Ontario health technology assessment series
-
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)
-
Ont Health Technol Assess Ser · Jan 2005
Intra-articular viscosupplementation with hylan g-f 20 to treat osteoarthritis of the knee: an evidence-based analysis.
To assess the effectiveness and cost-effectiveness of hylan G-F 20 as a substitute for existing treatments for pain due to osteoarthritis (OA) of the knee, other viscosupplementation devices, and/or as an adjunct to conventional therapy. Hylan G-F 20 (brand name Synvisc, which is manufactured by Genzyme) is a high molecular weight derivative of hyaluronan, a component of joint synovial fluid. It acts as a lubricant and shock absorber. It is administered by injection into the joint space to treat pain associated with OA of the knee. Although the injection procedure is an insured service in Ontario, the device, hylan G-F 20, is not. ⋯ When the benefits relative to the risks and costs are considered, NSAIDs and hylan G-F 20 appear comparable, as the table shows. Consequently, there's little evidence on which to recommend hylan G-F 20 over NSAIDs, except perhaps for patients who cannot tolerate NSAIDs, although this evidence is indirect, since no studies looked specifically at this population. (ABSTRACT TRUNCATED)
-
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.
-
Ont Health Technol Assess Ser · Jan 2005
Osteogenic protein-1 for long bone nonunion: an evidence-based analysis.
To assess the efficacy of osteogenic protein-1 (OP-1) for long bone nonunion. ⋯ Friedlaender et al. conducted a prospective, randomized, partially blinded clinical trial on the treatment tibial nonunions with OP-1. Tibial nonunions were chosen for this study because of their high frequency, challenging treatment requirements, and substantial morbidity. All of the nonunions were at least 9 months old and had shown no progress toward healing over the previous 3 months. The patients were randomized to receive either treatment with autologous bone grafting or treatment with OP-1 in a type-1 collagen carrier. Both groups received reduction and fixation with an intramedullary rod. Table 1 summarizes the clinical outcomes of this study. Table 1:Outcomes in a Randomized Clinical Trial on Tibial Nonunions: Osteogenic Protein-1 versus Autologous Bone GraftingClinical Indicator at 9 monthsSuccess by ProcedureOP-1 % (range)Autograft % (range)PWeight-bearing*8685not significantPain on Weight-bearing*8990not significantBridging seen on radiograph (at least 1 view)7584not significantBridging seen on radiograph (at least 3 views)6274not significantRepeated surgery*510not significantPhysician satisfaction8690not significantMean operative time in minutes (range)169 (58 - 420)178 (58 - 420)not significantMean operative blood loss in ml (range)254 (10-1,150)345 (35 - 1,200).049Mean length of stay in days (range)3.7 (0 - 18)4.1 (1 - 24)not significantPain at the donor siteN/A80N/AAt 6 months postsurgery20At 12 months postsurgery13Osteomyelitis % (number)3 (2/61)21 (13/61). (ABSTRACT TRUNCATED)
-
Ont Health Technol Assess Ser · Jan 2005
Endovascular repair of descending thoracic aortic aneurysm: an evidence-based analysis.
To conduct an assessment on endovascular repair of descending thoracic aortic aneurysm (TAA). ⋯ Mortality The results of a comparative study found that in-hospital mortality was not significantly different between ESG placement and surgery patients (2 [4.8%] for ESG vs. 6 [11.3%] for surgery).Pooled data from case series with a mean follow-up ranging from 12 to 38 months showed a 30-day mortality and late mortality rate of 3.9% and 5.5%, respectively. These rates are lower than are those reported in the literature for surgical repair of TAA.Case series showed that the most common cause of early death in patients undergoing endovascular repair is aortic rupture, and the most common causes of late death are cardiac events and aortoesophageal or aortobronchial fistula.Technical Success Rate Technical success rates reported by case series are 55% to 100% (100% and 94.4% in 2 studies with all elective cases, 89% in a study with 5% emergent cases, and 55% in a study with 42% emergent cases).Surgical Reintervention In the comparative study, 3 (7.1%) patients in the ESG group and 14 (26.5%) patients in the surgery group required surgical reintervention. In the ESG group, the reasons for surgical intervention were postoperative bleeding at the access site, paraplegia, and type 1 endoleak. In the surgical group, the reasons for surgery were duodenal perforation, persistent thoracic duct leakage, false aneurysm, and 11 cases of postoperative bleeding.Pooled data from case series show that 9 (2.6%) patients required surgical intervention. The reasons for surgical intervention were endoleak (3 cases), aneurysm enlargement and suspected infection (1 case), aortic dissection (1 case), pseudoaneurysm of common femoral artery (1 case), evacuation of hematoma (1 case), graft migration (1 case), and injury to the access site (1 case).Endovascular Revision In the comparative study, 3 (7.1%) patients required endovascular revision due to persistent endoleak.Pooled data from case series show that 19 (5.3%) patients required endovascular revision due to persistent endoleak.Graft Migration Two case series reported graft migration. In one study, 3 proximal and 4 component migrations were noted at 2-year follow-up (total of 5%). Another study reported 1 (3.7%) case of graft migration. Overall, the incidence of graft migration was 2.6%.Aortic Rupture In the comparative study, aortic rupture due to bare stent occurred in 1 case (2%). The pooled incidence of aortic rupture or dissection reported by case series was 1.4%.Postprocedural Complications In the comparative study, there were no statistically significant differences between the ESG and surgery groups in postprocedural complications, except for pneumonia. The rate of pneumonia was 9% for those who received an ESG and 28% for those who had surgery (P = .02). There were no cases of paraplegia in either group. The rate of other complications for ESG and surgery including stroke, cardiac, respiratory, and intestinal ischemia were all 5.1% for ESG placement and 10% for surgery. The rate for mild renal failure was 16% in the ESG group and 30% in the surgery group. The rate for severe renal failure was 11% for ESG placement and 10% for surgery.POOLED DATA FROM CASE SERIES SHOW THE FOLLOWING POSTPROCEDURAL COMPLICATION RATES IN THE ESG PLACEMENT GROUP: paraplegia (2.2%), stroke (3.9%), cardiac (2.9%), respiratory (8.7%), renal failure (2.8%), and intestinal ischemia (1%).Time-Related Outcomes The results of the comparative study show statistically significant differences between the ESG and surgery group for mean operative time (ESG, 2.7 hours; surgery, 5 hours), mean duration of intensive care unit stay (ESG, 11 days; surgery, 14 days), and mean length of hospital stay (ESG, 10 days; surgery, 30 days).The mean duration of intensive care unit stay and hospital stay derived from case series is 1.6 and 7.8 days, respectively. ONTARIO-BASED ECONOMIC ANALYSIS: In Ontario, the annual treatment figures for fiscal year 2004 include 17 cases of descending TAA repair procedures (source: Provincial Health Planning Database). Fourteen of these have been identified as "not ruptured" with a mean hospital length of stay of 9.23 days, and 3 cases have been identified as "ruptured," with a mean hospital length of stay of 28 days. However, because one Canadian Classification of Health Interventions code was used for both procedures, it is not possible to determine how many were repaired with an EVAR procedure or with an open surgical procedure. (ABSTRACT TRUNCATED)