Reliability of coded data to identify earliest indications of cognitive decline, cognitive evaluation and Alzheimer's disease diagnosis: a pilot study in England

OBJECTIVES

Evaluate the reliability of using diagnosis codes and prescription data to identify the timing of symptomatic onset, cognitive assessment and diagnosis of Alzheimer's disease (AD) among patients diagnosed with AD.

METHODS

This was a retrospective cohort study using the UK Clinical Practice Research Datalink (CPRD). The study cohort consisted of a random sample of 50 patients with first AD diagnosis in 2010-2013. Additionally, patients were required to have a valid text-field code and a hospital episode or a referral in the 3 years before the first AD diagnosis. The earliest indications of cognitive impairment, cognitive assessment and AD diagnosis were identified using two approaches: (1) using an algorithm based on diagnostic codes and prescription drug information and (2) using information compiled from manual review of both text-based and coded data. The reliability of the code-based algorithm for identifying the earliest dates of the three measures described earlier was evaluated relative to the comprehensive second approach. Additionally, common cognitive assessments (with and without results) were described for both approaches.

RESULTS

The two approaches identified the same first dates of cognitive symptoms in 33 (66%) of the 50 patients, first cognitive assessment in 29 (58%) patients and first AD diagnosis in 43 (86%) patients. Allowing for the dates from the two approaches to be within 30 days, the code-based algorithm's success rates increased to 74%, 70% and 94%, respectively. Mini-Mental State Examination was the most commonly observed cognitive assessment in both approaches; however, of the 53 tests performed, only 19 results were observed in the coded data.

CONCLUSIONS

The code-based algorithm shows promise for identifying the first AD diagnosis. However, the reliability of using coded data to identify earliest indications of cognitive impairment and cognitive assessments is questionable. Additionally, CPRD is not a recommended data source to identify results of cognitive assessments.

Potential cost savings to be made by slowing cognitive decline in mild Alzheimer's disease dementia using a model derived from the UK GERAS observational study

Background

Given the high costs associated with the care of those with Alzheimer’s disease (AD) dementia, we examined the likely impact of a reduction in the rate of cognitive decline upon cost outcomes associated with this disease.

Methods

Using the group of patients with mild AD dementia from the GERAS study, generalised linear modelling (GLM) was used to explore the relationship between change in cognition as measured using the Mini-Mental State Examination (MMSE) and UK overall costs (health care and social care costs, and total societal costs) associated with AD dementia.

Results

A total of 200 patients with mild AD dementia were identified. Least squares mean (LSM) ± standard error (SE) reduction in MMSE score was 3.6 ± 0.4 points over 18 months. Using GLM it was possible to calculate that this worsening in cognition was associated with an 8.7% increase in total societal costs, equating to an increase of approximately £2200 per patient over an 18-month period. If the rate of decline in cognition was reduced by 30% or 50%, the associated savings in total societal costs over 18 months would be approximately £670 and £1100, respectively, of which only £110 and £180, respectively, could be attributed to a saving of health care costs.

Conclusion

This study demonstrates that there are potential savings to be made in the care of patients with AD dementia through reducing the rate of cognitive decline. A reduction in wider societal costs is likely to be the main contributor to these potential savings, and need to be further evaluated when intervention costs and cost offsets can be measured.

Excess Costs Associated with Possible Misdiagnosis of Alzheimer's Disease Among Patients with Vascular Dementia in a UK CPRD Population

BACKGROUND

Prior diagnosis of Alzheimer's disease (AD) among patients later diagnosed with vascular dementia (VaD) has been associated with excess costs, suggesting potential benefits of earlier rule-out of AD diagnosis.

OBJECTIVE

To investigate whether prior diagnosis with AD among patients with VaD is associated with excess costs in the UK.

METHODS

Patients with a final VaD diagnosis, continuous data visibility for≥6 months prior to index date, and linkage to Hospital Episode Statistics data were retrospectively selected from de-identified Clinical Practice Research Datalink data. Patients with AD diagnosis before a final VaD diagnosis were matched to similar patients with no prior AD diagnosis using propensity score methods. Annual excess healthcare costs were calculated for 5 years post-index, stratified by time to final diagnosis.

RESULTS

Of 9,311 patients with VaD, 508 (6%) had prior AD diagnosis with a median time to VaD diagnosis exceeding 2 years from index date. Over the entire follow-up period, patients with prior AD diagnosis had accumulated healthcare costs that were approximately GBP2,000 higher than those for matched counterparts (mostly due to higher hospitalization costs). Cost differentials peaked particularly in the period including the final VaD diagnosis, with excess costs quickly declining thereafter.

CONCLUSION

Potential misdiagnosis of AD among UK patients with VaD resulted in substantial excess costs. The decline in excess costs following a final VaD diagnosis suggests potential benefits from earlier rule-out of AD.

Resource utilisation, costs and clinical outcomes in non-institutionalised patients with Alzheimer's disease: 18-month UK results from the GERAS observational study

BACKGROUND

Alzheimer's disease (AD), the commonest cause of dementia, represents a significant cost to UK society. This analysis describes resource utilisation, costs and clinical outcomes in non-institutionalised patients with AD in the UK.

METHODS

The GERAS prospective observational study assessed societal costs associated with AD for patients and caregivers over 18 months, stratified according to baseline disease severity (mild, moderate, or moderately severe/severe [MS/S]). All patients enrolled had an informal caregiver willing to participate in the study. Healthcare resource utilisation was measured using the Resource Utilization in Dementia instrument, and 18-month costs estimated by applying unit costs of services and products (2010 values). Total societal costs were calculated using an opportunity cost approach.

RESULTS

Overall, 526 patients (200 mild, 180 moderate and 146 MS/S at baseline) were recruited from 24 UK centres. Mini-Mental State Examination (MMSE) scores deteriorated most markedly in the MS/S patient group, with declines of 3.6 points in the mild group, 3.5 points in the moderate group and 4.7 points in the MS/S group; between-group differences did not reach statistical significance. Patients with MS/S AD dementia at baseline were more likely to be institutionalised (Kaplan-Meier probability 28% versus 9% in patients with mild AD dementia; p < 0.001 for difference across all severities) and had a greater probability of death (Kaplan-Meier probability 15% versus 5%; p = 0.013) at 18 months. Greater disease severity at baseline was also associated with concomitant increases in caregiver time and mean total societal costs. Total societal costs of £43,560 over 18 months were estimated for the MS/S group, versus £25,865 for the mild group and £30,905 for the moderate group (p < 0.001). Of these costs, over 50% were related to informal caregiver costs at each AD dementia severity level.

CONCLUSIONS

This study demonstrated a mean deterioration in MMSE score over 18 months in patients with AD. It also showed that AD is a costly disease, with costs increasing with disease severity, even when managed in the community: informal caregiver costs represented the main contributor to societal costs.

Are there different predictors of analgesic response between antidepressants and anticonvulsants in painful diabetic neuropathy?

BACKGROUND

To investigate baseline demographics and disease characteristics as predictors of the analgesic effect of duloxetine and pregabalin on diabetic peripheral neuropathic pain (DPNP).

METHODS

Based on data from the COMBO-DN study, a multinational clinical trial in DPNP, the potential impact of baseline characteristics on pain relief after 8-week monotherapy with 60 mg/day duloxetine or 300 mg/day pregabalin was assessed using analyses of covariance. Subgroups of interest were characterized regarding their baseline characteristics and efficacy outcomes.

RESULTS

A total of 804 patients were evaluated at baseline. A significant interaction with treatment was observed in the mood symptom subgroups with a larger pain reduction in duloxetine-treated patients having no mood symptoms [Hospital Anxiety and Depression Scale (HADS) depression or anxiety subscale score <11; -2.33 (duloxetine); -1.52 (pregabalin); p = 0.024]. There were no significant interactions between treatment for subgroups by age (<65 or ≥65 years), gender, baseline pain severity [Brief Pain Inventory Modified Short Form (BPI-MSF) average pain <6 or ≥6], diabetic neuropathy duration (≤2 or >2 years), baseline haemoglobin A1c (HbA1c) (<8% or ≥8%), presence of comorbidities and concomitant medication use.

CONCLUSIONS

Our analyses suggest that the efficacy of duloxetine and pregabalin for initial 8-week treatment in DPNP was consistent across examined subgroups based on demographics and disease characteristics at baseline except for the presence of mood symptoms. Duloxetine treatment appeared to be particularly beneficial in DPNP patients having no mood symptoms.

Individual residual symptoms and functional impairment in patients with depression

The aim of treatment of depression is remission of symptoms and functioning. Although there is a relationship between remission of symptoms and remission of functioning, it is not known how individual residual symptoms are related to functioning. Here we report a post-hoc analysis of two studies which treated depressed patients with duloxetine in an open fashion for 10-12 weeks. We evaluated the association of individual residual symptoms and functional impairment in patients who remitted or partially remitted after acute treatment. Logistic regression was used to investigate residual symptoms associated with functional impairment at endpoint. Our results suggest that in partial remitters, the only residual symptom associated with a reduction in the risk of having impaired function was the resolution of painful physical symptoms (PPS). In patients who remitted, the presence of residual core mood symptoms (CMS), particularly in patients without any anxiety, predicted impaired functioning. The resolution of PPS in the presence of residual CMS was associated with less risk of impaired functioning. Our results contribute to understand better the role of specific residual symptoms on functional impairment. To achieve normal functioning, intervention on specific residual symptoms is recommended.

Treatment and outcomes for patients with depression who are partial responders to SSRI treatment: post-hoc analysis findings from the FINDER European observational study

BACKGROUND

Remission is the goal in depression, but in practice many patients only experience a partial response to treatment. We sought to determine the prevalence, management and subsequent outcomes of partial responder patients.

METHODS

Patients enrolled in the naturalistic Factors Influencing Depression Endpoints Research (FINDER) study with the Hospital Anxiety and Depression Scale depression subscale (HADS-D) score >10 at baseline who received only SSRI(s) between 0 and 3 months comprised the study cohort (n=1147). Patients were categorized as remitters, partial responders or non-responders at 3 months and then followed up at 6 months.

RESULTS

At 3 months, 29.4% of the study population were considered non-responders, 27.6% were partial responders, and 39.3% were remitters. Most partial responders at 3 months remained on the same SSRI for the next 3 months. Of the 247 partial responders at 3 months and remained on the same SSRI(s) between 3 and 6 months, 10.9% met criteria for non-response at 6 months, 32.4% remained partial responders, and 56.3% achieved remission. Quality of life outcomes for the partial responders were significantly worse than those in remission (p<0.05).

LIMITATIONS

FINDER was an observational study; the current analysis was conducted post-hoc. Multivariable methods were not applied and findings are primarily descriptive and exploratory.

CONCLUSIONS

Partial response is common and patients in partial response have a poorer quality of life than those achieving remission. Despite this, the majority of partial responders continue to take the same SSRI. Our findings underscore the importance of continuing to strive for remission.

Efficacy and safety of duloxetine in the treatment of older adult patients with generalized anxiety disorder: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

This was a flexible-dosed study to evaluate the efficacy and safety of duloxetine 30-120 mg once daily in the treatment of generalized anxiety disorder (GAD) in older adult patients.

METHODS

Patients with GAD, who were at least 65 years of age, were randomly assigned to double-blind treatment with either duloxetine (N = 151) or placebo (N = 140). The primary efficacy measure was the Hamilton Anxiety Rating Scale (HAM-A) total score, and the primary endpoint was at week 10. Global functioning was assessed by the Sheehan Disability Scale (SDS). Safety and tolerability was assessed by the occurrence of treatment-emergent adverse events, serious adverse events, laboratory analyses, and vital signs. Analyses were conducted on an intent-to-treat basis.

RESULTS

The overall baseline mean HAM-A total score was 24, and SDS global score was 14. Completion rates were 75% for placebo and 76% for duloxetine. At week 10, duloxetine was superior to placebo on mean changes from baseline in HAM-A total scores (-15.9 vs. -11.7, p < 0.001) and in SDS global scores (-8.6 vs. -5.4, p < 0.001). Treatment-emergent adverse events occurred in ≥5% of duloxetine-treated patients and twice the rate than with placebo including constipation (9% vs. 4%, p = 0.06), dry mouth (7% vs. 1%, p = 0.02), and somnolence (6% vs. 2%, p = 0.14).

CONCLUSION

Duloxetine treatment was efficacious in the improvement of anxiety and functioning in older adult patients with GAD, and the safety profile was consistent with previous GAD studies.

Health care resource utilisation in primary care prior to and after a diagnosis of Alzheimer's disease: a retrospective, matched case-control study in the United Kingdom

BACKGROUND

This study examined medical resource utilisation patterns in the United Kingdom (UK) prior to and following Alzheimer's disease (AD) diagnosis.

METHODS

A patient cohort aged 65 years and older with newly diagnosed AD between January 2008 and December 2010 was identified through the UK's Clinical Practice Research Datalink (CPRD). Patients with a continuous record in the CPRD (formerly the General Practice Research Database [GPRD]) for both the 3 years prior to, and the 1 year following, AD diagnosis were eligible for inclusion. A control cohort was identified by matching general older adult (GOA) patients to patients with AD based on year of birth, gender, region, and Charlson Comorbidity Index at a ratio of 2:1. Medical resource utilisation was calculated in 6-month intervals over the 4-year study period. Comparisons between AD and GOA control cohorts were conducted using conditional logistic regression for patient characteristics and a generalised linear model for resource utilisation.

RESULTS

Data for the AD cohort (N = 3,896) and matched GOA control cohort (N = 7,792) were extracted from the CPRD. The groups were 65% female and the AD cohort had a mean age of 79.9 years (standard deviation 6.5 years) at the date of diagnosis. Over the entire study period, the AD cohort had a significantly higher mean primary care consultation rate than the GOA cohort (p < .0001). While the GOA cohort primary care consultation rate gradually increased over the 4-year period (ranging from 5 to 7 consultations per 6-month period), increases were more pronounced in the AD cohort (ranging from 6 to 11 consultations per 6-month period, peaking during the 6-month periods immediately prior to and post diagnosis). The AD cohort also had a higher overall specialty referral rate than the GOA cohort over the 4-year period (37% vs. 25%, respectively; p < .0001); the largest difference was during the 6 months immediately prior to AD diagnosis (17% vs. 5%, respectively; p < .0001).

CONCLUSIONS

In the UK, AD diagnosis is associated with significant increases in primary and secondary care resource utilisation, continuing beyond diagnosis. This evidence may be important to health care commissioners to facilitate effective mobilisation of appropriate AD-related health care resources.

Impact of patient selection and study characteristics on signal detection in placebo-controlled trials with antidepressants

An increasing rate of antidepressant trials fail due to large placebo responses. This analysis aimed to identify variables influencing signal detection in clinical trials of major depressive disorder. Patient-level data of randomized patients with a duloxetine dose ≥ 60 mg/day were obtained from Lilly. Total scores of the Hamilton Depression Rating scale (HAM-D) were used as efficacy endpoints. In total, 4661 patients from 14 studies were included in the analysis. The overall effect size (ES), based on the HAM-D total score at endpoint, between duloxetine and placebo was -0.272. Although no statistically significant interactions were found, the following results for factors influencing ES were seen: a very low ES (-0.157) in patients in the lowest baseline HAM-D category and in patients recruited in the last category of the recruitment period (-0.122). A higher ES in patients recruited in centers with a site-size at but not more than 2.5 times the average site-size for the study (-0.345). Study characteristics that resulted in low signal detection in our database were: <80% study completers, a HAM-D placebo response >5 points, a high variability of placebo response (SD > 7 points HAM-D), >6 post baseline visits per study, and use of an active control drug. Simpler trial designs, more homogeneous and mid-sized study sites, a primary analysis based on a higher cutoff blinded to investigators to avoid the influence of score inflation in mild patients and, if possible, studies without an active control group could lead to a better signal detection of antidepressive efficacy.

Quality of Life in Depressed Patients in UK Primary Care: The FINDER Study

OBJECTIVES

To investigate the impact of depression and its treatment on health-related quality of life (HRQoL) in a naturalistic, primary care setting in the UK.

METHODS

The Factors Influencing Depression Endpoints Research (FINDER) study was a European, 6-month, prospective, observational study designed to estimate HRQoL in patients with a clinical diagnosis of depression. This paper examines primary care patients recruited in the UK. HRQoL was measured at baseline and at 3 and 6 months after starting antidepressant therapy using the Short Form 36 Health Status Survey and the European Quality of Life-5 Dimensions (EQ-5D). Regression analysis was used to identify baseline and treatment variables independently and significantly associated with HRQoL. Further analyses included the effect of caseness for depression on HRQoL, the effect of moderate/severe pain at baseline on HRQoL, changes in overall pain, pain interference scores, and the use of different antidepressants by pain cohort.

RESULTS

A total of 608 patients was recruited from 58 centres and mean HRQoL was significantly below reported population norms at baseline. Most improvement in HRQoL was seen at 3 months for EQ-5D, with small additional improvement at 6 months. Worse HRQoL outcomes at 6 months were associated with higher somatic symptoms score, duration of depression at baseline, and switching within antidepressant classes. Patients meeting the criteria for caseness for depression, or with significant pain at baseline showed less improvement in HRQoL scores at 6 months.

CONCLUSION

Patients presenting with depression in primary care show reduced HRQoL compared to population norms. HRQoL improves during antidepressant treatment particularly within the first 3 months. Nonpainful somatic symptoms, socioeconomic factors, depression variables and switching within antidepressant class predict poor HRQoL outcome. Pain is a common symptom in depressed patients and remains after 6 months' treatment. Pain and somatic symptoms should be assessed in all patients with depression in primary care.

Incidence of diabetic peripheral neuropathic pain in primary care - a retrospective cohort study using the United Kingdom General Practice Research Database

PURPOSE

To determine the incidence of diabetic peripheral neuropathic pain (DPNP) in the United Kingdom (UK) primary care population using the General Practice Research Database (GPRD).

PATIENTS AND METHODS

This retrospective cohort study identified incident cases of DPNP in the UK GPRD between July 1, 2002 and June 30, 2011, using diagnostic codes. Trends in the incidence rate were examined by dividing the study period into 3-year periods: (1) July 1, 2002-June 30, 2005; (2) July 1, 2005-June 30, 2008; and (3) July 1, 2008-June 30, 2011. Patient characteristics (age, sex, comorbidities) and initial pharmacological treatment were described; the proportion of patients with incident DPNP, who had previously been screened for neuropathic symptoms, was determined.

RESULTS

Among almost 7.5 million persons contributing 38,118,838 person-years of observations in the GPRD, 6,779 new cases of DPNP were identified (45.5%, women), giving an incidence rate of 17.8 per 100,000 person-years (95% confidence interval [CI] 17.4-18.2). The incidence of DPNP increased with age, but it was stable over the three consecutive 3-year periods: 17.9, 17.2, and 18.4 cases per 100,000 person-years. Of the 6,779 patients with incident DPNP, 15.5% had prior neuropathic screening during the study period. The majority of patients with incident DPNP (84.5%) had a treatment for pain initiated within 28 days of first diagnosis. The most common first-line treatments prescribed were tricyclic antidepressants (27.2%), anticonvulsants (17.0%), and nonsteroidal anti-inflammatory drugs (14.9%), with 26.6% of patients receiving combination therapy as their initial treatment.

CONCLUSION

The incidence of DPNP in UK primary care has remained steady over the past 10 years. Our results suggest that DPNP is underdiagnosed, and initial treatment prescribed does not follow clinical guidelines.

A review of the suitability of duloxetine and venlafaxine for use in patients with depression in primary care with a focus on cardiovascular safety, suicide and mortality due to antidepressant overdose

Depression and anxiety disorders are among the most common disorders treated by general practitioners (GPs) in the UK. Since both disorders are associated with a significantly increased risk of suicide, including with antidepressant overdose, the safety of antidepressants in overdose is of paramount importance. Numerous updates relating to antidepressant safety have been issued by regulators in the UK which may have eroded GP confidence in antidepressants. Venlafaxine, a serotonin nor adrenaline reuptake inhibitor (SNRI) had primary care prescribing restrictions placed on it in 2004 due to concerns about cardiotoxicity and mortality in overdose. Although a review of the evidence led to a reversal of the majority of restrictions in 2006, evidence suggests GPs may still be cautious in their prescribing of venlafaxine and possibly other SNRI antidepressants for patients with depression and anxiety disorders. This paper reviews the evidence pertaining to the safety of SNRI antidepressants from a perspective of cardiovascular safety and overdose. The currently available evidence suggests a marginally higher toxicity of venlafaxine in overdose compared with another SNRI duloxetine and the selective serotonin reuptake inhibitors (SSRIs), although this may be related to differential patterns of prescribing in high-risk patients. Based on this review SNRIs have a positive risk benefit profile in the treatment of depression and generalized anxiety disorder in primary care, especially as second-line agents to SSRIs.

A 12-week nursing support programme for carers of children and adolescents in the UK with attention deficit hyperactivity disorder prescribed atomoxetine

INTRODUCTION

Patient support programmes are assuming greater importance in the UK in many therapeutic areas, mostly with the aim of improving adherence to medication and many being provided by the pharmaceutical industry. Atomoxetine is a noradrenaline reuptake inhibitor for the treatment of attention deficit hyperactivity disorder that has recently demonstrated incremental efficacy for at least 12 weeks. Issues of adherence may be predicted over this initial period particularly if adverse events are reported. The Strattera Support Service was initiated in 2006 ( funded by Eli Lilly) to provide advice, initially through telephone contact, by trained nurses during the first 12 weeks of atomoxetine therapy and is offered to carers of patients diagnosed with ADHD after atomoxetine has been prescribed. The aim of this pilot service evaluation is to assess discontinuation rates and compare them with historical control data.

METHODS

Data from patients in the service who initiated atomoxetine between 1 January 2009 and 31 March 2010 were analysed to provide a pilot service evaluation. Continuation rates of patients in the service who were taking atomoxetine at week 12 were assessed and compared with historical control data.

RESULTS

Between 1 January 2009 and 31 March 2010, 346 patients (300 male patients) enrolled in the programme and commenced treatment with atomoxetine. The mean age of patients was 10.5 years. At 12 weeks, 33 (9.5%) patients had discontinued treatment; continuation rates were similar regardless of age and sex. Discontinuation rates of 39% are reported from historical control data.

CONCLUSIONS

Preliminary data from a 12-week atomoxetine patient support programme are supportive that discontinuation rates may be lower than historically expected. Further service evaluations of this programme may be required.

Health care costs before and after diagnosis of depression in patients with unexplained pain: a retrospective cohort study using the United Kingdom General Practice Research Database

Purpose

To assess the impact of pain severity and time to diagnosis of depression on health care costs for primary care patients with pre-existing unexplained pain symptoms who subsequently received a diagnosis of depression.

Patients and methods

This retrospective cohort study analyzed 4000 adults with unexplained pain (defined as painful physical symptoms [PPS] without any probable organic cause) and a subsequent diagnosis of depression, identified from the UK General Practice Research Database using diagnostic codes. Patients were categorized into four groups based on pain severity (milder or more severe; based on number of pain-relief medications and use of opioids) and time to diagnosis of depression (≤1 year or>1 year from PPS index date). Annual health care costs were calculated (2009 values) and included general practitioner (GP) consultations, secondary care referrals, and prescriptions for pain-relief medications for the 12 months before depression diagnosis and in the subsequent 2 years. Multivariate models of cost included time period as a main independent variable, and adjusted for age, gender, and comorbidities.

Results

Total annual health care costs before and after depression diagnosis for the four patient groups were higher for the groups with more severe pain (£819–£988 versus £565–£628; P < 0.001 for all pairwise comparisons) and highest for the group with more severe pain and longer time to depression diagnosis in the subsequent 2 years (P < 0.05). Total GP costs were highest in the group with more severe pain and longer time to depression diagnosis both before and after depression diagnosis (P < 0.05). In the second year following depression diagnosis, this group also had the highest secondary care referral costs (P < 0.01). The highest drug costs were in the groups with more severe pain (P < 0.001), although costs within each group were similar before and after depression diagnosis.

Conclusion

Among patients with unexplained pain symptoms, significant pain in combination with longer time from pain symptoms to depression diagnosis contribute to higher costs for the UK health care system.

Noradrenergic function in generalized anxiety disorder: impact of treatment with venlafaxine on the physiological and psychological responses to clonidine challenge

Serotonin and noradrenaline reuptake inhibitor (SNRI) antidepressants have evidence of efficacy in the treatment of generalized anxiety disorder (GAD); however, it is not clear whether there is an advantage over selective serotonin reuptake inhibitor (SSRI) medicines and there is limited evidence for noradrenergic dysfunction in GAD. We tested whether a dysfunctional alpha-2 adrenoceptor system is present in patients with GAD and the effects of SNRI treatment on this system. The method used was an infusion of clonidine (a selective alpha-2 adrenergic receptor agonist) on psychological and physiological outcomes in three subject groups: 10 untreated GAD patients, five SNRI-treated GAD patients and seven normal controls. The clonidine challenge elicited sedation, a rise in growth hormone, decrease in blood pressure, decline in saccadic eye movement (SEM) variables, and improvement in verbal fluency as anticipated in the 22 subjects examined. Lower cortisol levels were found in controls and higher blood pressure readings in GAD-treated subjects, as well as evidence that GAD-treated subjects had SEMs that were intermediate between control and GAD subjects' scores and have less clonidine-induced sedation. The implications of these findings with reference to the study hypothesis in this small study are discussed.

Cost-effectiveness of venlafaxine XL compared with diazepam in the treatment of generalised anxiety disorder in the United Kingdom

This study used decision modelling to compare the cost-effectiveness of venlafaxine XL (Efexor XL) to that of diazepam to treat non-depressed patients suffering from generalised anxiety disorder (GAD), from the perspective of the United Kingdom's National Health Service (NHS). Starting treatment with venlafaxine XL instead of diazepam significantly increased the expected probability of being in remission by 83% at 6 months (from 16.8% to 30.7%), and the expected probability of relapsing at 6 months was decreased by 79% (from 16.9% to 3.5%). The expected 6-month NHS cost of using venlafaxine XL to treat GAD was estimated to be pounds sterling 353 compared to pounds sterling 311 with diazepam. Hence starting GAD treatment with venlafaxine XL (75 mg per day) instead of diazepam (5 mg three times per day) is clinically more effective and the cost-effective strategy for managing non-depressed patients suffering from GAD in the UK.

Cost effectiveness of representatives of three classes of antidepressants used in major depression in the UK

OBJECTIVE

To estimate the cost effectiveness of representatives of three different classes of antidepressants used in major depression in the UK NHS. DESIGN, PATIENTS AND INTERVENTIONS: A decision-tree model for the treatment of major depression was constructed by interviewing UK GPs and psychiatrists (as part of a Delphi panel). An important part of the tree was that patients in primary care were treated until remission (pre-morbid state). Three classes of antidepressants (serotonin and noradrenaline reuptake inhibitors [SNRIs; venlafaxine], selective serotonin reuptake inhibitors [SSRIs; fluoxetine, paroxetine and fluvoxamine] and tricyclic antidepressants [TCAs; amitriptyline]) were compared by populating the tree with clinical success rates determined by a meta-analysis and a clinical trial. Where there were insufficient data from clinical trials a Delphi panel was used. Costs within the tree were taken from UK data sources. Six-monthly costs and cost effectiveness were then calculated.

MAIN OUTCOME MEASURES AND RESULTS

Treatment costs for 6 months were pound 1285 for venlafaxine, pound 1348 for SSRIs and pound 1385 for amitriptyline. Cost effectiveness as measured by cost per symptom-free day was pound 21 for venlafaxine, pound 26 for SSRIs and pound 32 for TCAs (2001 values). Incremental cost-effectiveness analyses showed a treatment strategy of using venlafaxine and switching if necessary to an SSRI was dominant over all other strategies considered. Sensitivity testing demonstrated that the cost of an SSRI could be reduced to 4 pence daily and amitriptyline to zero before the expected 6-monthly cost of venlafaxine ceased to be the lowest.

CONCLUSION

The SNRI, venlafaxine, may be a cost-effective option compared with the SSRIs and TCAs when used as a first-line drug for depression in primary care in the UK. As this is a model, cost effectiveness can be suggested but not proven.

Pharmacoeconomic analysis of antidepressants for major depressive disorder in the United Kingdom

OBJECTIVE

To estimate the cost effectiveness of different classes of antidepressants in the UK National Health Service. DESIGN, PATIENTS AND INTERVENTIONS: The use of the serotonin (5-hydroxytryptamine; 5-HT) and noradrenaline (norepinephrine) reuptake inhibitor (SNRI) venlafaxine was compared with that of selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs) in patients with major depressive disorder (MDD). A meta-analysis determined the clinical success rate, and a decision tree was constructed by interviewing general practitioners and psychiatrists. Adding pharmacological and nonpharmacological treatment costs, meta-analytic rates were applied to the decision tree to calculate the expected cost and outcome for each drug. Cost effectiveness was determined using a composite measure of outcome [symptom-free days (SFD)].

MAIN OUTCOME MEASURES AND RESULTS

The meta-analysis included data from 44 studies on 4033 patients. The highest overall efficacy rate for outpatients with MDD was with venlafaxine use (73.7%), compared with 61.4% for SSRIs and 59.3% for TCAs. Treatment with venlafaxine yielded the lowest outpatient cost for a SFD (10.53 Pounds), compared with 13.23 Pounds for SSRIs and 15.52 Pounds for TCAs (1998 values).

CONCLUSIONS

Using this economic model, venlafaxine appears to be a cost-effective treatment for outpatients with MDD in the UK.

Oligosymptomatic hypocalcaemia in a patient with impaired parathyroid hormone activity

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