The use of cost per life year gained as a measurement of cost-effectiveness in Spain: a systematic review of recent publications

The objective of this study was to evaluate the methodological characteristics of cost-effectiveness evaluations carried out in Spain, since 1990, which include LYG as an outcome to measure the incremental cost-effectiveness ratio. METHODS: A systematic review of published studies was conducted describing their characteristics and methodological quality. We analyse the cost per LYG results in relation with a commonly accepted Spanish cost-effectiveness threshold and the possible relation with the cost per quality adjusted life year (QALY) gained when they both were calculated for the same economic evaluation. RESULTS: A total of 62 economic evaluations fulfilled the selection criteria, 24 of them including the cost per QALY gained result as well. The methodological quality of the studies was good (55%) or very good (26%). A total of 124 cost per LYG results were obtained with a mean ratio of 49,529 and a median of 11,490 (standard deviation of 183,080). Since 2003, a commonly accepted Spanish threshold has been referenced by 66% of studies. A significant correlation was found between the cost per LYG and cost per QALY gained results (0.89 Spearman-Rho, 0.91 Pearson). CONCLUSIONS: There is an increasing interest for economic health care evaluations in Spain, and the quality of the studies is also improving. Although a commonly accepted threshold exists, further information is needed for decision-making as well as to identify the relationship between the costs per LYG and per QALY gained.

O6-Methylguanine-DNA methyltransferase protein expression by immunohistochemistry in brain and non-brain systemic tumours: systematic review and meta-analysis of correlation with methylation-specific polymerase chain reaction

Background: The DNA repair protein O6-Methylguanine-DNA methyltransferase (MGMT) confers resistance to alkylating agents. Several methods have been applied to its analysis, with methylation-specific polymerase chain reaction (MSP) the most commonly used for promoter methylation study, while immunohistochemistry (IHC) has become the most frequently used for the detection of MGMT protein expression. Agreement on the best and most reliable technique for evaluating MGMT status remains unsettled. The aim of this study was to perform a systematic review and meta-analysis of the correlation between IHC and MSP. Methods A computer-aided search of MEDLINE (1950-October 2009), EBSCO (1966-October 2009) and EMBASE (1974-October 2009) was performed for relevant publications. Studies meeting inclusion criteria were those comparing MGMT protein expression by IHC with MGMT promoter methylation by MSP in the same cohort of patients. Methodological quality was assessed by using the QUADAS and STARD instruments. Previously published guidelines were followed for meta-analysis performance. Results Of 254 studies identified as eligible for full-text review, 52 (20.5%) met the inclusion criteria. The review showed that results of MGMT protein expression by IHC are not in close agreement with those obtained with MSP. Moreover, type of tumour (primary brain tumour vs others) was an independent covariate of accuracy estimates in the meta-regression analysis beyond the cut-off value. Conclusions Protein expression assessed by IHC alone fails to reflect the promoter methylation status of MGMT. Thus, in attempts at clinical diagnosis the two methods seem to select different groups of patients and should not be used interchangeably.

The influence of genetic and environmental factors among MDMA users in cognitive performance

This study is aimed to clarify the association between MDMA cumulative use and cognitive dysfunction, and the potential role of candidate genetic polymorphisms in explaining individual differences in the cognitive effects of MDMA. Gene polymorphisms related to reduced serotonin function, poor competency of executive control and memory consolidation systems, and high enzymatic activity linked to bioactivation of MDMA to neurotoxic metabolites may contribute to explain variations in the cognitive impact of MDMA across regular users of this drug. Sixty ecstasy polydrug users, 110 cannabis users and 93 non-drug users were assessed using cognitive measures of Verbal Memory (California Verbal Learning Test, CVLT), Visual Memory (Rey-Osterrieth Complex Figure Test, ROCFT), Semantic Fluency, and Perceptual Attention (Symbol Digit Modalities Test, SDMT). Participants were also genotyped for polymorphisms within the 5HTT, 5HTR2A, COMT, CYP2D6, BDNF, and GRIN2B genes using polymerase chain reaction and TaqMan polymerase assays. Lifetime cumulative MDMA use was significantly associated with poorer performance on visuospatial memory and perceptual attention. Heavy MDMA users (>100 tablets lifetime use) interacted with candidate gene polymorphisms in explaining individual differences in cognitive performance between MDMA users and controls. MDMA users carrying COMT val/val and SERT s/s had poorer performance than paired controls on visuospatial attention and memory, and MDMA users with CYP2D6 ultra-rapid metabolizers performed worse than controls on semantic fluency. Both MDMA lifetime use and gene-related individual differences influence cognitive dysfunction in ecstasy users.

Environmental factors, spatial variation, and specific requirements of Chironomidae in Mediterranean reference streams

Chironomidae spatial distribution was investigated at 63 near-pristine sites in 22 catchments of the Iberian Mediterranean coast. We used partial redundancy analysis to study Chironomidae community responses to a number of environmental factors acting at several spatial scales. The percentage of variation explained by local factors (23.3%) was higher than that explained by geographical (8.5%) or regional factors(8%). Catchment area, longitude, pH, % siliceous rocks in the catchment, and altitude were the best predictors of Chironomidae assemblages. We used a k-means cluster analysis to classified sites into 3 major groups based on Chironomidae assemblages. These groups were explained mainly by longitudinal zonation and geographical position, and were defined as 1) siliceous headwater streams, 2) mid-altitude streams with small catchment areas, and 3) medium-sized calcareous streams. Distinct species assemblages with associated indicator taxa were established for each stream category using IndVal analysis. Species responses to previously identified key environmental variables were determined, and optima and tolerances were established by weighted average regression. Distinct ecological requirements were observed among genera and among species of the same genus. Some genera were restricted to headwater systems (e.g., Diamesa), whereas others (e.g., Eukiefferiella) had wider ecological preferences but with distinct distributions among congenerics. In the present period of climate change, optima and tolerances of species might be a useful tool to predict responses of different species to changes in significant environmental variables, such as temperature and hydrology.

A systematic review of Twitter’s hashtags in public health: an example of a globally adopted standard

The objective is to find evidence and make recommendations on the use of Twitter in public health,particularly through the study of hashtags(#). This systematic review shows the use of Twitter in different areas of public health: epidemiological surveillance, health promotion, health protection and disease prevention. Articles on this subject published in indexed journals with impact factor show the importance of conversations to engage the attention of Twitter users by using citations (@ user) and retweets(RT); however, not much importance seems to be given to the use of hashtags(#), which are often assimilated to the concept of keywords. Although tracking recurring hashtagsshould be less expensive than computing Twitter content, the potential of hashtaggeddata has not been properly exploited or recognized over the past years, probably due to the lack of efficient tools.