from the 44 VA hospitals participating in the National VA Surgical Risk Study.

MAIN OUTCOME MEASURES

A global rating of quality of care based on chart review.

RESULTS

Ratings of overall quality of care did not differ significantly between patients from hospitals with higher and lower than expected mortality and morbidity. On some of the secondary measures, patient care was rated higher for hospitals with lower than expected operative mortality. At the patient level of analysis, those who died or developed complications and had a high predicted risk of mortality or morbidity were rated higher on quality of care than those with a low predicted risk of adverse outcome.

CONCLUSIONS

The absence of a relationship between most of our measures of process of care and risk-adjusted outcomes may be due to an insensitivity of chart reviews to hospital-level differences in quality of care. Site visits to National VA Surgical Risk Study hospitals with high and low risk-adjusted mortality and morbidity have detected differences on a number of dimensions of quality. The patient-level findings suggest that the risk-adjustment models are useful for screening adverse outcome cases for quality of care review.

Risk-adjusted surgical outcomes

Measures of risk-adjusted outcome are particularly suited for the assessment of the quality of surgical care. The reliability of measures of quality that use surgical outcomes is enhanced by prospective data acquisition and should be adjusted for the preoperative severity of illness. Such measures should be based only on reliable and validated data, and they should apply state-of-the-art analytical methods. The risk-adjusted postoperative mortality rate is useful as a quality measure only in specialties and operations expected to have a high rate of postoperative deaths. Risk-adjusted complications are more common but are limited as a comparative measure of quality by a lack of uniform definitions and data collection mechanisms. In specialties in which the expected postoperative mortality is low, risk-adjusted functional outcomes are promising measures for the assessment of the quality of surgical care. Measures of cost and patient satisfaction should also be incorporated in systems designed to measure the quality and cost-effectiveness of surgical care.

Outcome of myocardial infarction in Veterans Health Administration patients as compared with medicare patients

BACKGROUND

Some have the opinion that patients cared for in Veterans Health Administration (VHA) hospitals receive care of poorer quality than those cared for in non-VHA institutions. To assess the quality of care in VHA hospitals, we compared the outcome of acute myocardial infarction among patients in VHA and non-VHA institutions while controlling for potential confounders, including coexisting conditions and severity of illness.

METHODS

We studied 2486 veterans discharged from 81 VHA hospitals and 29,249 Medicare patients discharged from 1530 non-VHA hospitals, restricting our samples to men at least 65 years of age who were discharged with confirmed acute myocardial infarction. We compared coexisting conditions, severity of illness, and 30-day and 1-year mortality in the two samples.

RESULTS

VHA patients were significantly more likely than Medicare patients to have a recorded history of hypertension (64.3 percent vs. 57.3 percent), chronic obstructive pulmonary disease or asthma (30.9 percent vs. 23.5 percent), diabetes (34.8 percent vs. 29.0 percent), stroke (20.4 percent vs. 14.2 percent), or dementia (7.2 percent vs. 4.8 percent) (P<0.001 for all comparisons). According to both multivariate logistic regression and an analysis using 2265 matched pairs of VHA and Medicare patients, there were no significant differences in 30-day or 1-year mortality. The matched-pairs analysis found that the difference in mortality at 30 days (the mortality rate among Medicare patients minus the mortality rate among VHA patients), averaged over the 5-year age groups, was -0.8 percent (95 percent confidence interval, -2.8 percent to 1.3 percent), and the difference in mortality at 1 year was -1.3 percent (95 percent confidence interval, -3.9 percent to 1.3 percent).

CONCLUSIONS

VHA patients had more coexisting conditions than Medicare patients. Nevertheless, we found no significant difference in mortality between VHA and Medicare patients, a result that suggests a similar quality of care for acute myocardial infarction.

Comparison of complications after radical and partial nephrectomy: results from the National Veterans Administration Surgical Quality Improvement Program

OBJECTIVE

To determine whether radical nephrectomy causes less morbidity, less mortality and is associated with a shorter hospital stay than is partial nephrectomy.

PATIENTS AND METHODS

A total of 1885 nephrectomies (1373 radical and 512 partial) conducted between 1991 and 1998 in the Department of Veterans Affairs (VA) National Surgical Quality Improvement Program were evaluated. Using multivariate analyses, outcomes were risk-adjusted based on 45 preoperative variables to compare mortality and morbidity rates.

RESULTS

The unadjusted 30-day mortality was 2.0% for radical and 1.6% for partial nephrectomy (P = 0.58). Risk-adjusting the two groups did not result in a statistically significant difference in mortality. The 30-day overall morbidity rate was 15% for radical and 16.2% for partial nephrectomy (P = 0.52); risk-adjusted morbidity rates were not statistically different. There were no statistically significant differences in the rates of postoperative progressive renal failure, acute renal failure, urinary tract infection, prolonged ileus, transfusion requirement, deep wound infection, or extended length of stay.

CONCLUSIONS

Partial nephrectomy carried out in the VA program has low morbidity and mortality rates, comparable with the complication rates after radical nephrectomy.

Hospital- and community-based surveillance of methicillin-resistant Staphylococcus aureus: previous hospitalization is the major risk factor

OBJECTIVE

The purpose of the study was to determine the incidence and risk factors for the acquisition of methicillin-resistant Staphylococcus aureus (MRSA) in our community.

DESIGN

This study used a cross-sectional design to assess patients colonized or infected with MRSA.

PATIENTS

The study population consisted of residents of London, Ontario, Canada, who were identified as MRSA-positive for the first time in 1997.

SETTING

All acute- and chronic-care hospitals, long-term healthcare facilities, and community physicians' offices in the city of London participated in the study.

MAIN OUTCOME MEASURE

Incidence of MRSA in the community, risk factors for acquisition, especially previous hospitalization over a defined period, and strain type were evaluated.

RESULTS

In 1997, 331 residents of London were newly identified as MRSA-positive, representing an annual incidence of 100/100,000 persons (95% confidence interval, 88.8-110.7). Thirty-one (9.4%) individuals were not healthcare-facility patients in the previous month, and 11 (3.3%), 10 (3.0%), and 6 (1.8%) individuals had no such contact in the previous 3, 6, and 12 months, respectively. One hundred seventy-seven strains, including five of the isolates from patients with no healthcare-facility contact in the previous year, were typed. One hundred sixty (90.3%) of these isolates, including all typed strains from patients with no healthcare facility contact, belonged to a single clone.

CONCLUSION

These findings demonstrate that the incidence of MRSA is higher than previously reported and that hospital contact is the single most important risk factor for the acquisition of MRSA in our community. Screening for MRSA in previously hospitalized patients at the time of hospitalization may reduce nosocomial spread and indirectly reduce the incidence of MRSA in the community.

Changing demographic characteristics of women veterans: results from a national sample

Women veterans are a small but growing percentage of the U.S. veteran population. There are some indications that, along with this increase, the characteristics and military experiences of younger women veterans differ considerably from those of older colleagues. Many of these characteristics are not well defined, but they could have implications for women's health care needs and health policy initiatives. Using the first sample drawn from the Department of Veterans Affairs' new National Registry of Women Veterans, we designed and administered a telephone survey to a representative sample of women veterans across several major age groups. Groups approximated primary eras of military and wartime service based on the assumption that different eras might be associated with differing military experiences. We found a number of age-related similarities and differences in women veterans' demographic characteristics, military experiences, physical health symptoms, and functional outcomes. Women veterans in general also differed from female civilian counterparts on exposure to sexual trauma. Trends in the population of women veterans are likely to have implications for the variety of health care systems that treat women veterans.

Multifactorial risk index for predicting postoperative respiratory failure in men after major noncardiac surgery. The National Veterans Administration Surgical Quality Improvement Program

OBJECTIVE

To develop and validate a preoperative risk index for predicting postoperative respiratory failure (PRF).

SUMMARY BACKGROUND DATA

Respiratory failure is an important postoperative complication.

METHOD

Based on a prospective cohort study, cases from 44 Veterans Affairs Medical Centers (n = 81,719) were used to develop the models. Cases from 132 Veterans Affairs Medical Centers (n = 99,390) were used as a validation sample. PRF was defined as mechanical ventilation for more than 48 hours after surgery or reintubation and mechanical ventilation after postoperative extubation. Ventilator-dependent, comatose, do not resuscitate, and female patients were excluded.

RESULTS

PRF developed in 2,746 patients (3.4%). The respiratory failure risk index was developed from a simplified logistic regression model and included abdominal aortic aneurysm repair, thoracic surgery, neurosurgery, upper abdominal surgery, peripheral vascular surgery, neck surgery, emergency surgery, albumin level less than 30 g/L, blood urea nitrogen level more than 30 mg/dL, dependent functional status, chronic obstructive pulmonary disease, and age.

CONCLUSIONS

The respiratory failure risk index is a validated model for identifying patients at risk for developing PRF and may be useful for guiding perioperative respiratory care.

Risk factors for morbidity and mortality after colectomy for colon cancer

PURPOSE

Comorbid conditions affect the risk of adverse outcomes after surgery, but the magnitude of risk has not previously been quantified using multivariate statistical methods and prospectively collected data. Identifying factors that predict results of surgical procedures would be valuable in assessing the quality of surgical care. This study was performed to define risk factors that predict adverse events after colectomy for cancer in Department of Veterans Affairs Medical Centers.

METHODS

The National Veterans Affairs Surgical Quality Improvement Program contains prospectively collected and extensively validated data on more than 415,000 surgical operations. All patients undergoing colectomy for colon cancer from 1991 to 1995 who were registered in the National Veterans Affairs Surgical Quality Improvement Program database were selected for study. Independent variables examined included 68 preoperative and 12 intraoperative clinical risk factors; dependent variables were 21 specific adverse outcomes. Stepwise logistic regression analysis was used to construct models predicting the 30-day mortality rate and 30-day morbidity rates for each of the ten most frequent complications.

RESULTS

A total of 5,853 patients were identified; 4,711 (80 percent) underwent resection and primary anastomosis. One or more complications were observed in 1,639 of 5,853 (28 percent) patients. Prolonged ileus (439/5,853; 7.5 percent), pneumonia (364/5,853; 6.2 percent), failure to wean from the ventilator (334/5,853; 5.7 percent), and urinary tract infection (292/5,853; 5 percent) were the most frequent complications. The 30-day mortality rate was 5.7 percent (335/5,853). For most complications, 30-day in-hospital mortality rates were significantly higher for patients with a complication than for those without. Thirty-day mortality rates exceeded 50 percent if postoperative coma, cardiac arrest, a pre-existing vascular graft prosthesis that failed after colectomy, renal failure, pulmonary embolism, or progressive renal insufficiency occurred. Preoperative factors that predicted a high risk of 30-day mortality included ascites, serum sodium >145 mg/dl, "do not resuscitate" status before surgery, American Society of Anesthesiologists classes III and IV OR V, and low serum albumin.

CONCLUSIONS

Mortality rates after colectomy in Veterans Affairs hospitals are comparable with those reported in other large studies. Ascites, hypernatremia, do not resuscitate status before surgery, and American Society of Anesthesiologists classes III and IV OR V were strongly predictive of perioperative death. Clinical trials to decrease the complication rate after colectomy for colon cancer should focus on these risk factors.

A preliminary investigation of alternatives to fumagillin for the treatment of Loma salmonae infection in rainbow trout

The effects of the following six treatments against Loma salmonae, a microsporidian gill pathogen, were examined in rainbow trout: fumagillin (high dose), pyrimethamine + sulphaquinoxaline, albendazole, amprolium, fumagillin (low dose), and metronidazole. The fish were infected by mouth and the treatments were administered at intervals for a period of several weeks. The results were assessed on the basis of (1) delay in the formation of xenomas, and (2) the number of xenomas per gill arch. The first five treatments, in descending order of efficacy, delayed the formation of xenomas (P<0.01), but metronidazole had no such effect. Fumagillin (high or low dose) and albendazole both reduced the number of xenomas present 10 weeks after infection (P<0.01), but the other three treatments did not do so. From these results, both fumagillin and albendazole appeared to be of potential value in controlling L. salmonae infection in trout.

Positive predictive value of the diagnosis of acute myocardial infarction in an administrative database

OBJECTIVE

To determine the positive predictive value of ICD-9-CM coding of acute myocardial infarction and cardiac procedures.

METHODS

Using chart-abstracted data as the standard, we examined administrative data from the Veterans Health Administration for a national random sample of 5,151 discharges.

MAIN RESULTS

The positive predictive value of acute myocardial infarction coding in the primary position was 96.9%. The sensitivity and specificity of coding were, respectively, 96% and 99% for catheterization, 95.7% and 100% for coronary artery bypass graft surgery, and 90.3% and 99. 7% for percutaneous transluminal coronary angioplasty.

CONCLUSIONS

The positive predictive value of acute myocardial infarction and related procedure coding is comparable to or better than previously reported observations of administrative databases.

Relation of surgical volume to outcome in eight common operations: results from the VA National Surgical Quality Improvement Program

OBJECTIVE

To examine, in the Veterans Health Administration (VHA), the relation between surgical volume and outcome in eight commonly performed operations of intermediate complexity.

SUMMARY BACKGROUND DATA

In multihospital health care systems such as VHA, consideration is often given to closing low-volume surgical services, with the assumption that better surgical outcomes are achieved in hospitals with larger surgical volumes. Literature data to support this assumption in intermediate-complexity operations are either limited or controversial.

METHODS

The VHA National Surgical Quality Improvement Program data on nonruptured abdominal aortic aneurysmectomy, vascular infrainguinal reconstruction, carotid endarterectomy (CEA), lung lobectomy/pneumonectomy, open and laparoscopic cholecystectomy, partial colectomy, and total hip arthroplasty were used. Pearson correlation, analysis of variance, mixed effects hierarchical logistic regression, and automatic interaction detection analysis were used to assess the association of annual procedure/specialty volume with risk-adjusted 30-day death (and stroke in CEA).

RESULTS

Eight major surgical procedures (68,631 operations) were analyzed. No statistically significant associations between procedure or specialty volume and 30-day mortality rate (or 30-day stroke rate in CEA) were found.

CONCLUSIONS

In VHA hospitals, the procedure and surgical specialty volume in eight prevalent operations of intermediate complexity are not associated with risk-adjusted 30-day mortality rate from these operations, or with the risk-adjusted 30-day stroke rate from CEA. Volume of surgery in these operations should not be used as a surrogate for quality of surgical care.

Risk factors for prolonged length of stay after major elective surgery

OBJECTIVE

Length of stay (LOS) is an important outcome as a marker of resource consumption. Determining which factors increase LOS may provide information on reducing costs and improving the delivery of care. The purpose of this study was to determine the independent association of intraoperative process of care and postoperative events with prolonged LOS after adjusting for preoperative severity of illness in patients undergoing major elective surgery.

METHODS

Cases representing 11 elective operations from the National VA Surgical Quality Improvement Program were analyzed using multivariate logistic regression analysis. The outcome, prolonged LOS, was defined as an LOS greater than or equal to the 75th percentile (in days) for each operation. Hierarchical modeling was used to assess the independent association of groups of variables (preoperative patient characteristics, intraoperative process of care, and postoperative adverse events) with prolonged LOS.

RESULTS

For the 11 operations explored, there were 23,919 cases. Common preoperative variables associated with prolonged LOS were functional status, American Society of Anesthesiology class, and age. The most predictive intraoperative and postoperative variables included intraoperative blood transfusion, operative time, return to the operating room, and the number of complications after surgery.

CONCLUSIONS

Prolonged LOS is associated with preoperative, intraoperative, and postoperative factors. Although preoperative factors were independently associated with a prolonged LOS, the factors generating the highest risks for a prolonged LOS were the intraoperative process of care and postoperative adverse events. To reduce costs, efforts should be made to improve the intraoperative process of care and to minimize postoperative complications.

Increasing use of Medicare services by veterans with acute myocardial infarction

OBJECTIVES

Some of the nation's 26 million veterans have two government-financed health care entitlements: Medicare and the Department of Veterans Affairs (VA). The aims of this investigation were to examine trends where Medicare-eligible VA users are initially hospitalized for acute myocardial infarction (AMI) and then to assess rates of cardiac procedure use and mortality for veterans initially admitted to each system of care.

METHODS

We used VA and HCFA national databases to identify VA users (age range, > or = 65 years) who were initially admitted to a VAMC or Medicare financed hospital (Medicare hospital) with a primary diagnosis of AMI between January 1, 1992, and December 31, 1995, (n = 47,598). We examined the use of cardiac procedures (cardiac catheterization [CC], coronary artery bypass surgery [CABG], and coronary angioplasty [CA] and mortality (30-day and 1-year) by the type of initial admitting hospital within each system of care.

RESULTS

Almost 70% of VA users hospitalized for AMI were initially admitted to Medicare hospitals versus VAMCs between 1992 (64%) and 1995 (72%). After adjusting for patient characteristics in logistic models, VA users initially hospitalized in Medicare hospitals were significantly more likely to undergo cardiac procedures than were VA users hospitalized in VAMCs. Differences in the odds of receiving a procedure were most significant when comparing Medicare hospitals with on-site cardiac technology to VA hospitals without on-site cardiac technology (CC: OR 4.34, 95% CI 3.98-4.73; CABG: OR 2.16, 95% CI 1.92-2.43; CA: OR 4.56, 95% CI 3.98-5.25). We found no significant differences in 30-day and 1-year adjusted mortality rates between VA users initially admitted to VAMCs or Medicare hospitals.

CONCLUSIONS

Medicare-eligible VA users are increasingly hospitalized in Medicare hospitals for AMI. VA users cared for in Medicare hospitals receive more cardiac procedures but have the same survival as VA users cared for in VAMCs. These findings have policy implications for access, quality, and costs in both systems of care.

Racial variation in the use of laparoscopic cholecystectomy in the Department of Veterans Affairs medical system

BACKGROUND

While studies have found racial differences in the rates of use of established invasive cardiac and cerebrovascular procedures, no study has evaluated racial variation in the rates of adoption of new surgical procedures. For patients undergoing laparoscopic cholecystectomy, the procedure represents a new and safe option that shortens the duration of postoperative hospitalization by almost one week. In this study, we evaluated whether, in the equal access Veterans Affairs (VA) medical system, the rate of adoption of this procedure and improvements in the duration of postoperative hospitalization differed between African-American and Caucasian patients.

STUDY DESIGN

Data were obtained from two sources-administrative claims files and prospectively compiled dinical data from medical records and patient interviews. In both data sets, frequency of use, length of stay, and outcomes for African-American and Caucasian patients undergoing minimally invasive and open gallbladder surgery were analyzed for the first four years of use of the procedure in the VA system (1992 to 1995).

RESULTS

Analyses based on claims files indicated that, after adjustment for potentially confounding variables, African-American patients who underwent cholecystectomy in VA medical centers were 25% less likely to undergo a minimally invasive cholecystectomy during the first 4 years of use of the new procedure (adjusted odds ratio, 0.74; 95% confidence interval, 0.66-0.83). Shortening of the average postoperative length of stay from 9 days or more in the prelaparoscopic era to less than 4.5 days for patients undergoing the laparoscopic procedure occurred in the first year for Caucasian patients, but did not occur until the fourth year for African-American patients (p<0.001). The overall difference in postoperative length of stay between African-American and Caucasian patients more than doubled from 1.7 days before introduction of laparoscopic cholecystectomy to 3.8 days in the fourth year. In comparison, analyses based on nurse-compiled clinical data indicated that, after adjustment for relevant clinical factors, racial variations in the rate of laparoscopic surgery were even larger (adjusted odds ratio for laparoscopic versus open cholecystectomy for African-American versus Caucasian veterans, 0.68; 95% confidence interval, 0.55-0.84).

CONCLUSIONS

Compared to Caucasian patients, African-American patients who underwent cholecystectomy in VA medical centers had an approximately 25% to 32% lower likelihood of undergoing minimally invasive cholecystectomy procedures. The differences in rates of adoption of laparoscopic surgery did not appear to be from more comorbid illnesses among African-American patients. African-American and Caucasian veterans may differ in their preference for new surgical procedures like laparoscopic cholecystectomy. Conversely, VA physicians may have been less likely to recommend laparoscopic cholecystectomies to African-American patients.

Inactivation of misselected CD8 T cells by CD8 gene methylation and cell death

Misselected CD8 cells that express T cell receptors (TCRs) that do not recognize class I major histocompatibility complex (MHC) protein can emerge from thymic selection. A postthymic quality control mechanism that purges these cells from the repertoire is defined here. The failure of mature CD8 cells to simultaneously engage their TCR and CD8 coreceptor triggers an activation process that begins with inhibition of CD8 gene expression through remethylation and concludes with up-regulation of surface Fas and Fas ligand and cellular apoptosis. Thus, inhibition of a death signal through continued TCR-CD8 coengagement of MHC molecules is a key checkpoint for the continued survival of correctly selected T cells. Molecular defects that prevent delivery of the death signal to mistakenly selected T cells underlie the expansion of double-negative T cells, which is the cellular signature of a subset of systemic autoimmune diseases.

Prognostic models of thirty-day mortality and morbidity after major pulmonary resection

BACKGROUND

A part of the prospective, multi-institutional National Veterans Affairs Surgical Quality Improvement Program was developed to predict 30-day mortality and morbidity for patients undergoing a major pulmonary resection.

METHODS

Perioperative data were acquired from 194,319 noncardiac surgical operations at 123 Veterans Affairs Medical Centers between October 1, 1991, and August 31, 1995. Current Procedural Terminology code-based analysis was undertaken for major pulmonary resections (lobectomy and pneumonectomy). Preoperative, intraoperative, and outcome variables were collected. The 30-day mortality and morbidity models were developed by means of multivariable stepwise logistic regression with the preoperative and intraoperative variables used as independent predictors of outcome.

RESULTS

A total of 3516 patients (mean age 64 9 years) underwent either lobectomy (n = 2949) or pneumonectomy (n = 567). Thirty-day mortality was 4.0% for lobectomy (119/2949) and 11.5% for pneumonectomy (65/567). The preoperative predictors of 30-day mortality were albumin, do not resuscitate status, transfusion of more than 4 units, age, disseminated cancer, impaired sensorium, prothrombin time more than 12 seconds, type of operation, and dyspnea. When the intraoperative variables were considered, intraoperative blood loss was added to the preoperative model. In the presence of these intraoperative variables in the model, do not resuscitate status and prothrombin time more than 12 seconds were only marginally significant. Thirty-day morbidity, defined as the presence of 1 or more of the 21 predefined complications, was 23.8% for lobectomy (703/2949) and 25.7% for pneumonectomy (146/567). In multivariable models, independent preoperative predictors (P <.05) of 30-day morbidity were age, weight loss greater than 10% in the 6 months before surgery, history of chronic obstructive pulmonary disease, transfusion of more than 4 units, albumin, hemiplegia, smoking, and dyspnea. When intraoperative variables were added to the preoperative model, the duration of operation time and intraoperative transfusions were included in the model and albumin became marginally significant.

CONCLUSIONS

This analysis identifies independent patient risk factors that are associated with 30-day mortality and morbidity for patients undergoing a major pulmonary resection. This series provides an initial risk-adjustment model for major pulmonary resections. Future refinements will allow comparative assessment of surgical outcomes and quality of care at many institutions.

Preoperative serum albumin level as a predictor of operative mortality and morbidity: results from the National VA Surgical Risk Study

OBJECTIVE

To improve the precision and reliability of estimates of the association between preoperative serum albumin concentration and surgical outcomes.

DESIGN

Prospective observational study. Patients were followed up for 30 days postoperatively. Multiple logistic regression models were developed to evaluate serum albumin level as a predictor of operative mortality and morbidity in relation to 61 other preoperative patient risk variables.

SETTING

Forty-four tertiary care Veterans Affairs (VA) medical centers.

PATIENTS

A total of 54215 major noncardiac surgery cases from the National VA Surgical Risk Study.

MAIN OUTCOME MEASURES

Thirty-day operative mortality and morbidity.

RESULTS

A decrease in serum albumin from concentrations greater than 46 g/L to less than 21 g/L was associated with an exponential increase in mortality rates from less than 1% to 29% and in morbidity rates from 10% to 65%. In the regression models, albumin level was the strongest predictor of mortality and morbidity for surgery as a whole and within several subspecialties selected for further analysis. Albumin level was a better predictor of some types of morbidity, particularly sepsis and major infections, than other types.

CONCLUSIONS

Serum albumin concentration is a better predictor of surgical outcomes than many other preoperative patient characteristics. It is a relatively low-cost test that should be used more frequently as a prognostic tool to detect malnutrition and risk of adverse surgical outcomes, particularly in populations in whom comorbid conditions are relatively frequent.

Patterns of coordination and clinical outcomes: a study of surgical services

OBJECTIVE

To test the hypothesis that surgical services combining relatively high levels of feedback and programming approaches to the coordination of surgical staff would have better quality of care than surgical services using low levels of both coordination approaches as well as those surgical service using low levels of either coordination approach.

STUDY SETTING

A study sample of 44 academically affiliated surgical services that are part of the Department of Veterans Affairs.

STUDY DESIGN

In a cross-sectional analysis, surgical services were assigned to one of three groups based on their scores on feedback and programming coordination measures: high on both measures; high on one measure, low on the other; and low on both. Univariate and multivariate analyses were used to assess differences among these groups with respect to three quality indicators: risk-adjusted mortality, risk-adjusted morbidity, and staff perceptions of quality.

DATA COLLECTION/EXTRACTION METHODS

Risk-adjusted mortality and morbidity came from an outcomes reporting program within the Department of Veterans Affairs that entails the prospective collection of clinical data from patient charts. Data on coordination practices and perceived quality came from a survey of surgical staff at each of the 44 participating surgical services.

PRINCIPAL FINDINGS

The group of surgical services using high feedback and high programming had the best perceived quality. This group also had the lowest morbidity, but the difference was statistically significant with respect to only one of the two other groups: the group with low feedback and low programming. No significant group differences were found for mortality.

CONCLUSIONS

Study results provide partial support for the hypothesis that high levels of feedback and programming should be combined for optimal quality of care. Study results also suggest that staff coordination is more important for improving morbidity than mortality in surgical services.