Overexpression of polo-like kinase1 predicts a poor prognosis in hepatocellular carcinoma patients

AIM

To elucidate the role of overexpressed polo-like kinase1 (PLK1) in hepatocellular carcinoma (HCC).

METHODS

We prospectively collected clinicopathological, immunohistochemical and semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) data from 135 HCC patients undergoing successful hepatectomy. The correlations between PLK1 mRNA expression and clinicopathologic variables were analyzed by Mann-Whitney U test. Prognostic factors were identified by univariate and multivariate analyses.

RESULTS

Immunohistochemical results showed overexpression of PLK1 was mainly found in tumor tissues compared with tumor-free tissue. A similar mRNA result was obtained by semi-quantitative RT-PCR. A total of 111 samples were positive for PLK1 mRNA expression. The positive expression was correlated with venous invasion, tumor nodules and Edmondson grade. Furthermore, 1, 3, 5-year survival rates in the positive expression group were significantly lower than the negative control group. Multivariate analysis showed that positive PLK1 expression was an independent risk factor for HCC.

CONCLUSION

PLK1 could be a potential biomarker for diagnosis and therapy for HCC.

Cox Models With Smooth Functional Effect of Covariates Measured With Error

We propose, develop, and implement a fully Bayesian inferential approach for the Cox model when the log hazard function contains unknown smooth functions of the variables measured with error. Our approach is to model nonparametrically both the log-baseline hazard and the smooth components of the log-hazard functions using low-rank penalized splines. Careful implementation of the Bayesian inferential machinery is shown to produce remarkably better results than the naive approach. Our methodology was motivated by and applied to the study of progression time to chronic kidney disease as a function of baseline kidney function and applied to the Atherosclerosis Risk in Communities study, a large epidemiological cohort study. This article has supplementary material online.

Pathways between nonmedical opioid use/dependence and psychiatric disorders: results from the National Epidemiologic Survey on Alcohol and Related Conditions

BACKGROUND

While nonmedical use of opioids and psychiatric disorders are prevalent in the population, little is known about the temporal ordering between nonmedical opioid use and dependence and psychiatric disorders.

METHOD

Data were gathered in a face-to-face survey of the United States conducted in the 2001-2002 (NESARC wave 1). Participants were household and group quarters residents aged 18 years and older (n=43,093). Cox proportional hazards models with time-dependent covariates were used to investigate potential pathways between lifetime nonmedical opioid use/dependence and psychiatric disorders.

RESULTS

Preexisting psychiatric disorders (mood disorders, major depressive disorder, bipolar I disorder, anxiety disorders, panic and generalized anxiety disorders) were associated with an increased risk of nonmedical opioid use, with hazard ratios ranging from 2.2[95% CI=1.6-3.1] (any anxiety disorder) to 3.1[95% CI=2.4-2.4] (bipolar I disorder). Preexisting nonmedical opioid use was associated with an increased risk of onset of psychiatric disorders, with hazard ratios ranging from 2.8[95% CI=2.2-3.6] (generalized anxiety disorder) to 3.6[95% CI=2.6-4.9] (bipolar I disorder), adjusted for demographics and other illegal drug use. Nonmedical use of opioids led to the development of dependence more often among individuals with preexisting psychiatric disorders, hazard ratios were particularly strong for generalized anxiety disorder (HR=10.8, 95% CI=4.9-23.7) and bipolar I disorder (HR=9.7, 95% CI=5.4-17.3). Preexisting opioid dependence resulting from nonmedical opioid use was associated with an increased risk of onset of psychiatric disorders, with hazard ratios ranging from 4.9[95% CI=3.0-7.9] (mood disorders) to 8.5[95% CI=4.5-16.0] (panic disorder), adjusted for demographics and alcohol and/or other illegal drug dependence.

CONCLUSIONS

Our findings support a general vulnerability to nonmedical opioid use and major psychopathologies, as well as evidence for a 'self-medication' model for dependence resulting from nonmedical opioid use with bipolar disorder and generalized anxiety disorder.

Prevalent cases in observational studies of cancer survival: do they bias hazard ratio estimates?

Observational epidemiological studies often include prevalent cases recruited at various times past diagnosis. This left truncation can be dealt with in non-parametric (Kaplan-Meier) and semi-parametric (Cox) time-to-event analyses, theoretically generating an unbiased hazard ratio (HR) when the proportional hazards (PH) assumption holds. However, concern remains that inclusion of prevalent cases in survival analysis results inevitably in HR bias. We used data on three well-established breast cancer prognosticators - clinical stage, histopathological grade and oestrogen receptor (ER) status - from the SEARCH study, a population-based study including 4470 invasive breast cancer cases (incident and prevalent), to evaluate empirically the effectiveness of allowing for left truncation in limiting HR bias. We found that HRs of prognostic factors changed over time and used extended Cox models incorporating time-dependent covariates. When comparing Cox models restricted to subjects ascertained within six months of diagnosis (incident cases) to models based on the full data set allowing for left truncation, we found no difference in parameter estimates (P=0.90, 0.32 and 0.95, for stage, grade and ER status respectively). Our results show that use of prevalent cases in an observational epidemiological study of breast cancer does not bias the HR in a left truncation Cox survival analysis, provided the PH assumption holds true.

The impact of repression, hostility, and post-traumatic stress disorder on all-cause mortality: a prospective 16-year follow-up study

A common assumption is that repression of traumatic memories is harmful to health. To assess this, we examined all-cause mortality among a national random sample of 4462 male US Army veterans evaluated in 1985 and followed up in 2000. Our hypothesis was that repression on the Welsh R scale would be associated with increased future mortality. We also expected to find a repression x post-traumatic stress disorder (PTSD) interaction effect. Multivariate Cox regression results for all veterans and for theater veterans (Vietnam service) and era veterans (no Vietnam service) separately, revealed that while PTSD was significant in all models, no main or interaction effect was found for repression. In addition, for era veterans, higher repression symptoms were protective for future mortality (HR = 0.95, p = 0.03). For hostility symptoms, although no interaction effect was found by PTSD, a positive main effect was detected for hostility, but only for theater veterans (HR = 1.04, p = 0.034). Disease-specific results were nonsignificant. Similar to a recent study, we also found that repression symptoms were negatively correlated with PTSD symptoms (r = -0.109, p < 0.001), suggesting repression might be protective. Our study found no evidence that repression had an adverse health impact on men exposed to psychological trauma.

Timing of identification among children with an autism spectrum disorder: findings from a population-based surveillance study

OBJECTIVE

At what age are children with an autism spectrum disorder (ASD) identified by community providers? What factors influence the timing of when children are identified with ASDs? This study examined the timing of when children with ASDs are identified.

METHOD

Data came from 13 sites participating in the Centers for Disease Control and Prevention's 2002 multisite ongoing autism surveillance program, the Autism and Developmental Disabilities Monitoring Network. Survival analysis was used to examine factors that influence the timing of community-based identification and diagnosis.

RESULT

Data from health and education records reveal that the median age of identification was 5.7 years (SE 0.08 years). Parametric survival models revealed that several factors were associated with a younger age of identification: being male, having an IQ of 70 or lower, and having experienced developmental regression. Significant differences in the age of identification among the 13 sites were also discovered.

CONCLUSIONS

The large gap between the age at which children can be identified and when they actually are identified suggests a critical need for further research, innovation, and improvement in this area of clinical practice.

Polycyclic aromatic hydrocarbon-DNA adducts and survival among women with breast cancer

Polycyclic aromatic hydrocarbons (PAH) are mammary carcinogens in animal studies, and a few epidemiologic studies have suggested a link between elevated levels of PAH-DNA adducts and breast cancer incidence. An association between PAH-DNA adducts and survival among breast cancer cases has not been previously reported. We conducted a survival analysis among women with newly diagnosed invasive breast cancer between 1996 and 1997, enrolled in the Long Island Breast Cancer Study Project. DNA was isolated from blood samples that were obtained from cases shortly after diagnosis and assayed for PAH-DNA adducts using ELISA. Among the 722 cases with PAH-DNA adduct measurements, 97 deaths (13.4%) from all causes and 54 deaths (7.5%) due to breast cancer were reported to the National Death Index (NDI) by December 31, 2002. Using Cox proportional hazards models and controlling for age at diagnosis, we did not find evidence that all-cause mortality (hazard ratio (HR)=0.88; 95% confidence interval (CI): 0.57-1.37), or breast cancer mortality (HR=1.20; 95% CI: 0.63-2.28) was strongly associated with detectable PAH-DNA adduct levels compared with non-detectable adducts; additionally, no dose-response association was observed. Among a subgroup with treatment data (n=520), adducts were associated with over a two-fold higher mortality among those receiving radiation, but mortality for adducts was reduced among hormone therapy users. Results from this large population-based study do not provide strong support for an association between detectable PAH-DNA adducts and survival among women with breast cancer, except perhaps among those receiving radiation treatment.

30-MONTH POST-BREAST CANCER TREATMENT LYMPHOEDEMA

BACKGROUND: Quantification of lymphoedema (LE) has been problematic, and the reported incidence of LE varies greatly among women treated with surgery and radiation for breast cancer. AIMS: This study aims to describe LE occurrence over time among breast cancer survivors using four diagnostic criteria based on three measurement techniques. METHODS: Limb volume and symptom assessment data were followed after surgery every three months for 12 months, then every six months for 30 months. Limb volume changes (LVC) were measured by circumferences and by perometry, and by symptom experience via interview. Standard survival analysis methods identified when the criteria indicating LE were met. RESULTS: Trends in LE occurrence are reported for data from 211 participants. At 30 months post-treatment, LE incidence ranged from 41-91%, with 2cm being the highest estimation method and self-reported signs and symtoms (SS) the lowest. CONCLUSIONS: This 30-month analysis supports the previous 12-month analysis in finding the 2cm criteria as the most liberal definition of LE. Self-reporting of heaviness and swelling, along with 10% LVC, represented the most conservative definitions (41% and 45%, respectively).

PROPORTIONAL HAZARDS MODELS WITH CONTINUOUS MARKS

For time-to-event data with finitely many competing risks, the proportional hazards model has been a popular tool for relating the cause-specific outcomes to covariates [Prentice et al. Biometrics34 (1978) 541-554]. This article studies an extension of this approach to allow a continuum of competing risks, in which the cause of failure is replaced by a continuous mark only observed at the failure time. We develop inference for the proportional hazards model in which the regression parameters depend nonparametrically on the mark and the baseline hazard depends nonparametrically on both time and mark. This work is motivated by the need to assess HIV vaccine efficacy, while taking into account the genetic divergence of infecting HIV viruses in trial participants from the HIV strain that is contained in the vaccine, and adjusting for covariate effects. Mark-specific vaccine efficacy is expressed in terms of one of the regression functions in the mark-specific proportional hazards model. The new approach is evaluated in simulations and applied to the first HIV vaccine efficacy trial.

The prognostic value of anemia in patients with diastolic heart failure

Anemia is prevalent in heart-failure patients, and it has been associated with increased mortality rates. In a retrospective study, we evaluated the effects of anemia on long-term survival in patients who experienced purely diastolic heart failure.Heart-failure patients with preserved systolic function (left ventricular ejection fraction, > or =0.50) were evaluated retrospectively. Of 294 patients, 162 had anemia (group 1) and 132 had no anemia (group 2) upon baseline examination. Anemia was defined as a hemoglobin level below 12 g/dL in women and below 13 g/dL in men. Multivariate Cox proportional hazards regression was conducted in order to test whether hemoglobin levels were an independent predictor of 5-year hospitalization and mortality rates in patients with diastolic heart failure. A P value less than 0.05 was considered statistically significant.Group 1 patients had a shorter mean survival time (37.8 +/- 1.8 vs 44.9 +/- 1.8 mo, P = 0.01); however, there was no significant difference between the groups in hospitalization rate (7.2 +/- 7.1 vs 7.5 +/- 6.3, P = 0.677). In a subgroup analysis, anemia was a significant predictor of higher mortality rates in elderly patients (age, >75 yr) who had diastolic heart failure (P = 0.018).We found that anemia is associated with increased long-term mortality rates in patients who have diastolic heart failure. In addition, anemia appears to be an independent predictor of worse outcomes in elderly heart-failure patients.

Surgical repair of supravalvular aortic stenosis with use of Brom's technique: short-term results in 9 children

There are few published reports of the results of supravalvular aortic stenosis correction with the use of Brom's 3-patch technique. Herein, we report our use of this procedure and the short-term results therefrom.From 2002 through 2007, 9 children underwent surgical correction of localized supravalvular aortic stenosis at our hospital. The patients ranged in age from 5 to 14 years, and 8 had Williams syndrome. All operations were performed by the same surgical team.No clinically significant associated cardiac anomalies were encountered. Each aortic repair involved the use of pericardium, Dacron, or both. One patient had an uncorrected right coronary artery obstruction and died postoperatively of refractory supraventricular tachycardia. In all 8 patients who survived, postoperative transaortic blood pressure gradients were improved (range, 0-16 mmHg), and no repeat operations were needed after 6 to 55 months' follow-up.We consider Brom's technique to be safe in the repair of supravalvular aortic stenosis. In our limited series, it produced effective anatomic restoration, with good short-term and potentially good long-term results.

Clinical predictors of late death in survivors of acute myocardial infarction

Survivors of acute myocardial infarction have higher mortality rates than do the general population. This study examined the value of multiple clinical characteristics in predicting late death among patients who present with acute myocardial infarction.We reviewed the electronic medical records of patients who had been treated for acute myocardial infarction at our institution from 1992 through 2000. We abstracted the clinical, laboratory, electrocardiographic, echocardiographic, and treatment characteristics.Of 144 patients (79.2% men; 97.2% white; mean age, 63 +/- 14.2 yr) included in this analysis, 63 (43.8%) patients died during a follow-up period of 5.6 +/- 2.8 years (5 d-12.7 yr). Higher age (hazard ratio, 1.83 +/- 0.31 for every 10-year increase), elevated serum creatinine (hazard ratio, 2.87 +/- 0.76), and lower baseline left ventricular ejection fraction (hazard ratio, 0.74 +/- 0.21 for every 5% increase) were found to be predictors of late death after adjusting for the white blood cell count, the QRS duration, the presence of coronary revascularization or defibrillator implantation, and the history of coronary artery disease. Elevated white blood cell count predicted early but not late death. Patients with none of the above risk factors had 100% survival at 5 years, in comparison with 22.7% survival for those with 3 or more of the 4 risk factors identified above.In this study, we have identified clinical predictors of long-term survival after acute myocardial infarction that might help in prognostication, patient education, and risk modification.

A case-control study relating railroad worker mortality to diesel exhaust exposure using a threshold regression model

A case-control study of lung cancer mortality in U.S. railroad workers in jobs with and without diesel exhaust exposure is reanalyzed using a new threshold regression methodology. The study included 1256 workers who died of lung cancer and 2385 controls who died primarily of circulatory system diseases. Diesel exhaust exposure was assessed using railroad job history from the US Railroad Retirement Board and an industrial hygiene survey. Smoking habits were available from next-of-kin and potential asbestos exposure was assessed by job history review. The new analysis reassesses lung cancer mortality and examines circulatory system disease mortality. Jobs with regular exposure to diesel exhaust had a survival pattern characterized by an initial delay in mortality, followed by a rapid deterioration of health prior to death. The pattern is seen in subjects dying of lung cancer, circulatory system diseases, and other causes. The unique pattern is illustrated using a new type of Kaplan-Meier survival plot in which the time scale represents a measure of disease progression rather than calendar time. The disease progression scale accounts for a healthy-worker effect when describing the effects of cumulative exposures on mortality.

Graft and patient survival in kidney transplant recipients selected for de novo steroid-free maintenance immunosuppression

Steroid-free regimen is increasingly employed in kidney transplant recipients across transplant centers. However, concern remains because of the unknown impact of such an approach on long-term graft and patient survival. We studied the outcomes of steroid-free immunosuppression in a population-based U.S. cohort of kidney transplant recipients. All adult solitary kidney transplant recipients engrafted between January 1, 2000 and December 31, 2006 were stratified according to whether they were selected for a steroid-free or steroid-containing regimen at discharge. Multivariate Cox regression models were used to estimate graft and patient survival. The impact of the practice pattern on steroid use at individual transplant centers was analyzed. Among 95 755 kidney transplant recipients, 17.2% were steroid-free at discharge (n = 16 491). Selection for a steroid-free regimen was associated with reduced risks for graft failure and death at 1 year (HR 0.78, 95% CI 0.72-0.85, and HR 0.73, 95% CI 0.65-0.82, respectively, p < 0.0001) and 4 years (HR 0.83, 95% CI 0.78-0.87, and HR 0.76, 95% CI 0.71-0.83, respectively, p < 0.0001). This association was mostly observed at individual centers where less than 65% of recipients were discharged on the steroid-containing regimen. De novo steroid-free immunosuppression as currently practiced in the United States appears to carry no increased risk of adverse clinical outcomes in the intermediate term.

Prevalence of prognostic factors for cancer of the uterine cervix after radical hysterectomy

CONTEXT AND OBJECTIVE

Cancer of the uterine cervix is still very common in Brazil. It is important to evaluate factors that influence its prognosis. The aim here was to analyze the prevalence of prognostic anatomoclinical factors among patients with carcinoma of the uterine cervix undergoing radical hysterectomy.

DESIGN AND SETTING

Cross-sectional study on 301 patients with invasive carcinoma of the uterine cervix who underwent Level III Piver-Rutledge hysterectomy surgery at São Marcos Hospital.

METHODS

The following variables were analyzed: age, histological type, degree of differentiation, invasion of lymphatic, vascular and perineural space, lymph node metastasis, distance to nearest margin, tumor invasion depth, vaginal cuff size, largest diameter of the tumor, presence of necrosis and surgical margin involvement. Descriptive statistics, multiple regression analysis, Kaplan-Meier survival curves and the log-rank test were performed. A significance level of 5% was used.

RESULTS

The mean age was 48.27 years. The following were not important for the prognosis, in relation to survival analysis: degree of differentiation and tumor invasion depth; presence of lymphatic, blood and perineural invasions; distance to nearest margin; and vaginal cuff size. Tumor size (P < 0.036), presence of lymph node metastasis (P < 0.0004), necrosis (P < 0.05) and surgical margin involvement (P < 0.0015) presented impacts on survival. The overall survival with 98 months of follow-up was 88.35%.

CONCLUSION

The most prevalent prognostic factors were the presence of lymph node metastasis, tumor size and surgical margin involvement.

Lack of Socs2 expression reduces lifespan in high-growth mice

The high-growth (HG) phenotype in mice is characterized by a 30-50% postweaning overgrowth with a substantial increase in plasma insulin-like growth factor I (IGF1) levels, which is directly related to a deletion (hg) on chromosome 10 that includes the suppressor of cytokine signaling 2 (Socs2) gene. Reduced plasma IGF1 levels have been associated with extended lifespan in mice, although the aging-related effects of abnormally high IGF1 levels without elevated growth hormone levels have never been assessed in mammals. Within this context, the hg deletion was introgressed into C57BL/6J (B6) and FVB backgrounds, and a survival analysis was performed on the longevity records of 200 B6 (91 wild-type and 109 homozygous hg mutants) and 69 FVB (32 wild-type and 37 hg mutants) mice. Longevity was examined using a piecewise Weibull proportional hazards model solved through a Bayesian perspective and Markov chain Monte Carlo sampling. Lifespan was significantly reduced in both strains in homozygous hg mice, with a death risk between 3.689 (B6) and 4.347 (FVB) times higher than in wild-type mice (non-overlapped highest posterior density regions at 95%). These results highlight the effects of the Socs2 gene on aging regulation, likely related with variations described in plasma IGF1 levels. This result is consistent with previous research in dwarf mutant mice and other species, and characterizes the HG mutant mice as a unique and interesting animal model for accelerated aging research.

Inference for outcome probabilities in multi-state models

In bone marrow transplantation studies, patients are followed over time and a number of events may be observed. These include both ultimate events like death and relapse and transient events like graft versus host disease and graft recovery. Such studies, therefore, lend themselves for using an analytic approach based on multi-state models. We will give a review of such methods with emphasis on regression models for both transition intensities and transition- and state occupation probabilities. Both semi-parametric models, like the Cox regression model, and parametric models based on piecewise constant intensities will be discussed.

Infant feeding, HIV transmission and mortality at 18 months: the need for appropriate choices by mothers and prioritization within programmes

OBJECTIVES

To determine the late HIV transmission and survival risks associated with early infant feeding practices.

DESIGN

A nonrandomized intervention cohort.

METHODS

HIV-infected pregnant women were supported in their infant feeding choices. Infant feeding data were obtained weekly; blood samples from infants were taken monthly to diagnose HIV infection. Eighteen-month mortality and HIV transmission risk were assessed according to infant feeding practices at 6 months.

RESULTS

One thousand one hundred and ninety-three live-born infants were included. Overall 18-month probabilities of death (95% confidence interval) were 0.04 (0.03-0.06) and 0.53 (0.46-0.60) for HIV-uninfected and HIV-infected children, respectively. The eighteen-month probability of survival was not statistically significantly different for HIV-uninfected infants breastfed or replacement fed from birth. In univariate analysis of infant feeding practices, the probability of HIV-free survival beyond the first 6 months of life in children alive at 6 months was 0.98 (0.89-1.00) amongst infants replacement fed from birth, 0.96 (0.90-0.98; P = 0.25) and 0.91 (0.87-0.94; P = 0.03) in those breastfed for less or more than 6 months, respectively. In multivariable analyses, maternal unemployment and low antenatal CD4 cell count were independently associated with more than three-fold increased risk of infant HIV infection or death.

CONCLUSION

Breastfeeding and replacement feeding of HIV-uninfected infants were associated with similar mortality rates at 18 months. However, these findings were amongst mothers and infants who received excellent support to first make, and then practice, appropriate infant feeding choices. For programmes to achieve similar results, the quality of counselling and identification of mothers with low CD4 cell count need to be the targets of improvement strategies.

Evaluating competing adverse and beneficial outcomes using a mixture model

A competing risk framework occurs when individuals have the potential to experience only one of the several mutually exclusive outcomes. Standard survival methods often overestimate the cumulative incidence of events when competing events are censored. Mixture distributions have been previously applied to the competing risk framework to obtain inferences regarding the subdistribution of an event of interest. Often the competing event is treated as a nuisance, but it may be of interest to compare adverse events against the beneficial outcome when dealing with an intervention. In this paper, methods for using a mixture model to estimate an adverse-benefit ratio curve (ratio of the cumulative incidence curves for the two competing events) and the ratio of the subhazards for the two competing events are presented. A parametric approach is described with some remarks for extending the model to include uncertainty in the event type that occurred, left truncation in order to allow for time-dependent analyses, and uncertainty in the timing of the event resulting in interval censoring. The methods are illustrated with data from an HIV clinical cohort examining whether individuals initiating effective antiretroviral therapy have a greater risk of antiretroviral discontinuation or switching compared with HIV RNA suppression.

Clock-drawing potentially mediates the effect of depression on mortality: replication in three cohorts

OBJECTIVE

Previously studies have associated visuospatial tasks, particularly 'clock-drawing', with mortality. We sought to determine whether clock-drawing also mediates the association between depressive symptoms and mortality.

PARTICIPANTS

Non-institutionalized Hispanic and non-Hispanic White elderly volunteers.

MEASUREMENTS

Survival curves were generated as a function of baseline depressive symptom ratings. Significant models were adjusted for CLOX performance. CLOX is divided into CLOX1, a measure of executive control, and CLOX2, a measure of visuospatial skills.

DESIGN

Retrospective analysis of three longitudinal cohorts.

RESULTS

CLOX2 and depressive symptoms were both associated with mortality in unadjusted models. CLOX2 predicted survival independently of CLOX1 in all three cohorts. CLOX2 also attenuated, and/or mediated the association between depressive symptoms and mortality. These results withstood adjustment for age and education in all three cohorts.

CONCLUSION

Regardless of the sample examined, or the measure of depressive symptoms applied, the association between depressive symptoms and mortality appears to be at least partially mediated by visuospatial skills. This finding supports our hypothesis that right hemisphere structural brain disease, particularly that involving the insula, may mediate depression's effects on mortality.

A prospective study of PTSD and early-age heart disease mortality among Vietnam veterans: implications for surveillance and prevention

OBJECTIVE

To examine prospectively early-age heart disease (HD) among a national random sample of 4328 male Vietnam veterans, who did not have HD at baseline in 1985. Studies have suggested that posttraumatic stress disorder (PTSD) may result in cardiovascular disease. However, many past studies had important methodological limitations to their designs.

METHOD

Using Cox regressions, we assessed PTSD, age, race, intelligence, family history, obesity, smoking, alcohol abuse, antisocial personality, and depression in predicting HD mortality at follow-up in December 31, 2000. The men were <65 years old at follow-up.

RESULTS

Using two PTSD measures, a Diagnostic and Statistical Manual of Mental Disorders, 3rd Edition (DSM-III) measure (D-PTSD) and one developed by Keane (K-PTSD), we found that among Vietnam theater and era veterans combined (era veterans had no Vietnam service), having PTSD was associated with HD mortality for D-PTSD (hazard ratio (HR) = 2.25, p = .045) and approached significance for K-PTSD (HR = 2.16, p = .066). However, having higher PTSD symptoms on either scale was associated with mortality, with a 5-point increase associated with approximately 20% increase in mortality risk (all p < .05). Controlling for lifetime depression only slightly altered the results. The effects for theater veterans alone were stronger (D-PTSD: HR = 2.58, p = .025; K-PTSD: HR = 2.73, p = .022). Among theater veterans, controlling for lifetime depression or combat exposure made little difference.

CONCLUSION

PTSD was prospectively associated with HD mortality among veterans free of HD at baseline. This study suggests that early-age HD may be an outcome after military service among PTSD-positive veterans.

Baseline 6-min walk distance predicts survival in lung transplant candidates

In a large, prospectively followed, two-center cohort of patients listed for lung transplantation (n = 376), we used Cox proportional hazards models to determine the importance of baseline 6-min walk distance (6MWD) in predicting patient survival. 6MWD used as a continuous variable was a significant predictor of survival after adjusting for other important covariates when transplant was considered as a time-varying covariate (HR for each 500 ft increase in 6MWD = 0.57, 95% CI: 0.43-0.77, p = 0.0002). 6MWD remained an important predictor of survival in models that considered only survival to transplant (HR for each 500 ft increase in 6MWD = 0.41, 95% CI: 0.27-0.62, p < 0.0001) or survival only after transplant (HR for each 500 ft increase in 6MWD = 0.40, 95% CI: 0.22-0.72, p = 0.002). Unadjusted Kaplan-Meier analysis demonstrates significantly different survival by 6MWD tertiles (<900, 900-1200, or >1200 ft, p-value = 0.0001). In the overall model, 6MWD prediction of survival was relatively homogeneous across disease category (6MWD by disease interaction term, p-value = 0.63). Our results demonstrate a significant relationship between baseline 6MWD and survival among patients listed for lung transplantation that exists across all native disease categories and extends through transplantation. The 6MWD is thus a useful measure of both urgency and utility among patients awaiting lung transplantation.

Modeling time variant distributions of cellular lifespans: increases in circulating reticulocyte lifespans following double phlebotomies in sheep

Many pharmacodynamic (PD) models of cellular response assume a single and time invariant lifespan of all cells, despite the existence of a true underlying distribution of cellular lifespans and known changes in the lifespan distributions with time. To account for these features of cellular populations, a time variant cellular lifespan distribution PD model was formulated and theoretical aspects of modeling cellular populations presented. The model extends prior work assuming time variant "point distributions" of cellular lifespans (Freise et al. J Pharmacokinet Pharmacodyn 34:519-547, 2007) and models assuming a time invariant lifespan distribution (Krzyzanski et al. J Pharmacokinet Pharmacodyn 33:125-166, 2006). The formulated time variant lifespan distribution model was fitted to endogenous plasma erythropoietin (EPO), reticulocyte, and red blood cell (RBC) concentrations in sheep phlebotomized on two occasions, 8 days apart. The time variant circulating reticulocyte lifespan was modeled as a truncated and scaled Weibull distribution, with the location parameter of the distribution non-parametrically represented by an end constrained quadratic spline function. The formulated time variant lifespan distribution model was compared to the identical time invariant distribution, time variant "point distribution", and time invariant "point distribution" cellular lifespan models. Parameters of the time variant lifespan distribution model were well estimated with low standard errors. The mean circulating reticulocyte lifespan was estimated at 0.304 days, which rapidly increased over 3-fold following the first phlebotomy to a maximum of 1.03 days (P = 0.009). On average, the percentage of erythrocytes being released as reticulocytes maximally increased an estimated two-fold following the phlebotomies. The primary features of immature RBC physiology were captured by the model and gave results consistent with other estimates in sheep and humans. The comparison of the four lifespan models gave similar parameter estimates of the stimulation function and fits to the RBC data. However, the time invariant models fit the reticulocyte data poorly, while the time variant "point distribution" cellular lifespan model gave physiologically unrealistic estimates of the changes in the circulating reticulocyte lifespan under stress erythropoiesis. Thus the underlying physiology must be considered when selecting the most appropriate cellular lifespan model and not just the goodness-of-fit criteria. The proposed PD model and the numerical implementation allows for a flexible framework to incorporate time variant lifespan distributions when modeling populations of cells whose production or stimulation depends on endogenous growth factors and/or exogenous drugs.

High tumour islet macrophage infiltration correlates with improved patient survival but not with EGFR mutations, gene copy number or protein expression in resected non-small cell lung cancer

The purpose of this study was to investigate the prognostic value of tumour-associated macrophages with a focus on micro-anatomical localisation and determine whether molecular changes of the epidermal growth factor receptor (EGFR) are related to macrophage infiltration in resected non-small cell lung cancer (NSCLC). One hundred and forty-four patients were included in this study. Immunohistochemistry was used to identify CD68+ macrophages in the tumour islet and surrounding stroma. Epidermal growth factor receptor mutations were studied by direct sequencing. The EGFR gene copy number and protein expression were analysed by fluorescence in situ hybridisation and immunohistochemistry. Patients with a high tumour islet macrophage density survived longer than did the patient with a low tumour islet macrophage density (5-year overall survival rate was 63.9 vs 38.9%, P=0.0002). A multivariate Cox proportional hazard analysis revealed that the tumour islet macrophage count was an independent prognostic factor for survival (hazard ratio 0.471, 95% confidence interval 0.300-0.740). However, EGFR mutations, gene copy number, and protein expression were not related to the macrophage infiltration. In conclusion, tumour islet macrophage infiltration was identified as a strong favourable independent prognostic marker for survival but not correlated with the molecular changes of the EGFR in patients with resected NSCLC.

Combined hepatocellular cholangiocarcinomas; analysis of a large database

Aim:

Combined hepatocellular cholangiocarcinoma (combined tumor) has been described as either a variant of hepatoma or a variant of cholangiocarcinoma. Prior studies evaluated fewer than 50 patients with combined tumors, precluding multivariate analyses. Posited was the notion that analysis of a large database would yield more definite answers.

Methods:

This study used SEER (Surveillance, Epidemiology, and End Results Program of the National Cancer Institute) to analyze 282 combined tumors, 2,035 intrahepatic cholangiocarcinomas, and 19,336 hepatomas between the years 1973–2003. Multinomial logit regression calculated point estimates and 95% confidence intervals (c.i.) for relative risk (rr). Cox regression calculated point estimates and 95% confidence intervals (c.i.) for hazard ratios (ĥ).

Results:

Men less often had cholangiocarcinomas than they had combined tumors (rr = 0.63, c.i. = 0.49–0.81). Hepatomas less often than combined tumors presented with distant spread (rr = 0.56, c.i. = 0.43–0.72). Men (rr = 1.50, c.i. = 1.17–1.93) and patients with a known Asian or Pacific birthplace (rr = 2.36, c.i. = 1.56–3.56) more often had hepatomas than they had combined tumors. Among patients not known to have an Asian/Pacific birthplace, a diagnosis of cholangiocarcinoma (ĥ = 0.72, c.i. = 0.63–0.82) or hepatoma (ĥ = 0.75, c.i. = 0.66–0.86) provided a better prognosis than did a diagnosis of combined tumor.

Conclusion:

Combined tumors differ from hepatomas and cholangiocarcinomas in terms of distribution and survival patterns in the population; they should be considered neither cholangiocarcinomas nor hepatomas.

Mexiletine therapy for chronic pain: survival analysis identifies factors predicting clinical success

Mexiletine, a sodium channel blocker, treats neuropathic pain but its clinical value has been questioned due to its significant side effects and limited efficacy. We hypothesized that ongoing therapy with mexiletine would have limited patient acceptance, but that an analgesic response to intravenous (IV) lidocaine (a pharmacologically similar drug) would identify patients most likely to choose ongoing therapy with mexiletine. We identified a cohort of 37 patients with neuropathic pain who underwent IV lidocaine infusions at our institution and were subsequently prescribed mexiletine. Time until discontinuation of mexiletine was used as the primary endpoint. Time until discontinuation is a clinically relevant, discrete, objective endpoint gaining acceptance as a metric for assessing clinical performance of drugs with significant side effects and limited efficacy. We used the techniques of survival analysis to determine factors that predicted continued therapy with mexiletine. Median time to discontinuation of mexiletine was only 43 days. A stronger analgesic response to IV lidocaine significantly predicted continued acceptance of mexiletine therapy. Decreasing age and male gender also predicted continued acceptance of mexiletine therapy. Analyzing time to mexiletine discontinuation uncovers important limitations in mexiletine's clinical performance missed by studies with conventional endpoints, such as change in pain score. Despite claims of efficacy, acceptance of mexiletine therapy is poor overall. Test infusions with lidocaine identify patients most likely to continue mexiletine therapy. Further work is needed to confirm these results and evaluate the relative acceptance of mexiletine vs. other treatments of neuropathic pain.

Investigating the long-term influence of adolescent delinquency on drug use initiation

Prior research has found a positive relationship between delinquency and early onset of drug use. However, little is known about the influence of delinquency on drug initiation through mid-adulthood. This paper investigates the long-term relationship between serious adolescent delinquency and the onset of marijuana and cocaine use among an epidemiologically defined community sample of African American males and females followed from first grade through age 42. Using propensity score methods we match individuals on several etiological variables that may explain both delinquency and drug use in an attempt to examine the extent to which there may be a causal link between delinquency and drug use initiation. Through a comparison of survival curves on the unmatched and matched samples of serious delinquents and non-serious delinquents, we find that serious adolescent delinquency has at least some causal influence on drug use initiation that extends into mid-life. We discuss how these results can inform future research and delinquency and drug prevention and intervention initiatives.

CURRENT STATUS DATA WITH COMPETING RISKS: LIMITING DISTRIBUTION OF THE MLE

We study nonparametric estimation for current status data with competing risks. Our main interest is in the nonparametric maximum likelihood estimator (MLE), and for comparison we also consider a simpler 'naive estimator'. Groeneboom, Maathuis and Wellner [8] proved that both types of estimators converge globally and locally at rate n(1/3). We use these results to derive the local limiting distributions of the estimators. The limiting distribution of the naive estimator is given by the slopes of the convex minorants of correlated Brownian motion processes with parabolic drifts. The limiting distribution of the MLE involves a new self-induced limiting process. Finally, we present a simulation study showing that the MLE is superior to the naive estimator in terms of mean squared error, both for small sample sizes and asymptotically.

Bayesian Weibull tree models for survival analysis of clinico-genomic data

An important goal of research involving gene expression data for outcome prediction is to establish the ability of genomic data to define clinically relevant risk factors. Recent studies have demonstrated that microarray data can successfully cluster patients into low- and high-risk categories. However, the need exists for models which examine how genomic predictors interact with existing clinical factors and provide personalized outcome predictions. We have developed clinico-genomic tree models for survival outcomes which use recursive partitioning to subdivide the current data set into homogeneous subgroups of patients, each with a specific Weibull survival distribution. These trees can provide personalized predictive distributions of the probability of survival for individuals of interest. Our strategy is to fit multiple models; within each model we adopt a prior on the Weibull scale parameter and update this prior via Empirical Bayes whenever the sample is split at a given node. The decision to split is based on a Bayes factor criterion. The resulting trees are weighted according to their relative likelihood values and predictions are made by averaging over models. In a pilot study of survival in advanced stage ovarian cancer we demonstrate that clinical and genomic data are complementary sources of information relevant to survival, and we use the exploratory nature of the trees to identify potential genomic biomarkers worthy of further study.

The relationship between the Dimensions of Change Instrument and retention in therapeutic community treatment: the moderating influence of time in treatment

OBJECTIVES

The Dimensions of Change Instrument (DCI) (1) assesses aspects of the therapeutic community treatment process. More positive scores on two of the eight dimensions of treatment process assessed at the beginning of treatment, Clarity and Safety, and Resident Support, Sharing and Enthusiasm predict retention in treatment at 30, 90, 180, and 270 days as well as overall length of stay. This study explored whether these process subscales assessed at different phases predicted retention at the next phase, and of treatment.

METHODS

Five-hundred nineteen individuals, aged 18 to 62, undergoing therapeutic community treatment completed the DCI at baseline, one, three, six, and nine months of the therapeutic community treatment.

RESULTS

DCI scale scores at each stage of treatment predicted dropout in the subsequent period. In the early stages of treatment, higher scores predicted a higher probability of retention in the subsequent stage of treatment. In later stages, lower DCI scores predicted a higher probability of retention.

CONCLUSIONS

We conclude that predictions about retention made using the DCI scale scores are treatment stage dependent--the DCI predicts retention at the next stage but the direction of the scale prediction varies as a function of client tenure in treatment. This suggests that treatment processes that influence clients to remain early in treatment may change their valence for clients more advanced in treatment.

The TandemHeart as a bridge to a long-term axial-flow left ventricular assist device (bridge to bridge)

End-stage heart-failure patients in acute refractory cardiogenic shock with multi-organ dysfunction require aggressive medical therapy that includes inotropic support. Historically, the intra-aortic balloon pump was the last option for patients who were dying of acute cardiogenic shock. Short-term extracorporeal pulsatile or nonpulsatile cardiac assist devices or extracorporeal membrane oxygenation offered further treatment options; however, these therapies required invasive surgical procedures. Patients in this high-risk group had increased mortality rates from major procedures that required cardiopulmonary bypass. We used the TandemHeart, a percutaneously implanted device for short-term cardiac assistance, to lower the risk of death and improve hemodynamic performance and end-organ perfusion before implanting long-term assist devices in selected patients with signs of profound cardiogenic shock. Nine end-stage heart-failure patients (mean age, 37.7 yr) in acute refractory hemodynamic decompensation received a percutaneously implanted TandemHeart pump as a bridge to an implantable axial-flow pump. To determine the relative risk for these patients, prognostic scores were calculated before and after insertion of the TandemHeart. Percutaneous support times ranged from 1 to 22 days (mean, 5.9 d). The mean cardiac index before support, 1.02 L/(min.m2) (range, 0.0-1.8 L/[min.m2]) (0.0 L/[min.m2] implies active cardiopulmonary resuscitation), improved to 2.97 L/(min.m2) (range, 2.2-4.0 L/[min.m2]) during support. Three patients underwent successful cardiac transplantation; 5 are currently supported by axial-flow pumps; and 1 died of complications unrelated to the axial-flow pump, after 587 days. End-organ function and overall condition improved uniformly in our patients, thus decreasing the preoperative risk factors for implantation of the long-term device.

SEMIPARAMETRIC TRANSFORMATION MODELS WITH RANDOM EFFECTS FOR CLUSTERED FAILURE TIME DATA

We propose a general class of semiparametric transformation models with random effects to formulate the effects of possibly time-dependent covariates on clustered or correlated failure times. This class encompasses all commonly used transformation models, including proportional hazards and proportional odds models, and it accommodates a variety of random-effects distributions, particularly Gaussian distributions. We show that the nonparametric maximum likelihood estimators of the model parameters are consistent, asymptotically normal and asymptotically efficient. We develop the corresponding likelihood-based inference procedures. Simulation studies demonstrate that the proposed methods perform well in practical situations. An illustration with a well-known diabetic retinopathy study is provided.

The influence of legal coercion on dropout from substance abuse treatment: results from a national survey

Legal coercion is frequently used to leverage substance abuse treatment upon persons who would otherwise not seek it voluntarily. Various methodological and conceptual problems of the existing research have prevented a clear understanding of its effectiveness. The influence of legal coercion on retention in substance abuse treatment was examined using a national survey of programs in the public sector of care and three different treatment modalities including short-term residential (N=756), long-term residential (N=757), and outpatient treatment (N=1181). Legal coercion was found to reduce the risk of dropout across all three treatment modalities. The greatest effect was among persons in short-term residential treatment. The smallest effect was observed in outpatient treatment. This study shows that legal coercion significantly reduces the risk of dropout in substance abuse treatment. However, the differential effects across treatment conditions must be carefully considered when using coercion to involve individuals in treatment.

New use of teflon to reduce bleeding in modified bentall operation

We analyzed the postoperative short- and mid-term outcomes of a series of patients with annuloaortic ectasia who underwent a modified Bentall operation in our clinic from September 2000 through March 2006. The study included 44 patients. Their average age was 53.4 +/- 14.1 years. The underlying disease was degenerative aortic aneurysm in 42 patients (95.5%) and acute aortic dissection in 2 patients (4.5%). Six patients (13.6%) had Marfan phenotype. Aortic insufficiency was moderate in 30 patients (68.2%) and severe in 14 patients (31.8%). In our modification of the Bentall technique, we completed the resection of the aortic root while leaving 5 to 10 mm of native aortic wall tissue to support the anastomosis. A long piece of Teflon felt (width, 0.5-1 cm) was laid on the annulus, and nonpledgeted 2-0 polyester sutures were passed in turn through the Teflon felt, the preserved aortic tissue, and the aortic annulus. A thin piece of Teflon felt was also used in the coronary artery reimplantation sites. Fibrin glue was routinely applied to all anastomoses. There were no intraoperative deaths. One patient died in the hospital after surgery for acute type I aortic dissection. Another patient died 1 year after the operation from prosthetic-valve endocarditis. No patient required surgical correction of excessive postoperative bleeding. Kaplan-Meier curves showed overall survival of 0.94 (95% confidence intervals, 0.9-0.99). We consider our approach an easy, effective way to minimize bleeding from the anastomoses and at the aortic root--a common challenge in aortic surgery.

Model-based estimation of the link between the daily survival probability and a time-varying covariate, application to mosquitofish survival data

The survival probability in a group of individuals may evolve in time due to the influence of a time-varying covariate. In this paper we present a model-based approach allowing the estimation of the functional link between the survival probability and a time-varying covariate when data are grouped and time-period censored. The approach is based on an underlying model consisting in non-stationary Markov processes and describing the survival of individuals. The underlying model is aggregated in time and at the group level to handle the group structure of data and the censoring. The aggregation yields a generalized non-linear mixed model. Then, a Bayesian procedure allows the estimation of the model parameters and the description of the link between the survival probability and the time-varying covariate. This approach is applied in order to explore the relationship between the daily survival probability of mosquitofish (Gambusia holbrooki) and their time-varying lengths (small mosquitofish die with a higher rate than large ones because they are more affected by predation, cannibalism and environmental stress).

Combining clinical and genomic covariates via Cov-TGDR

Clinical covariates such as age, gender, tumor grade, and smoking history have been extensively used in prediction of disease occurrence and progression. On the other hand, genomic biomarkers selected from microarray measurements may provide an alternative, satisfactory way of disease prediction. Recent studies show that better prediction can be achieved by using both clinical and genomic biomarkers. However, due to different characteristics of clinical and genomic measurements, combining those covariates in disease prediction is very challenging. We propose a new regularization method, Covariate-Adjusted Threshold Gradient Directed Regularization (Cov-TGDR), for combining different type of covariates in disease prediction. The proposed approach is capable of simultaneous biomarker selection and predictive model building. It allows different degrees of regularization for different type of covariates. We consider biomedical studies with binary outcomes and right censored survival outcomes as examples. Logistic model and Cox model are assumed, respectively. Analysis of the Breast Cancer data and the Follicular lymphoma data show that the proposed approach can have better prediction performance than using clinical or genomic covariates alone.

Application of artificial neural network-based survival analysis on two breast cancer datasets

This paper applies artificial neural networks (ANNs) to the survival analysis problem. Because ANNs can easily consider variable interactions and create a non-linear prediction model, they offer more flexible prediction of survival time than traditional methods. This study compares ANN results on two different breast cancer datasets, both of which use nuclear morphometric features. The results show that ANNs can successfully predict recurrence probability and separate patients with good (more than five years) and bad (less than five years) prognoses. Results are not as clear when the separation is done within subgroups such as lymph node positive or negative.

Survival analysis of Korean end-stage renal disease patients according to renal replacement therapy in a single center

This study was to investigate clinical characteristics and any differential trends in survival among renal replacement therapy (hemodialysis [HD], peritoneal dialysis [PD], and kidney transplantation [KT]) in Korean end-stage renal disease (ESRD) population. We tried to analyze retrospectively the survival rate adjusted by risk factors and the relative risk stratified by key risk factors among 447 ESRD patients who began dialysis or had a kidney transplant at Ajou University Hospital from 1994 to 2004. In adjusted Cox survival curves, the KT patients had the best survival rate, and the HD patients had better survival than PD patients. The consistent trends in different subgroups stratified by age and diabetes were as following: 1) The risk of death for PD and HD was not proportional over time, 2) The relative risk of PD was similar or lower than that of HD for the first 12 months, but it became higher at later period. The significant predictors for mortality were age (over 55 yr), presence of diabetes, cerebrovascular accident at ESRD onset, and more than one time of hospitalization caused by malnutrition. Further large-scaled, multicenter-based comparative study is needed in Korean ESRD patients and more meticulous attention is required in high-risk patients.

Left ventricular aneurysmal repair within 30 days after acute myocardial infarction: early and mid-term outcomes

For safe resection, left ventricular aneurysmal repair after acute myocardial infarction is usually delayed. However, delaying surgery may not be possible or prudent in some patients who are clinically unstable after acute myocardial infarction. We retrospectively reviewed the early and mid-term outcomes of left ventricular aneurysmal repair in patients who had experienced acute myocardial infarction <30 days before the repair. From September 2001 through May 2006, 127 consecutive post-infarction patients underwent concurrent anteroapical left ventricular aneurysmal repair and coronary artery bypass grafting. In Group I (38 clinically unstable patients), the surgery was performed <30 days after myocardial infarction. In Group II, 89 patients underwent the surgery > or = 30 days after infarction. The mean follow-up period was 26.16 +/- 16.41 months. One Group I patient (2.6%) died in the hospital due to graft-versus-host reaction. Three Group II patients (3.4%) died: 2 of low cardiac output and 1 of multiple-organ failure. Hospital mortality rates were not statistically significant between groups (P=0.582). All patients required similar perioperative inotropic support, intra-aortic balloon pump support, and re-exploration for bleeding or cardiac tamponade. The actuarial survival rates were 94.7% (Group I) and 94.4% (Group II). Postoperative New York Heart Association functional class improved similarly in both groups. We infer that left ventricular aneurysmal repair with coronary revascularization < 30 days after a recent myocardial infarction is a feasible procedure, with acceptable morbidity and mortality rates. Our mid-term results were comparable with those for patients who underwent this surgery > or = 30 days after acute myocardial infarction.

Clinical overview of extrapulmonary small cell carcinoma

The objective of this study was to review the natural history of extrapulmonary small cell carcinoma (EPSCC) with specific emphasis on clinical features, response to treatment and survival. The records of all patients (n=34) with EPSCC treated at Yeungnam University Medical Center and Catholic University of Daegu Medical Center between 1998 and 2005 were retrieved and reviewed. The primary sites of tumor were the esophagus and thymus in 6 patients (17.6%) each, pancreas and stomach in 5 patients each (14.7%); other sites included were the cervix, abdominal lymph nodes, abdominal wall, bladder, colon, maxillary sinus, nasal cavity, ovary, parotid gland and liver. Twenty three patients out of 34 had limited disease. The median survival of all patients was 14 months. Independent prognostic factors included stage and primary tumor location. The prognosis for the patients with extensive disease and in the gastrointestinal group was unfavorable. EPSCC is a non homogeneous disease entity. As a result of its frequent recurrence, multimodal therapy has a better outcome even in cases of limited disease. Combination chemotherapy plays a central role for treatment of extensive disease in EPSCC. Further multicenter studies are now needed to determine more details regarding disease sub-class and optimal treatment modality.

Survival probability in ataxia telangiectasia

Ataxia telangiectasia is a rare, multiorgan neurodegenerative disorder with enhanced vulnerability to cancer and infection. Median survival in two large cohorts of patients with this disease, one prospective and one retrospective, is 25 and 19 years, with a wide range. Life expectancy does not correlate well with severity of neurological impairment.

Prognostic relevance of census-derived individual respondent incomes versus household incomes

BACKGROUND

Census-based measures of income derived from median income of a geographic area are often used in health research. Many national census surveys gather information on both the respondent's individual income and the income for the entire household, giving researchers a choice of census income measures. We compared the extent to which individual respondent income and household income (both obtained from census data) are associated with outcomes in a cohort of patients with cardiac disease.

METHODS

We used data from the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH), where postal codes were linked to the Postal Code Conversion File (PCCF) to determine each patient's census Dissemination Areas (DA). DA-derived median household income and median individual income were obtained from the 2001 Canadian Census and survival outcomes were then directly determined for income groupings defined by quintile. Two-year survival adjusted for age and sex was described with a proportional hazards analysis.

RESULTS

There were 9,397 patients undergoing cardiac catheterization between January 1, 2001 and March 31, 2002, with complete DA-level median income measures. Household income quintiles yielded a wider spread of survival across quintiles (range of 2-year estimated survival, 91.8% to 95.9% for household income versus 92.8% to 95.6% for respondent income), as well as a more progressive decline in survival as income decreased. This progressive decline was not seen for the respondent income measure.

CONCLUSIONS

The greater spread and progressive decline of survival for household income relative to respondent income leads us to conclude that household income is the better socio-economic determinant of health in our data and for the outcome measure we studied.

The Timing of Entry Into Fatherhood in Young, At-Risk Men

Timing of first fatherhood was examined in a sample of 206 at-risk, predominantly White men, followed prospectively for 17 years. An event history analysis was used to test a model wherein antisocial behavior, the contextual and familial factors that may contribute to the development of antisocial behavior, and common correlates of such behavior, including academic failure, substance use, and early initiation of sexual behaviors, lead both directly and indirectly to an early transition to fatherhood. Having a mother who was younger at first birth, low family SES, poor academic skills, failure to use condoms, and being in a cohabitating or marital relationship predicted entry into fatherhood. Implications of the findings for prevention of and intervention with early fathering are discussed.

Effect of canopy position on germination and seedling survival of epiphytic bromeliads in a Mexican humid montane forest

BACKGROUND AND AIMS

Seeds of epiphytes must land on branches with suitable substrates and microclimates to germinate and for the resulting seedlings to survive. It is important to understand the fate of seeds and seedlings in order to model populations, but this is often neglected when only established plants are included in analyses.

METHODS

The seeds of five bromeliad species were exposed to different canopy positions in a Mexican montane forest, and germination and early seedling survival were recorded. Additionally, the survival of naturally dispersed seedlings was monitored in a census over 2.5 years. Survival analysis, a procedure rarely used in plant ecology, was used to study the influence of branch characteristics and light on germination and seedling survival in natural and experimental populations.

KEY RESULTS

Experimental germination percentages ranged from 7.2 % in Tillandsia deppeana to 33.7 % in T. juncea, but the seeds of T. multicaulis largely failed to germinate. Twenty months after exposure between 3.5 and 9.4 % of the seedlings were still alive. There was no evidence that canopy position affected the probability of germination, but time to germination was shorter in less exposed canopy positions indicating that higher humidity accelerates germination. More experimental seedlings survived when canopy openness was high, whereas survival in census-seedlings was influenced by moss cover. While mortality decreased steadily with age in juveniles of the atmospheric Tillandsia, in the more mesomorphic Catopsis sessiliflora mortality increased dramatically in the dry season.

CONCLUSIONS

Seedling mortality, rather than the failure to germinate, accounts for the differential distribution of epiphytes within the canopy studied. With few safe sites to germinate and high seedling mortality, changes of local climate may affect epiphyte populations primarily through their seedling stage.

Is herpes zoster a marker for occult or subsequent malignancy?

BACKGROUND

It has been suggested that herpes zoster may be a marker for occult malignancy.

AIM

To examine the emergence of a subsequent cancer diagnosis in patients with and without herpes zoster.

DESIGN OF STUDY

Retrospective cohort study.

SETTING

Results were based on the database of Intego, an ongoing Belgian general practice-based morbidity registry, covering 37 general practitioners and including about 311 000 patient years between the years 1994 and 2000.

METHOD

Survival analysis comparing the emergence of malignancy in patients with and without herpes zoster.

RESULTS

The number of patients below the age of 65 years with herpes zoster, cancer or both was too low to draw any sensible conclusions. Above the age of 65 years we identified a significant increase of cancer emergence in the whole group and in females (hazard ratio = 2.65, 95% confidence interval = 1.43 to 4.90), but not in males. No difference could be identified in the first year after the herpes zoster infection.

CONCLUSION

Our results do not justify extensive testing for cancer in herpes zoster patients. The association we identified, however, leaves open a number of questions with respect to the physiopathology behind it.

Assessing lung cancer risk in railroad workers using a first hitting time regression model

This article examines the application of a first hitting time (FHT) model, using an operational time scale, to assess mortality risk differentials of the work environment. A major case application is presented that applies the model to three job categories of railroad workers. The data set involves a study of more than 50 000 workers with mortality assessed from 1959 to 1996. Lung cancer mortality was assessed because of a suspected link to diesel exhaust exposure. Based on a model that stipulates that death occurs when the disease state of a subject first hits a threshold value, the FHT model provides insights into factors influencing disease progression. In this application, in particular, the findings suggest that a job category in 1959 alters the risk of death from lung cancer.

Transmyocardial laser revascularization as an adjunct to coronary artery bypass grafting: a randomized, multicenter study with 4-year follow-up

We evaluated transmyocardial laser revascularization (TMLR) with coronary artery bypass grafting (CABG) versus CABG alone for severe coronary artery disease involving 21 myocardial region unsuited for CABG. At 4 centers, 44 consecutive patients were randomized for CABG+TMLR (n = 23) or CABG alone (n = 21). Operative and in-hospital mortality and morbidity rates were monitored. Clinical status was evaluated at hospital discharge, 1 year, and 4 years. Success was characterized by relief of angina and freedom from repeat revascularization and death. Preoperatively, 20 patients (47%) were at high risk. The CABG technique, number of grafts, and target vessels were similar in both groups. Patients undergoing CABG+TMLR received 25 +/- 11 laser channels. Their < or = 30-day mortality was 13% (3/23) compared with 28% (6/21) after CABG alone (P = 0.21). There were no significant intergroup differences in the number of intraoperative or in-hospital adverse events. The follow-up period was 50.3 +/- 17.8 months for CABG alone and 48.1 +/- 16.8 months for CABG+TMLR. Both groups had substantially improved angina and functional status at 1 and 4 years, with no significant differences in cumulative 4-year mortality. The incidence of repeat revascularization was 24% after CABG alone versus none after CABG+TMLR (P < 0.05). The 4-year event-free survival rate was 14% versus 39%, respectively (P < 0.064). In conclusion, CABG+TMLR appears safe and poses no additional threat for high-risk patients. Improved overall success and repeat revascularization rates may be due to better perfusion of ischemic areas not amenable to bypass. Further studies are warranted to determine whether these trends are indeed significant.

Neoadjuvant chemotherapy for locally advanced cervix cancer

BACKGROUND

Despite the enrollment of more than 3000 women in randomised trials, the benefits and risks of neoadjuvant chemotherapy in the treatment of locally advanced cervical cancer remained uncertain.

OBJECTIVES

This systematic review and individual patient data (IPD) meta-analysis aimed to assess the effect of neoadjuvant chemotherapy in two comparisons: (1) neoadjuvant chemotherapy followed by radical radiotherapy compared to the same radiotherapy alone; and (2) neoadjuvant chemotherapy followed by surgery compared to radical radiotherapy alone.

SEARCH STRATEGY

Medline and CancerLit searches were supplemented with information from trial registers and by hand searching relevant meeting proceedings and by discussion with relevant trialists and organisations. These searches have been updated regularly until December 2002.

SELECTION CRITERIA

To be included, trials had to be properly randomised and had to include patients with locally advanced cervical cancer who had received neoadjuvant cytotoxic chemotherapy before radiotherapy or surgery or both treatments. Concurrent chemoradiotherapy trials were not included. The comparisons had to be unconfounded by use of additional agents or interventions. Patient enrollment should have started after 1 January 1975 and be completed by September 2000.

DATA COLLECTION AND ANALYSIS

We collected, validated and re-analysed updated trial data on all randomised patients from all relevant trials. Any queries were resolved and the final database entries verified by the responsible trial investigator, data manager or statistician. Two separate sets of analyses (by intention-to-treat) were carried out according to the treatment comparisons (1 and 2) already described. For all outcomes, we obtained overall pooled hazard ratios using the fixed effect model. To explore the potential impact of trial design, we pre-planned analyses that grouped trials by important aspects of their design that might influence the treatment effect. To investigate the effects of neoadjuvant chemotherapy within pre-specified subgroups of patients stratified logrank analyses were done on the primary endpoint of survival.

MAIN RESULTS

In the first comparison, we obtained data from 18 trials and 2074 patients. When all trials were considered together, a high level of statistical heterogeneity suggested that the results could not be combined indiscriminately. A substantial amount of heterogeneity was explained by separate analyses of groups of trials. Trials using chemotherapy cycle lengths shorter than 14 days (HR = 0.83, 95% CI = 0.69 to 1.00, p = 0.046) or cisplatin dose intensities greater than 25 mg/m2 per week (HR = 0.91, 95% CI = 0.78 to 1.05, p = 0.20) tended to show an advantage for neoadjuvant chemotherapy on survival. In contrast, trials using cycle lengths longer than 14 days (HR = 1.25, 95% CI = 1.07 to 1.46, p = 0.005) or cisplatin dose intensities lower than 25 mg/m2 per week (HR = 1.35, 95% CI = 1.11 to 1.14, p = 0.002) tended to show a detrimental effect of neoadjuvant chemotherapy on survival. In the second comparison, data from 5 trials and 872 patients were obtained. The combined results from all trials (HR = 0.65, 95% CI = 0.53 to 0.80, p = 0.0004) indicated a highly significant reduction in the risk of death with neoadjuvant chemotherapy, but there were some differences between trials in their design and results.

REVIEWERS' CONCLUSIONS

Despite some unexplained heterogeneity, the timing and dose intensity of cisplatin-based neoadjuvant chemotherapy appears to have an important impact on whether or not it benefits women with locally advanced cervical cancer and warrants further exploration.

Estimating the efficacy of interventions to prevent mother-to-child transmission of human immunodeficiency virus in breastfeeding populations: comparing statistical methods

Postnatal transmission of human immunodeficiency virus infection through breastfeeding complicates evaluating the efficacy of interventions aimed to reduce mother-to-child transmission risk. Results from trials in Africa evaluating either peripartum antiretroviral therapy or refraining from breastfeeding show an estimated long-term efficacy at 15-24 months of age between 25 and 50 percent. Differences in statistical methods, duration of follow-up, and age at weaning hinder direct comparison between trials. The authors recently outlined theoretically preferred statistical methods for evaluating interventions aimed to reduce risk of mother-to-child transmission of human immunodeficiency virus. When multiple test results and/or supplementary information is available, the more sophisticated methods account for the fact that exact age at infection is unknown, that risk for infection ends at weaning, or that censoring due to death may be informative. The authors apply these methods to four scenarios, using data from four randomized trials carried out in Africa between 1995 and 2000. The authors' findings suggest that, to estimate the cumulative proportion infected at age 6 weeks, a standard Kaplan-Meier approach is likely to give valid results. For estimation of this proportion at age 18 months, more sophisticated methods, such as the extension of the Kaplan-Meier procedure to interval-censored data and competing risks, would be preferred.