969 resultados para calendar
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BACKGROUND: Highly active antiretroviral therapy (HAART) for the treatment of HIV infection was introduced a decade ago. We aimed to examine trends in the characteristics of patients starting HAART in Europe and North America, and their treatment response and short-term prognosis. METHODS: We analysed data from 22,217 treatment-naive HIV-1-infected adults who had started HAART and were followed up in one of 12 cohort studies. The probability of reaching 500 or less HIV-1 RNA copies per mL by 6 months, and the change in CD4 cell counts, were analysed for patients starting HAART in 1995-96, 1997, 1998, 1999, 2000, 2001, and 2002-03. The primary endpoints were the hazard ratios for AIDS and for death from all causes in the first year of HAART, which were estimated using Cox regression. RESULTS: The proportion of heterosexually infected patients increased from 20% in 1995-96 to 47% in 2002-03, and the proportion of women from 16% to 32%. The median CD4 cell count when starting HAART increased from 170 cells per muL in 1995-96 to 269 cells per muL in 1998 but then decreased to around 200 cells per muL. In 1995-96, 58% achieved HIV-1 RNA of 500 copies per mL or less by 6 months compared with 83% in 2002-03. Compared with 1998, adjusted hazard ratios for AIDS were 1.07 (95% CI 0.84-1.36) in 1995-96 and 1.35 (1.06-1.71) in 2002-03. Corresponding figures for death were 0.87 (0.56-1.36) and 0.96 (0.61-1.51). INTERPRETATION: Virological response after starting HAART improved over calendar years, but such improvement has not translated into a decrease in mortality.
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Much controversy exists over whether the course of schizophrenia, as defined by the lengths of repeated community tenures, is progressively ameliorating or deteriorating. This article employs a new statistical method proposed by Wang and Chen (2000) to analyze the Denmark registry data in Eaton, et al (1992). The new statistical method correctly handles the bias caused by induced informative censoring, which is an interaction of the heterogeneity of schizophrenia patients and long-term follow-up. The analysis shows a progressive deterioration pattern in terms of community tenures for the full registry cohort, rather than a progressive amelioration pattern as reported for a selected sub-cohort in Eaton, et al (1992). When adjusted for the long-term chronicity of calendar time, no significant progressive pattern was found for the full cohort.
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Submicroscopic changes in chromosomal DNA copy number dosage are common and have been implicated in many heritable diseases and cancers. Recent high-throughput technologies have a resolution that permits the detection of segmental changes in DNA copy number that span thousands of basepairs across the genome. Genome-wide association studies (GWAS) may simultaneously screen for copy number-phenotype and SNP-phenotype associations as part of the analytic strategy. However, genome-wide array analyses are particularly susceptible to batch effects as the logistics of preparing DNA and processing thousands of arrays often involves multiple laboratories and technicians, or changes over calendar time to the reagents and laboratory equipment. Failure to adjust for batch effects can lead to incorrect inference and requires inefficient post-hoc quality control procedures that exclude regions that are associated with batch. Our work extends previous model-based approaches for copy number estimation by explicitly modeling batch effects and using shrinkage to improve locus-specific estimates of copy number uncertainty. Key features of this approach include the use of diallelic genotype calls from experimental data to estimate batch- and locus-specific parameters of background and signal without the requirement of training data. We illustrate these ideas using a study of bipolar disease and a study of chromosome 21 trisomy. The former has batch effects that dominate much of the observed variation in quantile-normalized intensities, while the latter illustrates the robustness of our approach to datasets where as many as 25% of the samples have altered copy number. Locus-specific estimates of copy number can be plotted on the copy-number scale to investigate mosaicism and guide the choice of appropriate downstream approaches for smoothing the copy number as a function of physical position. The software is open source and implemented in the R package CRLMM available at Bioconductor (http:www.bioconductor.org).
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In medical follow-up studies, ordered bivariate survival data are frequently encountered when bivariate failure events are used as the outcomes to identify the progression of a disease. In cancer studies interest could be focused on bivariate failure times, for example, time from birth to cancer onset and time from cancer onset to death. This paper considers a sampling scheme where the first failure event (cancer onset) is identified within a calendar time interval, the time of the initiating event (birth) can be retrospectively confirmed, and the occurrence of the second event (death) is observed sub ject to right censoring. To analyze this type of bivariate failure time data, it is important to recognize the presence of bias arising due to interval sampling. In this paper, nonparametric and semiparametric methods are developed to analyze the bivariate survival data with interval sampling under stationary and semi-stationary conditions. Numerical studies demonstrate the proposed estimating approaches perform well with practical sample sizes in different simulated models. We apply the proposed methods to SEER ovarian cancer registry data for illustration of the methods and theory.
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The fulcrum upon which were leveraged many of the dramatic progressive changes in Montana that are documented "In the Crucible of Change" series was the lead up to, preparation, writing and adoption of the 1972 Montana Constitution. As Montana citizens exhibited their concern over the dysfunctional state government in MT under its 1889 Constitution, one of the areas that stood out as needing serious change was the Montana Legislature. Meeting for only sixty calendar days every two years, the Legislature regularly tried to carry off the subterfuge of stopping the wall clock at 11:59 PM on the sixtieth day and placing a shroud over it so they could continue to conduct business as if it were still the 60th day. Lawyers hired by the Anaconda Company drafted most bills that legislators wanted to have introduced. Malapportionment, especially in the State Senate where each county had one Senator regardless of their population, created a situation where Petroleum County with 800 residents had one senator while neighboring Yellowstone County with 80,000 people also had one senator -- a 100-1 differential in representation. Reapportionment imposed by rulings of the US Supreme Court in the mid-1960s created great furor in rural Montana to go along with the previous dissatisfaction of the urban centers. Stories of Anaconda Company “thumbs up – thumbs down” control of the votes were prevalent. Committee meeting and votes were done behind closed doors and recorded votes were non-existent except for the nearly meaningless final tally. People were in the dark about the creation of laws that affected their daily lives. It was clear that change in the Legislature had to take the form of change in the Constitution and, because it was not likely that the Legislature would advance Constitutional amendments on the subject, a convention seemed the only remedy. Once that Convention was called and went to work, it became apparent that the Legislative Article provided both opportunity for change and danger that too dramatic a change might sink the whole new document. The activities of the Legislative Committee and the whole Convention when acting upon Legislative issues provides one of the more compelling stories of change. The story of the Legislative Article of the Montana Constitution is discussed in this episode by three major players who were directly involved in the effort: Jerry Loendorf, Arlyne Reichert and Rich Bechtel. Their recollections of the activities surrounding the entire Constitutional Convention and specifically the Legislative Article provide an insider’s perspective of the development of the entire Constitution and the Legislative portion which was of such a high degree of interest to the people of Montana during the important period of progressive change documented “In the Crucible of Change.” Jerry Loendorf, who served as Chair of the Legislative Committee at the 1972 Montana Constitutional Convention, received a BA from Carroll College in 1961 and a JD from the University of Montana Law School in 1964. Upon graduation he served two years as a law clerk for the Montana Supreme Court after which he was for 34 years a partner in the law firm of Harrison, Loendorf & Posten, Duncan. In addition to being a delegate to the Constitutional Convention, Jerry served on the Board of Labor Appeals from 2000 to 2004. He was designated a Montana Special Assistant Attorney General to represent the state in federal court on the challenge to the results of the ratification election of Montana's Constitution in 1972. Jerry served on the Carroll College Board of Directors in the late 1960s and then again as a member of the Board of Trustees of Carroll College from 2001 to 2009. He has served on the Board of Directors of the Rocky Mountain Development Council since 1970 and was on the board of the Helena YMCA from 1981 to 1987. He also served on the board of the Good Samaritan Ministries from 2009 to 2014. On the business side, Jerry was on the Board of Directors of Valley Bank to Helena from 1980 to 2005. He is a member of the American Bar Association, State Bar of Montana, the First Judicial District Bar Association, and the Montana Trial Lawyers Association. Carroll College awarded Jerry the Warren Nelson Award 1994 and the Insignias Award in 2007. At Carroll College, Jerry has funded the following three scholarship endowments: George C and Helen T Loendorf, Gary Turcott, and Fr. William Greytek. Arlyne Reichert, Great Falls Delegate to the Constitutional Convention and former State Legislator, was born in Buffalo, NY in 1926 and attended University of Buffalo in conjunction with Cadet Nurses Training during WWII. She married a Montanan in Great Falls in 1945 and was widowed in 1968. She is mother of five, grandmother of seven, great-grandmother of four. Arlyne was employed by McLaughlin Research Institute in Great Falls for 23 years, serving as Technical Editor of Transplantation Journal in 1967, retiring as Assistant Director in 1989. In addition to being a state legislator (1979 Session) and a delegate to the 1972 Montana Constitutional Convention, she has filled many public roles, including Cascade County Study Commissioner (1974), MT Comprehensive Health Council, US Civil Rights Commission MT Advisory Committee, MT Capitol Restoration Committee, and Great Falls Public Library Trustee. Arlyne has engaged in many non-profit activities including League of Women Voters (State & Local Board Officer – from where her interest in the MT Constitutional change developed), Great Falls Public Radio Association (President & Founder), American Cancer Society (President Great Falls Chapter), Chair of MT Rhodes Scholarship Committee, and Council Member of the National Civic League. She also served a while as a Television Legislative Reporter. Arlyne has been recipient of numerous awards, the National Distinguished Citizens Award from the National Municipal League, two Women of Achievement Awards from Business & Professional Women, the Salute to Women Award by YWCA, Heritage Preservation Award from Cascade County Historical Society and the State of Montana, and the Heroes Award from Humanities Montana. She remains active, serving as Secretary-Treasurer of Preservation Cascade, Inc., and as Board Member of the McLaughlin Research Institute. Her current passion is applied to the preservation/saving of the historic 10th Street Bridge that crosses the Missouri River in Great Falls. Rich Bechtel of Helena was born in Napa, California in 1945 and grew up as an Air Force brat living in such places as Bitberg, Germany, Tripoli, Libya, and Sevilla, Spain. He graduated from Glasgow High School and the University of Montana. Rich was a graduate assistant for noted Montana History professor Professor K. Ross Toole, but dropped out of graduate school to pursue a real life in Montana politics and government. Rich has had a long, varied and colorful career in the public arena. He currently is the Director of the Office of Taxpayer Assistance & Public Outreach for MT’s Department of Revenue. He previously held two positions with the National Wildlife Federation in Washington, DC (Sr. Legislative Representative [1989-91] and Sr. Legislative Representative for Wildlife Policy [2004-2006]). While in Washington DC, he also was Assistant for Senator Lee Metcalf (D-MT), 1974-1976; Federal-State Coordinator for State of Montana, 1976-1989; Director of the Western Governors’ Association Washington Office, 1991-2000; and Director of Federal Affairs for Governor Kitzhaber of Oregon, 2001- 2003. Earlier in Montana Government, between 1971 and 1974, Rich was Research Analyst for MT Blue Ribbon Commission on Postsecondary Education, Legislative Consultant and Bill Drafter for MT Legislative Council, Research Analyst for the MT Constitutional Convention Commission where he provided original research on legislatures, as well as Researcher/Staff for the MT Constitutional Convention Legislative Committee, from where he drafted the various provisions of the Legislative Article and the majority and minority reports on behalf of the Committee members. Rich has represented Montana’s Governor on a trade and cultural mission to Republic of China and participated in US-German Acid Rain Committee sessions in Germany and with European Economic Community environmental officials in Belgium. He is married to Yvonne Seng (Ph.D.) - T’ai Chi apprentice; author and birder.
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Hodgkin lymphoma (HL) risk is elevated among persons infected with HIV (PHIV) and has been suggested to have increased in the era of combined antiretroviral therapy (cART). Among 14,606 PHIV followed more than 20 years in the Swiss HIV Cohort Study (SHCS), determinants of HL were investigated using 2 different approaches, namely, a cohort and nested case-control study, estimating hazard ratios (HRs) and matched odds ratios, respectively. Forty-seven incident HL cases occurred during 84,611 person-years of SHCS follow-up. HL risk was significantly higher among men having sex with men (HR vs intravenous drug users = 2.44, 95% confidence interval [CI], 1.13-5.24) but did not vary by calendar period (HR for 2002-2007 vs 1995 or earlier = 0.65, 95% CI, 0.29-1.44) or cART use (HR vs nonusers = 1.02, 95% CI, 0.53-1.94). HL risk tended to increase with declining CD4(+) cell counts, but these differences were not significant. A lower CD4(+)/CD8(+) ratio at SHCS enrollment or 1 to 2 years before HL diagnosis, however, was significantly associated with increased HL risk. In conclusion, HL risk does not appear to be increasing in recent years or among PHIV using cART in Switzerland, and there was no evidence that HL risk should be increased in the setting of improved immunity.
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The objective of this study was to describe the all-cause mortality of participants in the Swiss Hepatitis C Cohort compared to the Swiss general population. Patients with hepatitis C virus (HCV) infection attending secondary and tertiary care centres in Switzerland. One thousand six hundred and forty-five patients with HCV infection were followed up for a mean of over 2 years. We calculated all-cause standardized mortality ratios (SMR) and 95% confidence intervals (CI) using age, sex and calendar year-specific Swiss all-cause mortality rates. Multivariable Poisson regression was used to model the variability of SMR by cirrhotic status, HCV genotype, infection with hepatitis B virus or HIV, injection drug use and alcohol intake. Sixty-one deaths were recorded out of 1645 participants. The crude all-cause SMR was 4.5 (95% CI: 3.5-5.8). Patients co-infected with HIV had a crude SMR of 20 (95% CI: 11.1-36.1). The SMR of 1.1 (95% CI: 0.63-2.03) for patients who were not cirrhotic, not infected with HBV or HIV, did not inject drugs, were not heavy alcohol consumers (
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BACKGROUND: This collaboration of seven observational clinical cohorts investigated risk factors for treatment-limiting toxicities in both antiretroviral-naive and experienced patients starting nevirapine-based combination antiretroviral therapy (NVPc). METHODS: Patients starting NVPc after 1 January 1998 were included. CD4 cell count at starting NVPc was classified as high (>400/microl/>250/microl for men/women, respectively) or low. Cox models were used to investigate risk factors for discontinuations due to hypersensitivity reactions (HSR, n = 6547) and discontinuation of NVPc due to treatment-limiting toxicities and/or patient/physician choice (TOXPC, n = 10,186). Patients were classified according to prior antiretroviral treatment experience and CD4 cell count/viral load at start NVPc. Models were stratified by cohort and adjusted for age, sex, nadir CD4 cell count, calendar year of starting NVPc and mode of transmission. RESULTS: Median time from starting NVPc to TOXPC and HSR were 162 days [interquartile range (IQR) 31-737] and 30 days (IQR 17-60), respectively. In adjusted Cox analyses, compared to naive patients with a low CD4 cell count, treatment-experienced patients with high CD4 cell count and viral load more than 400 had a significantly increased risk for HSR [hazard ratio 1.45, confidence interval (CI) 1.03-2.03] and TOXPC within 18 weeks (hazard ratio 1.34, CI 1.08-1.67). In contrast, treatment-experienced patients with high CD4 cell count and viral load less than 400 had no increased risk for HSR 1.10 (0.82-1.46) or TOXPC within 18 weeks (hazard ratio 0.94, CI 0.78-1.13). CONCLUSION: Our results suggest it may be relatively well tolerated to initiate NVPc in antiretroviral-experienced patients with high CD4 cell counts provided there is no detectable viremia.
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Accumulation and delta O-18 data from Alpine ice cores provide information on past temperature and precipitation. However, their correlation with seasonal or annual mean temperature and precipitation at nearby sites is often low. This is partly due to the irregular sampling of the atmosphere by the ice core (i.e. ice cores almost only record precipitation events and not dry periods) and the possible incongruity between annual layers and calendar years. Using daily meteorological data from a nearby station and reanalyses, we replicate the ice core from the Grenzgletscher (Switzerland, 4200m a.s.l.) on a sample-by-sample basis by calculating precipitation-weighted temperature (PWT) over short intervals. Over the last 15 yr of the ice core record, accumulation and delta O-18 variations can be well reproduced on a sub-seasonal scale. This allows a wiggle-matching approach for defining quasi-annual layers, resulting in high correlations between measured quasi-annual delta O-18 and PWT. Further back in time, the agreement deteriorates. Nevertheless, we find significant correlations over the entire length of the record (1938-1993) of ice core delta O-18 with PWT, but not with annual mean temperature. This is due to the low correlations between PWT and annual mean temperature, a characteristic which in ERA-Interim reanalysis is also found for many other continental mid-to-high-latitude regions. The fact that meteorologically very different years can lead to similar combinations of PWT and accumulation poses limitations to the use of delta O-18 from Alpine ice cores for temperature reconstructions. Rather than for reconstructing annual mean temperature, delta O-18 from Alpine ice cores should be used to reconstruct PWT over quasi-annual periods. This variable is reproducible in reanalysis or climate model data and could thus be assimilated into conventional climate models.
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OBJECTIVES Zidovudine (ZDV) is recommended for first-line antiretroviral therapy (ART) in resource-limited settings. ZDV may, however, lead to anemia and impaired immunological response. We compared CD4+ cell counts over 5 years between patients starting ART with and without ZDV in southern Africa. DESIGN Cohort study. METHODS Patients aged at least 16 years who started first-line ART in South Africa, Botswana, Zambia, or Lesotho were included. We used linear mixed-effect models to compare CD4+ cell count trajectories between patients on ZDV-containing regimens and patients on other regimens, censoring follow-up at first treatment change. Impaired immunological recovery, defined as a CD4+ cell count below 100 cells/μl at 1 year, was assessed in logistic regression. Analyses were adjusted for baseline CD4+ cell count and hemoglobin level, age, sex, type of regimen, viral load monitoring, and calendar year. RESULTS A total of 72,597 patients starting ART, including 19,758 (27.2%) on ZDV, were analyzed. Patients on ZDV had higher CD4+ cell counts (150 vs.128 cells/μl) and hemoglobin level (12.0 vs. 11.0 g/dl) at baseline, and were less likely to be women than those on other regimens. Adjusted differences in CD4+ cell counts between regimens containing and not containing ZDV were -16 cells/μl [95% confidence interval (CI) -18 to -14] at 1 year and -56 cells/μl (95% CI -59 to -52) at 5 years. Impaired immunological recovery was more likely with ZDV compared to other regimens (odds ratio 1.40, 95% CI 1.22-1.61). CONCLUSION In southern Africa, ZDV is associated with inferior immunological recovery compared to other backbones. Replacing ZDV with another nucleoside reverse transcriptase inhibitor could avoid unnecessary switches to second-line ART.
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Financial, economic, and biological data collected from cow-calf producers who participated in the Illinois and Iowa Standardized Performance Analysis (SPA) programs were used in this study. Data used were collected for the 1996 through 1999 calendar years, with each herd within year representing one observation. This resulted in a final database of 225 observations (117 from Iowa and 108 from Illinois) from commercial herds with a range in size from 20 to 373 cows. Two analyses were conducted, one utilizing financial cost of production data, the other economic cost of production data. Each observation was analyzed as the difference from the mean for that given year. The independent variable utilized in both the financial and economic models as an indicator of profit was return to unpaid labor and management per cow (RLM). Used as dependent variables were the five factors that make up total annual cow cost: feed cost, operating cost, depreciation cost, capital charge, and hired labor, all on an annual cost per cow basis. In the economic analysis, family labor was also included. Production factors evaluated as dependent variables in both models were calf weight, calf price, cull weight, cull price, weaning percentage, and calving distribution. Herd size and investment were also analyzed. All financial factors analyzed were significantly correlated to RLM (P < .10) except cull weight, and cull price. All economic factors analyzed were significantly correlated to RLM (P < .10) except calf weight, cull weight and cull price. Results of the financial prediction equation indicate that there are eight measurements capable of explaining over 82 percent of the farm-to-farm variation in RLM. Feed cost is the overriding factor driving RLM in both the financial and economic stepwise regression analyses. In both analyses over 50 percent of the herd-to-herd variation in RLM could be explained by feed cost. Financial feed cost is correlated (P < .001) to operating cost, depreciation cost, and investment. Economic feed cost is correlated (P < .001) with investment and operating cost, as well as capital charge. Operating cost, depreciation, and capital charge were all negatively correlated (P < .10) to herd size, and positively correlated (P < .01) to feed cost in both analyses. Operating costs were positively correlated with capital charge and investment (P < .01) in both analyses. In the financial regression model, depreciation cost was the second critical factor explaining almost 9 percent of the herd-to-herd variation in RLM followed by operating cost (5 percent). Calf weight had a greater impact than calf price on RLM in both the financial and economic regression models. Calf weight was the fourth indicator of RLM in the financial model and was similar in magnitude to operating cost. Investment was not a significant variable in either regression model; however, it was highly correlated to a number of the significant cost variables including feed cost, depreciation cost, and operating cost (P < .001, financial; P < .10, economic). Cost factors were far more influential in driving RLM than production, reproduction, or producer controlled marketing factors. Of these cost factors, feed cost had by far the largest impact. As producers focus attention on factors that affect the profitability of the operation, feed cost is the most critical control point because it was responsible for over 50 percent of the herd-to-herd variation in profit.
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BACKGROUND: HCV coinfection remains a major cause of morbidity and mortality among HIV-infected individuals and its incidence has increased dramatically in HIV-infected men who have sex with men(MSM). METHODS: Hepatitis C virus (HCV) coinfection in the Swiss HIV Cohort Study(SHCS) was studied by combining clinical data with HIV-1 pol-sequences from the SHCS Drug Resistance Database(DRDB). We inferred maximum-likelihood phylogenetic trees, determined Swiss HIV-transmission pairs as monophyletic patient pairs, and then considered the distribution of HCV on those pairs. RESULTS: Among the 9748 patients in the SHCS-DRDB with known HCV status, 2768(28%) were HCV-positive. Focusing on subtype B(7644 patients), we identified 1555 potential HIV-1 transmission pairs. There, we found that, even after controlling for transmission group, calendar year, age and sex, the odds for an HCV coinfection were increased by an odds ratio (OR) of 3.2 [95% confidence interval (CI) 2.2, 4.7) if a patient clustered with another HCV-positive case. This strong association persisted if transmission groups of intravenous drug users (IDUs), MSMs and heterosexuals (HETs) were considered separately(in all cases OR >2). Finally we found that HCV incidence was increased by a hazard ratio of 2.1 (1.1, 3.8) for individuals paired with an HCV-positive partner. CONCLUSIONS: Patients whose HIV virus is closely related to the HIV virus of HIV/HCV-coinfected patients have a higher risk for carrying or acquiring HCV themselves. This indicates the occurrence of domestic and sexual HCV transmission and allows the identification of patients with a high HCV-infection risk.
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BACKGROUND Human herpes virus 8 (HHV-8) is the underlying infectious cause of Kaposi sarcoma (KS) and other proliferative diseases; that is, primary effusion lymphoma and multicentric Castleman disease. In regions with high HHV-8 seroprevalence in the general population, KS accounts for a major burden of disease. Outside these endemic regions, HHV-8 prevalence is high in men who have sex with men (MSM) and in migrants from endemic regions. We aim to conduct a systematic literature review and meta-analysis in order 1) to define the global distribution of HHV-8 seroprevalence (primary objective) and 2) to identify risk factors for HHV-8 infection, with a focus on HIV status (secondary objective). METHODS/DESIGN We will include observational studies reporting data on seroprevalence of HHV-8 in children and/or adults from any region in the world. Case reports and case series as well as any studies with fewer than 50 participants will be excluded. We will search MEDLINE, EMBASE, and relevant conference proceedings without language restriction. Two reviewers will independently screen the identified studies and extract data on study characteristics and quality, study population, risk factors, and reported outcomes, using a standardized form. For the primary objective we will pool the data using a fully bayesian approach for meta-analysis, with random effects at the study level. For the secondary objective (association of HIV and HHV-8) we aim to pool odds ratios for the association of HIV and HHV-8 using a fully bayesian approach for meta-analysis, with random effects at the study level. Sub-group analyses and meta-regression analyses will be used to explore sources of heterogeneity, including factors such as geographical region, calendar years of recruitment, age, gender, ethnicity, socioeconomic status, different risk groups for sexually and parenterally transmitted infections (MSM, sex workers, hemophiliacs, intravenous drug users), comorbidities such as organ transplantation and malaria, test(s) used to measure HHV-8 infection, study design, and study quality. DISCUSSION Using the proposed systematic review and meta-analysis, we aim to better define the global seroprevalence of HHV-8 and its associated risk factors. This will improve the current understanding of HHV-8 epidemiology, and could suggest measures to prevent HHV-8 infection and to reduce its associated cancer burden.
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BACKGROUND There is debate over using tenofovir or zidovudine alongside lamivudine in second-line antiretroviral therapy (ART) following stavudine failure. We analyzed outcomes in cohorts from South Africa, Zambia and Zimbabwe METHODS: Patients aged ≥16 years who switched from a first-line regimen including stavudine to a ritonavir-boosted lopinavir-based second-line regimen with lamivudine or emtricitabine and zidovudine or tenofovir in seven ART programs in southern Africa were included. We estimated the causal effect of receiving tenofovir or zidovudine on mortality and virological failure using Cox proportional hazards marginal structural models. Its parameters were estimated using inverse probability of treatment weights. Baseline characteristics were age, sex, calendar year and country. CD4 cell count, creatinine and hemoglobin levels were included as time-dependent confounders. RESULTS 1,256 patients on second-line ART, including 958 on tenofovir, were analyzed. Patients on tenofovir were more likely to have switched to second-line ART in recent years, spent more time on first-line ART (33 vs. 24 months) and had lower CD4 cell counts (172 vs. 341 cells/μl) at initiation of second-line ART. The adjusted hazard ratio comparing tenofovir with zidovudine was 1.00 (95% confidence interval 0.59-1.68) for virologic failure and 1.40 (0.57-3.41) for death. CONCLUSIONS We did not find any difference in treatment outcomes between patients on tenofovir or zidovudine; however, the precision of our estimates was limited. There is an urgent need for randomized trials to inform second-line ART strategies in resource-limited settings.
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Purpose The purpose of this study is to explore the periodical patterns of events and deaths related to cardiovascular disease (CVD), acute myocardial infarction (AMI) and stroke in Swiss adults (≥18years). Methods Mortality data for period 1969–2007 (N=869,863 CVD events) and hospitalization data for period 1997–2008 (N=959,990 CVD events) were used. The annual, weekly and circadian distribution of CVD-related deaths and events were assessed. Multivariate analysis was conducted using multinomial logistic regression adjusting for age, gender and calendar year and considering deaths from respiratory diseases, accidents or other causes as competitive events. Results CVD deaths and hospitalizations occurred less frequently in the summer months. Similar patterns were found for AMI and stroke. No significant weekly variation for CVD deaths was found. Stratification by age and gender showed subjects aged <65years to present a higher probability of dying on Mondays and Saturday, only for men. This finding was confirmed after multivariate adjustment. Finally, a circadian variation in CVD mortality was observed, with a first peak in the morning (8–12am) and a smaller second peak in the late afternoon (2–6pm). This pattern persisted after multivariate adjustment and was more pronounced for AMI than for stroke. Conclusion There is a periodicity of hospitalizations and deaths related to CVD, AMI and stroke in Switzerland. This pattern changes slightly according to the age and sex of the subjects. Although the underlying mechanisms are not fully identified, preventive measures should take into account these aspects to develop better strategies of prevention and management of CVD.