Do Tropical Cyclones Shape Shorebird Habitat Patterns? Biogeoclimatology of Snowy Plovers in Florida

Background

The Gulf coastal ecosystems in Florida are foci of the highest species richness of imperiled shoreline dependent birds in the USA. However environmental processes that affect their macroecological patterns, like occupancy and abundance, are not well unraveled. In Florida the Snowy Plover (Charadrius alexandrinus nivosus) is resident along northern and western white sandy estuarine/ocean beaches and is considered a state-threatened species.

Methodology/Principal Findings

Here we show that favorable nesting areas along the Florida Gulf coastline are located in regions impacted relatively more frequently by tropical cyclones. The odds of Snowy Plover nesting in these areas during the spring following a tropical cyclone impact are seven times higher compared to the odds during the spring following a season without a cyclone. The only intensity of a tropical cyclone does not appear to be a significant factor affecting breeding populations.

Conclusions/Significance

Nevertheless a future climate scenario featuring fewer, but more extreme cyclones could result in a decrease in the breeding Snowy Plover population and its breeding range. This is because the spatio-temporal frequency of cyclone events was found to significantly affect nest abundance. Due to the similar geographic range and habitat suitability, and no decrease in nest abundance of other shorebirds in Florida after the cyclone season, our results suggest a common bioclimatic feedback between shorebird abundance and tropical cyclones in breeding areas which are affected by cyclones.     

Effects of positive interactions, size symmetry of competition and abiotic stress on self-thinning in simulated plant populations

Background and Aims

Competition drives self-thinning (density-dependent mortality) in crowded plant populations. Facilitative interactions have been shown to affect many processes in plant populations and communities, but their effects on self-thinning trajectories have not been investigated.

Methods

Using an individual-based ‘zone-of-influence’ model, we studied the potential effects of the size symmetry of competition, abiotic stress and facilitation on self-thinning trajectories in plant monocultures. In the model, abiotic stress reduced the growth of all individuals and facilitation ameliorated the effects of stress on interacting individuals.

Key Results

Abiotic stress made the log biomass – log density relationship during self-thinning steeper, but this effect was reduced by positive interactions among individuals. Size-asymmetric competition also influenced the self-thinning slope.

Conclusions

Although competition drives self-thinning, its course can be affected by abiotic stress, facilitation and competitive symmetry.     

Impacts of Different Grades of Tropical Cyclones on Infectious Diarrhea in Guangdong, 2005-2011

Objective

Guangdong province is one of the most vulnerable provinces to tropical cyclones in China. Most prior studies concentrated on the relationship between tropical cyclones and injuries and mortality. This study aimed to explore the impacts of different grades of tropical cyclones on infectious diarrhea incidence in Guangdong province, from 2005 to 2011.

Methods

Mann-Whitney U test was firstly used to examine if infectious diarrhea were sensitive to tropical cyclone. Then unidirectional 1:1 case-crossover design was performed to quantitatively evaluate the relationship between daily number of infectious diarrhea and tropical cyclone from 2005 to 2011 in Guangdong, China. Principal component analysis (PCA) was applied to eliminate multicollinearity. Multivariate logistic regression model was used to estimate the hazard ratios (HRs) and the 95% confidence intervals (CI).

Results

There were no significant relationships between tropical cyclone and bacillary dysentery, amebic dysentery, typhoid, and paratyphoid cases. Infectious diarrhea other than cholera, dysentery, typhoid and paratyphoid significantly increased after tropical cyclones. The strongest effect were shown on lag 1 day (HRs = 1.95, 95%CI = 1.22, 3.12) and no lagged effect was detected for tropical depression, tropical storm, severe tropical storm and typhoon, with the largest HRs (95%CI) of 2.16 (95%CI = 1.69, 2.76), 2.43 (95%CI = 1.65, 3.58) and 2.21 (95%CI = 1.65, 2.69), respectively. Among children below 5 years old, the impacts of all grades of tropical cyclones were strongest at lag 0 day. And HRs were 2.67 (95%CI = 1.10, 6.48), 2.49 (95%CI = 1.80, 3.44), 4.89 (95%CI = 2.37, 7.37) and 3.18 (95%CI = 2.10, 4.81), respectively.

Conclusion

All grades of tropical cyclones could increase risk of other infectious diarrhea. Severe tropical storm has the strongest influence on other infectious diarrhea. The impacts of tropical cyclones on children under 5 years old were higher than total population.     

A Single Locus Is Responsible for Salinity Tolerance in a Chinese Landrace Barley (Hordeum vulgare L.)

Introduction

Salinity and waterlogging are two major abiotic stresses severely limiting barley production. The lack of a reliable screening method makes it very hard to improve the tolerance through breeding programs.

Methods

This work used 188 DH lines from a cross between a Chinese landrace variety, TX9425 (waterlogging and salinity tolerant), and a Japanese malting barley, Naso Nijo (waterlogging and salinity sensitive), to identify QTLs associated with the tolerance.

Results

Four QTLs were found for waterlogging tolerance. The salinity tolerance was evaluated with both a hydroponic system and in potting mixture. In the trial with potting mixture, only one major QTL was identified to associate with salinity tolerance. This QTL explained nearly 50% of the phenotypic variation, which makes it possible for further fine mapping and cloning of the gene. This QTL was also identified in the hydroponic experiment for different salt-related traits. The position of this QTL was located at a similar position to one of the major QTLs for waterlogging tolerance, indicating the possibility of similar mechanisms controlling both waterlogging and salinity tolerance.

Conclusion

The markers associated with the QTL provided a unique opportunity in breeding programs for selection of salinity and waterlogging tolerance.     

Effects of Intra-Aortic Balloon Counterpulsation Pump on Mortality of Acute Myocardial Infarction

Background

Several randomized controlled trials (RCTs) have evaluated the effect of intra-aortic balloon counterpulsation pump(IABP) on the mortality of acute myocardial infarction (AMI).

Objectives

To analyze the relevant RCT data on the effect of IABP on mortality and the occurrence of bleeding in AMI.

Data Sources

Published RCTs on the treatment of AMI by IABP were retrieved in searches of Medline, EMBASE, Cochrane and other related databases. The last search was conducted on July 20, 2014.

Study Eligibility Criteria

Randomized clinical trials comparing IABP to controls as treatment for AMI.

Participants

Patients with AMI.

Synthesis Methods

The primary endpoint was mortality, and the secondary endpoint was bleeding events. To account for to heterogeneity, a random-effects model was used to analyze the study data.

Results

Ten trials with a total population of 973 patients that were included in the analysis showed no significant difference in 2-month mortality between the IABP and the control groups. The 6-month mortality in the IABP group was not significantly lower than in the control group in the four RCTs that enrolled 59 AMI patients with CS. But in the four that enrolled AMI 66 patients without CS, the data showed opposite conclusion.

Conclusions

IABP cannot reduce within 2 months and 6–12 months mortality of AMI patients with CS as well as within 2 months mortality of AMI patients without CS, but can reduce 6–12 months mortality of AMI patients without CS. In addition, IABP can increase the risk of bleeding.     

Pollinator shifts as triggers of speciation in painted petal irises (Lapeirousia: Iridaceae)

Background and Aims

Adaptation to different pollinators has been hypothesized as one of the main factors promoting the formation of new species in the Cape region of South Africa. Other researchers favour alternative causes such as shifts in edaphic preferences. Using a phylogenetic framework and taking into consideration the biogeographical scenario explaining the distribution of the group as well as the distribution of pollinators, this study compares pollination strategies with substrate adaptations to develop hypotheses of the primary factors leading to speciation in Lapeirousia (Iridaceae), a genus of corm-bearing geophytes well represented in the Cape and presenting an important diversity of pollination syndromes and edaphic preferences.

Methods

Phylogenetic relationships are reconstructed within Lapeirousia using nuclear and plastid DNA sequence data. State-of-the-art methods in biogeography, divergence time estimation, character optimization and diversification rate assessments are used to examine the evolution of pollination syndromes and substrate shifts in the history of the group. Based on the phylogenetic results, ecological factors are compared for nine sister species pairs in Lapeirousia.

Key Results

Seventeen pollinator shifts and ten changes in substrate types were inferred during the evolution of the genus Lapeirousia. Of the nine species pairs examined, all show divergence in pollination syndromes, while only four pairs present different substrate types.

Conclusions

The available evidence points to a predominant influence of pollinator shifts over substrate types on the speciation process within Lapeirousia, contrary to previous studies that favoured a more important role for edaphic factors in these processes. This work also highlights the importance of biogeographical patterns in the study of pollination syndromes.     

Serpentine Soils Do Not Limit Mycorrhizal Fungal Diversity

Background

Physiologically stressful environments tend to host depauperate and specialized biological communities. Serpentine soils exemplify this phenomenon by imposing well-known constraints on plants; however, their effect on other organisms is still poorly understood.

Methodology/Principal Findings

We used a combination of field and molecular approaches to test the hypothesis that serpentine fungal communities are species-poor and specialized. We conducted surveys of ectomycorrhizal fungal diversity from adjacent serpentine and non-serpentine sites, described fungal communities using nrDNA Internal Transcribed Spacer (ITS) fragment and sequence analyses, and compared their phylogenetic community structure. Although we detected low fungal overlap across the two habitats, we found serpentine soils to support rich fungal communities that include representatives from all major fungal lineages. We failed to detect the phylogenetic signature of endemic clades that would result from specialization and adaptive radiation within this habitat.

Conclusions/Significance

Our results indicate that serpentine soils do not constitute an extreme environment for ectomycorrhizal fungi, and raise important questions about the role of symbioses in edaphic tolerance and the maintenance of biodiversity.     

The Effect of Hospital Volume on Mortality in Patients Admitted with Severe Sepsis

Importance

The association between hospital volume and inpatient mortality for severe sepsis is unclear.

Objective

To assess the effect of severe sepsis case volume and inpatient mortality.

Design Setting and Participants

Retrospective cohort study from 646,988 patient discharges with severe sepsis from 3,487 hospitals in the Nationwide Inpatient Sample from 2002 to 2011.

Exposures

The exposure of interest was the mean yearly sepsis case volume per hospital divided into tertiles.

Main Outcomes and Measures

Inpatient mortality.

Results

Compared with the highest tertile of severe sepsis volume (>60 cases per year), the odds ratio for inpatient mortality among persons admitted to hospitals in the lowest tertile (≤10 severe sepsis cases per year) was 1.188 (95% CI: 1.074–1.315), while the odds ratio was 1.090 (95% CI: 1.031–1.152) for patients admitted to hospitals in the middle tertile. Similarly, improved survival was seen across the tertiles with an adjusted inpatient mortality incidence of 35.81 (95% CI: 33.64–38.03) for hospitals with the lowest volume of severe sepsis cases and a drop to 32.07 (95% CI: 31.51–32.64) for hospitals with the highest volume.

Conclusions and Relevance

We demonstrate an association between a higher severe sepsis case volume and decreased mortality. The need for a systems-based approach for improved outcomes may require a high volume of severely septic patients.     

Morphological evolution in the variable resin-producing Detarieae (Fabaceae): do morphological characters retain a phylogenetic signal?

Background and Aims

Previous molecular phylogenetic studies disagree with the informal generic-level taxonomic groups based on morphology. In this study morphological characters in the caesalpinioid clade Detarieae are evaluated within a phylogenetic framework as a means of better understanding phylogenetic relationships and morphological evolution.

Methods

Morphological characters were observed and scored for representative species of Detarieae focusing on the resin-producing genera. Phylogenetic analyses were carried out with morphological characters alone and then combined with DNA sequences.

Key Results

Despite a high level of homoplasy, morphological data support several clades corresponding to those recovered in molecular phylogenetic analyses. The more strongly supported clades are each defined by at least one morphological synapomorphy. Several characters (e.g. apetaly) previously used to define informal generic groups evolved several times independently, leading to the differences observed with the molecular phylogenetic analyses. Although floral evolution is complex in Detarieae some patterns are recovered.

Conclusions

New informal taxonomic groupings are proposed based on the present findings. Floral evolution in the diverse Detarieae clade is characterized by a repeated tendency toward zygomorphy through the reduction of lateral petals and toward complete loss of petals.Key words: Caesalpinioideae, Detarieae, floral evolution, Leguminosae, morphology, phylogeny, resins, taxonomy     

Monitoring of Antiretroviral Therapy and Mortality in HIV Programmes in Malawi,South Africa and Zambia: Mathematical Modelling Study

Objectives

Mortality in patients starting antiretroviral therapy (ART) is higher in Malawi and Zambia than in South Africa. We examined whether different monitoring of ART (viral load [VL] in South Africa and CD4 count in Malawi and Zambia) could explain this mortality difference.

Design:

Mathematical modelling study based on data from ART programmes.

Methods

We used a stochastic simulation model to study the effect of VL monitoring on mortality over 5 years. In baseline scenario A all parameters were identical between strategies except for more timely and complete detection of treatment failure with VL monitoring. Additional scenarios introduced delays in switching to second-line ART (scenario B) or higher virologic failure rates (due to worse adherence) when monitoring was based on CD4 counts only (scenario C). Results are presented as relative risks (RR) with 95% prediction intervals and percent of observed mortality difference explained.

Results

RRs comparing VL with CD4 cell count monitoring were 0.94 (0.74–1.03) in scenario A, 0.94 (0.77–1.02) with delayed switching (scenario B) and 0.80 (0.44–1.07) when assuming a 3-times higher rate of failure (scenario C). The observed mortality at 3 years was 10.9% in Malawi and Zambia and 8.6% in South Africa (absolute difference 2.3%). The percentage of the mortality difference explained by VL monitoring ranged from 4% (scenario A) to 32% (scenarios B and C combined, assuming a 3-times higher failure rate). Eleven percent was explained by non-HIV related mortality.

Conclusions

VL monitoring reduces mortality moderately when assuming improved adherence and decreased failure rates.     

Variable response of three Trifolium repens ecotypes to soil flooding by seawater

Background and Aims

Despite concerns about the impact of rising sea levels and storm surge events on coastal ecosystems, there is remarkably little information on the response of terrestrial coastal plant species to seawater inundation. The aim of this study was to elucidate responses of a glycophyte (white clover, Trifolium repens) to short-duration soil flooding by seawater and recovery following leaching of salts.

Methods

Using plants cultivated from parent ecotypes collected from a natural soil salinity gradient, the impact of short-duration seawater soil flooding (8 or 24 h) on short-term changes in leaf salt ion and organic solute concentrations was examined, together with longer term impacts on plant growth (stolon elongation) and flowering.

Key Results

There was substantial Cl^– and Na⁺ accumulation in leaves, especially for plants subjected to 24 h soil flooding with seawater, but no consistent variation linked to parent plant provenance. Proline and sucrose concentrations also increased in plants following seawater flooding of the soil. Plant growth and flowering were reduced by longer soil immersion times (seawater flooding followed by drainage and freshwater inputs), but plants originating from more saline soil responded less negatively than those from lower salinity soil.

Conclusions

The accumulation of proline and sucrose indicates a potential for solute accumulation as a response to the osmotic imbalance caused by salt ions, while variation in growth and flowering responses between ecotypes points to a natural adaptive capacity for tolerance of short-duration seawater soil flooding in T. repens. Consequently, it is suggested that selection for tolerant ecotypes is possible should the predicted increase in frequency of storm surge flooding events occur.     

Different anthropometric adiposity measures and their association with cardiovascular disease risk factors: a meta-analysis

Objectives

To investigate which anthropometric adiposity measure has the strongest association with cardiovascular disease (CVD) risk factors in Caucasian men and women without a history of CVD.

Design

Systematic review and meta-analysis.

Methods

We searched databases for studies reporting correlations between anthropometric adiposity measures and CVD risk factors in Caucasian subjects without a history of CVD. Body mass index (BMI), waist circumference, waist-to-hip ratio, waist-to-height ratio and body fat percentage were considered the anthropometric adiposity measures. Primary CVD risk factors were: systolic blood pressure, diastolic blood pressure, high density lipoprotein (HDL) cholesterol, triglycerides and fasting glucose. Two independent reviewers performed abstract, full text and data selection.

Results

Twenty articles were included describing 21,618 males and 24,139 females. Waist circumference had the strongest correlation with all CVD risk factors for both men and women, except for HDL and LDL in men. When comparing BMI with waist circumference, the latter showed significantly better correlations to CVD risk factors, except for diastolic blood pressure in women and HDL and total cholesterol in men.

Conclusions

We recommend the use of waist circumference in clinical and research studies above other anthropometric adiposity measures, especially compared with BMI, when evaluating CVD risk factors.     

Effect of HDL-Raising Drugs on Cardiovascular Outcomes: A Systematic Review and Meta-Regression

Background

Substantial residual cardiovascular risk remains after optimal LDL lowering in patients of established coronary artery disease. A number of therapeutic agents that raise HDL-C have been tested in clinical trials to cover this risk. However, the results of clinical trials are conflicting.

Objectives

To determine whether raising HDL-C with pharmacologic therapies translates into beneficial cardiovascular outcomes and to find out if this change was proportional to the percentage change in HDL levels.

Methods

Electronic and printed sources were searched up to August, 2013 for randomised controlled trials (RCTs) using at least one of the HDL raising therapies for secondary prevention of adverse cardiovascular events over optimal LDL levels. Data from eligible studies were pooled for the following outcomes: all cause mortality, cardiovascular disease mortality, hospitalization for unstable angina, non-fatal myocardial infarction, coronary revascularization and ischemic stroke. Mantel Haensnzel fixed effect model was used preferentially. Meta-regression was done to see the correlation of change in HDL levels and cardiovascular outcomes. Pooled odds ratios with 95% confidence interval (CI) were calculated.

Results

A total of 12 RCTs including 26,858 patients with follow up period ranging from 1 year to 6.2 years were included in the analysis. Pooled analysis showed no significant difference in all-cause mortality between the treatment and control group (Pooled OR 1.07; 95% CI 0.98–1.16, p = 0.15). No significant difference was found between the groups for any of the secondary outcomes. Similarly no correlation was seen between percentage change in HDL and adverse cardiovascular outcomes on meta-regression analysis.

Conclusion

Increasing HDL levels via pharmacological manipulation beyond optimal lipid lowering therapy for secondary prevention is not beneficial.     

Functional biogeography as evidence of gene transfer in hypersaline microbial communities

Background

Horizontal gene transfer (HGT) plays a major role in speciation and evolution of bacteria and archaea by controlling gene distribution within an environment. However, information that links HGT to a natural community using relevant population-genetics parameters and spatial considerations is scarce. The Great Salt Lake (Utah, USA) provides an excellent model for studying HGT in the context of biogeography because it is a contiguous system with dispersal limitations due to a strong selective salinity gradient. We hypothesize that in spite of the barrier to phylogenetic dispersal, functional characteristics—in the form of HGT—expand beyond phylogenetic limitations due to selective pressure.

Methodology and Results

To assay the functional genes and microorganisms throughout the GSL, we used a 16S rRNA oligonucleotide microarray (Phylochip) and a functional gene array (GeoChip) to measure biogeographic patterns of nine microbial communities. We found a significant difference in biogeography based on microarray analyses when comparing Sørensen similarity values for presence/absence of function and phylogeny (Student''s t-test; p = 0.005).

Conclusion and Significance

Biogeographic patterns exhibit behavior associated with horizontal gene transfer in that informational genes (16S rRNA) have a lower similarity than functional genes, and functional similarity is positively correlated with lake-wide selective pressure. Specifically, high concentrations of chromium throughout GSL correspond to an average similarity of chromium resistance genes that is 22% higher than taxonomic similarity. This suggests active HGT may be measured at the population level in microbial communities and these biogeographic patterns may serve as a model to study bacteria adaptation and speciation.     

Eosinophil Inversely Associates with Type 2 Diabetes and Insulin Resistance in Chinese Adults

Context

Limited population-based study focused on relationship between eosinophil and type 2 diabetes (T2D).

Objectives

We aimed to evaluate the relationship between peripheral eosinophil percentage and glucose metabolism and insulin resistance in a large sample size of Chinese population aged 40 and older.

Design and Methods

A cross-sectional study was performed among 9,111 Chinese adults including 3,561 men and 5,550 women. The glucose metabolism status was confirmed by 75-g oral glucose tolerance test. Homeostasis model assessment of insulin resistance index and serum insulin levels were used to evaluate insulin resistance. Homeostasis model assessment-B was used to evaluate β cell function.

Results

The average age of participants was 58.5 years. The prevalence of T2D decreased across the tertiles of eosinophil percentage (21.3%, 18.2% and 16.9%, P<0.0001). Each one tertile increase of eosinophil percentage inversely associated with risk of T2D when referred not only to normal glucose tolerance (NGT) (odds ratio (OR) 0.81, 95% CI 0.76–0.87, P< 0.0001), but also to impaired glucose regulation (OR 0.89, 95% CI 0.83–0.97, P = 0.006), respectively, after adjustment for the confounding factors. Compared with the first tertile, the third tertile of eosinophil percentage associated with a 23% decrease of insulin resistance in NGT participants after full adjustments (P = 0.005). Each 1-standard deviation of increment of eosinophil percentage associated with a 37% decrease of insulin resistance (P = 0.005).

Conclusions

Higher peripheral eosinophil percentage was associated with decreased risk of T2D. The inverse relation to insulin resistance was detected in NGT participants.     

Coryphoid Palm Leaf Fossils from the Maastrichtian–Danian of Central India with Remarks on Phytogeography of the Coryphoideae (Arecaceae)

Premise of research

A large number of fossil coryphoid palm wood and fruits have been reported from the Deccan Intertrappean beds of India. We document the oldest well-preserved and very rare costapalmate palm leaves and inflorescence like structures from the same horizon.

Methodology

A number of specimens were collected from Maastrichtian–Danian sediments of the Deccan Intertrappean beds, Ghughua, near Umaria, Dindori District, Madhya Pradesh, India. The specimens are compared with modern and fossil taxa of the family Arecaceae.

Pivotal results

Sabalites dindoriensis sp. nov. is described based on fossil leaf specimens including basal to apical parts. These are the oldest coryphoid fossil palm leaves from India as well as, at the time of deposition, from the Gondwana- derived continents.

Conclusions

The fossil record of coryphoid palm leaves presented here and reported from the Eurasian localities suggests that this is the oldest record of coryphoid palm leaves from India and also from the Gondwana- derived continents suggesting that the coryphoid palms were well established and wide spread on both northern and southern hemispheres by the Maastrichtian–Danian. The coryphoid palms probably dispersed into India from Europe via Africa during the latest Cretaceous long before the Indian Plate collided with the Eurasian Plate.     

Phylogenetic analysis reveals a scattered distribution of autumn colours

Background and Aims

Leaf colour in autumn is rarely considered informative for taxonomy, but there is now growing interest in the evolution of autumn colours and different hypotheses are debated. Research efforts are hindered by the lack of basic information: the phylogenetic distribution of autumn colours. It is not known when and how autumn colours evolved.

Methods

Data are reported on the autumn colours of 2368 tree species belonging to 400 genera of the temperate regions of the world, and an analysis is made of their phylogenetic relationships in order to reconstruct the evolutionary origin of red and yellow in autumn leaves.

Key Results

Red autumn colours are present in at least 290 species (70 genera), and evolved independently at least 25 times. Yellow is present independently from red in at least 378 species (97 genera) and evolved at least 28 times.

Conclusions

The phylogenetic reconstruction suggests that autumn colours have been acquired and lost many times during evolution. This scattered distribution could be explained by hypotheses involving some kind of coevolutionary interaction or by hypotheses that rely on the need for photoprotection.Key words: Autumn colour, leaf colour, comparative analysis, coevolution, photoprotection, phylogenetic analysis     

Paleogene radiation of a plant pathogenic mushroom

Background

The global movement and speciation of fungal plant pathogens is important, especially because of the economic losses they cause and the ease with which they are able to spread across large areas. Understanding the biogeography and origin of these plant pathogens can provide insights regarding their dispersal and current day distribution. We tested the hypothesis of a Gondwanan origin of the plant pathogenic mushroom genus Armillaria and the currently accepted premise that vicariance accounts for the extant distribution of the species.

Methods

The phylogeny of a selection of Armillaria species was reconstructed based on Maximum Parsimony (MP), Maximum Likelihood (ML) and Bayesian Inference (BI). A timeline was then placed on the divergence of lineages using a Bayesian relaxed molecular clock approach.

Results

Phylogenetic analyses of sequenced data for three combined nuclear regions provided strong support for three major geographically defined clades: Holarctic, South American-Australasian and African. Molecular dating placed the initial radiation of the genus at 54 million years ago within the Early Paleogene, postdating the tectonic break-up of Gondwana.

Conclusions

The distribution of extant Armillaria species is the result of ancient long-distance dispersal rather than vicariance due to continental drift. As these finding are contrary to most prior vicariance hypotheses for fungi, our results highlight the important role of long-distance dispersal in the radiation of fungal pathogens from the Southern Hemisphere.     

Hospitalization Rates and Post-Operative Mortality for Abdominal Aortic Aneurysm in Italy over the Period 2000–2011

Background

Recent studies have reported declines in incidence, prevalence and mortality for abdominal aortic aneurysms (AAAs) in various countries, but evidence from Mediterranean countries is lacking. The aim of this study is to examine the trend of hospitalization and post-operative mortality rates for AAAs in Italy during the period 2000–2011, taking into account the introduction of endovascular aneurysm repair (EVAR) in 1990s.

Methods

This retrospective cohort study was carried out in Emilia-Romagna, an Italian region with 4.5 million inhabitants. A total of 19,673 patients hospitalized for AAAs between 2000 and 2011, were identified from the hospital discharge records (HDR) database. Hospitalization rates, percentage of OSR and EVAR and 30-day mortality rates were calculated for unruptured (uAAAs) and ruptured AAAs (rAAAs).

Results

Adjusted hospitalization rates decreased on average by 2.9% per year for uAAAs and 3.2% for rAAAs (p<0.001). The temporal trend of 30-day mortality rates remained stable for both groups. The percentage of EVAR for uAAAs increased significantly from 2006 to 2011 (42.7 versus 60.9% respectively, mean change of 3.9% per year, p<0.001). No significant difference in mortality was found between OSR and EVAR for uAAAs and rAAAs.

Conclusions

The incidence and trend of hospitalization rates for rAAAs and uAAAs decreased significantly in the last decade, while 30-day mortality rates in operated patients remained stable. OSR continued to be the most common surgery in rAAAs, although the gap between OSR and EVAR recently declined. The EVAR technique became the preferred surgery for uAAAs since 2008.