Ontario health technology assessment series
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Ont Health Technol Assess Ser · Jan 2011
Continuous glucose monitoring for patients with diabetes: an evidence-based analysis.
To determine the effectiveness and cost-effectiveness of continuous glucose monitoring combined with self-monitoring of blood glucose compared with self-monitoring of blood glucose alone in the management of diabetes. ⋯ Moderate quality evidence that CGM + SMBG: is not more effective than self monitoring of blood glucose (SMBG) alone in the reduction of HbA1c using insulin infusion pumps for Type 1 diabetes.is not more effective than SMBG alone in the reduction of hypoglycemic or severe hypoglycemic events using insulin infusion pumps for Type 1 diabetes.
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Ont Health Technol Assess Ser · Jan 2011
Endovascular radiofrequency ablation for varicose veins: an evidence-based analysis.
The objective of the MAS evidence review was to conduct a systematic review of the available evidence on the safety, effectiveness, durability and cost-effectiveness of endovascular radiofrequency ablation (RFA) for the treatment of primary symptomatic varicose veins. ⋯ THE MAS EVIDENCE SEARCH ON THE SAFETY AND EFFECTIVENESS OF ENDOVASCULAR RFA ABLATION OF VV IDENTIFIED THE FOLLOWING EVIDENCE: three HTAs, nine systematic reviews, eight randomized controlled trials (five comparing RFA to surgery and three comparing RFA to ELT), five controlled clinical trials and fourteen cohort case series (four were multicenter registry studies). The majority (12⁄14) of the cohort studies (3,664) evaluating RFA for VV involved treatment with first generation RFA catheters and the great saphenous vein (GSV) was the target vessel in all studies. Major adverse events were uncommonly reported and the overall pooled major adverse event rate extracted from the cohort studies was 2.9% (105⁄3,664). Imaging defined treatment effectiveness of vein closure rates were variable ranging from 68% to 96% at post-operative follow-up. Vein ablation rate at 6-month follow-up was reported in four studies with rates close to 90%. Only one study reported vein closure rates at 2 years but only for a minority of the eligible cases. The two studies reporting on RFA ablation with the more efficient second generation catheters involved better follow-up and reported higher ablation rates close to 100% at 6-month follow-up with no major adverse events. A large prospective registry trial that recruited over 1,000 patients at thirty-four largely European centers reported on treatment success in six overlapping reports on selected patient subgroups at various follow-up points up to 5 year. However, the follow-up for eligible recruited patients at all time points was low resulting in inadequate estimates of longer term treatment efficacy. The overall level of evidence of randomized trials comparing RFA with surgical ligation and vein stripping (n = 5) was graded as low to moderate. In all trials RFA ablation was performed with first generation catheters in the setting of the operating theatre under general anaesthesia, usually without tumescent anaesthesia. Procedure times were significantly longer after RFA than surgery. Recovery after treatment was significantly quicker after RFA both with return to usual activity and return to work with on average a one week less of work loss. Major adverse events occurring after surgery were higher [(1.8% (n=4) vs. 0.4% (n = 1) than after RFA but not significantly. Treatment effectiveness measured by imaging defined vein absence or vein closure was comparable in the two treatment groups. Significant improvements in vein symptoms and quality of life over baseline were reported for both treatment groups. (ABSTRACT TRUNCATED)
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Ont Health Technol Assess Ser · Jan 2010
Positron emission tomography for the assessment of myocardial viability: an evidence-based analysis.
In July 2009, the Medical Advisory Secretariat (MAS) began work on Non-Invasive Cardiac Imaging Technologies for the Assessment of Myocardial Viability, an evidence-based review of the literature surrounding different cardiac imaging modalities to ensure that appropriate technologies are accessed by patients undergoing viability assessment. This project came about when the Health Services Branch at the Ministry of Health and Long-Term Care asked MAS to provide an evidentiary platform on effectiveness and cost-effectiveness of non-invasive cardiac imaging modalities.After an initial review of the strategy and consultation with experts, MAS identified five key non-invasive cardiac imaging technologies that can be used for the assessment of myocardial viability: positron emission tomography, cardiac magnetic resonance imaging, dobutamine echocardiography, and dobutamine echocardiography with contrast, and single photon emission computed tomography.A 2005 review conducted by MAS determined that positron emission tomography was more sensitivity than dobutamine echocardiography and single photon emission tomography and dominated the other imaging modalities from a cost-effective standpoint. However, there was inadequate evidence to compare positron emission tomography and cardiac magnetic resonance imaging. Thus, this report focuses on this comparison only. For both technologies, an economic analysis was also completed.The Non-Invasive Cardiac Imaging Technologies for the Assessment of Myocardial Viability is made up of the following reports, which can be publicly accessed at the MAS website at: www.health.gov.on.ca/mas or at www.health.gov.on.ca/english/providers/program/mas/mas_about.htmlPOSITRON EMISSION TOMOGRAPHY FOR THE ASSESSMENT OF MYOCARDIAL VIABILITY: An Evidence-Based AnalysisMAGNETIC RESONANCE IMAGING FOR THE ASSESSMENT OF MYOCARDIAL VIABILITY: An Evidence-Based Analysis ⋯ Positron emission tomography (PET) is a nuclear medicine technique used to image tissues based on the distinct ways in which normal and abnormal tissues metabolize positron-emitting radionuclides. Radionuclides are radioactive analogs of common physiological substrates such as sugars, amino acids, and free fatty acids that are used by the body. The only licensed radionuclide used in PET imaging for viability assessment is F-18 fluorodeoxyglucose (FDG). During a PET scan, the radionuclides are injected into the body and as they decay, they emit positively charged particles (positrons) that travel several millimetres into tissue and collide with orbiting electrons. (ABSTRACT TRUNCATED)
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Ont Health Technol Assess Ser · Jan 2010
Neuroimaging for the evaluation of chronic headaches: an evidence-based analysis.
The objectives of this evidence based review are: i) To determine the effectiveness of computed tomography (CT) and magnetic resonance imaging (MRI) scans in the evaluation of persons with a chronic headache and a normal neurological examination.ii) To determine the comparative effectiveness of CT and MRI scans for detecting significant intracranial abnormalities in persons with chronic headache and a normal neurological exam.iii) To determine the budget impact of CT and MRI scans for persons with a chronic headache and a normal neurological exam. ⋯ One systematic review, 1 small RCT, and 1 observational study met the inclusion and exclusion criteria. The systematic review completed by Detsky, et al. reported the likelihood ratios of specific clinical variables to predict significant intracranial abnormalities. The RCT completed by Howard et al., evaluated whether neuroimaging persons with chronic headache increased or reduced patient anxiety. The prospective observational study by Sempere et al., provided evidence for the pre-test probability of intracranial abnormalities in persons with chronic headache as well as minimal data on the comparative effectiveness of CT and MRI to detect intracranial abnormalities. OUTCOME 1: PRE-TEST PROBABILITY. The pre-test probability is usually related to the prevalence of the disease and can be adjusted depending on the characteristics of the population. The study by Sempere et al. determined the pre-test probability (prevalence) of significant intracranial abnormalities in persons with chronic headaches defined as headache experienced for at least a 4 week duration with a normal neurological exam. There is a pre-test probability of 0.9% (95% CI 0.5, 1.4) in persons with chronic headache and normal neurological exam. The highest pre-test probability of 5 found in persons with cluster headaches. The second highest, that of 3.7, was reported in persons with indeterminate type headache. There was a 0.75% rate of incidental findings. LIKELIHOOD RATIOS FOR DETECTING A SIGNIFICANT ABNORMALITY: Clinical findings from the history and physical may be used as screening test to predict abnormalities on neuroimaging. The extent to which the clinical variable may be a good predictive variable can be captured by reporting its likelihood ratio. The likelihood ratio provides an estimate of how much a test result will change the odds of having a disease or condition. The positive likelihood ratio (LR+) tells you how much the odds of having the disease increases when a test is positive. The negative likelihood ratio (LR-) tells you how much the odds of having the disease decreases when the test is negative. Detsky et al., determined the likelihood ratio for specific clinical variable from 11 studies. There were 4 clinical variables with both statistically significant positive and negative likelihood ratios. These included: abnormal neurological exam (LR+ 5.3, LR- 0.72), undefined headache (LR+ 3.8, LR- 0.66), headache aggravated by exertion or valsalva (LR+ 2.3, LR- 0.70), and headache with vomiting (LR+ 1.8, and LR- 0.47). There were two clinical variables with a statistically significant positive likelihood ratio and non significant negative likelihood ratio. These included: cluster-type headache (LR+ 11, LR- 0.95), and headache with aura (LR+ 12.9, LR- 0.52). Finally, there were 8 clinical variables with both statistically non significant positive and negative likelihood ratios. These included: headache with focal symptoms, new onset headache, quick onset headache, worsening headache, male gender, headache with nausea, increased headache severity, and migraine type headache. OUTCOME 2: RELIEF FROM ANXIETY Howard et al. completed an RCT of 150 persons to determine if neuroimaging for headaches was anxiolytic or anxiogenic. Persons were randomized to receiving either an MRI scan or no scan for investigation of their headache. The study population was stratified into those persons with a Hospital Anxiety and Depression scale (HADS) > 11 (the high anxiety and depression group) and those < 11 (the low anxiety and depression) so that there were 4 groups: Group 1: High anxiety and depression, no scan group Group 2: High anxiety and depression, scan group Group 3: Low anxiety and depression, no scan group Group 4: Low anxiety and depression, scan group ANXIETY: There was no evidence for any overall reduction in anxiety at 1 year as measured by a visual analogue scale of 'level of worry' when analysed by whether the person received a scan or not. Similarly, there was no interaction between anxiety and depression status and whether a scan was offered or not on patient anxiety. Anxiety did not decrease at 1 year to any statistically significant degree in the high anxiety and depression group (HADS positive) compared with the low anxiety and depression group (HADS negative). There are serious methodological limitations in this study design which may have contributed to these negative results. First, when considering the comparison of 'scan' vs. (ABSTRACT TRUNCATED)
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Ont Health Technol Assess Ser · Jan 2010
Endovascular laser therapy for varicose veins: an evidence-based analysis.
The objective of the MAS evidence review was to conduct a systematic review of the available evidence on the safety, effectiveness, durability and cost-effectiveness of endovascular laser therapy (ELT) for the treatment of primary symptomatic varicose veins (VV). ⋯ The MAS evidence search identified 14 systematic reviews, 29 cohort studies on safety and effectiveness, four cost studies and 12 randomized controlled trials involving ELT, six of these comparing endovascular laser with surgical ligation and saphenous vein stripping. Since 2007, 22 cohort studies involving 10,883 patients undergoing ELT of the great saphenous vein (GSV) have been published. Imaging defined treatment effectiveness of mean vein closure rates were reported to be greater than 90% (range 93%- 99%) at short term follow-up. Longer than one year follow-up was reported in five studies with life table analysis performed in four but the follow up was still limited at three and four years. The overall pooled major adverse event rate, including DVT, PE, skin burns or nerve damage events extracted from these studies, was 0.63% (69/10,883). The overall level of evidence of randomized trials comparing ELT with surgical ligation and vein stripping (n= 6) was graded as moderate to high. Recovery after treatment was significantly quicker after ELT (return to work median number of days, 4 vs. 17; p= .005). Major adverse events occurring after surgery were higher [(1.8% (n=4) vs. 0.4% (n = 1) 1 but not significantly. Treatment effectiveness as measured by imaging vein absence or closure, symptom relief or quality of life similar in the two treatment groups and both treatments resulted in statistically significantly improvements in these outcomes. Recurrence was low after both treatments at follow up but neovascularization (growth of new vessels, a key predictor of long term recurrence was significantly more common (18% vs. 1%; p = .001) after surgery. Although patient satisfaction was reported to be high (>80%) with both treatments, patient preferences evaluated through recruitment process, physician reports and consumer groups were strongly in favour of ELT. For patients minimal complications, quick recovery and dependability of outpatient scheduling were key considerations. As clinical effectiveness of the two treatments was similar, a cost-analysis was performed to compare differences in resources and costs between the two procedures. A budget impact analysis for introducing ELT as an insured service was also performed. The average case cost (based on Ontario hospital costs and medical resources) for surgical vein stripping was estimated to be $1,799. Because of the uncertainties with resources associated with ELT, in addition to the device related costs, hospital costs were varied and assumed to be the same as or less than (40%) those for surgery resulting in an average ELT case cost of $2,025 or $1,602. (ABSTRACT TRUNCATED)