Ontario health technology assessment series
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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.
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Ont Health Technol Assess Ser · Jan 2005
Arthroscopic lavage and debridement for osteoarthritis of the knee: an evidence-based analysis.
The purpose of this review was to determine the effectiveness and adverse effects of arthroscopic lavage and debridement, with or without lavage, in the treatment of symptoms of osteoarthritis (OA) of the knee, and to conduct an economic analysis if evidence for effectiveness can be established. QUESTIONS ASKED: Does arthroscopic lavage improve motor function and pain associated with OA of the knee?Does arthroscopic debridement improve motor function and pain associated with OA of the knee?If evidence for effectiveness can be established, what is the duration of effect?What are the adverse effects of these procedures?What are the economic considerations if evidence for effectiveness can be established? ⋯ Arthroscopic debridement of the knee has thus far only been found to be effective for medial compartmental OA. All other indications should be reviewed with a view to reducing arthroscopic debridement as an effective therapy. Arthroscopic lavage of the knee is not indicated for any stage of OA. There is very poor quality evidence on the effectiveness of debridement with partial meniscectomy in the case of meniscal tears in OA of the knee.
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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
Implantable cardioverter defibrillators. Prophylactic use: an evidence-based analysis.
The use of implantable cardiac defibrillators (ICDs) to prevent sudden cardiac death (SCD) in patients resuscitated from cardiac arrest or documented dangerous ventricular arrhythmias (secondary prevention of SCD) is an insured service. In 2003 (before the establishment of the Ontario Health Technology Advisory Committee), the Medical Advisory Secretariat conducted a health technology policy assessment on the prophylactic use (primary prevention of SCD) of ICDs for patients at high risk of SCD. The Medical Advisory Secretariat concluded that ICDs are effective for the primary prevention of SCD. Moreover, it found that a more clearly defined target population at risk for SCD that would be likely to benefit from ICDs is needed, given that the number needed to treat (NNT) from recent studies is 13 to 18, and given that the per-unit cost of ICDs is $32,000, which means that the projected cost to Ontario is $770 million (Cdn). Accordingly, as part of an annual review and publication of more recent articles, the Medical Advisory Secretariat updated its health technology policy assessment of ICDs. ⋯ Using the GRADE Working Group criteria, the quality of these 3 trials was examined (Table 2). Quality refers to the criteria such as the adequacy of allocation concealment, blinding and follow-up. Consistency refers to the similarity of estimates of effect across studies. If there is important unexplained inconsistency in the results, our confidence in the estimate of effect for that outcome decreases. Differences in the direction of effect, the size of the differences in effect, and the significance of the differences guide the decision about whether important inconsistency exists. Directness refers to the extent to which the people interventions and outcome measures are similar to those of interest. For example, there may be uncertainty about the directness of the evidence if the people of interest are older, sicker or have more comorbidity than those in the studies. As stated by the GRADE Working Group, the following definitions were used to grade the quality of the evidence: HIGH: Further research is very unlikely to change our confidence n the estimate of effect.MODERATE: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.LOW: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.VERY LOW: Any estimate of effect is very uncertain.Table 2:Quality of Evidence - MADIT I, MADIT II, and SCD-HeFT*TrialDesignQualityConsistencyDirectness†Quality GradeMADIT IRCTImbalance in β-blocker usage between study arms.The overall number of patients from which the study was drawn was not reported.Selection bias may have occurred since patients were selected for randomization if they did not respond to procainamide, thereby introducing a potential bias into the medication arm.Specific details regarding allocation concealment and blinding procedures were not provided.Single-chamber ICD used in study.Trial started with transthoracic implants, and then switched to nontransthoracic implants.Ischemic cardiomyopathy only.5-year NNT = 2.The overall number of Moderate patients from which the study was drawn was not reported.Selection bias may have occurred since patients were selected for randomization if they did not respond to procainamide, thereby introducing a potential bias into the medication arm.ModerateMADIT IIRCT~ 90% of patients were recruited ≥6 months post-MI; 20% of control group died after mean 20-month follow-up.How and where patients recruited?Specific details regarding allocation concealment/blinding procedures not provided.Subset had MADIT I criteria; post hoc analysis of incomplete data suggested "weak-moderate evidence that ICD effect greater in inducible than noninducible patients in MADIT II." (5;6)First study to assess both single- and dual-chamber ICD devices for primary prevention.Programming of device and medications left to the discretion of the patients' physician.Higher rate of hospitalization for new or worsened heart failure in the group receiving the ICDs compared to conventional therapy (19.9% versus 14.9% respectively).Ischemic cardiomyopathy only.5-year NNT = 6.How and where patients Weak recruited?Subset had MADIT I criteria.WeakSCD-HeFTRCTStatistically significant difference in β-blocker usage between treatment groups at last follow-up.Drug arms double-blinded.Shock-only single-lead device. Antitachycardia pacing not permitted.Ischemic and nonischemic cardiomyopathy.There was a statistically significant difference in terms of the NYHA prespecified subgroups analysis. The NYHA subgroups were prespecified a priori and the results of the interaction tests were significant. Yet, ICD treatment had a significant benefit in patients in NYHA class II but not in those in NYHA class III. (ABSTRACT TRUNCATED)
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Ont Health Technol Assess Ser · Jan 2005
Use of automated external defibrillators in cardiac arrest: an evidence-based analysis.
The objectives were to identify the components of a program to deliver early defibrillation that optimizes the effectiveness of automated external defibrillators (AEDs) in out-of-hospital and hospital settings, to determine whether AEDs are cost-effective, and if cost-effectiveness was determined, to advise on how they should be distributed in Ontario. ⋯ The OPALS study model appears cost-effective, and effectiveness can be further enhanced by training community volunteers to improve the bystander-initiated CPR rates. Deployment of AEDs in all public access areas and in houses and apartments is not cost-effective. Further research is needed to examine the benefit of in-home use of AEDs in patients at high risk of cardiac arrest.