Bayesian Estimation of Mixed Multinomial Logit Models: Advances and Simulation-Based Evaluations

Variational Bayes (VB) methods have emerged as a fast and computationally-efficient alternative to Markov chain Monte Carlo (MCMC) methods for scalable Bayesian estimation of mixed multinomial logit (MMNL) models. It has been established that VB is substantially faster than MCMC at practically no compromises in predictive accuracy. In this paper, we address two critical gaps concerning the usage and understanding of VB for MMNL. First, extant VB methods are limited to utility specifications involving only individual-specific taste parameters. Second, the finite-sample properties of VB estimators and the relative performance of VB, MCMC and maximum simulated likelihood estimation (MSLE) are not known. To address the former, this study extends several VB methods for MMNL to admit utility specifications including both fixed and random utility parameters. To address the latter, we conduct an extensive simulation-based evaluation to benchmark the extended VB methods against MCMC and MSLE in terms of estimation times, parameter recovery and predictive accuracy. The results suggest that all VB variants with the exception of the ones relying on an alternative variational lower bound constructed with the help of the modified Jensen's inequality perform as well as MCMC and MSLE at prediction and parameter recovery. In particular, VB with nonconjugate variational message passing and the delta-method (VB-NCVMP-Delta) is up to 16 times faster than MCMC and MSLE. Thus, VB-NCVMP-Delta can be an attractive alternative to MCMC and MSLE for fast, scalable and accurate estimation of MMNL models

Clinical effectiveness of dolutegravir in the treatment of HIV/AIDS

Huda Taha,1 Archik Das,2 Satyajit Das1,3 1Integrated Sexual Health Service Coventry and Warwickshire Partnership NHS Trust, Coventry, 2School of Medicine, Birmingham University, Birmingham, 3Coventry University, Coventry, UK Abstract: Dolutegravir (DTG) is a second-generation integrase strand transfer inhibitor (INSTI), which has now been licensed to be used in different countries including the UK. Earlier studies have demonstrated that DTG when used with nucleoside backbone in treatment-naïve and -experienced patients has been well tolerated and demonstrated virological suppression comparable to other INSTIs and superiority against other first-line agents, including efavirenz and boosted protease inhibitors. Like other INSTIs, DTG uses separate metabolic pathways compared to other antiretrovirals and is a minor substrate for CYP-450. It does not appear to have a significant interaction with drugs, which uses the CYP-450 system. Nonetheless, it uses renal solute transporters that may potentially inhibit the transport of other drugs and can have an effect on the elimination of other drugs. However, the impact of this mechanism appears to be very minimal and insignificant clinically. The side effect profiles of DTG are similar to raltegravir and have been found to be well tolerated. DTG has a long plasma half-life and is suitable for once daily use without the need for a boosting agent. DTG has all the potential to be used as a first-line drug in combination with other nucleoside backbones, especially in the form of a single tablet in combination with abacavir and lamivudine. The purpose of this review article is to present the summary of the available key information about the clinical usefulness of DTG in the treatment of HIV infection. Keywords: dolutegravir, integrase inhibitors, HIV, antiretroviral, treatmen

Low uptake of antiretroviral therapy after admission with human immunodeficiency virus and tuberculosis in KwaZulu-Natal, South Africa.

A prospective cohort study was conducted among human immunodeficiency virus (HIV) infected in-patients with tuberculosis (TB) or other opportunistic infections (OIs) in South Africa to estimate subsequent antiretroviral therapy (ART) uptake and survival