Ontario health technology assessment series
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To conduct an evidence-based analysis of the effectiveness and cost-effectiveness of bariatric surgery. ⋯ Bariatric surgery generally is effective for sustained weight loss of about 16% for people with BMIs of at least 40 kg/m(2) or at least 35 kg/m(2) with comorbid conditions (including diabetes, high lipid levels, and hypertension). It also is effective at resolving the associated comorbid conditions. This conclusion is largely based on level 3a evidence from the prospectively designed Swedish Obese Subjects study, which recently published 10-year outcomes for patients who had bariatric surgery compared with patients who received nonsurgical treatment. (1)Regarding specific procedures, there is evidence that malabsorptive techniques are better than other banding techniques for weight loss and resolution of comorbid illnesses. However, there are no published prospective, long-term, direct comparisons of these techniques available.Surgery for morbid obesity is considered an intervention of last resort for patients who have attempted first-line forms of medical management, such as diet, increased physical activity, behavioural modification, and drugs. In the absence of direct comparisons of active nonsurgical intervention via caloric restriction with bariatric techniques, the following observations are made:A recent systematic review examining the efficacy of major commercial and organized self-help weight loss programs in the United States concluded that the evidence to support the use of such programs was suboptimal, except for one trial on Weight Watchers. Furthermore, the programs were associated with high costs, attrition rates, and probability of regaining at least 50% of the lost weight in 1 to 2 years. (2)A recent randomized controlled trial reported 1-year outcomes comparing weight loss and metabolic changes in severely obese patients assigned to either a low-carbohydrate diet or a conventional weight loss diet. At 1 year, weight loss was similar for patients in each group (mean, 2-5 kg). There was a favourable effect on triglyceride levels and glycemic control in the low-carbohydrate diet group. (3)A decision-analysis model showed bariatric surgery results in increased life expectancy in morbidly obese patients when compared to diet and exercise. (4)A cost-effectiveness model showed bariatric surgery is cost-effective relative to nonsurgical management. (5)Extrapolating from 2003 data from the United States, Ontario would likely need to do 3,500 bariatric surgeries per year. It currently does 508 per year, including out-of-country surgeries.
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Ont Health Technol Assess Ser · Jan 2005
Biventricular pacing (cardiac resynchronization therapy): an evidence-based analysis.
In 2002, (before the establishment of the Ontario Health Technology Advisory Committee), the Medical Advisory Secretariat conducted a health technology policy assessment on biventricular (BiV) pacing, also called cardiac resynchronization therapy (CRT). The goal of treatment with BiV pacing is to improve cardiac output for people in heart failure (HF) with conduction defect on ECG (wide QRS interval) by synchronizing ventricular contraction. The Medical Advisory Secretariat concluded that there was evidence of short (6 months) and longer-term (12 months) effectiveness in terms of cardiac function and quality of life (QoL). More recently, a hospital submitted an application to the Ontario Health Technology Advisory Committee to review CRT, and the Medical Advisory Secretariat subsequently updated its health technology assessment. ⋯ Owing to the limitations of drug therapy, cardiac transplantation and device therapies have been used to try to improve QoL and survival of patients with chronic HF. Ventricular pacing is an emerging treatment option for patients with severe HF that does not respond well to medical therapy. Traditionally, indications for pacing include bradyarrhythmia, sick sinus syndrome, atrioventricular block, and other indications, including combined sick sinus syndrome with atrioventricular block and neurocardiogenic syncope. Recently, BiV pacing as a new, adjuvant therapy for patients with chronic HF and mechanical dyssynchrony has been investigated. Ventricular dysfunction is a sign of HF; and, if associated with severe intraventricular conduction delay, it can cause dyssynchronous ventricular contractions resulting in decreased ventricular filling. The therapeutic intent is to activate both ventricles simultaneously, thereby improving the mechanical efficiency of the ventricles. About 30% of patients with chronic HF have intraventricular conduction defects. (6) These conduction abnormalities progress over time and lead to discoordinated contraction of an already hemodynamically compromised ventricle. Intraventricular conduction delay has been associated with clinical instability and an increased risk of death in patients with HF. (7) Hence, BiV pacing, which involves pacing left and right ventricles simultaneously, may provide a more coordinated pattern of ventricular contraction and thereby potentially reduce QRS duration, and intraventricular and interventricular asynchrony. People with advanced chronic HF, a wide QRS complex (i.e., the portion of the electrocardiogram comprising the Q, R, and S waves, together representing ventricular depolarization), low left ventricular ejection fraction and contraction dyssynchrony in a viable myocardium and normal sinus rhythm, are the target patients group for BiV pacing. One-half of all deaths in HF patients are sudden, and the mode of death is arrhythmic in most cases. Internal cardioverter defibrillators (ICDs) combined with BiV pacemakers are therefore being increasingly considered for patients with HF who are at high risk of sudden death. CURRENT IMPLANTATION TECHNIQUE FOR CARDIAC RESYNCHRONIZATION: Conventional dual-chamber pacemakers have only 2 leads: 1 placed in the right atrium and the other in the right ventricle. The technique used for BiV pacemaker implantation also uses right atrial and ventricular pacing leads, in addition to a left ventricle lead advanced through the coronary sinus into a vein that runs along the ventricular free wall. This permits simultaneous pacing of both ventricles to allow resynchronization of the left ventricle septum and free wall. MODE OF OPERATION: Permanent pacing systems consist of an implantable pulse generator that contains a battery and electronic circuitry, together with 1 (single-chamber pacemaker) or 2 (dual-chamber pacemaker) leads. Leads conduct intrinsic atrial or ventricular signals to the sensing circuitry and deliver the pulse generator charge to the myocardium (muscle of the heart). COMPLICATIONS OF BIVENTRICULAR PACEMAKER IMPLANTATION: The complications that may arise when a BiV pacemaker is implanted are similar to those that occur with standard pacemaker implantation, including pneumothorax, perforation of the great vessels or the myocardium, air embolus, infection, bleeding, and arrhythmias. Moreover, left ventricular pacing through the coronary sinus can be associated with rupture of the sinus as another complication. CONCLUSION OF 2003 REVIEW OF BIVENTRICULAR PACEMAKERS BY THE MEDICAL ADVISORY SECRETARIAT: The randomized controlled trials (RCTs) the Medical Advisory Secretariat retrieved analyzed chronic HF patients that were assessed for up to 6 months. Other studies have been prospective, but nonrandomized, not double-blinded, uncontrolled and/or have had a limited or uncalculated sample size. Short-term studies have focused on acute hemodynamic analyses. The authors of the RCTs reported improved cardiac function and QoL up to 6 months after BiV pacemaker implantation; therefore, there is level 1 evidence that patients in ventricular dyssynchrony who remain symptomatic after medication might benefit from this technology. Based on evidence made available to the Medical Advisory Secretariat by a manufacturer, (8) it appears that these 6-month improvements are maintained at 12-month follow-up. To date, however, there is insufficient evidence to support the routine use of combined ICD/BiV devices in patients with chronic HF with prolonged QRS intervals. SUMMARY OF UPDATED FINDINGS SINCE THE 2003 REVIEW: Since the Medical Advisory Secretariat's review in 2003 of biventricular pacemakers, 2 large RCTs have been published: COMPANION (9) and CARE-HF. (10) The characteristics of each trial are shown in Table 1. The COMPANION trial had a number of major methodological limitations compared with the CARE-HF trial. Table 1:Characteristics of the COMPANION and CARE-HF Trials*COMPANION, 2004CARE-HF, 2005Optimal Therapy vs. BiV Pacing vs. BiV Pacing/ICD†Optimal Therapy vs. BiV PacingPopulationNew York Heart Association class III/IV heart failureEF† ≤ 0.35QRS† ≥ 120 msN1,520(optimal therapy, n = 308; BiV pacing, n = 617; BiV pacing/ICD, n = 595)813Follow-up (months)Median, 16Mean, 29Comment- Definition of "hospitalization" in primary outcome changed 3 times during trial w/o documentation in protocol and FDA† not notified (dominant outcome for composite endpoint).- Dropouts/withdrawals/crossovers not clearly described.- Study terminated early.- No direct comparison between BiV pacing vs. BiV pacing/ICD.- High number of patients withdrew from optimal therapy to device arms.- Not blinded.Not blinded*COMPANION; (9) CARE-HF. (ABSTRACT TRUNCATED)
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Ont Health Technol Assess Ser · Jan 2005
Sacral nerve stimulation for urinary urge incontinence, urgency-frequency, urinary retention, and fecal incontinence: an evidence-based analysis.
The aim of this review was to assess the effectiveness, safety, and cost of sacral nerve stimulation (SNS) to treat urinary urge incontinence, urgency-frequency, urinary retention, and fecal incontinence. ⋯ In summary, there is level 2 evidence to support the effectiveness of SNS to treat people with urge incontinence, urgency-frequency, or urinary retention. There is level 4 evidence to support the effectiveness of SNS to treat people with fecal incontinence. To qualify for SNS, people must meet the following criteria: Be refractory to behaviour and/or drug therapyHave had a successful test stimulation before implantation; successful test stimulation is defined by a 50% or greater improvement in voiding function based on the results of a voiding diary. Test stimulation periods range from 3 to 7 days for patients with urinary dysfunctions, and from 2 to 3 weeks for patients with fecal incontinence.Be able to record voiding diary data, so that clinical results of the implantation can be evaluated.Patients with stress incontinence, urinary retention due to obstruction and neurogenic conditions (such as diabetes with peripheral nerve involvement) are ineligible for sacral nerve stimulation. Physicians will need to learn how to use the InterStim System for Urinary Control. Requirements for training include these: Physicians must be experienced in the diagnosis and treatment of lower urinary tract disorders and should be trained in the implantation and use of the InterStim System for Urinary Control. (ABSTRACT TRUNCATED)
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Ont Health Technol Assess Ser · Jan 2005
Deep brain stimulation for Parkinson's disease and other movement disorders: an evidence-based analysis.
To determine the effectiveness and adverse effects of deep brain stimulation (DBS) in the treatment of symptoms of idiopathic Parkinson's disease, essential tremor, and primary dystonia and to do an economic analysis if evidence for effectiveness is established. ⋯ According to the estimates of prevalence and evidence of effectiveness, there is a shortfall in the numbers of DBS currently done in Ontario for drug-resistant PD, essential tremor, and primary dystonia.Since complication rates are lower if DBS is performed in specialized centres, the number of sites should be limited.The cost per procedure to institutions with the expertise to undertake DBS and the human resource considerations are likely to be limiting factors in the further diffusion of DBS.
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Ont Health Technol Assess Ser · Jan 2005
Hyperbaric oxygen therapy for non-healing ulcers in diabetes mellitus: an evidence-based analysis.
To examine the effectiveness and cost-effectiveness of hyperbaric oxygen therapy (HBOT) to treat people with diabetes mellitus (DM) and non-healing ulcers. This policy appraisal systematically reviews the published literature in the above patient population, and applies the results and conclusions of the review to current health care practices in Ontario, Canada. Although HBOT is an insured service in Ontario, the costs for the technical provision of this technology are not covered publicly outside the hospital setting. Moreover, access to this treatment is limited, because many hospitals do not offer it, or are not expanding capacity to meet the demand. ⋯ In 2003, the Ontario Health Technology Advisory Committee recommended a more coordinated strategy for wound care in Ontario to the Ministry of Health and Long-term Care. This strategy has begun at the community care and long-term care institution levels, but is pending in other areas of the health care system. There are about 700,000 people in Ontario with diabetes; of these, 10% to 15% may have a foot ulcer sometime in their lifetimes. Foot ulcers are treatable, however, when they are identified, diagnosed and treated early according to best practice guidelines. Routine follow-up for people with diabetes who may be at risk for neuropathy and/or peripheral vascular disease may prevent subsequent foot ulcers. There are 4 chambers that provide HBOT in Ontario. Fewer than 20 people with DM received HBOT in 2003. The quality of the evidence assessing the effectiveness of HBOT as an adjunct to standard therapy for people with non-healing diabetic foot ulcers is low, and the results are inconsistent. The results of a recent meta-analysis that found benefit of HBOT to prevent amputation are therefore uncertain. Future well-conducted studies may change the currently published estimates of effectiveness for wound healing and prevention of amputation using HBOT in the treatment of non-healing diabetic foot ulcers. Although HBOT is an insured service in Ontario, a well conducted, randomized controlled trial that has wound healing and amputation as the primary end-points is needed before this technology is used widely among patients with foot wounds due to diabetes.