Prescribing Trends of Anticholinergic Drugs Between 1989 and 2017: A UK Biobank Study

Prescription drugs with anticholinergic properties are commonly prescribed and negatively impact physical performance, cognitive function, and increase the risk of falls and dementia. The prevalence of anticholinergic drugs is high in later life, when there is an increased risk of adverse drug effects. Recent, in-depth longitudinal analyses of specifically anticholinergic prescribing in Europe is lacking. Prescriptions for the UK-Biobank participants (n=222,122) were ascertained from primary care electronic patient records. We assigned anticholinergic activity to each drug by using a composite score. We used linear regression to study the association between current anticholinergic burden and time period, explore secular trends in anticholinergic use, and various demographic factors. We further explored the results in the context of different classes of prescriptions drugs. 74 distinct drugs in the sample (1.1%) had anticholinergic effects. An individual’s overall anticholinergic burden increased nonlinearly (linear estimate=0.474, quadratic estimate = 0.094, both p<2.2x10-16) between 1989 (mean=0.09, σ=0.009) and 2000 (mean=0.22, σ=0.006) and increased nonlinearly (linear estimate=0.282, quadratic estimate=0.074, both p<2.2x10-16) from 2000 to 2016 (mean=0.27, σ=0.009). The proportion of patients prescribed at least one anticholinergic drug per month increased from 6.1% to 16.7% from 1989 to 2000 and increased to 18.6% by 2016. When adjusted for sex and polypharmacy, age was negatively associated with recent cross-sectional anticholinergic burden (estimate=-0.042, p<2.2x10-16). Our results demonstrate an increase in prescribing of anticholinergic drugs over the past 30 years and indicate contemporary deprescribing of anticholinergic drugs in the later decades of life.

Limit Law of the Local Linear Estimate of the Conditional Hazard Function for Functional Data

In this work, we treat a prediction problem via the conditional hazard function of a scalar response variable Y given a functional random variable X by using the local linear technique. The main purpose of this paper is to investigate the asymptotic normality of the nonparametric estimator of the conditional hazard function, under some general conditions. A simulation study, conducted to assess finite sample behavior, demonstrates the superiority of our method than the standard kernel method

Guaranteed Estimates for the Length of Branches of Periodic Orbits for Equivariant Hopf Bifurcation

Connected branches of periodic orbits originating at a Hopf bifurcation point of a differential system are considered. A computable estimate for the range of amplitudes of periodic orbits contained in the branch is provided under the assumption that the nonlinear terms satisfy a linear estimate in a ball. If the estimate is global, then the branch is unbounded. The results are formulated in an equivariant setting where the system can have multiple branches of periodic orbits characterized by different groups of symmetries. The nonlocal analysis is based on the equivariant degree method, which allows us to handle both generic and degenerate Hopf bifurcations. This is illustrated by examples.

Algorithm for calculating the covariance matrix of the noise jammer estimated position

The study considers an algorithm for identifying the noise jammers tracks and estimates the coordinates of the assumed position of such a jammer as a linear estimate of the true position with minimal dispersion. An algorithm for calculating the covariance matrix of the resulting estimate is proposed. Findings of the research can be used to modify and develop algorithms which ensure the operation of a promising anti-aircraft missile system for noise jamming.