Edith Poku

Health state utilities in patients with diabetic retinopathy, diabetic macular oedema and age-related macular degeneration: a systematic review

BackgroundHealth state utility values (HSUVs) are important in the assessment of the cost effectiveness of new interventions. In the case of visual conditions, models generally tend have tended to be built around a set of health states defined by visual acuity (VA). The aim of this review was to assess the impact of VA on HSUVs in patients with diabetic retinopathy, diabetic macular oedema or age-related macular degeneration.MethodsA systematic literature search was undertaken in major bibliographic databases to identify articles reporting on the relationship between HSUVs and vision. Data were extracted for population characteristics, visual levels and estimated utilities. Evidence from reported statistical models, where available, was considered in the evaluation of vision in the better-seeing eye and the worse-seeing eye. Due to the heterogeneity of included studies, a narrative synthesis was undertaken.ResultsOf the 17 relevant studies, 9 studies had data that could be used in the analysis of the impact of vision on HSUVs. Visual loss was associated with a marked impact on health utilities. However, the relationship was not comparable between conditions or by measure of HSUVs. Key results included the finding that overall, self-rated time-trade off estimates were more likely to discriminate between different VA levels than EQ-5D values. Additionally, a stronger correlation was observed between HSUVs and better-seeing eye VA compared to worse-seeing eye VA.ConclusionsVisual acuity has a significant impact on HSUVs. Nevertheless, care must be taken in the interpretation and use of estimates in cost-effectiveness models due to differences in measures and population diversity.

Pre-hospital non-invasive ventilation for acute respiratory failure: a systematic review and cost-effectiveness evaluation

BACKGROUND Non-invasive ventilation (NIV), in the form of continuous positive airway pressure (CPAP) or bilevel inspiratory positive airway pressure (BiPAP), is used in hospital to treat patients with acute respiratory failure. Pre-hospital NIV may be more effective than in-hospital NIV but requires additional ambulance service resources. OBJECTIVES We aimed to determine the clinical effectiveness and cost-effectiveness of pre-hospital NIV compared with usual care for adults presenting to the emergency services with acute respiratory failure and to identify priorities for future research. DATA SOURCES Fourteen electronic databases and research registers (including MEDLINE In-Process & Other Non-Indexed Citations, MEDLINE, EMBASE, and Cumulative Index to Nursing and Allied Health Literature) were searched from inception to August 2013, supplemented by hand-searching reference lists and contacting experts in the field. REVIEW METHODS We included all randomised or quasi-randomised controlled trials of pre-hospital NIV in patients with acute respiratory failure. Methodological quality was assessed according to established criteria. An aggregate data network meta-analysis (NMA) of mortality and intubation was used to jointly estimate intervention effects relative to usual care. A NMA, using individual patient-level data (IPD) and aggregate data where IPD were not available, was carried out to assess whether or not covariates were treatment effect modifiers. A de novo economic model was developed to explore the costs and health outcomes when pre-hospital NIV (specifically CPAP provided by paramedics) and standard care (in-hospital NIV) were applied to a hypothetical cohort of patients with acute respiratory failure. RESULTS The literature searches identified 2284 citations. Of the 10 studies that met the inclusion criteria, eight were randomised controlled trials and two were quasi-randomised trials (six CPAP; four BiPAP; sample sizes 23-207 participants). IPD were available from seven trials (650 patients). The aggregate data NMA suggested that CPAP was the most effective treatment in terms of mortality (probability = 0.989) and intubation rate (probability = 0.639), and reduced both mortality [odds ratio (OR) 0.41, 95% credible interval (CrI) 0.20 to 0.77] and intubation rate (OR 0.32, 95% CrI 0.17 to 0.62) compared with standard care. The effect of BiPAP on mortality (OR 1.94, 95% CrI 0.65 to 6.14) and intubation rate (OR 0.40, 95% CrI 0.14 to 1.16) compared with standard care was uncertain. The combined IPD and aggregate data NMA suggested that sex was a statistically significant treatment effect modifier for mortality. The economic analysis showed that pre-hospital CPAP was more effective and more expensive than standard care, with an incremental cost-effectiveness ratio of £20,514 per quality-adjusted life-year (QALY) and a 49.5% probability of being cost-effective at the £20,000-per-QALY threshold. Variation in the incidence of eligible patients had a marked impact on cost-effectiveness and the expected value of sample information for a future randomised trial. LIMITATIONS The meta-analysis lacked power to detect potentially important differences in outcome (particularly for BiPAP), the intervention was not always compared with the best alternative care (in-hospital NIV) in the primary studies and findings may not be generalisable. CONCLUSIONS Pre-hospital CPAP can reduce mortality and intubation rates, but cost-effectiveness is uncertain and the value of further randomised evaluation depends on the incidence of suitable patients. A feasibility study is required to determine if a large pragmatic trial of clinical effectiveness and cost-effectiveness is appropriate. STUDY REGISTRATION The study is registered as PROSPERO CRD42012002933. FUNDING The National Institute for Health Research Health Technology Assessment programme.

Patient-reported outcome measures in patients with peripheral arterial disease: a systematic review of psychometric properties.

BackgroundPeripheral arterial disease (PAD) is generally associated with considerable morbidity and reduced quality of life. Patient-reported outcome measures (PROMs) provide important information about the burden of disease and impact of treatment in affected patients.ObjectivesThe objective of the review was to identify and appraise studies reporting the psychometric evaluation of PROMs administered to a specified population of patients with PAD with a view to recommending suitable PROMs.MethodsA systematic review of peer-reviewed English language articles was undertaken to identify primary studies reporting psychometric properties of PROMs in English-speaking patients with various stages of PAD. Comprehensive searches were completed up until January 2015. Study selection, data extraction and quality assessment were undertaken independently by at least two researchers. Findings were presented as tabular and narrative summaries based on accepted guidance.ResultsPsychometric evaluation of 6 generic and 7 condition-specific PROMs reported in 14 studies contributed data to the review. The frequently reported measure was the SF-36 (n = 11 studies); others included the Walking Impairment Questionnaire (n = 8 studies), EQ-5D (n = 5 studies) and the Vascular Quality of Life Questionnaire (n = 3 studies). Studies included a diverse PAD population and varied in methodology, including approach to validation of PROMs.ConclusionsVarious PROMs have been validated in patients with PAD but no study provided evidence of a full psychometric evaluation in the patient population. Careful selection is required to identify reliable and valid PROMs to use in clinical and research settings.

The safety of intravitreal bevacizumab monotherapy in adult ophthalmic conditions: Systematic review

Objectives To assess the safety of intravitreal bevacizumab (IVB) as a monotherapy and to evaluate the relationship between quality of treatment and adverse events. Data sources Cochrane Library, Ovid MEDLINE, MEDLINE in-process, Ovid EMBASE and Toxicology Literature Online (TOXLINE) from January 2009 to May 2012. Studies included in an earlier systematic review were also assessed for inclusion. Study eligibility criteria, participants and interventions Randomised controlled trials (RCTs), controlled trials or observational studies including ≥10 participants reporting adverse events data following IVB monotherapy as a primary treatment in patients (aged 18 years or more) with any eye condition were included. Study appraisal and synthesis methods Study selection was undertaken independently by a minimum of two reviewers using pre-defined criteria. Data abstraction and quality assessment were performed by one reviewer, and then checked by a second reviewer. Study quality was assessed for only RCTs in accordance to the Cochrane Risk of Bias Tool. Additional items relating to safety data were also assessed. Results were tabulated or meta-analysed as appropriate. Results 22 RCTs and 67 observational studies were included. Only two RCTs reported valid safety data. Rates of serious adverse events following treatment were low. There was insufficient data to explore the relationship between the incidence of adverse events and quality of IVB injection. Limitations A majority of relevant existing studies were characterised by small sample sizes, unclear diagnostic criteria and reporting of safety outcomes. Conclusions and implications of key findings Available evidence demonstrates low rates of serious local and systemic adverse events following treatment. However, the role of IVB quality in the incidence of adverse events remains unclear. Robust evidence is needed to examine the relationship between the incidence of adverse events and variables such as injection techniques, pre-existing risk factors (eg, immunosuppression, cross-contamination) and quality of IVB treatment.

Echocardiography in newly diagnosed atrial fibrillation patients: a systematic review and economic evaluation

OBJECTIVE To investigate the clinical effectiveness and cost-effectiveness of transthoracic echocardiography (TTE) in all patients who are newly diagnosed with atrial fibrillation (AF). DESIGN Narrative synthesis reviews were conducted on the prognostic and diagnostic accuracy of TTE for, and prevalence of, pathologies in patients with AF. Databases were searched from inception. MEDLINE searches were conducted from March to August 2010, and reference lists of articles checked. There were 44 diagnostic accuracy studies, five prognostic studies, and 16 prevalence studies accepted into the review. Given the complexity of the many pathologies identified by TTE, the variety of potential changes to clinical management, and paucity of data, the model focused on changes to oral anticoagulation (OAC). The mathematical model assessed the cost-effectiveness of TTE for patients with AF who were not routinely given OAC, assuming, if left atrial abnormality was detected, that the higher risk of stroke warranted OAC; this meant that patients with a CHADS2 (cardiac failure, hypertension, age, diabetes, stroke doubled) score of 0 [dabigatran etexilate (Pradaxa, Boehringer Ingelheim)/rivaroxaban (Xarelto, Bayer Schering)] or 0/1 (warfarin) were included. A simplified approach evaluated the additional quality-adjusted life-years (QALYs) required in order for TTE to be perceived as cost-effective at a threshold of £20,000 per QALY. SETTING Transthoracic echocardiography is usually performed in cardiology clinics but may be used in primary or non-specialist secondary care. PARTICIPANTS Patients with newly diagnosed AF. INTERVENTION Transthoracic echocardiography. MAIN OUTCOME MEASURES Prognosis, diagnostic sensitivity or specificity of TTE, prevalence of pathologies in patients with AF, cost-effectiveness and QALYs. RESULTS Prognostic studies indicated that TTE-diagnosed left ventricular dysfunction, increased left atrial diameter and valvular abnormality were significantly associated with an increased risk of stroke, mortality or thromboembolism. There was a high prevalence (around 25-30%) of ischaemic heart disease, valvular heart disease and heart failure in patients with AF. Diagnostic accuracy of TTE was high, with most pathologies having specificity of ≥ 0.8 and sensitivity of ≥ 0.6. The mathematical model predicted that when the CHADS2 tool is used the addition of TTE in identifying patients with left atrial abnormality appears to be cost-effective for informing some OAC decisions. In the simplified approach a threshold of 0.0033 was required for a TTE to be cost-effective. CONCLUSIONS When CHADS2 was used, the addition of TTE in identifying patients with left atrial abnormality was cost-effective for informing some OAC decisions. A simple analysis indicates that the number of QALYs required for TTE to be cost-effective is small, and that if benefits beyond those associated with a reduction in stroke are believed probable then TTE is likely to be cost-effective in all scenarios. Our findings suggest that further research would be useful, following up newly diagnosed patients with AF who have undergone TTE, to study treatments given as a result of TTE diagnoses and subsequent cardiovascular events. This could identify additional benefits of routine testing, beyond stroke prevention. Studies assessing the proportion of people with a CHADS2 score of 0 or 1 that have left atrial abnormality would provide better estimates of the cost-effectiveness of TTE, and allow more accurate estimates of the sensitivity and specificity of TTE for identifying left atrial abnormality in AF to be obtained. STUDY REGISTRATION PROSPERO CRD42011001354. FUNDING The National Institute for Health Research Health Technology Assessment programme.

Systematic review and qualitative evidence synthesis of patient-reported outcome measures for abdominal aortic aneurysm

The aim was to identify and evaluate existing patient‐reported outcome measures (PROMs) for use in patients with an abdominal aortic aneurysm (AAA) to inform the selection for use in surgical practice.

Economic impact of Tegaderm chlorhexidine gluconate (CHG) dressing in critically ill patients

Purpose: To estimate the economic impact of a TegadermTM chlorhexidine gluconate (CHG) gel dressing compared with a standard intravenous (i.v.) dressing (defined as non-antimicrobial transparent film dressing), used for insertion site care of short-term central venous and arterial catheters (intravascular catheters) in adult critical care patients using a cost-consequence model populated with data from published sources. Material and Methods: A decision analytical cost-consequence model was developed which assigned each patient with an indwelling intravascular catheter and a standard dressing, a baseline risk of associated dermatitis, local infection at the catheter insertion site and catheter-related bloodstream infections (CRBSI), estimated from published secondary sources. The risks of these events for patients with a Tegaderm CHG were estimated by applying the effectiveness parameters from the clinical review to the baseline risks. Costs were accrued through costs of intervention (i.e. Tegaderm CHG or standard intravenous dressing) and hospital treatment costs depended on whether the patients had local dermatitis, local infection or CRBSI. Total costs were estimated as mean values of 10,000 probabilistic sensitivity analysis (PSA) runs. Results: Tegaderm CHG resulted in an average cost-saving of £77 per patient in an intensive care unit. Tegaderm CHG also has a 98.5% probability of being cost-saving compared to standard i.v. dressings. Conclusions: The analyses suggest that Tegaderm CHG is a cost-saving strategy to reduce CRBSI and the results were robust to sensitivity analyses.

Systematic review of patient-reported outcome measures in patients with varicose veins

Varicose veins can affect quality of life. Patient‐reported outcome measures (PROMs) provide a direct report from the patient about the impact of the disease without interpretation from clinicians or anyone else. The aim of this study was to examine the quality of the psychometric evidence for PROMs used in patients with varicose veins.

Systematic review of carotid artery procedures and the volume–outcome relationship in Europe

Hospitals that conduct more procedures on the carotid arteries may achieve better outcomes. In the context of ongoing reconfiguration of UK vascular services, this systematic review was conducted to evaluate the relationship between the volume of carotid procedures and outcomes, including mortality and stroke.

Systematic Review of Carotid Artery Procedures and the Volume-Outcome Relationship in Europe

Study design: This study was a search of studies that reported the effect of hospital or clinician volume on carotid endarterectomy (CEA) and stenting (CAS) outcomes restricted to European populations using MEDLINE, Embase, the Cochrane Library, Science Citation Index, and CINAHL from December 2014 to June 2016. Key findings: Eleven eligible studies were identified (233,411 participants): 5 from the UK, 2 from Sweden, 1 each from Germany, Finland, and Italy, and a combinedGerman,Austrian, andSwiss population. Two large studies (179,736patients) suggested an inverse relationshipbetweenhospital volumeandmortalityandcombinedmortality andstroke followingCEA.An inverse relationshipwasalso identifiedby2of3 small studiesofCEA.Theevidencewas lessclear for CAS;multiple analyses in three studiesdidnot identify convincingevidenceof anassociation. Limiteddata areavailableon the relationshipbetweenclinician volume and outcome in CAS. Conclusion: The evidence from the largest and highest-quality studies included in this review support the centralization of CEA. Commentary: Althoughmany studies have showna correlationbetweenhospital procedure volumeandoutcomes,manyhave also shown that themore important factor is thevolumeof the individual surgeonor interventionalist. Thisassociationmakes senseparticularly forCEA,where itwouldnotbesurprising that an outstanding vascular surgeon performing these operations at a small hospital where no one else performs CEAs obtained excellent results. Itmay be that the large-volumehospitalsdrawexcellentsurgeonsandthehospital itselfhas little impactonoutcomes.Theothervariable thathasbeenshowntohavea strong impact on CEA outcomes is the specialist performing the surgery. Several past studies have shown that vascular surgeons have better outcomes than general surgeons or neurosurgeons when performing CEA. The results of the current study are not surprising, but the plea for centralization of CEAsmakes senseonly if the surgeons at aparticular hospital havebeen shown toobtainexcellent results. On the otherhand, itmaybedifficult to expect a surgeon, especially a board-certified vascular surgeon, to tell patients to travel 2 hours, or even to go across town, to a hospital that doesmore CEAs than his or her hospital does, when that individual has tracked his or her own results andmet accepted standards in terms of low stroke andmortality rates.