Fluctuation analysis of lung function as a predictor of long-term response to beta2-agonists

The response to beta(2)-agonists differs between asthmatics and has been linked to subsequent adverse events, even death. Possible determinants include beta(2)-adrenoceptor genotype at position 16, lung function and airway hyperresponsiveness. Fluctuation analysis provides a simple parameter alpha measuring the complex correlation properties of day-to-day peak expiratory flow. The present study investigated whether alpha predicts clinical response to beta(2)-agonist treatment, taking into account other conventional predictors. Analysis was performed on previously published twice-daily peak expiratory flow measurements in 66 asthmatic adults over three 6-month randomised order treatment periods: placebo, salbutamol and salmeterol. Multiple linear regression was used to determine the association between alpha during the placebo period and response to treatment (change in the number of days with symptoms), taking into account other predictors namely beta(2)-adrenoceptor genotype, lung function and its variability, and airway hyperresponsiveness. The current authors found that alpha measured during the placebo period considerably improved the prediction of response to salmeterol treatment, taking into account genotype, lung function or its variability, or airway hyperresponsiveness. The present study provides further evidence that response to beta(2)-agonists is related to the time correlation properties of lung function in asthma. The current authors conclude that fluctuation analysis of lung function offers a novel predictor to identify patients who may respond well or poorly to treatment.

Short- and long-term mortality and causes of death in HIV/tuberculosis patients in Europe

Mortality of HIV/tuberculosis (TB) patients in Eastern Europe is high. Little is known about their causes of death. This study aimed to assess and compare mortality rates and cause of death in HIV/TB patients across Eastern Europe and Western Europe and Argentina (WEA) in an international cohort study. Mortality rates and causes of death were analysed by time from TB diagnosis (<3 months, 3-12 months or >12 months) in 1078 consecutive HIV/TB patients. Factors associated with TB-related death were examined in multivariate Poisson regression analysis. 347 patients died during 2625 person-years of follow-up. Mortality in Eastern Europe was three- to ninefold higher than in WEA. TB was the main cause of death in Eastern Europe in 80%, 66% and 61% of patients who died <3 months, 3-12 months or >12 months after TB diagnosis, compared to 50%, 0% and 15% in the same time periods in WEA (p<0.0001). In multivariate analysis, follow-up in WEA (incidence rate ratio (IRR) 0.12, 95% CI 0.04-0.35), standard TB-treatment (IRR 0.45, 95% CI 0.20-0.99) and antiretroviral therapy (IRR 0.32, 95% CI 0.14-0.77) were associated with reduced risk of TB-related death. Persistently higher mortality rates were observed in HIV/TB patients in Eastern Europe, and TB was the dominant cause of death at any time during follow-up. This has important implications for HIV/TB programmes aiming to optimise the management of HIV/TB patients and limit TB-associated mortality in this region.