Ontario health technology assessment series
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Ont Health Technol Assess Ser · Jan 2006
Polysomnography in patients with obstructive sleep apnea: an evidence-based analysis.
The objective of this health technology policy assessment was to evaluate the clinical utility and cost-effectiveness of sleep studies in Ontario. ⋯ Based on cross-sectional data from the Wisconsin Sleep Cohort Study of 602 men and women aged 30 to 60 years, it is estimated that the prevalence of sleep-disordered breathing is 9% in women and 24% in men, on the basis of more than five AHI events per hour of sleep. Among the women with sleep disorder breathing, 22.6% had daytime sleepiness and among the men, 15.5% had daytime sleepiness. Based on this, the prevalence of OSA in the middle-aged adult population is estimated to be 2% in women and 4% in men. Snoring is present in 94% of OSA patients, but not all snorers have OSA. Women report daytime sleepiness less often compared with their male counterparts (of similar age, body mass index [BMI], and AHI). Prevalence of OSA tends to be higher in older age groups compared with younger age groups. DIAGNOSTIC VALUE OF POLYSOMNOGRAPHY: It is believed that PSG in the sleep laboratory is more accurate than in-home PSG. In the absence of a gold standard, however, claims of accuracy cannot be substantiated. In general, there is poor correlation between PSG variables and clinical variables. A variety of cut-off points of AHI (> 5, > 10, and > 15) are arbitrarily used to diagnose and categorize severity of OSA, though the clinical importance of these cut-off points has not been determined. Recently, a study of the use of a therapeutic trial of CPAP to diagnose OSA was reported. The authors studied habitual snorers with daytime sleepiness in the absence of other medical or psychiatric disorders. Using PSG as the reference standard, the authors calculated the sensitivity of this test to be 80% and its specificity to be 97%. Further, they concluded that PSG could be avoided in 46% of this population. OBSTRUCTIVE SLEEP APNEA AND OBESITY: Obstructive sleep apnea is strongly associated with obesity. Obese individuals (BMI >30 kg/m(2)) are at higher risk for OSA compared with non-obese individuals and up to 75% of OSA patients are obese. It is hypothesized that obese individuals have large deposits of fat in the neck that cause the upper airway to collapse in the supine position during sleep. The observations reported from several studies support the hypothesis that AHIs (or RDIs) are significantly reduced with weight loss in obese individuals. OBSTRUCTIVE SLEEP APNEA AND CARDIOVASCULAR DISEASES: Associations have been shown between OSA and comorbidities such as diabetes mellitus and hypertension, which are known risk factors for myocardial infarction and stroke. Patients with more severe forms of OSA (based on AHI) report poorer quality of life and increased health care utilization compared with patients with milder forms of OSA. From animal models, it is hypothesized that sleep fragmentation results in glucose intolerance and hypertension. There is, however, no evidence from prospective studies in humans to establish a causal link between OSA and hypertension or diabetes mellitus. It is also not clear that the associations between OSA and other diseases are independent of obesity; in most of these studies, patients with higher values of AHI had higher values of BMI compared with patients with lower AHI values. A recent meta-analysis of bariatric surgery has shown that weight loss in obese individuals (mean BMI = 46.8 kg/m(2); range = 32.30-68.80) significantly improved their health profile. Diabetes was resolved in 76.8% of patients, hypertension was resolved in 61.7% of patients, hyperlipidemia improved in 70% of patients, and OSA resolved in 85.7% of patients. This suggests that obesity leads to OSA, diabetes, and hypertension, rather than OSA independently causing diabetes and hypertension. (ABSTRACT TRUNCATED)
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Ont Health Technol Assess Ser · Jan 2006
Optimum methadone compliance testing: an evidence-based analysis.
The objective of this analysis was to determine the diagnostic utility of oral fluid testing collected with the Intercept oral fluid collection device. ⋯ A total of 854 potential citations were retrieved. After reviewing titles and abstracts, 2 met the inclusion and exclusion criteria. Two other relevant studies were found after corresponding with the author of the 2 studies retrieved from the literature search. Therefore a total of 4 published studies are included in this analysis. All 4 studies carried out by the same investigator meet the definition of Medical Advisory Secretariat level III (not a-randomized controlled trial with contemporaneous controls) study design. In each of the studies, paired urine and oral fluid specimens where obtained from drug users. Urine collection was not observed in the studies however, laboratory tests for pH and creatinine were used to determine the reliability of the specimen. Urine specimens thought to be diluted and unreliable were removed from the evaluation. Urinalysis was used as the criterion measurement for which to determine the sensitivity and specificity of oral fluid testing by the Intercept oral fluid device for opiates, benzodiazepines, cocaine and marijuana. Alcohol was not tested in any of the 4 studies. From these 4 studies, the following conclusions were drawn: The evidence indicates that oral fluid testing with the Intercept oral fluid device has better specificity than sensitivity for opiates, benzodiazepines, cocaine and marijuana.THE SENSITIVITY OF ORAL FLUIDS TESTING WITH THE INTERCEPT ORAL FLUID DEVICE SEEMS TO BE FROM BEST TO WORST: cocaine > benzodiazepines >opiates> marijuana.The sensitivity and specificity for opiates of the Intercept oral fluid device ranges from 75 to 90% and 97- 100% respectively.The consequences of opiate false-negatives by oral fluid testing with the Intercept oral fluid device need to be weighed against the disadvantages of urine testing, including invasion of privacy issues and adulteration and substitution of the urine specimen.The window of detection is narrower for oral fluid drug testing than urinalysis and because of this oral fluid testing may best be applied in situations where there is suspected frequent drug use. When drug use is thought to be less frequent or remote, urinalysis may offer a wider (24-48 hours more than oral fluids) window of detection.The narrow window of detection for oral fluid testing may mean more frequent testing is needed compared to urinalysis. This may increase the expense for drug testing in general.POC oral fluid testing is not yet available and may limit the practical utility of this drug testing methodology. POC urinalysis by immunoassay is available.The possible applications of oral fluid testing may include:Because of its narrow window of detection compared to urinalysis oral fluid testing may best be used during periods of suspected frequent or recent drug use (within 24 hours of drug testing). This is not to say that oral fluid testing is superior to urinalysis during these time periods.In situations where an observed urine specimen is difficult to obtain. This may include persons with "shy bladder syndrome" or with other urinary conditions limiting their ability to provide an observed urine specimen.When the health of the patient would make urine testing unreliable (e,g., renal disease)As an alternative drug testing method when urine specimen tampering practices are suspected to be affecting the reliability of the urinalysis test.Possible limiting Factors to Diffusion of Oral Fluid Technology No oral fluid POC test equivalent to onsite urine dips or POC analyzer reducing immediacy of results for patient care.Currently, physicians get reimbursed directly for POC urinalysis. (ABSTRACT TRUNCATED)
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Ont Health Technol Assess Ser · Jan 2006
Artificial discs for lumbar and cervical degenerative disc disease -update: an evidence-based analysis.
To assess the safety and efficacy of artificial disc replacement (ADR) technology for degenerative disc disease (DDD). ⋯ Lumbar Artificial Disc Replacement Since the 2004 Medical Advisory Secretariat health technology policy assessment, data from 2 RCTs and 6 case series assessing the effectiveness and adverse events profile of lumbar ADR to treat DDD has become available. The GRADE quality of this evidence is moderate for effectiveness and for short-term (2-year follow-up) complications; it is very low for ASD.The effectiveness of lumbar ADR is not inferior to that of spinal fusion for the treatment of lumbar DDD. The rates for device failure and neurological complications 2 years after surgery did not differ between ADR and fusion patients. Based on a Bayesian meta-analysis, lumbar ADR is 79% superior to lumbar spinal fusion.The rate of major complications after lumbar ADR is between 0% and 13% per device implanted. The rate of ASD in 1 case series was 2% over an 11-year follow-up period.Outcome data for lumbar ADR beyond a 2-year follow-up are not yet available.Cervical Artificial Disc Replacement Since the 2004 Medical Advisory Secretariat health technology policy assessment, 4 case series have been added to the body of evidence assessing the effectiveness and adverse events profile of cervical ADR to treat DDD. The GRADE quality of this evidence is very low for effectiveness as well as for the adverse events profile. Sparse outcome data are available.Because data are sparse, the effectiveness of cervical ADR compared with spinal fusion cannot be determined at this time.The rate of major complications was assessed up to 2 years after surgery; it ranged from 0% to 8.1% per device implanted. The rate of ASD is not reported in the clinical trial literature.
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Ont Health Technol Assess Ser · Jan 2006
Enhanced External Counterpulsation (EECP): An Evidence-Based Analysis.
To assess the effectiveness, and cost effectiveness of EECP in patients with severe anginal symptoms, secondary to chronic coronary disease, who are unresponsive to exhaustive pharmacotherapy and not candidates for surgical/percutaneous revascularization procedures (e.g., angioplasty, coronary bypass surgery). To assess the effectiveness, and cost effectiveness of EECP in patients with heart failure. ⋯ The Cochrane and INAHTA databases yielded 3 HTAs or systematic reviews on EECP treatment (Blue Cross Blue Shield Technology Evaluation Center [BCBS TEC], ECRI, and the Centers for Medicare and Medicaid Services [CMS]). A search of Medline and Embase December 2005 - March 2006 (after the literature search cutoff from the most recent HTA) was conducted using key words enhanced external counterpulsation, EECP, angina, myocardial ischemia, congestive heart failure. This search produced 1 study which met the inclusion criteria. This level 4a study was inferior in quality to the RCT which formed the basis of the 2003 Medical Advisory Secretariat recommendation. BCBS reviewed the evidence through November 2005 to determine if EECP improves health outcomes for refractory chronic stable angina pectoris or chronic stable HF. (12) BCBS concluded that the available evidence is not sufficient to permit conclusions of the effect of EECP on health outcomes. Both controlled trials had methodologic flaws (MUST EECP and MUST EECP quality of life studies). The case series and observational studies for both indications while suggestive of a treatment benefit from EECP have shortcomings as well. On March 20 2006, CMS posted their proposed coverage decision memorandum for external counterpulsation therapy. (ABSTRACT TRUNCATED)
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The objective of this analysis is to review a spectrum of functional brain imaging technologies to identify whether there are any imaging modalities that are more effective than others for various brain pathology conditions. This evidence-based analysis reviews magnetoencephalography (MEG), magnetic resonance spectroscopy (MRS), positron emission tomography (PET), and functional magnetic resonance imaging (fMRI) for the diagnosis or surgical management of the following conditions: Alzheimer's disease (AD), brain tumours, epilepsy, multiple sclerosis (MS), and Parkinson's disease (PD). ⋯ There is evidence to indicate that PET can accurately diagnose AD; however, at this time, there is no evidence to suggest that a diagnosis of AD with PET alters the clinical outcomes of patients. The addition of MRS or O-(2-(18)F-Fluoroethyl)-L-Tyrosine (FET)-PET to gadolinium (Gd)-enhanced MRI for distinguishing malignant from benign tumours during primary diagnosis may provide a higher specificity than Gd-enhanced MRI alone. The clinical utility of additional imaging in patients to distinguish malignant from benign tumours is unclear, because patients with a suspected brain tumour will likely undergo a biopsy despite additional imaging results. The addition of MRS, FET-PET, or MRI T2 to Gd-enhanced MRI for the differentiation of recurrence from radiation necrosis may provide a higher specificity than Gd-enhanced MRI alone. The clinical utility of additional imaging in patients with a suspected recurrence is in the monitoring of patients. Based on the evidence available, it is unclear if one of the imaging modalities (MRS, FET-PET, or MRI T2) offers significantly improved specificity over another. There may be a role for fMRI in the identification of surgical candidates for tumour resection; however, this requires further research. Based on the studies available, it is unclear if MEG has similar accuracy in localizing seizure foci to intracranial electroencephalogram (ICEEG). More high-quality research is needed to establish whether there is a difference in accuracy between MEG and ICEEG. The results of the studies comparing PET to noninvasive electroencephalogram (EEG) did not demonstrate that PET was more accurate at localizing seizure foci; however, there may be some specific conditions, such as tuberous sclerosis, where PET may be more accurate than noninvasive EEG. There may be some clinical utility for MEG or fMRI in presurgical functional mapping; however, this needs further investigation involving comparisons with other modalities. The clinical utility of MRS has yet to be established for patients with epilepsy. Positron emission tomography has high sensitivity and specificity in the diagnosis of PD and the differential diagnosis of parkinsonian syndromes; however, it is unclear at this time if the addition of PET in the diagnosis of these conditions contributes to the treatment and clinical outcomes of patients. There is limited clinical utility of functional brain imaging in the management of patients with MS at this time. Diagnosis of MS is established through clinical history, evoked potentials, and MRI. Magnetic resonance imaging can identify the multifocal white lesions and other structural characteristics of MS.