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Peter Bacchetti

Publications and source records attributed to Peter Bacchetti.

49 records · Page 3Linked to original sources
PubMed2002

HIV-related neuropathology, 1985 to 1999: rising prevalence of HIV encephalopathy in the era of highly active antiretroviral therapy.

Postmortem neuropathologic reports for a consecutive series of 436 HIV-seropositive patients who died between 1985 and 1999 were matched with clinical data for 371 of them. Cases were divided into four groups depending on the date of death. The chosen time periods reflected the type of antiretroviral therapy available: before 1987 (before zidovudine); 1987-1992, the period of monotherapy (nucleoside analog reverse transcriptase inhibitors [NRTIs]); 1993-1995, the era of the use of dual NRTI combinations; and 1996-1999, the era of highly active antiretroviral therapy (HAART) containing protease inhibitors. Fifty-seven percent of our cases in this group had been prescribed HAART. In our study population, accessibility to the latest antiretroviral therapy was widespread. The total number of HIV autopsies declined after the advent of combination therapy. The prevalence of opportunistic infections-cytomegalovirus, toxoplasmosis, cryptococcosis, and central nervous system lymphoma-decreased over time. Cerebral tuberculosis, aspergillosis, herpes, and progressive multifocal leukoencephalopathy showed a downward trend, but the numbers were too low for statistical analyses. The incidence of HIV encephalopathy increased over time (p =.014). The rising prevalence of HIV encephalopathy at time of death may reflect a longer survival time after initial HIV infection in the HAART era. Although combination therapies decrease overall mortality and prevalence of CNS opportunistic infections, these therapies may be less active in preventing direct HIV-1 effects on the brain.

AIDS Dementia Complex↗
PubMed2002

Does patient sex affect human immunodeficiency virus levels?

We undertook a critical epidemiological review of the available evidence concerning whether women have lower levels of human immunodeficiency virus (HIV) RNA than do men at similar stages of HIV infection. The 13 studies included in this analysis reported viral load measurements in HIV-infected men and women at a single point in time (cross-sectional studies) or over time (longitudinal studies). Seven of the 9 cross-sectional studies demonstrated that women had 0.13-0.35 log(10) ( approximately 2-fold) lower levels of HIV RNA than do men, despite controlling for CD4(+) cell count. Four longitudinal studies revealed that women had 0.33-0.78 log(10) (2- to 6-fold) lower levels of HIV RNA than do men, even when controlling for time since seroconversion. Adjustment for possible confounders of the relationship between sex and viral load, including age, race, mode of virus transmission, and antiretroviral therapy use, did not change this outcome. This finding is significant, because viral loads are frequently used to guide the initiation and modification of antiretroviral therapy.

Cross-Sectional Studies↗
PubMed2002

Association of journal quality indicators with methodological quality of clinical research articles.

CONTEXT: The ability to identify scientific journals that publish high-quality research would help clinicians, scientists, and health-policy analysts to select the most up-to-date medical literature to review. METHODS: To assess whether journal characteristics of (1) peer-review status, (2) citation rate, (3) impact factor, (4) circulation, (5) manuscript acceptance rate, (6) MEDLINE indexing, and (7) Brandon/Hill Library List indexing are predictors of methodological quality of research articles, we conducted a cross-sectional study of 243 original research articles involving human subjects published in general internal medical journals. RESULTS: The mean (SD) quality score of the 243 articles was 1.37 (0.22). All journals reported a peer-review process and were indexed on MEDLINE. In models that controlled for article type (randomized controlled trial [RCT] or non-RCT), journal citation rate was the most statistically significant predictor (0.051 increase per doubling; 95% confidence interval [CI], 0.037-0.065; P<.001). In separate analyses by article type, acceptance rate was the strongest predictor for RCT quality (-0.113 per doubling; 95% CI, -0.148 to -0.078; P<.001), while journal citation rate was the most predictive factor for non-RCT quality (0.051 per doubling; 95% CI, 0.044-0.059; P<.001). CONCLUSIONS: High citation rates, impact factors, and circulation rates, and low manuscript acceptance rates and indexing on Brandon/Hill Library List appear to be predictive of higher methodological quality scores for journal articles.

Biomedical Research↗
PubMed2002

Liver transplantation for hepatocellular carcinoma: comparison of the proposed UCSF criteria with the Milan criteria and the Pittsburgh modified TNM criteria.

We previously proposed modified staging criteria for predicting acceptable outcome after orthotopic liver transplantation (OLT) for hepatocellular carcinoma (HCC). These were solitary tumor < or = 6.5 cm, or three or fewer nodules with the largest lesion < or = 4.5 cm and total tumor diameter < or = 8 cm, without gross vascular invasion (University of California, San Francisco [UCSF] criteria). In this study, we further evaluated the performance of the Milan criteria (solitary tumor < or = 5 cm, or three or fewer lesions none > 3 cm), the UCSF criteria, and the Pittsburgh modified tumor-node-metastasis (TNM) criteria. Pathologic HCC staging according to each set of criteria was performed in 70 patients. The difference in survival when comparing 24 patients with HCC exceeding Milan criteria versus 46 patients meeting Milan criteria did not reach statistical significance (HR, 2.0; P = .12). Using our definition for acceptable 2-year survival to be > or = 70%, the 14 patients (20%) meeting UCSF criteria but exceeding Milan criteria had a 2-year survival of 86% (95% CI, 54% to 96%). Survival for Pittsburgh stage I, II, and IIIA patients as a group was significantly better than for stages IIIB and IVA patients combined (HR, 4.2; P = .007), and similar to survival for patients meeting UCSF criteria. Advanced tumor exceeding UCSF criteria served reasonably well as a surrogate marker for poorly differentiated grade and microvascular invasion. In conclusion, our analyses suggest that UCSF criteria better predict acceptable posttransplant outcome than Milan criteria. UCSF criteria confer a different advantage over Pittsburgh criteria, which require information on microvascular invasion that is difficult to ascertain preoperatively without the attendant risk of biopsy.

Adult↗
PubMed2002

Effect of managed care on preventable hospitalization rates in California.

BACKGROUND: Hospitalization rates for ambulatory care-sensitive (ACS) conditions have emerged as a potential indicator of health care access and quality. The effect of managed care on reducing these potentially preventable hospitalizations is unknown. OBJECTIVE: To ascertain whether increases in managed care penetration were associated with changes in hospitalization rates for ACS conditions. DESIGN AND SETTING: Longitudinal analysis between 1990 and 1997 of all California hospitalizations for ACS conditions aggregated to 394 small areas. MEASURES: Association of change in ACS hospitalization rate with change in managed care penetration. RESULTS: In unadjusted analysis there was no association between the change in managed care penetration and the change in hospitalization rates for ACS conditions over time. However, in a multivariate model that controlled for changes in area demographics and hospitalization rates for marker conditions that were assumed to be stable over time, the change in managed care penetration was negatively associated with a small but statistically significant change in the ACS hospitalization rate. Each 10-point increase in percentage private managed care penetration was associated with a 3.1% decrease in the ACS hospitalization rate (95% CI, -5.4% to -0.8%) CONCLUSIONS: Overall, in California, an increase in the penetration of private managed care in a community was associated with a decrease in ACS admission rates. Additional research is needed to determine if the observed association is causal, the mechanism of the effect and whether it represents an improvement in patients' health outcomes.

Adult↗
PubMed2002

Generalized additive models with interval-censored data and time-varying covariates: application to human immunodeficiency virus infection in hemophiliacs.

We describe a method for extending smooth nonparametric modeling methods to time-to-event data where the event may be known only to lie within a window of time. Maximum penalized likelihood is used to fit a discrete proportional hazards model that also models the baseline hazard, and left-truncation and time-varying covariates are accommodated. The implementation follows generalized additive modeling conventions, allowing both parametric and smooth terms and specifying the amount of smoothness in terms of the effective degrees of freedom. We illustrate the method on a well-known interval-censored data set on time of human immunodeficiency virus infection in a multicenter study of hemophiliacs. The ability to examine time-varying covariates, not available with previous methods, allows detection and modeling of nonproportional hazards and use of a time-varying covariate that fits the data better and is more plausible than a fixed alternative.

Biometry↗
PubMed2002

US evaluation of fetal growth: prediction of neonatal outcomes.

PURPOSE: To determine whether fetal growth measured at serial ultrasonographic (US) examinations can predict neonatal morbidity, independent of whether gestational age is known. MATERIALS AND METHODS: Women (n = 321) who had singleton pregnancies and underwent two or more second- or third-trimester obstetric US examinations were included in a retrospective cohort analysis. Inadequate fetal growth was defined as growth at or below the 10th percentile. The relative risk of each poor outcome was calculated for fetuses with inadequate growth, compared with the risk for fetuses with normal growth. RESULTS: Inadequate fetal growth was associated with 3.9 times the risk of a birth weight less than 2,500 g, 17.7 times the risk of a birth weight less than the 3rd percentile for gestational age, 2.3 times the risk of preterm birth, 2.6 times the risk of a long newborn hospital stay, and 3.6 times the risk of neonatal intensive care unit admission. After adjusting for confounding variables, including fetal weight, fetal growth remained a significant predictor of small birth size and poor outcomes. Inadequate growth predicted the risk of poor outcomes, even when gestational age was unknown. When inadequate growth was used to identify fetuses at risk, 21%-67% of neonates who were small at birth or had poor outcomes were identified at false-positive rates of only 5%-9%. For all outcomes, inadequate growth enabled identification of more fetuses with poor birth outcomes than low estimated fetal weight. CONCLUSION: Morbidity is significantly increased among fetuses who demonstrate less than expected growth. Growth between two US examinations can be used to estimate the risk of neonatal morbidity, even when gestational age is unknown.

Adult↗
PubMed2002

Peripheral vascular disease risk factors among patients undergoing hemodialysis.

Peripheral vascular disease (PVD) is common among patients undergoing hemodialysis, but little is known regarding the risk factors for PVD in this population. Data from waves 1, 3, and 4 of the United States Renal Data System Dialysis Morbidity and Mortality Study were used to examine cross-sectional associations of a range of conventional cardiovascular risk factors and uremia- or dialysis-related variables with PVD. Univariate and multivariate logistic regression models were developed using wave 3 and 4 data. Odds ratios for the multivariate model derived using wave 3 and 4 data were then compared with those obtained with the wave 1 data set. For both data sets, PVD was positively associated with the duration of dialysis (vintage) and malnourished status and was negatively associated with serum albumin and parathyroid hormone levels and predialysis diastolic BP. Kt/V was negatively associated with PVD in waves 3 and 4 but not in wave 1. PVD was associated with increasing age, white (versus non-white) race, male gender, diabetes mellitus, coronary artery disease, cerebrovascular disease, smoking, and left ventricular hypertrophy, as for the general population, but not with hypertension or hyperlipidemia. In conclusion, PVD among hemodialysis patients is associated with both dialysis-specific variables and most conventional cardiovascular risk factors other than hypertension and hyperlipidemia. Future studies should prospectively examine the association of these variables identified in cross-sectional analyses with the de novo development of PVD in this population.

Aged↗
PubMedDate not supplied

Quantifying smoking cessation outcomes: from The Women's Initiative for Nonsmoking Study (X): methodological implications.

BACKGROUND: Classification of smoking status has a major impact on the conclusions drawn from smoking cessation intervention research, yet few studies have addressed this critical issue. OBJECTIVES: The aim of this study was to compare three classifications (naïve, optimistic, and pessimistic) of smoking cessation outcomes or smoking status from the Women's Initiative for Nonsmoking Study (WINS). METHODS: This is a longitudinal prospective study nested within a randomized clinical trial (RCT) design of WINS, an RCT of 277 women over the age of 18 years who reported smoking cigarettes continuously for 1 month prior to a cardiovascular event requiring hospital admission. Women were randomized to either the usual care group (UC) or the intervention group (IG). Recruitment for WINS occurred between October 1996 and December 1998 in 10 hospitals in the San Francisco Bay area. Follow-up data on smoking status was obtained from the UC and the IG using a structured telephone interview at 6 and 12 months from baseline and was confirmed by family members and salivary cotinine levels. RESULTS: Seven-day point prevalence(self-report of not smoking in the past 7 days; "not even a puff") using the naïve (the most liberal) classification yields a greater number of nonsmokers than the pessimistic or most conservative classification (cotinine level verification of smoking status). The classification of smoking status also affects time to continuous smoking. The pessimistic classification results in the shortest time to continuous smoking, whereas the opposite is observed with the naïve classification. DISCUSSION: It is important to critically evaluate the underlying assumptions made by study investigators when measuring and reporting smoking status. The classification of smoking status and the selection of analysis, meaning point prevalence versus survival analysis, affect study results and contribute to the variability observed in the research findings of smoking cessation intervention trials and the challenges faced in making appropriate comparisons across studies.

Adult↗
PubMedDate not supplied

Women's Initiative for Nonsmoking-VII: evaluation of health service utilization and costs among women smokers with cardiovascular disease.

PURPOSE: The Women's Initiative for Nonsmoking (WINS), a randomized clinical trial of a smoking cessation intervention for women with cardiovascular disease, permitted an assessment of the types and costs of health services women used during the 30 months after their hospitalization with cardiovascular disease. METHODS: A prospective design nested within WINS was used for this study. A structured telephone interview guide included questions about medical services and 15 categories of prevention services, including cardiac rehabilitation at 6, 12, 24, and 30 months. Costs were estimated from state and national databases. RESULTS: The 277 women studied had a mean age of 60.7 +/- 10 years. They had smoked approximately 40 +/- 11.4 years. More than 50% of the women had one or more risk factors for cardiovascular disease. During the first 6 months after the index hospitalization, 94% had a physician visit, 39% had an emergency-room visit, and 36% had a hospital admission. Prevention services used were home healthcare by nurse or home health aide (26%), a cardiac rehabilitation program, including Multifit and Heart Smart (19%), and physical therapy (14%). Usage decreased over the 30 months. For the women who used any service, the mean total monthly cost per woman was 913 dollars +/- 1204 dollars. CONCLUSIONS: This is the first report on health service use by women smokers with cardiovascular disease. Data collection using a telephone interview guide proved feasible for evaluating health service use. The greatest costs resulted from hospital admissions and physician and emergency-room visits. Considering the high prevalence of risk factors in this cohort, secondary prevention services were severely underutilized. By increasing referrals to such services, physicians and nurses might influence women to reduce their risk for subsequent cardiovascular disease.

Aftercare↗
PubMedDate not supplied

Management of hepatitis C-infected liver transplant recipients at large North American centres: changes in recent years.

Large (>or=45 transplants per year) North American liver transplant centres were surveyed regarding management of hepatitis C virus (HCV). A total of 25/41 (59%) and 28/48 (58%) of centres responded to the surveys in 1998 and 2003, respectively, with 17 centres participating in both surveys. HCV was the most common indication for transplantation. Use of protocol liver biopsies was higher in 2003 and 60% used them to monitor HCV disease. Fewer centres reported modifying primary immunosuppression (IMS) for HCV-positive (vs. non-HCV) patients in 2003 (26%) vs. 1998 (56%). IMS was most frequently tacrolimus-based, but mycophenolate mofetil use increased in 2003 (52% vs. 23% in 1998). In both years, approximately 40% treated allograft rejection differently in HCV-positive recipients, with less use of OKT3 in 2003. Combination anti-HCV therapy for 12 months or more was the treatment of choice and growth factor use was common (68%). HCV-positive recipients were considered candidates for retransplantation but HCV-specific criteria were used in decision-making. Practice of centres changed over time with an increase in HCV transplantation and use of protocol liver biopsies, and a trend towards lesser modification of IMS in HCV-positive recipients. We conclude that there is considerable variability in the management of HCV among transplant programs and over time.

Canada↗