Extent of resection in the management of duodenal adenocarcinoma

BACKGROUND

It has been postulated that segmental duodenal resection (SR) is not an adequate operation for patients with adenocarcinoma of the duodenum and that pancreaticoduodenectomy (PD) is the procedure of choice, regardless of the tumor site. However, data from previous studies do not clearly support this position.

METHODS

We reviewed the records of 63 patients treated for duodenal adenocarcinoma from 1979 through 1998. Perioperative outcome, patient survival, and extent of lymphadenectomy were compared in patients who underwent PD and SR.

RESULTS

The overall morbidity for PD and SR was 27% and 18%, respectively (not significant [NS]). Patients who underwent SR had a 5-year survival of 60% versus 30% for patients who underwent PD (NS). Lymph node status was a prognostic factor for survival (P = 0.014). The mean number of lymph nodes in the specimens was 9.9 +/- 2.1 for PD and 8.3 +/- 4.4 for SR (NS).

CONCLUSIONS

Segmental duodenal resection for patients with duodenal adenocarcinoma is associated with acceptable postoperative morbidity and long-term survival. The procedure is especially well suited for distal duodenal tumors. Clearance of lymph nodes and outcome are comparable to PD.

Interictal Executive Dysfunction in Migraineurs Without Aura: Relationship With Duration and Intensity of Attacks

Subjects with migraine are at increased risk of subcortical white matter lesions (WML). Reports of cognitive testing in adults with migraine have yielded inconsistent results. We performed a cross-sectional study to assess whether migraine without aura (MwA) is associated with impairment in executive functioning, a typical cognitive correlate of subcortical WML. Forty-five subjects with MwA and 90 controls, matched for age and education, underwent a cognitive battery of tests evaluating executive functions. The following migraine characteristics were collected: age at onset and length of migraine history, and frequency, duration and intensity of attacks. Subjects with MwA performed significantly lower than controls in tests evaluating complex, multifactorial executive functions. After multiple adjustments, the duration and intensity of migraine attacks significantly predicted cognitive disturbances. In the interictal phase of MwA there is evidence of mild executive dysfunction. The cumulative effects of repeated migraine attacks on prefronto-cerebellar loop probably account for our results.

Association between apolipoprotein E epsilon4 allele and apathy in probable Alzheimer's disease

OBJECTIVE

There have been inconclusive results to date on the association between the Apolipoprotein E (ApoE) genotype and neuropsychiatric symptoms (NPS) in Alzheimer's disease (AD). We investigated whether ApoE epsilon4 allele is associated with NPS in probable AD.

METHOD

Data for 197 subjects with probable AD were analysed. The Neuropsychiatric Inventory was used to evaluate the frequency and severity of NPS. Multiple logistic regression models were used to test the association between ApoE genotype and NPS in AD.

RESULTS

The ApoE epsilon3/3 genotype was present in 52.3%, epsilon3/4 in 44.1%, and epsilon4/4 in 3.6% of patients. ApoE epsilon4 carriers showed a higher frequency of apathy than non-carriers. After multiple adjustments, the ApoE epsilon4 allele was significantly associated with apathy.

CONCLUSION

Our results suggest a relationship between the ApoE epsilon4 allele and apathy in patients with AD.

Linking excess mortality to mobility data during the first wave of COVID-19 in England and Wales

Non-pharmaceutical interventions have been implemented worldwide to curb the spread of COVID-19. However, the effectiveness of such governmental measures in reducing the mortality burden remains a key question of scientific interest and public debate. In this study, we leverage digital mobility data to assess the effects of reduced human mobility on excess mortality, focusing on regional data in England and Wales between February and August 2020. We estimate a robust association between mobility reductions and lower excess mortality, after adjusting for time trends and regional differences in a mixed-effects regression framework and considering a five-week lag between the two measures. We predict that, in the absence of mobility reductions, the number of excess deaths could have more than doubled in England and Wales during this period, especially in the London area. The study is one of the first attempts to quantify the effects of mobility reductions on excess mortality during the COVID-19 pandemic.

Modelling general patterns of digit preference

In many applications data can be interpreted as indirect observations of a latent distribution. A typical example is the phenomenon known as digit preference, i.e. the tendency to round outcomes to pleasing digits. The composite link model (CLM) is a useful framework to uncover such latent distributions. Moreover, when applied to data showing digit preferences, this approach allows estimation of the proportions of counts that were transferred to neighbouring digits. As the estimating equations generally are singular or severely ill-conditioned, we impose smoothness assumptions on the latent distribution and penalize the likelihood function. To estimate the misreported proportions, we use a weighted least-squares regression with an added L1 penalty. The optimal smoothing parameters are found by minimizing the Akaike’s information Criterion (AIC). The approach is verified by a simulation study and several applications are presented.

Prevalence of headache in patients with Behçet's disease without overt neurological involvement

The aims of the present study were to evaluate the prevalence of headache and the frequency of different headache syndromes in patients with Behçet's Disease (BD) without neurological involvement and to investigate the relationship with other clinical, and behavioural variables. Twenty-seven BD patients and 27 control subjects underwent a validated semistructured questionnaire based on the International Headache Society criteria. Levels of anxiety and depression, disease activity, and current medication were collected. Headache occurred in 88.9% of BD patients. There was no difference in the prevalence of the different headache syndromes between BD patients and controls. Only migraine without aura (MwA) was significantly more frequent in BD patients than controls (44.4% vs. 11.1%, respectively, P= 0.013). No relationship was found between MwA and clinical, and behavioural variables. Among headache syndromes, MwA showed the highest frequency in BD. A vascular or neuronal subclinical dysfunction could justify this association. A careful interview for migraine might be included in the diagnostic work-up of BD.

Sums of smooth exponentials to decompose complex series of counts

Representing the conditional mean in Poisson regression directly as a sum of smooth components can provide a realistic model of the data generating process. Here, we present an approach that allows such an additive decomposition of the expected values of counts. The model can be formulated as a penalized composite link model and can, therefore, be estimated by a modified iteratively weighted least-squares algorithm. Further shape constraints on the smooth additive components can be enforced by additional penalties, and the model is extended to two dimensions. We present two applications that motivate the model and demonstrate the versatility of the approach.

Regional disparities in Canadian adult and old-age mortality: A comparative study based on smoothed mortality ratio surfaces and age at death distributions

This paper examines adult and old-age mortality differentials in Canada between 1930 and 2007 at the provincial level, using theCanadian Human Mortality Database and the flexible smoothing P-spline method in two-dimensions well-suited to the study of smallpopulations. Our analysis reveals that provincial disparities in adult mortality in general, and among the elderly population in particular,are substantial in Canada. Moreover, based on the modal age at death and the standard deviation of ages at death above the mode,provincial disparities at older ages have barely reduced over time, despite the great mortality improvements in all provinces since the early 20th century. In the last few years studied, evidence of the shifting mortality regime was found among females in most Western and Central provinces, while all males were still undergoing an old-age mortality compression regime.

Smoothing, Decomposing and Forecasting Mortality Rates

The Lee-Carter (LC) model represents a landmark paper in mortality forecasting. While having been widely accepted and adopted, the model has some limitations that hinder its performance. Some variants of the model have been proposed to deal with these drawbacks individually, none coped with them all at the same time. In this paper, we propose a Three-Component smooth Lee-Carter (3C-sLC) model which overcomes many of the issues simultaneously. It decomposes mortality development into childhood, early-adult and senescent mortality, which are described, individually, by a smooth variant of the LC model. Smoothness is enforced to avoid irregular patterns in projected life tables, and complexity in the forecasting methodology is unaltered with respect to the original LC model. Component-specific schedules are considered in projections, providing additional insights into mortality forecasts. We illustrate the proposed approach to mortality data for ten low-mortality populations. The 3C-sLC captures mortality developments better than a smooth improved version of the LC model, and it displays wider prediction intervals. The proposed approach provides actuaries, demographers, epidemiologists and social scientists in general with a unique and valuable tool to simultaneously smooth, decompose and forecast mortality.

Effects of levodopa oral bolus on the kinematics of the pointing movements in Parkinson's disease patients

We studied the time-course of a levodopa oral bolus effects on the kinematics of patients affected by a mild akinetic-rigid form of idiopathic Parkinson's disease (PD). Eleven PD patients were evaluated: a) in OFF-state, that is before their first medication or after its withdrawal, b) in ON-state, that is at 1/2, 1, 2, 3, 4, 5, 6, 24, 30 and 48 hours after the administration of 250 mg of levodopa plus 25mg of carbidopa. The main kinematics (i. e.movement time, peak of velocity, peak of acceleration and peak of deceleration) of pointing movements to six target-stimuli placed on the horizontal plane of a table were recorded. Clinical conditions were assessed according to the Motor Examination section of the Unified Parkinson's Disease Rating Scale. The levopoda bolus had stable clinical effects only within the first six hours from its administration. The decline of the clinical response was marked by the changes of peak acceleration whereas other kinematics (i. e. movement time and the peak of velocity) changed also in the late observations (24, 30 and 48 hours after drug intake). The dissociation between the persistent improvement on movement time on peak velocity and the rapid deterioration of levodopa effects on early kinematics (i. e. peak acceleration) could be accounted for by a progressive decline in movement programming.

The curse of the plateau. Measuring confidence in human mortality estimates at extreme ages

In recent years, the importance of describing mortality at the limits of the life span has led to a number of relevant and controversial studies. Whereas considerable efforts have been devoted to collecting data and estimating models on the oldest-old individuals, the testing of statistical confidence about the conclusions of analyses at extreme ages has been largely neglected. How certain can we be in saying that the risk of dying increases, levels out, or, paradoxically, decreases over age 105? Can we recognize particular mortality age patterns at such high ages? In this paper, it is shown that very little can be confidently asserted about mortality at extreme ages. Instead of analysing actual data, we perform a series of simulation studies mimicking actual scenarios from controlled mechanisms. Our findings are thus robust with respect to factors such as particular observation schemes, heterogeneity, and data quality issues. Given the sample sizes currently available and the levels of mortality experienced in present populations, we show that before age 110, only a Gompertzian increase of mortality may be detected. Afterwards a plateau will be regularly recognized as the most suitable pattern, regardless of the complexity of the true underlying mortality.

Cohort-based smoothing methods for age-specific contact rates

The use of social contact rates is widespread in infectious disease modeling since it has been shown that they are key driving forces of important epidemiological parameters. Quantification of contact patterns is crucial to parameterize dynamic transmission models and to provide insights on the (basic) reproduction number. Information on social interactions can be obtained from population-based contact surveys, such as the European Commission project POLYMOD. Estimation of age-specific contact rates from these studies is often done using a piecewise constant approach or bivariate smoothing techniques. For the latter, typically, smoothness is introduced in the dimensions of the respondent's and contact's age (i.e., the rows and columns of the social contact matrix). We propose a smoothing constrained approach-taking into account the reciprocal nature of contacts-introducing smoothness over the diagonal (including all subdiagonals) of the social contact matrix. This modeling approach is justified assuming that when people age their contact behavior changes smoothly. We call this smoothing from a cohort perspective. Two approaches that allow for smoothing over social contact matrix diagonals are proposed, namely (i) reordering of the diagonal components of the contact matrix and (ii) reordering of the penalty matrix ensuring smoothness over the contact matrix diagonals. Parameter estimation is done in the likelihood framework by using constrained penalized iterative reweighted least squares. A simulation study underlines the benefits of cohort-based smoothing. Finally, the proposed methods are illustrated on the Belgian POLYMOD data of 2006. Code to reproduce the results of the article can be downloaded on this GitHub repository https://github.com/oswaldogressani/Cohort_smoothing.

Estimating transition coefficients for reconstructing coherent series of mortality by cause of Death

Regular revisions of the classification of diseases and the consequent disruptions of mortality series are well-known issues in long-term cause-of-death analysis. Given basic assumptions and medical knowledge about possible exchanges across causes of death in the revision years, redistribution of counts of causes of death into a new classification can be viewed as a constrained optimization problem. Penalized likelihood within a quadratic programming framework allows estimation of exchanges that vary smoothly over age groups. The approach is illustrated using both German data on malignant neoplasms and French data on heart diseases.

Reassessing socioeconomic inequalities in mortality via distributional similarities

Commonly used measures of socioeconomic inequalities in mortality, such as the slope and the relative index of inequality, are based on summary measures of the group-specific age-at-death distributions (e.g. standardized mortality rate or life expectancy). While this approach is informative, it ignores valuable information contained in the group-specific distributions. A recent approach applied a measure of distributional dissimilarity (the non-overlap index) to measure lifespan stratification. In this paper, we rigorously evaluate and further implement the multi-group extension of the non-overlap index ( S P ) to measure socioeconomic inequalities in mortality across a number of groups, and assess whether differences across countries and over time are driven by mortality or compositional changes in two applications with different data availability: educational groups (Sweden and Denmark) and groups defined by an area-level deprivation measure (England). Our findings suggest that the multi-group S P is sensitive not only to changes in the means or variances, but also to broader mortality changes that affect distributional shapes. The method can be employed to any context where mortality rates by age are available by sub-groups. Furthermore, levels and trends in mortality inequalities computed with the multigroup S P often differ compared to other conventional summary-based measures. Moreover, we find that the contribution of mortality changes to changes in inequalities is generally greater than that of the changes in the population composition. Whereas levels and trends of inequalities may depend on whether life expectancy- or lifespan variation-based measures are employed, the multi-group S P provides a holistic perspective by capturing both dimensions simultaneously.