Intensive versus standard dose statin therapy: the costs and benefits for patients with acute coronary syndrome

Introduction: Recent NICE guidance in England and Wales states that statin therapy for secondary CVD should "usually be initiated with a drug with a low acquisition cost (taking into account required daily dose and product price per dose)". Intensive dose statin therapy is more costly than standard dose, but offers additional benefits and may potentially be more cost effective for a sub-group of high risk patients. Objective: To determine if the strategy of treating ACS patients with intensive dose statin compared with standard dose statin can be considered to be cost effective and to what extent these results are influenced by the age of the patient at start of treatment. Methods: A Markov model was used to explore the costs and health outcomes associated with a lifetime of intensive dose (represented by 80mg atorvastatin) versus standard dose (represented by 20mg simvastatin) treatment for patients with acute coronary syndrome. Health states included unstable angina, MI, stroke, fatal CHD, fatal stroke, or non vascular death. The benefits associated with statin treatment were modelled by applying the relative risks from a meta-analysis of 4 large RCTs reporting clinical endpoints. Costs and utilities assigned to health states were derived from a review of published evidence. Results: Treatment with intensive dose statin therapy offers additional benefits over standard dose therapy. The cost offsets through avoided events are less than the associated treatment costs and result in a cost per QALY of around £24,000 for patients with ACS starting treatment at 60 years of age and falling to around £14,000 for patients starting treatment at 70 years. The key driver of cost effectiveness is the relative risk for mortality. Conclusions: This analysis suggests that intensive statin regimens (represented by atorvastatin 80mg/day) are cost effective compared with standard statin regimens (represented by simvastatin 20mg/day) for patients with ACS over the age of 60 years. A recent registry study reports a mean age of 70 years for ACS patients admitted to UK hospitals and hence this comparison applies to the great majority of ACS patients

Intensive versus standard dose statin therapy: the costs and benefits for patients with acute coronary syndrome

Introduction: Recent NICE guidance in England and Wales states that statin therapy for secondary CVD should "usually be initiated with a drug with a low acquisition cost (taking into account required daily dose and product price per dose)". Intensive dose statin therapy is more costly than standard dose, but offers additional benefits and may potentially be more cost effective for a sub-group of high risk patients. Objective: To determine if the strategy of treating ACS patients with intensive dose statin compared with standard dose statin can be considered to be cost effective and to what extent these results are influenced by the age of the patient at start of treatment. Methods: A Markov model was used to explore the costs and health outcomes associated with a lifetime of intensive dose (represented by 80mg atorvastatin) versus standard dose (represented by 20mg simvastatin) treatment for patients with acute coronary syndrome. Health states included unstable angina, MI, stroke, fatal CHD, fatal stroke, or non vascular death. The benefits associated with statin treatment were modelled by applying the relative risks from a meta-analysis of 4 large RCTs reporting clinical endpoints. Costs and utilities assigned to health states were derived from a review of published evidence. Results: Treatment with intensive dose statin therapy offers additional benefits over standard dose therapy. The cost offsets through avoided events are less than the associated treatment costs and result in a cost per QALY of around £24,000 for patients with ACS starting treatment at 60 years of age and falling to around £14,000 for patients starting treatment at 70 years. The key driver of cost effectiveness is the relative risk for mortality. Conclusions: This analysis suggests that intensive statin regimens (represented by atorvastatin 80mg/day) are cost effective compared with standard statin regimens (represented by simvastatin 20mg/day) for patients with ACS over the age of 60 years. A recent registry study reports a mean age of 70 years for ACS patients admitted to UK hospitals and hence this comparison applies to the great majority of ACS patients

Information capacity of quantum observable

In this paper we consider the classical capacities of quantum-classical channels corresponding to measurement of observables. Special attention is paid to the case of continuous observables. We give the formulas for unassisted and entanglement-assisted classical capacities $C,C_{ea}$ and consider some explicitly solvable cases which give simple examples of entanglement-breaking channels with $C<C_{ea}.$ We also elaborate on the ensemble-observable duality to show that $C_{ea}$ for the measurement channel is related to the $\chi$-quantity for the dual ensemble in the same way as $C$ is related to the accessible information. This provides both accessible information and the $\chi$-quantity for the quantum ensembles dual to our examples.Comment: 13 pages. New section and references are added concerning the ensemble-observable dualit

Universal geometric approach to uncertainty, entropy and information

It is shown that for any ensemble, whether classical or quantum, continuous or discrete, there is only one measure of the "volume" of the ensemble that is compatible with several basic geometric postulates. This volume measure is thus a preferred and universal choice for characterising the inherent spread, dispersion, localisation, etc, of the ensemble. Remarkably, this unique "ensemble volume" is a simple function of the ensemble entropy, and hence provides a new geometric characterisation of the latter quantity. Applications include unified, volume-based derivations of the Holevo and Shannon bounds in quantum and classical information theory; a precise geometric interpretation of thermodynamic entropy for equilibrium ensembles; a geometric derivation of semi-classical uncertainty relations; a new means for defining classical and quantum localization for arbitrary evolution processes; a geometric interpretation of relative entropy; and a new proposed definition for the spot-size of an optical beam. Advantages of the ensemble volume over other measures of localization (root-mean-square deviation, Renyi entropies, and inverse participation ratio) are discussed.Comment: Latex, 38 pages + 2 figures; p(\alpha)->1/|T| in Eq. (72) [Eq. (A10) of published version

Use of cumulative mortality data in patients with acute myocardial infarction for early detection of variation in clinical practice: observational study

OBJECTIVES: Use of cumulative mortality adjusted for case mix in patients with acute myocardial infarction for early detection of variation in clinical practice. DESIGN: Observational study. SETTING: 20 hospitals across the former Yorkshire region. PARTICIPANTS: All 2153 consecutive patients with confirmed acute myocardial infarction identified during three months. MAIN OUTCOME MEASURES: Variable life­adjusted displays showing cumulative differences between observed and expected mortality of patients; expected mortality calculated from risk model based on admission characteristics of age, heart rate, and systolic blood pressure. RESULTS: The performance of two individual hospitals over three months was examined as an example. One, the smallest district hospital in the region, had a series of 30 consecutive patients but had five more deaths than predicted. The variable life­adjusted display showed minimal variation from that predicted for the first 15 patients followed by a run of unexpectedly high mortality. The second example was the main tertiary referral centre for the region, which admitted 188 consecutive patients. The display showed a period of apparently poor performance followed by substantial improvement, where the plot rose steadily from a cumulative net lives saved of - 4 to 7. These variations in patient outcome are unlikely to have been revealed during conventional audit practice. CONCLUSIONS: Variable life­adjusted display has been integrated into surgical care as a graphical display of risk­adjusted survival for individual surgeons or centres. In combination with a simple risk model, it may have a role in monitoring performance and outcome in patients with acute myocardial infarction

How to find the holonomy algebra of a Lorentzian manifold

Manifolds with exceptional holonomy play an important role in string theory, supergravity and M-theory. It is explained how one can find the holonomy algebra of an arbitrary Riemannian or Lorentzian manifold. Using the de~Rham and Wu decompositions, this problem is reduced to the case of locally indecomposable manifolds. In the case of locally indecomposable Riemannian manifolds, it is known that the holonomy algebra can be found from the analysis of special geometric structures on the manifold. If the holonomy algebra $\mathfrak{g}\subset\mathfrak{so}(1,n-1)$ of a locally indecomposable Lorentzian manifold $(M,g)$ of dimension $n$ is different from $\mathfrak{so}(1,n-1)$, then it is contained in the similitude algebra $\mathfrak{sim}(n-2)$. There are 4 types of such holonomy algebras. Criterion how to find the type of $\mathfrak{g}$ are given, and special geometric structures corresponding to each type are described. To each $\mathfrak{g}$ there is a canonically associated subalgebra $\mathfrak{h}\subset\mathfrak{so}(n-2)$. An algorithm how to find $\mathfrak{h}$ is provided.Comment: 15 pages; the final versio

Efficient measurements, purification, and bounds on the mutual information

When a measurement is made on a quantum system in which classical information is encoded, the measurement reduces the observers average Shannon entropy for the encoding ensemble. This reduction, being the {\em mutual information}, is always non-negative. For efficient measurements the state is also purified; that is, on average, the observers von Neumann entropy for the state of the system is also reduced by a non-negative amount. Here we point out that by re-writing a bound derived by Hall [Phys. Rev. A {\bf 55}, 100 (1997)], which is dual to the Holevo bound, one finds that for efficient measurements, the mutual information is bounded by the reduction in the von Neumann entropy. We also show that this result, which provides a physical interpretation for Hall's bound, may be derived directly from the Schumacher-Westmoreland-Wootters theorem [Phys. Rev. Lett. {\bf 76}, 3452 (1996)]. We discuss these bounds, and their relationship to another bound, valid for efficient measurements on pure state ensembles, which involves the subentropy.Comment: 4 pages, Revtex4. v3: rewritten and reinterpreted somewha

Soliton molecules in trapped vector Nonlinear Schrodinger systems

We study a new class of vector solitons in trapped Nonlinear Schrodinger systems modelling the dynamics of coupled light beams in GRIN Kerr media and atomic mixtures in Bose-Einstein condensates. These solitons exist for different spatial dimensions, their existence is studied by means of a systematic mathematical technique and the analysis is made for inhomogeneous media

Institutional Learning and Change: an introduction

Originally published by the International Service for National Agricultural Research as: Watts, J. R. Mackay, D. Horton, A. Hall, B. Douthwaite, R. Chambers and A. Acosta. (2003). Institutional learning and change: An introduction. ISNAR Discussion Paper No.03-10, The Hague: International Service for National Agricultural ResearchThroughout the world, the pace of environmental, social and technological change is accelerating, and this in turn has major implications for the poor and their development prospects. Traditional transfer-of-technology approaches to agricultural research can no longer keep pace with the complex, diverse, risk-prone and dynamic realities of poor farmers. If agricultural research organizations are to be more successful in reducing poverty and increasing the sustainability of agricultural production systems, they must become less isolated, more interconnected and more responsive. In so doing, they must transform themselves into learning organizations, more in touch with field realities and better able to learn and to change. Recent research on the poverty alleviating impacts of technology associated with the Consultative Group on International Agricultural Research (CGIAR) has identified institutional learning and change (ILAC) as a key area for intervention if research is to be more efficient and effective in serving the poor