The burden of neurological comorbidities in six autoimmune bullous diseases: a population-based study

BACKGROUND

Apart from bullous pemphigoid (BP), the association of other autoimmune bullous diseases (AIBDs) with neurological conditions is poorly understood.

OBJECTIVE

To estimate the association between a wide array of AIBDs and neurological conditions.

METHODS

A retrospective cross-sectional study recruited patients with BP, mucous membrane pemphigoid (MMP), epidermolysis bullosa acquisita (EBA), pemphigoid gestationis (PG), pemphigus vulgaris (PV) and pemphigus foliaceus (PF). These patients were compared with their age- and sex-matched control subjects with regard to the lifetime prevalence of Parkinson's disease (PD), Alzheimer's disease (AD), stroke, epilepsy and multiple sclerosis (MS). Logistic regression was used to calculate OR for specified neurological disorders.

RESULTS

The current study included 1743, 251, 106, 126, 860 and 103 patients diagnosed with BP, MMP, EBA, PG, PV and PF, respectively. These patients were compared with 10 141, 1386, 606, 933, 5142 and 588 matched controls, respectively. Out of the investigated neurological conditions, PD associated with BP (OR, 2.71; 95% CI, 2.19-3.35); AD with BP (OR, 2.11; 95% CI, 1.73-2.57), MMP (OR, 2.37; 95% CI, 1.03-5.47), EBA (OR, 6.00; 95% CI, 1.90-18.97) and PV (OR, 2.24; 95% CI, 1.40-3.60); stroke with BP (OR, 1.84; 95% CI, 1.55-2.19) and EBA (OR, 2.79; 95% CI, 1.11-7.01); and epilepsy with BP (OR, 2.18; 95% CI, 1.72-2.77) and PV (OR, 1.80; 95% CI, 1.19-2.73). MS did not significantly cluster with any of the six AIBDs.

CONCLUSION

In addition to BP, EBA and PV were found to cluster with neurological comorbidities. Patients with these AIBDs with compatible symptoms may be carefully assessed for comorbid neurological disorders.

Long-term survival in patients with coronary artery disease undergoing percutaneous coronary intervention with or without intracoronary pressure wire guidance: a report from SCAAR

Background

Intracoronary pressure wire measurements of fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) provide decision-making guidance during percutaneous coronary intervention (PCI). However, limited data exist on the impact of FFR/iFR on long-term clinical outcomes in patients with stable angina, unstable angina (UA)/non-ST-segment elevation myocardial infarction (NSTEMI), or STEMI.

Methods

We used data from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR) on all patients in Sweden undergoing PCI (with or without FFR/iFR guidance) for stable angina, UA/NSTEMI, or STEMI between January 2005 and March 2018. The primary endpoint was all-cause mortality and the secondary endpoints were stent thrombosis or restenosis and periprocedural complications. The primary model was multilevel Cox proportional-hazards regression using an instrumental variable (IV) to adjust for known and unknown confounders with treating hospital as a treatment-preference instrument. The following variables were entered into Cox proportional-hazards regression in addition to the IV: age, sex, diabetes, indication for PCI, severity of coronary disease, smoking status, hypertension, hyperlipidemia, previous myocardial infarction, previous PCI, previous coronary artery bypass graft, type of stent.

Results

In total, 151,001 patients underwent PCI: 31,514 (20.9%) for stable angina, 74,982 (49.6%) for UA/NSTEMI, and 44,505 (29.5%) for STEMI. Of these, FFR/iFR guidance was used in 11,433 patients (7.6%): 5029 (44.0%) with stable angina, 5989 (52.4%) with UA/NSTEMI, and 415 (3.6%) with STEMI; iFR was used in 1156 (10.1%) of these patients. After a median follow-up of 1784 (range 1–4824) days, the FFR/iFR group had lower adjusted risk estimates for all-cause mortality [hazard ratio (HR) 0.79; 95% confidence interval (CI) 0.69–0.91; P=0.001] and stent thrombosis and restenosis (HR 0.13; 95% CI 0.09–0.19; P<0.001). The number of periprocedural complications did not differ significantly between the groups (odds ratio 0.69; 95% CI 0.30–1.55; P=0.368). There was no interaction between FFR/iFR and indication for PCI. We found no difference between FFR and iFR (HR 1.12; 95% CI 0.90–1.59; P=0.216).

Conclusions

In this observational study, the use of FFR/IFR was associated with a lower risk of long-term mortality in patients undergoing PCI for stable angina, UA/NSTEMI, or STEMI. Our study supports the current European and American guidelines for the use of FFR/iFR during PCI and shows that intracoronary pressure wire guidance has prognostic benefit in patients with stable angina as well as in patients with the acute coronary syndrome.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Heart and Lung Foundation, ALF Västra Götaland, Swedish Scientific Council

Prevalence and age distribution of pemphigus and pemphigoid diseases among paediatric patients in Germany

BACKGROUND

Autoimmune bullous diseases are rare and mostly occur in adults. Several cases and small case series have been described in children, but no systematic study about the prevalence of autoimmune bullous diseases (AIBD) in children is available.

PATIENTS AND METHODS

We analysed data of 1.7 million children insured in the largest German health insurance company based on the ICD-10-GM classification for the year 2015. Data were adjusted to the general German population based on the data of the Federal Statistical Office for the year 2015.

RESULTS

The prevalence of AIBD was calculated to 101.1/million children in 2015, resulting in about 1351 patients below the age of 18 years in Germany. The highest prevalence of all AIBD was seen for pemphigus vulgaris (30.5/million children) followed by linear IgA disease (24.5/million children) and bullous pemphigoid (4.9/million children).

CONCLUSION

Autoimmune bullous diseases in minors are scarce but should be taken into consideration in patients with pruritus and/or blisters and erosions on the skin and/or mucous membranes. Treatment is challenging, and due to the rarity of AIBD in minors, the management of these disorders in this patient population is best performed in specialized centres in a multidisciplinary approach, including paediatric dermatologists or dermatologists and paediatricians.

Sex-related response to bivalirudin and unfractionated heparin in patients with acute myocardial infarction undergoing percutaneous coronary intervention: A subgroup analysis of the VALIDATE-SWEDEHEART trial

Aims:

Our aim was to study the impact of sex on anticoagulant treatment outcomes during percutaneous coronary intervention in acute myocardial infarction patients.

Methods:

This study was a prespecified analysis of the Bivalirudin versus Heparin in ST-Segment and Non ST-Segment Elevation Myocardial Infarction in Patients on Modern Antiplatelet Therapy in the Swedish Web System for Enhancement and Development of Evidence-based Care in Heart Disease Evaluated according to Recommended Therapies Registry Trial (VALIDATE-SWEDEHEART) trial, in which patients with myocardial infarction were randomised to bivalirudin or unfractionated heparin during percutaneous coronary intervention. The primary outcome was the composite of death, myocardial infarction or major bleeding at 180 days.

Results:

There was a lower risk of the primary outcome in women assigned to bivalirudin than to unfractionated heparin (13.6% vs 17.1%, hazard ratio 0.78, 95% confidence interval (0.60–1.00)) with no significant difference in men (11.8% vs 11.2%, hazard ratio 1.06 (0.89–1.26), p for interaction 0.05). The observed difference was primarily due to lower risk of major bleeding (Bleeding Academic Research Consortium definition 2, 3 or 5) associated with bivalirudin in women (8.9% vs 11.8%, hazard ratio 0.74 (0.54–1.01)) but not in men (8.5% vs 7.3%, hazard ratio 1.16 (0.94–1.43) in men, p for interaction 0.02). Conversely, no significant difference in the risk of Bleeding Academic Research Consortium 3 or 5 bleeding, associated with bivalirudin, was found in women 4.5% vs 5.4% (hazard ratio 0.84 (0.54–1.31)) or men 2.9% vs 2.1% (hazard ratio 1.36 (0.93–1.99)). Bleeding Academic Research Consortium 2 bleeding occurred significantly less often in women assigned to bivalirudin than to unfractionated heparin. The risk of death or myocardial infarction did not significantly differ between randomised treatments in men or women.

Conclusion:

In women, bivalirudin was associated with a lower risk of adverse outcomes, compared to unfractionated heparin, primarily due to a significant reduction in Bleeding Academic Research Consortium 2 bleeds.

Two Models for Outcome Prediction

Objectives: Accurately predicting disease progress from a set of predictive variables is an important aspect of clinical work. For binary outcomes, the classical approach is to develop prognostic logistic regression (LR) models. Alternatively, machine learning algorithms were proposed with artificial neural networks (ANN) having become popular over the last decades. Although some studies have compared predictive accuracies of LR and ANN models, some concerns regarding their methodological quality have been voiced. Our comparison has the advantage of being based on two large independent data sets allowing for elaborate model development and independent validation.

Methods: From the German Stroke Database, a learning data set including 1754 prospectively recruited patients with acute ischemic stroke was used. Utilizing LR and ANN, two prognostic models were developed predicting restitution of functional independence and survival after 100 days. The resulting models were applied to classify 1470 patients with acute ischemic stroke; this test data set was collected independently from the learning data. Error fractions in the test data were determined, and differences in error fractions between the algorithms were calculated with 95% confidence intervals.

Results: For most prognostic models, error fractions in the test data were below 40%. There was no difference between the algorithms except for the model predicting completely versus incompletely restituted or deceased patients (difference in error fractions = 4.01% [2.10-5.96%], p = 0.0001).

Conclusions: The conscientiously applied LR remains the gold standard for prognostic modelling; however, ANN can be an alternative automated “quick and easy” multivariate analysis.

Assessing Applicability of Ontological Principles to Different Types of Biomedical Vocabularies

Objectives: Recently, ontological principles have been applied to numerous biomedical vocabularies, with the intention to identify mistakes and poor modeling decisions. No doubt, such applications are useful and necessary for terminological systems like SNOMED CT based on an axiomatic logical formalism.

Methods: In the following review, ontology is dealt with by focussing on particularly two aspects: the problem of ISA-overloading and the intrusion of epistemology-loaded terms in biomedical vocabularies. Both aspects are considered with respect to three types of biomedical vocabularies.

Results: Opposed to concept-oriented terminological systems, the purpose-specific organization of descriptors in thesauri and classes in statistical classifications on an extra aggregation level make it impossible to apply ontological principles. On the contrary, their intended purpose presupposes specific mechanisms that are in conflict with those principles.

Conclusions: Interestingly, for thesauri and classifications there are rather similar initiatives linking the extra level of descriptors and classes on the one hand and an intermediate concept level on the other hand. Such an approach proved beneficial for maintaining and translating thesauri and classifications.

Why is it difficult to wash aphids off from superhydrophobic kale?

Many varieties of the cabbage family have leaves covered with superhydrophobic epicuticular wax, which provides them with self-cleaning characteristics. Since the wax also lowers insect adhesion, rinsing of the leaves with water should be an effective way of removing the insects. Conversely, we report that superhydrophobicity of tuscan kale increases resistance of aphids to hydrodynamic removal. The exterior surface of the insects is also superhydrophobic and acts as an extension of the leaf's surface. As a result even at moderate impact velocities impinging water drops cannot penetrate under the pests. Consequently, liquid impact aids the insect's adhesion by increasing the normal compressive forces they experience. We show that on a hydrophilic arugula leaf this mechanism is absent, and aphids can be easily washed off with water, as it is able to penetrate underneath them. As for removal of aphids from Tuscan kale, we show that lower surface tension liquids, such as oils and soapy water are more effective, because they are able to wet both the plant and insect surfaces. We also show that aerodynamic removal of aphids consisting of simply exposing the invaded leaf to an air flow is most effective.

Microscale Mechanism of Age Dependent Wetting Properties of Prickly Pear Cacti (Opuntia)

Cacti thrive in xeric environments through specialized water storage and collection tactics such as a shallow, widespread root system that maximizes rainwater absorption and spines adapted for fog droplet collection. However, in many cacti, the epidermis, not the spines, dominates the exterior surface area. Yet, little attention has been dedicated to studying interactions of the cactus epidermis with water drops. Surprisingly, the epidermis of plants in the genus Opuntia, also known as prickly pear cacti, has water-repelling characteristics. In this work, we report that surface properties of cladodes of 25 taxa of Opuntia grown in an arid Sonoran climate switch from water-repelling to superwetting under water impact over the span of a single season. We show that the old cladode surfaces are not superhydrophilic, but have nearly vanishing receding contact angle. We study water drop interactions with, as well as nano/microscale topology and chemistry of, the new and old cladodes of two Opuntia species and use this information to uncover the microscopic mechanism underlying this phenomenon. We demonstrate that composition of extracted wax and its contact angle do not change significantly with time. Instead, we show that the reported age dependent wetting behavior primarily stems from pinning of the receding contact line along multilayer surface microcracks in the epicuticular wax that expose the underlying highly hydrophilic layers.

[Quality Assurance using routine data: Overdiagnosis by radiological imaging for back pain]

Background and Problem: Acute nonspecific back pain disorders are typically self-limiting. According to the national guideline low back pain, only in case of clinical suspicion of a serious course radiological imaging should take place immediately. Otherwise, the guideline recommends waiting at least six weeks.

PATIENTS AND METHODOLOGY

Using Statutory Health Insurance (SHI) routine data of the Techniker Krankenkasse we analyzed how many of the insured persons suffering from acute back pain for the first time with no indication of a serious outcome received a non-indicated diagnostic imaging.

RESULTS

In about 10 % diagnostic imaging is conducted after initial diagnosis. If an imaging is carried out, roughly one third of these cases takes place ahead of time or is completely unnecessary. Methodically this is a very conservative estimation, thus it seems likely that the extent of overdiagnosis in actual medical care situation is even larger.

CONCLUSIONS

Every third patient who received radiological diagnostics due to first acute nonspecific back pain underwent the procedure more quickly than recommended (less than six weeks). Overdiagnosis is not only economically problematic but also with respect to patient orientation and patient safety. It may cause substantial damage to patients - either by the use of diagnostics itself or by means of therapies initiated after diagnostics.

Inhibition of Condensation Frosting by Arrays of Hygroscopic Antifreeze Drops

The formation of frost and ice can have negative impacts on travel and a variety of industrial processes and is typically addressed by dispensing antifreeze substances such as salts and glycols. Despite the popularity of this anti-icing approach, some of the intricate underlying physical mechanisms are just being unraveled. For example, recent studies have shown that in addition to suppressing ice formation within its own volume, an individual salt saturated water microdroplet forms a region of inhibited condensation and condensation frosting (RIC) in its surrounding area. This occurs because salt saturated water, like most antifreeze substances, is hygroscopic and has water vapor pressure at its surface lower than water saturation pressure at the substrate. Here, we demonstrate that for macroscopic drops of propylene glycol and salt saturated water, the absolute RIC size can remain essentially unchanged for several hours. Utilizing this observation, we demonstrate that frost formation can be completely inhibited in-between microscopic and macroscopic arrays of propylene glycol and salt saturated water drops with spacing (S) smaller than twice the radius of the RIC (δ). Furthermore, by characterizing condensation frosting dynamics around various hygroscopic drop arrays, we demonstrate that they can delay complete frosting over of the samples 1.6 to 10 times longer than films of the liquids with equivalent volume. The significant delay in onset of ice nucleation achieved by dispensing propylene glycol in drops rather than in films is likely due to uniform dilution of the drops driven by thermocapillary flow. This transport mode is absent in the films, leading to faster dilution, and with that facilitated homogeneous nucleation, near the liquid-air interface.

[Age- and Gender-specific Costs as Well as Drug Therapies of ADHD Patients]

Backround and Objectives: Attention deficit hyperactivity disorder (ADHD) is one of the most commonly diagnosed mental disorders in children and adolescents. The rate of persistence into adulthood varies up to 60% and shows the importance of the disease. Here we present age-stratified cost information on adult patients, as well as data on occupational therapy, medication and multimodal treatment. Furthermore, we also investigated retrospectively if methylphenidate was prescribed for adults already before its approval in 2011.

METHODS

Claims data of a major German insurance fund (Techniker Krankenkasse) was available. Inclusion criteria were patients with ADHD diagnosis, either hospitalized or treated on an outpatient basis in 2006, 2007 and 2008 and insured over this period. This enabled identifying this disease as chronic. The data were analyzed as part of a control group design (1:3). Cost differences were examined as also the odds ratios for the burden of comorbidities and use of atomoxetine and methylphenidate.

RESULTS

77.9% of the identified ADHD patients were male (mean age: 16.5 years ±11.1). The mean total costs of patient treatment were € 2,032 (±4,112). The odds ratio was highest for the indication developmental disorders of scholastic skills (15.4) and differed between the sexes (female: 24.0 vs. male: 14.2). Drug prescription was higher in male than in female patients (atomoxetine: 7.2 vs. 5.9% and methylphenidate 59.1 vs. 48.4%).

CONCLUSIONS

This study provides important insights into the importance of the adult ADHD collective. There were increasing resource consumption identified in adult ADHD patients. In addition, methylphenidate was used off-label for treating adults already before 2011 and its approval in 2011 provided increased certainty for physicians regarding prescription of this drug.

[Brachytherapy for Prostate Cancer: Potentials and Limitations of Social Health Insurance Data for Benefit Assessment]

BACKGROUND

Due to the insufficient data base the Federal Joint Committee (G-BA) had in 2009 after 7 years of deliberation decided to initiate consultation regarding ambulatory brachytherapy for localised prostate cancer for 10 years from social health insurance (SHI) benefits. The aim is to gain more findings by means of comparative studies.

PROBLEM

Based on the non-availability of clinical primary data of a methodologically acceptable level, it was analysed to what extent secondary data of the SHI may be used in order to arrive at valid conclusions for benefit aspects.

METHODS

As base approx. 8 million insured of TK with their data of cost reimbursement between 2006 and 2011 were considered. In SHI secondary data no clinical information regarding tumour stage and other prognostic factors are available. Therefore, a novel method with therapy-specific multisectoral inclusion and exclusion criteria, respectively, was developed in order to differentiate between localised and advanced tumours of the prostate. Overall survival, relapse-free survival, event-free survival and side-effects associated to prostate cancer were analysed.

RESULTS

Out of 87 822 insured persons with the diagnosis prostate cancer, 795 with PBT, 10 936 with RP and 1 925 with EBRT were investigated in detail. The 4-year event-free survival rate was 73% for RP, 77% for PBT and 71% for EBRT. Many prostate cancer-specific side effects appeared already before intervention. Side effects of the intestinal tract (23.8%) and sexual impairments (26.5%) were more frequent for EBRT than for RP (17.1%/14.8%) and PBT (16.4%/13.2%).

CONCLUSION

By means of SHI secondary data and adequate operationalisation important findings regarding relevant aspects of prostate cancer in healthcare research can be generated. However, these hold methodological limitations and are not suited to draw valid conclusions for benefit assessment. Based solely on SHI routine data valid statements regarding comparative benefit assessment are limited. Limitations could be reduced by applying a record linkage with clinical data. Such primary data should include information on tumour stages as well as therapy assignment and observation of survival time.

[Additional Costs for Care of Patients with Multi-Resistant Pathogens--An Analysis from the Perspective of a Statutory Health Insurance]

Aim of this study was to determine the additional expenditures for a German statutory health insurance which are induced by patients with multi-resistant bacteria. Therefore a nationwide cross-sectional data analysis using routine data of the health insurance "Techniker Krankenkasse" was conducted. In the consideration of costs we included expenditures for inpatient and outpatient care and on drugs in a time period of 12 months. A control group was matched by age, gender, basic disease, quarterly period and region. On average additional costs of 17,500 Euro per insured were calculated due to the presence of multi-resistant bacteria. The hypothesis was corroborated in that the level of these costs differ widely by age, gender and basic disease.

Evaluating methods for intersectoral comparison of quality of care. A routine data analysis of elective percutaneous coronary interventions

OBJECTIVES

To compare the quality of care regarding the use of elective percutaneous coronary interventions (PCIs) in the inpatient and outpatient setting and to evaluate different methods of confounder control in this context.

METHODS

Based on data of three statutory health insurances including more than nine million insurance members, a retrospective cohort study between 2005 and 2009 was conducted. The occurrence of myocardial infarction, stroke, further coronary intervention and death was ascertained following the first PCI in the study period, which was preceded by a one-year period without a PCI. A Cox proportional hazard model was used to assess the influence of the setting of the elective PCI on the risk for complications after the PCI for each outcome separately. Age, sex, the number of diseases of the Elixhauser comorbidity measure, past acute coronary syndrome, coronary artery disease, dyslipidemia, past stroke, past coronary artery bypass surgery and the year of the PCI were included as covariables. The analyses were repeated in a propensity score matched cohort as well as in inverse probability of treatment weighted analyses.

RESULTS

The cohort comprised 4,269 patients with an outpatient PCI and 26,044 patients with an inpatient PCI. The majority of the analyses revealed no statistically significant effect of the setting of the PCI on the risk of myocardial infarction, stroke and further coronary interventions, whereas a reduced mortality risk was observed for outpatient PCIs. Similar results were obtained in the propensity score analyses.

CONCLUSIONS

The analysis revealed that the adjusted risk for complications following an elective PCI is similar between the inpatient and the outpatient setting. For mortality the risk differed but this might be explained by residual or unmeasured confounding. The different methods applied in this study revealed mostly similar results. Since our study only covered one aspect of quality of care in the field of PCI and did not consider drug treatment in hospital or in the outpatient setting, further studies are needed which include these aspects.

[Physicians' prescription behavior of potentially inappropriate medications for elderly people: an analysis using the PRISCUS list based on TK routine data]

BACKGROUND

Referring to the German PRISCUS list, the paper analyzes differences in the prescription of potentially inadequate medication (PIM) between older and younger patients. We account for changes in the development over time and for the influence of the publication of the PRISCUS list.

METHODS

The retrospective study analyzes pharmaceutical prescriptions based on data from the Techniker Krankenkasse for the years 2008-20012. Age groups are compared regarding PIM prescriptions as share of total prescriptions within therapeutic areas (based on ATC codes). For a comparison of prescribed daily doses between age groups the median of those younger than 65 was indexed to the value 100.

RESULTS

The share of older insured with at least one PRISCUS prescription declined from 21,7 % in 2008 to 18,9 % in 2012. Moreover, the total share of PIM prescriptions is steadily higher for elderly persons. Comparing major therapeutic areas shows a heterogeneous picture. An influence of the PRISCUS list on the prescription behavior is not observable.

CONCLUSION

The share of PIM prescriptions in the TK sample is slightly declining over time. Unexpectedly, the total share is higher for the elderly than for those below 65. With regard to different therapeutic areas, results are less clear. For future research, our findings emphasize the need to rely on the applied methods.

[Incidence and prevalence of type 2 diabetes mellitus in Germany: an analysis based on 5.43 million patients]

BACKGROUND AND OBJECTIVE

Based on claims-data of 5.43 million members of a large German statutory health insurance fund in 2008 (Techniker Krankenkasse), the aim of this contribution is to update and more precisely quantify age- and gender-specific prevalence and incidence of type 2 diabetes mellitus (T2DM) in a German setting.

METHODS

A patient was classified as T2DM prevalent if he or she had received at least two outpatient diagnoses of T2DM in two different quarters of the year and/or had received at least one T2DM diagnosis during inpatient treatment between 01/01/2006 and 12/31/2008. A patient was considered to have had new onset T2DM in 2008 under one of three conditions: 1. no diagnosis of T2DM in 2006 and 2007, 2. no presripction of oral antidiabetics in 2006 and 2007, 3. either one inpatient or two outpatient diagnoses of T2DM conducted in two different quarters of 2008 or one outpatient T2DM diagnosis in 2006/07 when the second diagnosis was made in 2008.

RESULTS

A total of 254,524 patients had T2DM. Compared to the total membership of the medical insurance fund, the prevalence of T2DM was 4.69 %. The average age was 64.8 years, and 66.37 % were male. The incidence of T2DM in our sample was 2.814 cases per 1,000 person-years in men and 1.690 cases in 1,000 person-years in women. Based on our sample and on official population data, 4,704,585 patients (5.75 %) in Germany would be T2DM prevalent in 2009. The number of incident T2DM cases would amount to 215,746 patients (0.264 %).

CONCLUSIONS

T2DM is one of the most common chronic diseases in Germany. The expected demographic changes in Germany will increase the burden on the German health system caused by T2DM.

Computer-Aided Diagnosis of Multiple Sclerosis

The study aims to develop a computer-assisted decision support based on cerebrospinal fluid (CSF) and blood findings to improve their value and ease the diagnostic procedure of chronic inflammatory diseases (CIDs) of central nervous system (CNS). Data were collected from patients suffering from multiple sclerosis (MS,n = 73), from another CID of the CNS (n = 22), or a psychiatric disease (control group, CTRL,n = 12). Univariate and multivariate analyses were performed using multiple logistic regression and artificial neural networks. Differentiating between MS and CID, no parameter could be disclosed that could provide a meaningful decision support. However, multivariate analysis obtained a statistically significant classification (sensitivity = 84.9%, specificity = 54.5%,p < 0.001). On the contrary, multivariate analysis based on the differentiation between MS vs. CTRL, gave good results (sensitivity = 95.9%, specificity = 83.3%,p < 0.001). It became evident from standard laboratory findings that there is a significant potential for computer-aided decision support.

Is late stent thrombosis in drug-eluting stents a real clinical issue? A single-center experience and review of the literature

BACKGROUND

Randomized studies have not found an increased rate of late stent thrombosis (LAST) in drug-eluting stents (DES) compared with bare metal stents (BMS) but those studies were statistically not powered to show such a difference. At the same time there is an increasing number of reports of LAST in DES patients in the current literature.

PATIENTS AND METHODS

We tried to describe the incidence of LAST in an unselected DES and BMS patient population. All patients who underwent stenting in our hospital between October 2003 and March 2006 were included in the study (n=1377). A total of 424 (30.1%) patients were treated with only BMS stents, 520 (37.8%) with paclitaxel-eluting stents (PES), 384 (27.9%) with sirolimus-eluting stents (SES) and 49 (3.6%) with BMS and DES. Long-term follow-up of all patients was used to determine the incidence of LAST as defined by angiographically proven stent thrombosis associated with acute symptoms more than 30 days after stent implantation. Followup was between 1 month and 2 years 7 months (mean 12 months). Patients treated with DES were younger (66+/-11 years) than BMS patients (72+/-10 years; p<0.001) and more often had diabetes (24.2% vs 17.4%; p < 0.001). A previous PCI had been performed in 27.1% of DES patients vs 13.9% of BMS patients (p < 0.001).

RESULTS

There were 9 cases of LAST: 2 with SES (at 6 and 11 months after implantation), 6 with PES (at 6, 9 (2x), 10, 16 and 26 months), and one with BMS (at 22 months). All patients with LAST presented with STEMI and without an angina history that suggested restenosis. Two cases were related to complete cessation of antiplatelet therapy, one because of patient non-compliance (SES), one after aspirin was stopped for orthopedic surgery (BMS). Two cases occurred within 1 month of cessation of clopidogrel therapy and while these patients were on aspirin therapy. Five cases occurred on aspirin monotherapy 2, 3, 4, 10 and 20 months, respectively after planned cessation of clopidogrel. None of the cases occurred under dual antiplatelet therapy. All patients underwent primary PCI; none died.

CONCLUSION

Angiographically proven LAST occurred in our unselected patient population with an incidence of 0.84% in patients treated with DES and 0.21% in BMS patients within a mean follow-up of 12 months (p = 0.36). LAST may indeed occur in clinically stable patients while on aspirin monotherapy. Since LAST led in all patients to STEMI it seems to be a serious clinical issue that prompts further investigation and discussion of length of dual platelet therapy.