The effectiveness and cost-effectiveness of biomarkers for the prioritisation of patients awaiting coronary revascularisation: a systematic review and decision model

OBJECTIVE

To determine the effectiveness and cost-effectiveness of a range of strategies based on conventional clinical information and novel circulating biomarkers for prioritising patients with stable angina awaiting coronary artery bypass grafting (CABG).

DATA SOURCES

MEDLINE and EMBASE were searched from 1966 until 30 November 2008.

REVIEW METHODS

We carried out systematic reviews and meta-analyses of literature-based estimates of the prognostic effects of circulating biomarkers in stable coronary disease. We assessed five routinely measured biomarkers and the eight emerging (i.e. not currently routinely measured) biomarkers recommended by the European Society of Cardiology Angina guidelines. The cost-effectiveness of prioritising patients on the waiting list for CABG using circulating biomarkers was compared against a range of alternative formal approaches to prioritisation as well as no formal prioritisation. A decision-analytic model was developed to synthesise data on a range of effectiveness, resource use and value parameters necessary to determine cost-effectiveness. A total of seven strategies was evaluated in the final model.

RESULTS

We included 390 reports of biomarker effects in our review. The quality of individual study reports was variable, with evidence of small study (publication) bias and incomplete adjustment for simple clinical information such as age, sex, smoking, diabetes and obesity. The risk of cardiovascular events while on the waiting list for CABG was 3 per 10,000 patients per day within the first 90 days (184 events in 9935 patients with a mean of 59 days at risk). Risk factors associated with an increased risk, and included in the basic risk equation, were age, diabetes, heart failure, previous myocardial infarction and involvement of the left main coronary artery or three-vessel disease. The optimal strategy in terms of cost-effectiveness considerations was a prioritisation strategy employing biomarker information. Evaluating shorter maximum waiting times did not alter the conclusion that a prioritisation strategy with a risk score using estimated glomerular filtration rate (eGFR) was cost-effective. These results were robust to most alternative scenarios investigating other sources of uncertainty. However, the cost-effectiveness of the strategy using a risk score with both eGFR and C-reactive protein (CRP) was potentially sensitive to the cost of the CRP test itself (assumed to be 6 pounds in the base-case scenario).

CONCLUSIONS

Formally employing more information in the prioritisation of patients awaiting CABG appears to be a cost-effective approach and may result in improved health outcomes. The most robust results relate to a strategy employing a risk score using conventional clinical information together with a single biomarker (eGFR). The additional prognostic information conferred by collecting the more costly novel circulating biomarker CRP, singly or in combination with other biomarkers, in terms of waiting list prioritisation is unlikely to be cost-effective.

Cigarette smoking and panic: a critical review of the literature

OBJECTIVE

Cigarette smoking increases the risk of panic disorder with or without agoraphobia's emerging. Although the cause of this comorbidity remains controversial, the main explanations are that (1) cigarette smoking promotes panic by inducing respiratory abnormalities/lung disease or by increasing potentially fear-producing bodily sensations, (2) nicotine produces physiologic effects characteristic of panic by releasing norepinephrine, (3) panic disorder promotes cigarette smoking as self-medication, and (4) a shared vulnerability promotes both conditions. The aim of this review was to survey the literature in order to determine the validity of these explanatory models.

DATA SOURCES

Studies were identified by searching English language articles published from 1960 to November 27, 2008, in MEDLINE using the key words: nicotine AND panic, tobacco AND panic, and smoking AND panic.

STUDY SELECTION

Twenty-four studies were reviewed and selected according to the following criteria: panic disorder with or without agoraphobia and nicotine dependence, when used, diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised, Fourth Edition, or Fourth Edition, Text Revision; no additional comorbidity or, if present, adjustment for it in the statistical analyses; use of adult or adolescent samples; comparison with a nonclinical control group or application of a crossover design.

DATA EXTRACTION

Non-significant results or trends only were reported as no difference. Data on anxiety disorders or substance abuse in general were not included.

DATA SYNTHESIS

Panic and cigarette smoking each appear to have the capacity to serve as a causal factor/facilitator in the development of the other. Although the temporal pattern and the pathogenetic explanations of such a co-occurrence are still being discussed, cigarette smoking tends to precede the onset of panic and to promote panic itself.

CONCLUSIONS

Additional studies are strongly recommended.

Breed predisposition to congenital alacrima in dogs

OBJECTIVE

To evaluate the clinical characteristics and breed predisposition of congenital alacrima in dogs. Animals studied Dogs with congenital keratoconjunctivitis sicca.

PROCEDURES

A search of the medical records of the University of Tennessee Veterinary Teaching Hospital from 1974-2005 and the University of California-Davis Veterinary Teaching Hospital from 1986-2006 for dogs under 1 year of age with a diagnosis of keratoconjunctivitis sicca (KCS) was performed. These cases were further reviewed for dogs with a Schirmer's tear test I of <or= 5 mm/min before 6 months of age, with no known causes for KCS, which did not respond to appropriate KCS therapy; these cases were considered to have congenital alacrima. These breeds were compared to all other breeds using the Fisher's exact test with correction for multiple comparisons.

RESULTS

Congenital alacrima was identified in 19 dogs representing 11 breeds and mixed breeds. Yorkshire Terriers and Bedlington Terriers were statistically overrepresented compared to reference populations (P < 0.01 and P = 0.04, respectively).

CONCLUSIONS

Yorkshire terriers are significantly at risk for congenital alacrima compared to other breeds. The significance of the increase in congenital alacrima in Bedlington Terriers in this study may not be clinically relevant and may be due to the small total number of dogs of this breed that presented to the both hospitals. Based on the poor response to therapy in humans with congenital alacrima, it may be prudent to offer guarded prognoses for KCS in juvenile Yorkshire terriers.

Biological challenge procedures used to study co-occurring nicotine dependence and panic disorder

A wide array of biological challenge procedures - including carbon dioxide inhalation, hyperventilation, and breath holding - have been used to model panic in laboratory settings. Originally used to study developmental processes in panic disorder (PD), these procedures, along with nicotine patch administration and self-administered smoking, have recently been applied to help understand the etiology of co-occurring nicotine dependence and PD. The goals of the present paper are to review studies that have employed biological challenges to study the comorbid condition, identify the advantages and limitations of the various procedures, describe desirable outcome measures for use in biological challenges, and present recommendations for future challenge studies in this field. We argue that biological challenges, though in need of standardization, are useful for studying the development, maintenance, prevention, and treatment of comorbid nicotine dependence and PD.

Linkages between cigarette smoking outcome expectancies and negative emotional vulnerability

The present investigation examined whether smoking outcome expectancies, as measured by the Smoking Consequences Questionnaire (SCQ; [Brandon, T.H., & Baker, T.B., (1991). The Smoking Consequences Questionnaire: The subjective expected utility of smoking in college students. Psychological Assessment, 3, 484-491.]), were incrementally related to emotional vulnerability factors among an adult sample of 202 daily cigarette smokers (44.6% women; M(age)=23.78 years, SD=9.69 years). After controlling for cigarettes smoked/day, past 30-day marijuana use, current alcohol consumption, and coping style, negative reinforcement/negative affect reduction outcome expectancies were significantly associated with greater levels of negative affectivity, emotional dysregulation, and anxiety sensitivity. The observed effects for negative reinforcement/negative affect reduction also were independent of shared variance with other outcome expectancies. Negative personal consequences outcome expectancies were significantly and incrementally related to anxiety sensitivity, but not negative affectivity or emotional dysregulation. Findings are discussed in terms of the role of negative reinforcement/negative affect reduction smoking outcome expectancies and clinically-relevant negative emotional vulnerability for better understanding cigarette smoking-negative mood problems.

Fear reactivity to bodily sensations among heavy smokers and nonsmokers

Individuals who smoke are more likely to experience panic attacks and develop panic disorder than those in the general population. One possible explanation is that smokers may experience a heightened fear response to somatic disturbances. To date, few laboratory studies have tested this hypothesis directly. The present study examined 24 adult heavy smokers (10 females) in 12-hr nicotine withdrawal and 24 adult nonsmokers (12 females) on subjective and physiological reactivity to a 4-min carbon dioxide rebreathing challenge. Results indicate that, despite an attenuated acceleration in respiration during the challenge, smokers experienced a significantly greater increase in self-reported panic symptoms than nonsmokers. In addition, smokers reported significantly greater trait levels of suffocation fear prior to the challenge. Findings are discussed with respect to the role of smoking in panic vulnerability.

Urge to gamble in problem gamblers exposed to a casino environment

Cue-reactivity has received increased attention in addiction research, though not for gambling in particular. We examined cue reactivity in 18 problem gamblers by accompanying them to a gaming casino and measuring their subjective urge to gamble over a 1-h period. Half of the sample was additionally exposed to a gambling-specific negative mood induction (NMI) manipulation via guided imagery. Overall, about two-thirds of the sample reported moderate to high-gambling urges during the casino exposure. Additionally, the NMI reduced cue-reactivity. Finally, gambling urges in both groups decreased over the course of the exposure sessions. These findings suggest that a majority of problem gamblers experience the urge to gamble when exposed to gambling cues and that the intensity of these urges decrease with time, especially in the presence of a gambling-relevant NMI. Cue exposure should be studied further as a potential tool in the treatment of problem gambling.

Alcohol use disorders and panic disorder: a review of the evidence of a direct relationship

OBJECTIVE

It is generally agreed that alcohol use disorders and panic disorder with (PD[A]) or without agoraphobia (PD) tend to occur within the same individual. However, the cause of this comorbidity remains controversial. Three main explanations are that (1) PD(A) promotes pathologic alcohol use as self-medication, (2) chronic alcohol use and alcohol withdrawal induce changes in the neurochemical system that promote panic, and (3) a third factor, such as familial transmission, promotes both conditions. The aim of this review was to survey the literature in order to determine the validity of these explanatory models.

DATA SOURCES

A review of epidemiologic, family, and laboratory studies was performed. Studies were identified using PubMed (English-language articles published from 1960 to 2006, using the search term alcohol and panic).

STUDY SELECTION

Twenty studies were reviewed and selected according to the following criteria: PD(A) and alcohol abuse/dependence diagnosed according to the DSM, no additional comorbidity, use of adult samples, comparison with a nonclinical control group, or application of a crossover design.

DATA EXTRACTION

Nonsignificant results or trends only were reported as "no difference." Data on "anxiety disorders" or "substance abuse" in general were not included.

DATA SYNTHESIS

In PD(A), alcohol lessens anxious apprehension, thereby decreasing the likelihood of panic. In alcohol use disorders, alcohol increases CO2 sensitivity and may thereby promote panic. In both cases, a significant familial transmission contributes to the co-occurrence.

CONCLUSION

Findings would seem to indicate that PD(A) and alcohol use disorders can both serve to initiate the other via independent mechanisms. Further studies are warranted.

Evidence for respiratory and nonrespiratory subtypes in panic disorder

Recently researchers have posited a "respiratory" subtype of panic disorder (PD), which differs from "nonrespiratory" subtypes in phenomenology and perhaps treatment response. This study was designed to further examine evidence for the existence of a respiratory subtype in PD. Individuals with PD with prominent respiratory symptoms (PD-R; n=10) and without prominent respiratory symptoms (PD-NR; n=23), as well as healthy controls (n=27), underwent a standardized 5% CO(2) rebreathing challenge. Ventilatory response and subjective sensation of suffocation were continuously recorded. The PD-R group exhibited greater subjective suffocation levels, rates of respiration, and propensity to terminate the procedure voluntarily than did the other two groups, which in turn did not differ on these measures. Findings are consistent with the existence of a respiratory subtype of PD, which differs from nonrespiratory subtypes in CO(2) sensitivity.

The clinical effectiveness and cost-effectiveness of enzyme replacement therapy for Gaucher's disease: a systematic review

OBJECTIVES

The aim of this review is to determine the clinical effectiveness and cost-effectiveness of enzyme replacement therapy (ERT) in the treatment of symptomatic Gaucher's disease.

DATA SOURCES

Major electronic databases were searched from their inception to August 2003; and updated from January 2003 to July/August 2004.

REVIEW METHODS

Databases were searched for studies that met the criteria and selected data were extracted and evaluated. Studies were assessed for their relevance to the UK context and the review objective. The bibliographic databases were also searched to identify existing cost studies, economic evaluations and models. A Markov decision model was constructed based on patients moving between states defined by the modified Severity Score Index (SSI). Most of the parameters were derived from the published literature. ERT was assumed to restore patients to full health in the base case.

RESULTS

Sixty-three studies were included, all suggestive of benefit with ERT. However, the way in which the effects translate into patient well-being and survival or the need for services and resources has not been reliably estimated. Quality of life improvements with ERT have been reported. Nonetheless, studies based on the Short Form 36 (SF-36) indicate that patients treated with ERT continue to have reduced health-related quality of life (HRQoL) compared with the general population. No study attached utility values to quality of life measures for ERT-treated patients. Thirty-one studies relevant to the natural history of the disease were found. Sixteen looked at multiple clinical characteristics of a cohort of patients with type I Gaucher's disease. There was considerable within-study and between-study heterogeneity, but all showed that Gaucher's disease was a progressive condition. Some suggested that the disease may become more indolent in adulthood; however, studies were discrepant on this point. Most disease is diagnosed in adulthood, although about one-quarter presented in childhood, these patients having the most severe symptoms and greatest rate of progression. Modelling of natural history was undertaken using the five papers that reported the SSI for each patient, along with patient-level data on age, age at diagnosis, splenectomy status and genotype, to address the question of whether disease stabilises in adulthood and the degree of correlation between phenotype and genotype. Analysis of the available data suggested that disease progression is likely to slow markedly in adulthood and that genotype is a useful predictor of clinical expression of the disease. Five studies looked at quality of life. Data on this topic were also obtained from the registries. The evidence suggests that the vast majority of the clinical characteristics of type I Gaucher's disease have little impact on subjective HRQoL and that therefore for the majority of people with type I Gaucher's disease this may not be a severe condition. Bone and skeletal symptoms contribute most to the morbidity of the disease and can lead to severe pain and immobility. The mean cost per patient treated was approximately pounds sterling 86,000 per annum in England and Wales. The cost per patient varied considerably by dose. Four existing economic evaluations were found, all of which calculated a very high cost per quality-adjusted life-year (QALY). Using the Markov decision model, ERT was assumed to restore patients to full health in the base case. The estimated incremental cost per QALY [incremental cost-effectiveness ratio (ICER)] in the base case ranged from pounds sterling 380,000 to pounds sterling 476,000 per QALY, depending on genotype. Univariate sensitivity analyses examined ERT not restoring full health, more severe disease progression in the untreated cohort, and only treating the most severely affected patients. These produced ICERs of approximately pounds sterling 1.4 million, pounds sterling 296,000 and pounds sterling 275,000 per QALY, respectively. The base-case unit cost of the drug is pounds sterling 2.975. The unit cost would have had to be reduced ten-fold, to pounds sterling 0.30, to obtain an ICER of pounds sterling 30,000 per QALY. At a unit cost of pounds sterling 1 the ICER would be pounds sterling 120,000 per QALY.

CONCLUSIONS

Although ERT for treating the 'average' Gaucher's disease patient exceeds the normal upper threshold for cost-effectiveness seen in NHS policy decisions by over ten-fold, some argue that since orphan drug legislation encouraged the manufacture of Cerezyme, and Gaucher's disease can be defined as an orphan disease, the NHS has little option but to provide it, despite its great expense. More information is required before the generalisability of the findings can be determined. Although data from the UK have been used wherever possible, these were very thin indeed. Nonetheless, even large errors in estimates of the distribution of genotype, genotype--phenotype associations, effectiveness and numbers of patients will not reduce the ICER to anywhere near the upper level of treatments usually considered cost-effective. Further research could help to clarify the many uncertainties that exist. However, although doing so will be of clinical interest, it is questionable whether, within the current pricing environment, such research would have any substantive impact on policy decisions. It is highly improbable that, whatever the findings of such research, the ICER could be brought down by the orders of magnitude required to make ERT an efficient use of health service resources. (The possible exception to this would be investigating the most efficient alternative treatment strategies for using ERT in a paediatric population only.) Moreover, if under equity considerations for orphan diseases the NHS feels it is important to provide this drug, regardless of its cost-effectiveness, then refining the precision of the ICER estimate also becomes superfluous.

Optimizing a canine survival model of orthotopic lung transplantation

INTRODUCTION

While acute models of orthotopic lung transplantation have been described in dogs, the technical considerations of developing a survival model in this species have not been elaborated. Herein, we describe optimization of a canine survival model of orthotopic lung transplantation.

METHODS

Protocols of orthotopic left lung transplantation and single lung ventilation were established in acute experiments (n=9). Four dogs, serving as controls, received autologous, orthotopic lung transplants. Allogeneic transplants were performed in 16 DLA-identical and 16 DLA-mismatched unrelated recipient dogs. Selective right lung ventilation was utilized in all animals. A Malecot tube was left in the pleural space connected to a Heimlich valve for up to 24 hours. To date, animals have been followed up to 24 months by chest radiography, pulmonary function tests, bronchoscopy with lavage, and open biopsies.

RESULTS

Long-term survival was achieved in 34/36 animals. Two recipients died intraoperatively secondary to cardiac arrest. All animals were extubated on the operating table, and in all cases the chest tube was removed within 24 hours. Major complications included thrombosis of the pulmonary artery and subcritical stenosis of bronchial anastamosis. One recipient underwent successful treatment of a small bowel intussusception.

CONCLUSIONS

We report our experience in developing a survival canine model of orthotopic single lung transplantation. While short-term survival following canine lung transplantation is achievable, we report particular considerations that facilitate animal comfort, early extubation, and lung reexpansion in the immediate postoperative period, further optimizing use of this species for experimental modeling of long-term complications after lung transplantation.

Effect of nicotine on 35% CO2-induced anxiety: A study in healthy volunteers

Panic disorder and cigarette smoking co-occur at a rate that exceeds what would be expected by chance. Theoretically, cigarette smoking may (a) attenuate panicky symptoms via cognitive factors or pharmacological action, (b) contribute to the development of panic disorder, or (c) share an etiological vulnerability with panic. The present study was aimed at testing whether nicotine has a direct influence on laboratory-elicited panic. In a placebo-controlled, double-blind, randomized, cross-over study, 33 healthy nonsmokers underwent a 35% CO2 challenge after transdermal administration of a nicotine patch on one test day and a placebo patch on another test day. Physiological measures (blood pressure, heart rate) and rating scale scores (Panic Symptom List [PSL], Visual Analog Scale of Anxiety, State-Trait Anxiety Inventory) were assessed. Compared with the placebo condition, nicotine increased diastolic blood pressure (p < .1), heart rate (p < .001), and PSL scores (p < .005) prior to the CO2 challenge but did not affect responding to the CO2 challenge itself. Results are consistent with the notion that nicotine promotes autonomic activation. However, the present study did not provide direct evidence that nicotine elicits panic in healthy volunteers. Replication in a clinical sample is warranted.

Evaluation of canine serum for the presence of antiretinal autoantibodies in sudden acquired retinal degeneration syndrome

OBJECTIVE

To determine the presence of serum antiretinal antibodies in sudden acquired retinal degeneration syndrome (SARDS) affected dogs and the size of the antigen to which these antibodies bind via the use of enzyme-linked immunosorbent assay (ELISA) and Western blot immunoassays.

ANIMALS STUDIED

Serum was collected from 13 dogs affected by SARDS and five dogs with normal ocular examinations.

PROCEDURES

All serum samples were subjected to ELISA with saline-soluble canine retinal tissue and Western blot analyses with SDS solubilized normal canine retinal tissue as the antigen. Antirecoverin (23 kDa) and antiheat shock cognate (65 kDa) antibodies were used as positive controls for both procedures. Affinity-purified goat antidog IgG and IgM labeled with horseradish peroxidase were used for all clinical samples and goat antirabbit IgG was used as the secondary antibody for the positive controls.

RESULTS

ELISA demonstrated antibody reaction with all samples. Western blot immunoassays identified multiple bands in all canine serum samples, as well as in negative controls. Approximate sizes of the bands were 25 and 50 kDa, corresponding to IgG light and heavy chains, respectively.

CONCLUSION

No antiretinal autoantibodies were identified in the serum of dogs affected by SARDS as compared to normal canine patients.

Suffocation and respiratory responses to carbon dioxide and breath holding challenges in individuals with panic disorder

OBJECTIVE

Findings showing that individuals with panic disorder (PD) are prone to experience panic attacks when inhaling CO2-enriched air have given rise to the hypothesis that physiological systems underlying the experience of suffocation may be important in the etiology of PD. In this study, we tested several predictions stemming from this view.

METHODS

Forty individuals with PD and 32 controls underwent both a breath-holding challenge and a CO2 rebreathing challenge. A wide array of physiological and psychological responses, including continuous measurements of subjective suffocation, was recorded.

RESULTS

Individuals with PD experienced elevated physiological reactivity to both challenges and greater levels of suffocation sensations during the rebreathing challenge. Furthermore, PD individuals who experienced a panic attack in response to the rebreathing challenge exhibited faster but shallower breathing during the challenge than did other PD individuals.

CONCLUSION

Findings are consistent with theories linking PD to hypersensitive brain systems underlying the experience of suffocation. The possibility that subjective suffocation was in part mediated by peripheral interoceptive disturbances (vs. brainstem dysregulation) is discussed.

Cost-effectiveness of alternative strategies for the initial medical management of non-ST elevation acute coronary syndrome: systematic review and decision-analytical modelling

OBJECTIVES

To identify and prioritise key areas of clinical uncertainty regarding the medical management of non-ST elevation acute coronary syndrome (ACS) in current UK practice.

DATA SOURCES

Electronic databases. Consultations with clinical advisors. Postal survey of cardiologists.

REVIEW METHODS

Potential areas of important uncertainty were identified and 'decision problems' prioritised. A systematic literature review was carried out using standard methods. The constructed decision model consisted of a short-term phase that applied the results of the systematic review and a long-term phase that included relevant information from a UK observational study to extrapolate estimated costs and effects. Sensitivity analyses were undertaken to examine the dependence of the results on baseline parameters, using alternative data sources. Expected value of information analysis was undertaken to estimate the expected value of perfect information associated with the decision problem. This provided an upper bound on the monetary value associated with additional research in the area.

RESULTS

Seven current areas of clinical uncertainty (decision problems) in the drug treatment of unstable angina patients were identified. The agents concerned were clopidogrel, low molecular weight heparin, hirudin and intravenous glycoprotein antagonists (GPAs). Twelve published clinical guidelines for unstable angina or non-ST elevation ACS were identified, but few contained recommendations about the specified decision problems. The postal survey of clinicians showed that the greatest disagreement existed for the use of small molecule GPAs, and the greatest uncertainty existed for decisions relating to the use of abciximab (a large molecule GPA). Overall, decision problems concerning the GPA class of drugs were considered to be the highest priority for further study. Selected papers describing the clinical efficacy of treatment were divided into three groups, each representing an alternative strategy. The strategy involving the use of GPAs as part of the initial medical management of all non-ST elevation ACS was the optimal choice, with an incremental cost-effectiveness ratio (ICER) of 5738 pounds per quality-adjusted life-year (QALY) compared with no use of GPAs. Stochastic analysis showed that if the health service is willing to pay 10,000 pounds per additional QALY, the probability of this strategy being cost-effective was around 82%, increasing to 95% at a threshold of 50,000 pounds per QALY. A sensitivity analysis including an additional strategy of using GPAs as part of initial medical management only in patients at particular high risk (as defined by age, ST depression or diabetes) showed that this additional strategy was yet more cost-effective, with an ICER of 3996 pounds per QALY compared with no treatment with GPA. Value of information analysis suggested that there was considerable merit in additional research to reduce the level of uncertainty in the optimal decision. At a threshold of 10,000 pounds per QALY, the maximum potential value of such research in the base case was calculated as 12.7 million pounds per annum for the UK as a whole. Taking account of the greater uncertainty in the sensitivity analyses including clopidogrel, this figure was increased to approximately 50 million pounds.

CONCLUSIONS

This study suggests the use of GPAs in all non-ST elevation ACS patients as part of their initial medical management. Sensitivity analysis showed that virtually all of the benefit could be realised by treating only high-risk patients. Further clarification of the optimum role of GPAs in the UK NHS depends on the availability of further high-quality observational and trial data. Value of information analysis derived from the model suggests that a relatively large investment in such research may be worthwhile. Further research should focus on the identification of the characteristics of patients who benefit most from GPAs as part of medical management, the comparison of GPAs with clopidogrel as an adjunct to standard care, follow-up cohort studies of the costs and outcomes of high-risk non-ST elevation ACS over several years, and exploring how clinicians' decisions combine a normative evidence-based decision model with their own personal behavioural perspective.

Acute nicotine withdrawal symptoms and anxious responding to bodily sensations: A test of incremental predictive validity among young adult regular smokers

Although previous work has found associations between panic and smoking, little research has investigated potential mechanisms by which smoking may contribute to panic problems. The present investigation evaluated the incremental validity of acute nicotine withdrawal symptoms (elicited by an average of 2h of nicotine deprivation) relative to negative affectivity, anxiety sensitivity, and nicotine dependence in predicting anxiety responding to 3-min voluntary hyperventilation. The sample consisted of 90 regular smokers (46 females), as defined by smoking >or= 10 cigarettes per day for at least 1 year, recruited through the general community. Consistent with prediction, greater levels of pre-challenge nicotine withdrawal symptoms uniquely predicted post-challenge intensity of panic symptoms and anxiety relative to other established factors. Findings are discussed in the context of how regular smoking may promote panic symptomotology.

Follow-up Study of Anxiety Disorder and Alcohol Dependence in Comorbid Alcoholism Treatment Patients

BACKGROUND

Anxiety disorders are present in a high percentage of alcoholism treatment patients. We tested the prediction that having a comorbid anxiety disorder increases the prospective risk for relapse to drinking after alcoholism treatment. We also explored the prospective associations of specific anxiety syndromes (and depression) with drinking and anxiety outcomes.

METHODS

We assessed the diagnostic status and daily drinking patterns of 82 individuals approximately one week after they entered alcoholism treatment (baseline) and again approximately 120 days later (follow-up) (n=53).

RESULTS

Consistent with study predictions, those with a baseline anxiety disorder (approximately 55%) were significantly more likely than others to meet various definitions of drinking relapse over the course of the follow-up. Regression models showed that baseline social phobia was the single best predictor of a return to any drinking after treatment, whereas panic disorder was the single best predictor of a relapse to alcohol dependence after treatment. Having multiple anxiety disorders (versus any specific anxiety disorder) at the baseline was the strongest predictor of having at least one active ("persistent") anxiety disorder at the follow-up. Cross-sectional analysis at the follow-up showed that anxiety disorder persisted in the absence of a relapse to alcohol dependence far more often than relapse to alcohol dependence occurred in the absence of a persistent anxiety disorder.

CONCLUSIONS

Screening for comorbid anxiety disorder in alcoholism treatment patients is warranted and, where found, should be considered a marker of high relapse risk relative to that of noncomorbid patients. The capacity of specific anxiety treatment to mitigate relapse risk among comorbid patients remains an open question.

The moderating effects of tension-reduction alcohol outcome expectancies on placebo responding in individuals with social phobia

We conjectured that individual differences in tension-reduction alcohol outcome expectancies (TR-AOEs) could produce widely varying responses to manipulations in alcohol-placebo studies and tested this idea by having individuals with social phobia give speeches in front of a group. One speech occurred before and one after participants consumed either a placebo beverage or a control beverage (i.e., a nonalcoholic drink described as containing no alcohol). Study results indicate that the placebo manipulation reduced cognitive and affective symptoms of anxiety to a greater extent for males with high TR-AOEs than for males with low TR-AOEs. This pattern was not found for women in the placebo group or for individuals in the control group. These findings demonstrate a moderating effect of TR-AOEs on the association between the consumption of a placebo beverage and response to an anxiety challenge and highlight the importance of accounting for gender and outcome expectancies when evaluating psychoactive substances.

CO(2) hypersensitivity in recently abstinent alcohol dependent individuals:; A possible mechanism underlying the high risk for anxiety disorder among alcoholics

Alcohol, administered acutely, is known to cause CO(2) hyposensitivity. CO(2) hypersensitivity associated with anxiogenic hyperventilation (HV) could reasonably be expected to emerge as an opponent process upon withdrawal from chronic alcohol use. To test this hypothesis, we applied two well-known methods to quantify CO(2) sensitivity in recently detoxified alcohol-dependent individuals and never alcohol-disordered individuals who are social drinkers. We found that the alcoholic group exhibited significantly greater CO(2) sensitivity than did controls in response to both challenges. Indirect evidence of chronic HV was also obtained. These findings implicate the effect of chronic alcohol use on CNS-based CO(2) sensitivity in heightening the vulnerability to disturbing anxiety symptoms and syndromes exhibited by alcoholic individuals. Future work must verify that pathological drinking actually causes the dysregulated respiratory responding observed in this study as is inferred in our conclusions.

Systematic review and economic decision modelling for the prevention and treatment of influenza A and B

OBJECTIVES

To establish the clinical and cost-effectiveness of amantadine, oseltamivir and zanamivir compared to standard care for the treatment and prevention of influenza.

DATA SOURCES

Electronic databases. Reference lists of identified articles and key publications. Relevant trials.

REVIEW METHODS

A systematic review and meta-analysis of the randomised evidence was undertaken to investigate the effectiveness of oseltamivir and zanamivir compared to standard care for treatment and prophylaxis use for influenza A and B. An additional systematic review of the effectiveness of amantadine for treatment and prophylaxis use for influenza A in children and the elderly was also undertaken. Economic decision models were constructed to examine the cost-effectiveness and cost-utility of the alternative strategies for treating and preventing influenza A and/or B. This was informed by the systematic reviews outlined above and additional sources of information where required.

RESULTS

The systematic review of the treatment of influenza found that oseltamivir reduced the median duration of symptoms in the influenza positive group by 1.38 days for the otherwise healthy adult population, 0.5 day for the high-risk population, and 1.5 days for the children population. This compared to 1.26 days, 1.99 days, and 1.3 for the similar groups for inhaled zanamivir. The systematic review of the prevention of influenza found that the relative risk reduction for oseltamivir was between approximately 75 and 90% and approximately 70 and 90% for inhaled zanamivir depending on the strategy adopted and the population under consideration. For the economic model a base case was constructed that focussed primarily on the health benefits generated by shortening the period of influenza illness. This base case found that, compared to standard care, the estimated cost per quality-adjusted life year ranged from pound 6190 to pound 31,529 for healthy adults, from pound 4535 to pound 22,502 for the 'high-risk' group, from pound 6117 to pound 30,825 for children, and from pound 5057 to pound 21,781 for the residential care elderly population. The base case model included valuations of the health effects of pneumonia (and otitis media in the children's model) based on observed rates in the trials. However it does not include the cost of hospitalisations as only very limited data was available for the effects of antivirals on hospitalisation rates. As for mortality rates, deaths from influenza were rare in trials of neuraminidase inhibitors (NIs). Therefore, suitable data on mortality were not available from these sources. As avoided hospitalisation costs and avoided mortality are potentially important we also carried out sensitivity analysis that involved extrapolating the observed reductions in pneumonias in the NI trials to hospitalisations and deaths. In all four models the cost-effectiveness of NIs is substantially improved by this extrapolation. For prophylaxis, antiviral drugs were compared with vaccination as preventative strategies. In all cases the cost-effectiveness ratios for vaccination were either low or cost-saving. In the base case the cost-effectiveness of antivirals was relatively unfavourable, there were scenarios relating to the elderly residential care model where antivirals as an additional strategy could be cost-effective.

CONCLUSIONS

The cost-effectiveness varies markedly between the intervention strategies and target populations. The estimate of cost effectiveness is also sensitive to variations in certain key parameters of the model, for example the proportion of all influenza-like illnesses that are influenza. The effectiveness literature that was used to inform the economic decision model spans many decades and hence great caution should be exercised when interpreting the results of indirect intervention comparisons from the model. Further randomised trials making direct comparisons would be valuable to verify the model's findings.

Does patient knowledge affect the colorectal cancer risk in ulcerative colitis?

OBJECTIVES

Formal efforts to improve patient education are associated with fewer disease complications in a number of conditions. The possible relationship between knowledge about ulcerative colitis and its cancer risk, and the development of colorectal cancer using a previously developed and validated instrument-the Crohn's and colitis knowledge (CCKNOW) score-were investigated.

METHODS

The 24 item CCKNOW questionnaire was mailed to patients known to have developed colorectal cancer as a complication of ulcerative colitis (cases) and to colitics from the Leicestershire inflammatory bowel disease patient database who had not developed cancer (controls).

RESULTS

The mean (SD) CCKNOW scores for cases was 8.21 (3.02) and for controls was 8.27 (4.3). These scores did not differ significantly between cases and controls (difference 0.06, 95% confidence interval (CI) -1.7 to 1.5, p=0.9). There were four times as many members of the National Association of Crohn's and Colitis (NACC) in the control group compared with the cancer group and patients who are members of NACC achieve statistically significantly higher scores than non-members (11.6 v 7.8, p=0.05, 95% CI -0.1 to 7.6). However, after adjusting for NACC membership, the CCKNOW score did not appear to be associated with having developed cancer (odds ratio 1.04, 95% CI 0.92 to 1.18, p=0.5).

CONCLUSIONS

The CCKNOW scores were comparable in cases and controls. Thus, in a retrospective study, no evidence has been demonstrated of an association between patient knowledge and the risk of developing colorectal cancer in patients with ulcerative colitis. However, knowledge may have been increased in cases as a direct result of having had colorectal cancer as a complication of ulcerative colitis.