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Biomedical subjects

Terry P Klassen

Publications and source records attributed to Terry P Klassen.

At least 19 recordsLinked to original sources
PubMed2006

Efficacy and safety of exogenous melatonin for secondary sleep disorders and sleep disorders accompanying sleep restriction: meta-analysis.

OBJECTIVE: To conduct a systematic review of the efficacy and safety of exogenous melatonin in managing secondary sleep disorders and sleep disorders accompanying sleep restriction, such as jet lag and shiftwork disorder. DATA SOURCES: 13 electronic databases and reference lists of relevant reviews and included studies; Associated Professional Sleep Society abstracts (1999 to 2003). STUDY SELECTION: The efficacy review included randomised controlled trials; the safety review included randomised and non-randomised controlled trials. QUALITY ASSESSMENT: Randomised controlled trials were assessed by using the Jadad Scale and criteria by Schulz et al, and non-randomised controlled trials by the Downs and Black checklist. DATA EXTRACTION AND SYNTHESIS: One reviewer extracted data and another reviewer verified the data extracted. The inverse variance method was used to weight studies and the random effects model was used to analyse data. MAIN RESULTS: Six randomised controlled trials with 97 participants showed no evidence that melatonin had an effect on sleep onset latency in people with secondary sleep disorders (weighted mean difference -13.2 (95% confidence interval -27.3 to 0.9) min). Nine randomised controlled trials with 427 participants showed no evidence that melatonin had an effect on sleep onset latency in people who had sleep disorders accompanying sleep restriction (-1.0 (-2.3 to 0.3) min). 17 randomised controlled trials with 651 participants showed no evidence of adverse effects of melatonin with short term use (three months or less). CONCLUSIONS: There is no evidence that melatonin is effective in treating secondary sleep disorders or sleep disorders accompanying sleep restriction, such as jet lag and shiftwork disorder. There is evidence that melatonin is safe with short term use.

Adolescent↗
PubMed2005

Publication bias of randomized controlled trials in emergency medicine.

OBJECTIVES: To determine the publication status and time to publication of randomized controlled trials (RCTs) that were presented at the Society for Academic Emergency Medicine (SAEM) meetings from 1995 to 2003. The impact of positive-outcome bias, time-lag bias, and gray literature bias also was assessed. METHODS: Retrospective cohort study of RCT abstracts presented at nine SAEM scientific meetings. Electronic searches identified publications from the abstracts. RESULTS: Of 4,399 abstracts, 383 (8.7%; 95% confidence interval [CI] = 7.8% to 9.5%) were identified as RCTs. One hundred ninety-four (50.7%; 95% CI = 45.7% to 55.7%) were subsequently published up to May 2004. The median time to publication was 32 months (95% CI = 23 to 41), with 59% of RCT abstracts published within five years of presentation. No evidence of positive-outcome bias or time-lag bias was identified; however, changes from abstract to manuscript were found. Manuscripts were less likely to endorse the experimental intervention than were abstracts (OR, 0.2; 95% CI = 0.0 to 0.6). CONCLUSIONS: The proportion of emergency medicine RCT abstracts published is slightly lower than that for other biomedical specialties; however, biases reported by investigators in other biomedical areas do not appear to be as problematic in emergency medicine research. Differences between conclusions from abstracts and manuscripts must be considered when employing meeting abstracts as a source of evidence for future research or for systematic reviews in emergency medicine.

Abstracting and Indexing↗
PubMed2005

Children in reviews: methodological issues in child-relevant evidence syntheses.

BACKGROUND: The delivery of optimal medical care to children is dependent on the availability of child relevant research. Our objectives were to: i) systematically review and describe how children are handled in reviews of drug interventions published in the Cochrane Database of Systematic Reviews (CDSR); and ii) determine when effect sizes for the same drug interventions differ between children and adults. METHODS: We systematically identified all of the reviews relevant to child health in the CDSR 2002, Issue 4. Reviews were included if they investigated the efficacy or effectiveness of a drug intervention for a condition that occurs in both children and adults. Information was extracted on review characteristics including study methods, results, and conclusions. RESULTS: From 1496 systematic reviews, 408 (27%) were identified as relevant to both adult and child health; 52% (213) of these included data from children. No significant differences were found in effect sizes between adults and children for any of the drug interventions or conditions investigated. However, all of the comparisons lacked the power to detect a clinically significant difference and wide confidence intervals suggest important differences cannot be excluded. A large amount of data was unavailable due to inadequate reporting at the trial and systematic review level. CONCLUSION: Overall, the findings of this study indicate there is a paucity of child-relevant and specific evidence generated from evidence syntheses of drug interventions. The results indicate a need for a higher standard of reporting for participant populations in studies of drug interventions.

Adolescent↗
PubMed2005

Which resources should be used to identify RCT/CCTs for systematic reviews: a systematic review.

BACKGROUND: Systematic reviewers seek to comprehensively search for relevant studies and summarize these to present the most valid estimate of intervention effectiveness. The more resources searched, the higher the yield, and thus time and costs required to conduct a systematic review. While there is an abundance of evidence to suggest how extensive a search for randomized controlled trials (RCTs) should be, it is neither conclusive nor consistent. This systematic review was conducted in order to assess the value of different resources to identify trials for inclusion in systematic reviews. METHODS: Seven electronic databases, four journals and Cochrane Colloquia were searched. Key authors were contacted and references of relevant articles screened. Included studies compared two or more sources to find RCTs or controlled clinical trials (CCTs). A checklist was developed and applied to assess quality of reporting. Data were extracted by one reviewer and checked by a second. Medians and ranges for precision and recall were calculated; results were grouped by comparison. Meta-analysis was not performed due to large heterogeneity. Subgroup analyses were conducted for: search strategy (Cochrane, Simple, Complex, Index), expertise of the searcher (Cochrane, librarian, non-librarian), and study design (RCT and CCT). RESULTS: Sixty-four studies representing 13 electronic databases met inclusion criteria. The most common comparisons were MEDLINE vs. handsearching (n = 23), MEDLINE vs. MEDLINE+handsearching (n = 13), and MEDLINE vs. reference standard (n = 13). Quality was low, particularly for the reporting of study selection methodology. Overall, recall and precision varied substantially by comparison and ranged from 0 to 100% and 0 to 99%, respectively. The trial registries performed the best with median recall of 89% (range 84, 95) and median precision of 96.5% (96, 97), although these results are based on a small number of studies. Inadequate or inappropriate indexing was the reason most cited for missing studies. Complex and Cochrane search strategies (SS) performed better than Simple SS. CONCLUSION: Multiple-source comprehensive searches are necessary to identify all RCTs for a systematic review, although indexing needs to be improved. Although trial registries demonstrated the highest recall and precision, the Cochrane SS or a Complex SS in consultation with a librarian are recommended. Continued efforts to develop CENTRAL should be supported.

Databases, Bibliographic↗
PubMed2005

Challenges in systematic reviews of therapeutic devices and procedures.

The authors discuss 3 challenges in conducting and interpreting any systematic review that are particularly relevant for systematic reviews of therapeutic devices or surgical procedures: 1) inclusion or exclusion of grey literature, 2) the role of nonrandomized studies, and 3) issues in applying the results to clinical care that are unique to the surgical and therapeutic device literature. The authors also discuss empirical evidence related to these topics and illustrate how reviewers in the Agency for Healthcare Research and Quality's Evidence-based Practice Center program have dealt with these challenges in developing evidence reports for decision makers and clinicians about therapeutic devices or surgical procedures.

Clinical Trials as Topic↗
PubMed2005

A systematic review of intravenous gamma globulin for therapy of acute myocarditis.

BACKGROUND: Intravenous gamma globulin (IVGG) is commonly used in the management of acute myocarditis. The objective of this study was to systematically review the literature evaluating this practice. METHODS: We conducted a comprehensive search (electronic databases, trials registries, conference proceedings, reference lists, contact with authors) to identify studies evaluating the use of IVGG in adults and children with a clinical or histologically proven diagnosis of myocarditis of possible viral etiology and symptoms of less than six months duration. Two reviewers independently screened the searches, applied inclusion criteria, and graded the evidence. RESULTS: Results were described qualitatively; data were not pooled because only one randomized controlled trial (RCT) with 62 patients was identified. The RCT showed no benefit with respect to cardiac function, functional outcome, or event-free survival. A small, uncontrolled trial (n = 10) showed significant improvement in LVEF from a mean of 24% to 41% 12 months after IVGG in nine survivors. A retrospective cohort study of pediatric patients showed improvement in cardiac function and a trend towards improved survival in patients receiving IVGG (n = 21) versus historic controls (n = 25). Ten case reports and two case series (total n = 21) described improvement in cardiac function after administration of IVGG; two case reports showed no benefit of IVGG. One case of hemolytic anemia was attributed to IVGG. CONCLUSION: There is insufficient data from methodologically strong studies to recommend routine use of IVGG for acute myocarditis. Future randomized studies that take into account the etiology of acute myocarditis will be required to determine the efficacy of IVGG.

Acute Disease↗
PubMed2005

Effectiveness of a home-based balance-training program in reducing sports-related injuries among healthy adolescents: a cluster randomized controlled trial.

BACKGROUND: Sport is the leading cause of injury requiring medical attention among adolescents. We studied the effectiveness of a home-based balance-training program using a wobble board in improving static and dynamic balance and reducing sports-related injuries among healthy adolescents. METHODS: In this cluster randomized controlled trial, we randomly selected 10 of 15 high schools in Calgary to participate in the fall of 2001. We then recruited students from physical education classes and randomly assigned them, by school, to either the intervention (n = 66) or the control (n = 61) group. Students in the intervention group participated in a daily 6-week and then a weekly 6-month home-based balance-training program using a wobble board. Students at the control schools received testing only. The primary outcome measures were timed static and dynamic balance, 20-m shuttle run and vertical jump, which were measured at baseline and biweekly for 6 weeks. Self-reported injury data were collected over the 6-month follow-up period. RESULTS: At 6 weeks, improvements in static and dynamic balance were observed in the intervention group but not in the control group (difference in static balance 20.7 seconds, 95% confidence interval [CI] 10.8 to 30.6 seconds; difference in dynamic balance 2.3 seconds, 95% CI 0.7 to 4.0 seconds). There was evidence of a protective effect of balance training in over 6 months (relative risk of injury 0.2, 95% CI 0.05 to 0.88). The number needed to treat to avoid 1 injury over 6 months was 8 (95% CI 4 to 35). INTERPRETATION: Balance training using a wobble board is effective in improving static and dynamic balance and reducing sports-related injuries among healthy adolescents.

Adolescent↗
PubMed2005

A randomized, double-blind, placebo-controlled noninferiority trial of amoxicillin for clinically diagnosed acute otitis media in children 6 months to 5 years of age.

OBJECTIVES: Debate continues with respect to a "watch and wait" approach versus immediate antibiotic treatment for the initial treatment of acute otitis media. In this double-blind noninferiority trial, we compared clinical improvement rates at 14 days for children (6 months to 5 years of age) with acute otitis media who were randomly assigned to receive amoxicillin or placebo. METHODS: We enrolled healthy children who presented to clinics or the emergency department with a new episode of acute otitis media during the fall and winter months in Ottawa (from December 1999 to the end of March 2002). The children were randomly assigned to receive amoxicillin (60 mg/kg daily) or placebo for 10 days. Telephone follow-up was performed on each of days 1, 2 and 3 and once between day 10 and day 14. The primary outcome was clinical resolution of symptoms, defined as absence of receipt of an antimicrobial (other than the amoxicillin in the treatment group) at any time during the 14-day period. Secondary outcomes were the presence of pain and fever and the activity level in the first 3 days, recurrence rates, and the presence of middle ear effusion at 1 and 3 months. RESULTS: According to clinical scoring, 415 of the 512 children who could be evaluated had moderate disease. At 14 days 84.2% of the children receiving placebo and 92.8% of those receiving amoxicillin had clinical resolution of symptoms (absolute difference -8.6%, 95% confidence interval -14.4% to -3.0%). Children who received placebo had more pain and fever in the first 2 days. There were no statistical differences in adverse events between the 2 groups, nor were there any significant differences in recurrence rates or middle ear effusion at 1 and 3 months. INTERPRETATION: Our results did not support the hypothesis that placebo was noninferior to amoxicillin (i.e., that the 14-day cure rates among children with clinically diagnosed acute otitis media would not be substantially worse in the placebo group than the treatment group). Nevertheless, delaying treatment was associated with resolution of clinical signs and symptoms in most of the children.

Acute Disease↗
PubMed2005

For randomized controlled trials, the quality of reports of complementary and alternative medicine was as good as reports of conventional medicine.

OBJECTIVE: To compare the quality of reporting of reports randomized controlled trials (RCTs) published in English and in languages other than English (LOE), and to determine whether there were differences between conventional medicine (CM) and complementary and alternative medicine (CAM) reports. STUDY DESIGN AND SETTING: We examined more than 600 RCTs associated with 125 systematic reviews. We extracted characteristics of each RCT using a standardized data collection form. We assessed quality using the Jadad scale and the adequacy of allocation concealment. RESULTS: There were only minor differences in the quality of reports of RCTs published in English compared with other languages (median quality score of 3 vs. 2, P=.10), and the quality of reports of CAM RCTs was similar to the CM reports (median score of 3 vs. 2, P=.14). There was no effect of language of publication on quality of reporting for CM trials (median score of 2 vs. 2, P=.12). Among CAM trials, however, overall quality scores were higher for reports in English than for reports in other languages (median score of 3 vs. 2, P=.04). CONCLUSION: The overall quality of reports published in languages other than English is similar to that of English-language reports. Moreover, the overall quality of reporting of RCTs of CAM interventions is as good as that for CM interventions.

Bibliometrics↗
PubMed2005

Language of publication restrictions in systematic reviews gave different results depending on whether the intervention was conventional or complementary.

OBJECTIVE: To assess whether language of publication restrictions impact the estimates of an intervention's effectiveness, whether such impact is similar for conventional medicine and complementary medicine interventions, and whether the results are influenced by publication bias and statistical heterogeneity. STUDY DESIGN AND SETTING: We set out to examine the extent to which including reports of randomized controlled trials (RCTs) in languages other than English (LOE) influences the results of systematic reviews, using a broad dataset of 42 language-inclusive systematic reviews, involving 662 RCTs, including both conventional medicine (CM) and complementary and alternative medicine (CAM) interventions. RESULTS: For CM interventions, language-restricted systematic reviews, compared with language-inclusive ones, did not introduce biased results, in terms of estimates of intervention effectiveness (random effects ration of odds rations ROR=1.02; 95% CI=0.83-1.26). For CAM interventions, however, language-restricted systematic reviews resulted in a 63% smaller protective effect estimate than language-inclusive reviews (random effects ROR=1.63; 95% CI=1.03-2.60). CONCLUSION: Language restrictions do not change the results of CM systematic reviews but do substantially alter the results of CAM systematic reviews. These findings are robust even after sensitivity analyses, and do not appear to be influenced by statistical heterogeneity and publication bias.

Complementary Therapies↗
PubMed2005

Systematic reviews involving complementary and alternative medicine interventions had higher quality of reporting than conventional medicine reviews.

OBJECTIVE: To compare the quality of systematic reviews reported in English and in languages other than English, and to determine whether there are differences between conventional medicine (CM) and complementary and alternative medicine (CAM) reports. STUDY DESIGN AND SETTING: We used the Oxman and Guyatt (OG) scale to assess the quality of reporting in 130 systematic reviews: 50 were language-restricted, 32 were language-inclusive but only English-language (EL) trials contained (inclusive-EL), and 48 were language-inclusive and included trials published in languages other than English (inclusive-LOE). Of the 130 reviews, 105 addressed CM interventions and 25 addressed CAM interventions. RESULTS: Comparison of the systematic reviews showed that the quality of reporting and reporting characteristics are not affected by inclusion or exclusion of LOE; however, the quality of reporting of systematic reviews involving CAM interventions is higher than that of reviews focusing on CM interventions. CONCLUSION: Informal comparison of the OG scale with the data collected on quality assessments showed that the OG scale performs well overall but may not identify important differences in comprehensiveness of the search strategy and avoidance of bias in study selection. Further research is required to determine the best methods for assessing quality of systematic reviews and whether the effect of language restrictions is dependent on the type of intervention (CM or CAM).

Bias↗
PubMed2005

The influence of display and statistical factors on the interpretation of metaanalysis results by physicians.

OBJECTIVE: The objective of this study was to determine the extent to which various factors affect the interpretation of metaanalytic results by physicians. STUDY DESIGN: A sample of 120 physicians, selected from The Royal College of Physicians and Surgeons of Canada (RCPSC), was randomly assigned to 1 of 6 groups (n = 20) created from a combination of 3 summary measures and 2 levels of disease severity. The intervention consisted of a written scenario and 4 individual displays of metaanalyses (M-A), each followed by questions related to the interpretation of results of M-A. Two final questions examined statistical familiarity/proficiency with the summary measures used. DATA ANALYSIS: Analyses of variance examined main effects and interactions among 4 factors: summary measure, disease severity, effect size, and statistical consistency of the studies comprising the metaanalysis. Two outcomes were examined: interpretation of the treatment effect and confidence in the interpretation of the treatment effect. PRINCIPAL FINDINGS: Physicians were more likely to favor treatment when the results of the primary randomized, controlled trials (RCTs) were statistically homogeneous (P = 0.001) and when the overall effect size was large (P = 0.001). Also, physicians were more likely to be confident when the results were homogeneous (P = 0.001) and when effect size was large (P = 0.000). Interactions also revealed that the effect of statistical consistency of contributing to RCTs was greatest when data were presented as risk difference for treatment outcome (P = 0.026) and when effect size was small (P = 0.000). CONCLUSIONS: The interpretation of metaanalytic displays is influenced by the overall effect size of M-A, the statistical consistency of the contributing RCTs, and interactions of these factors with display factors.

Adult↗
PubMed2005

The efficacy and safety of exogenous melatonin for primary sleep disorders. A meta-analysis.

BACKGROUND: Exogenous melatonin has been increasingly used in the management of sleep disorders. PURPOSE: To conduct a systematic review of the efficacy and safety of exogenous melatonin in the management of primary sleep disorders. DATA SOURCES: A number of electronic databases were searched. We reviewed the bibliographies of included studies and relevant reviews and conducted hand-searching. STUDY SELECTION: Randomized controlled trials (RCTs) were eligible for the efficacy review, and controlled trials were eligible for the safety review. DATA EXTRACTION: One reviewer extracted data, while the other verified data extracted. The Random Effects Model was used to analyze data. DATA SYNTHESIS: Melatonin decreased sleep onset latency (weighted mean difference [WMD]: -11.7 minutes; 95% confidence interval [CI]: -18.2, -5.2)); it was decreased to a greater extent in people with delayed sleep phase syndrome (WMD: -38.8 minutes; 95% CI: -50.3, -27.3; n=2) compared with people with insomnia (WMD: -7.2 minutes; 95% CI: -12.0, -2.4; n=12). The former result appears to be clinically important. There was no evidence of adverse effects of melatonin. CONCLUSIONS: There is evidence to suggest that melatonin is not effective in treating most primary sleep disorders with short-term use (4 weeks or less); however, additional large-scale RCTs are needed before firm conclusions can be drawn. There is some evidence to suggest that melatonin is effective in treating delayed sleep phase syndrome with short-term use. There is evidence to suggest that melatonin is safe with short-term use (3 months or less).

Humans↗
PubMed2005

Current pharmacological options in the treatment of croup.

Croup is one of the most common respiratory illnesses seen in the acute paediatric setting. It can be a cause of acute stridor and/or respiratory distress in young children. Research has shown that therapy aimed at reducing symptoms and inflammation can reduce complications such as the need for intubation, hospitalisation and improve quality of life for parents and children. Corticosteroids are the primary treatment option that will accomplish both goals and can be used in out-patient and in-patient settings. Corticosteroids may be given orally, parenterally or in wet nebulised form; however, oral administration is the preferred route. Wet nebulised adrenaline (racaemic or l-adrenaline) is also an effective treatment for more severe cases of croup. Recent studies have shown that mist/humidified air provides no additional symptom improvement, nor does it alter the overall cause of the disease process. Currently, there is insufficient randomised controlled trial evidence to support the role of heliox in the short-term treatment of croup.

Administration, Inhalation↗
PubMed2005

Development of a clinical static and dynamic standing balance measurement tool appropriate for use in adolescents.

BACKGROUND AND PURPOSE: There is a need in sports medicine for a static and dynamic standing balance measure to quantify balance ability in adolescents. The purposes of this study were to determine the test-retest reliability of timed static (eyes open) and dynamic (eyes open and eyes closed) unipedal balance measurements and to examine factors associated with balance. SUBJECTS: Adolescents (n=123) were randomly selected from 10 Calgary high schools. METHODS: This study used a repeated-measures design. One rater measured unipedal standing balance, including timed eyes-closed static (ECS), eyes-open dynamic (EOD), and eyes-closed dynamic (ECD) balance at baseline and 1 week later. Dynamic balance was measured on a foam surface. Reliability was examined using both intraclass correlation coefficients (ICCs) and Bland and Altman statistical techniques. Multiple linear regressions were used to examine other potentially influencing factors. RESULTS: Based on ICCs, test-retest reliability was adequate for ECS, EOD, and ECD balance (ICC=.69, .59, and .46, respectively). The results of Bland and Altman methods, however, suggest that caution is required in interpreting reliability based on ICCs alone. Although both ECS balance and ECD balance appear to demonstrate adequate test-retest reliability by ICC, Bland and Altman methods of agreement demonstrate sufficient reliability for ECD balance only. Thirty percent of the subjects reached the 180-second maximum on EOD balance, suggesting that this test is not appropriate for use in this population. Balance ability (ECS and ECD) was better in adolescents with no past history of lower-extremity injury. DISCUSSION AND CONCLUSION: Timed ECD balance is an appropriate and reliable clinical measurement for use in adolescents and is influenced by previous injury.

Adolescent↗
PubMed2004

A randomized trial of a single dose of oral dexamethasone for mild croup.

BACKGROUND: The benefits of dexamethasone treatment for moderate-to-severe croup are well established. However, most children with croup have mild symptoms, and it is unknown whether they would derive the same degree of benefit from dexamethasone treatment as children with more severe disease. METHODS: We conducted a double-blind trial at four pediatric emergency departments in which 720 children with mild croup were randomly assigned to receive one oral dose of either dexamethasone (0.6 mg per kilogram of body weight) or placebo. The children had mild croup, as defined by a score of < or =2 on the croup scoring system of Westley et al. The primary outcome was a return to a medical care provider for croup within seven days after treatment. The secondary outcome was the presence of ongoing symptoms of croup on days 1, 2, and 3 after treatment. Other outcomes included economic costs, hours of sleep lost by the child, and stress on the part of the parent in relation to the child's illness. RESULTS: Baseline clinical characteristics were similar in the two groups. Return to medical care was significantly lower in the dexamethasone group (7.3 percent vs. 15.3 percent, P<0.001). In the dexamethasone group, there was quicker resolution of croup symptoms (P=0.003), less lost sleep (P<0.001), and less stress on the part of the parent (P<0.001). CONCLUSIONS: For children with mild croup, dexamethasone is an effective treatment that results in consistent and small but important clinical and economic benefits. Although the long-term effects of this treatment are not known, our data support the use of dexamethasone in most, if not all, children with croup.

Administration, Oral↗