Continuous time-interaction processes for population size estimation, with an application to drug dealing in Italy.

We introduce a time-interaction point process where the occurrence of an event can increase (self-excitement) or reduce (self-correction) the probability of future events. Self-excitement and self-correction are allowed to be triggered by the same event, at different timescales; other effects such as those of covariates, unobserved heterogeneity, and temporal dependence are also allowed in the model. We focus on capture-recapture data, as our work is motivated by an original example about the estimation of the total number of drug dealers in Italy. To do so, we derive a conditional likelihood formulation where only subjects with at least one capture are involved in the inference process. The result is a novel and flexible continuous-time population size estimator. A simulation study and the analysis of our motivating example illustrate the validity of our approach in several scenarios.

Efficient Computation of Spatial Entropy Measures.

Entropy indices are commonly used to evaluate the heterogeneity of spatially arranged data by exploiting various approaches capable of including spatial information. Unfortunately, in practical studies, difficulties can arise regarding both the availability of computational tools for fast and easy implementation of these indices and guidelines supporting the correct interpretation of the results. The present work addresses such issues for the most known spatial entropy measures: the approach based on area partitions, the one based on distances between observations, and the decomposable spatial entropy. The newly released version of the R package SpatEntropy is introduced here and we show how it properly supports researchers in real case studies. This work also answers practical questions about the spatial distribution of nesting sites of an endangered species of gorillas in Cameroon. Such data present computational challenges, as they are marked points in continuous space over an irregularly shaped region, and covariates are available. Several aspects of the spatial heterogeneity of the nesting sites are addressed, using both the original point data and a discretised pixel dataset. We show how the diversity of the nesting habits is related to the environmental covariates, while seemingly not affected by the interpoint distances. The issue of scale dependence of the spatial measures is also discussed over these data. A motivating example shows the power of the SpatEntropy package, which allows for the derivation of results in seconds or minutes with minimum effort by users with basic programming abilities, confirming that spatial entropy indices are proper measures of diversity.

High-cost drugs for rare diseases: their expenditure and value based on a regional area-based study.

Background: in the field of rare diseases (RDs) most of the European studies on budget impact analysis of drugs that have been conducted often lay on theoretical assumptions and focus only on Orphan drugs (ODs). Objectives: we aimed to estimate the budget impact of specific drugs for non-oncological RDs, both ODs and non-ODs, using real-world data about patients residing in Veneto Region (Italy) and to describe its expenditure structure and dynamics. Methods: a population-based multi-source observational study was conducted using data from Regional administrative databases; an ad-hoc drugs' list specific for RDs including both ODs and non-ODs and classifying them by ATC codes has been created. Results: In 2019, the total expenditure for drugs specific for RDs was EUR 97.2 million (6.6% of the total Regional budget). The RD drug list included 58 ATC codes, of which 15 ATC had an annual budget impact over EUR 1 million ("blockbuster drugs"). The most expensive treatment was a non-OD drug (Coagulation factor VIII). The two most represented therapeutical areas were the metabolic and the hematological ones. Conclusions: Cost analyses on RD high-cost drugs expenditure should consider any specific RD drug, not only ODs. Expenditure dynamics for RD drugs are peculiar showing "blockbuster drugs". Some therapeutical areas seem to be lacking in the drug research field.

Neuroleptic-Induced Parkinsonism in Elderly Patients Diagnosed With Psychotic Major Depression and Dementia of the Alzheimer Type.

The authors prospectively examined elderly patients diagnosed with major depression with psychotic features (MD-P) and patients diagnosed with dementia of the Alzheimer Type (DAT) for neuroleptic-induced parkinsonism (NIP) during perphenazine treatment. Baseline parkinsonian symptoms did not differ between groups. With treatment, mean NIP score doubled in DAT patients but remained unchanged in the MD-P group. The difference between groups was highly significant and remained so after the effects of age, perphenazine dose, and duration of perphenazine treatment were controlled. Although the mechanisms underlying these differences in NIP development remain to be determined, clinical guidelines for neuroleptic dosages in elderly patients need to account for variability in neuroleptic tolerance between diagnostic groups.

Comparative Effects of Sertraline and Nortriptyline on Body Sway in Older Depressed Patients.

This study examined effects of nortriptyline and sertraline on the balance and stability of depressed geriatric inpatients. Body sway was measured with a stable force-platform at three timepoints: before starting antidepressant medication, 5-7 days after medication was initiated, and 1 week later. A group of healthy, unmedicated older volunteers was evaluated under the same conditions as patients. In sertraline-treated patients (n = 10), significant differences (P < 0.05) between baseline and the first week of treatment were found in the force-platform measurements of sway length (L) and area of the center of pressure (Ao), with patients' eyes both open and closed. This change in postural stability occurred in the absence of orthostatic hypotension. By the second week of treatment, neither variable was found to be significantly different from baseline. In the nonmedicated volunteers (n = 20) and in the group of patients receiving nortriptyline (n = 11), no significant changes in postural stability were found.