David N. Flynn

Patient-Important Outcomes in Registered Diabetes Trials

CONTEXT Concerns about the safety and efficacy of diabetes interventions persist, in part because randomized clinical trials (RCTs) have not measured their effect on patient-important outcomes, ie, death and quality of life (morbidity, pain, function). OBJECTIVE To systematically determine the extent to which ongoing and future RCTs in diabetes will ascertain patient-important outcomes. DATA SOURCES On November 10, 2007, we searched primary RCT registries ClinicalTrials.gov (http://www.clinicaltrials.gov), International Standard Randomized Controlled Trial Number Register (http://isrctn.org), and Australian New Zealand Clinical Trials Registry (http://www.anzctr.org.au). STUDY SELECTION We identified phase 2 through 4 RCTs enrolling patients with diabetes. Of 2019 RCTs, 1054 proved eligible. We randomly sampled 50% of the eligible RCTs (527 of 1054) and selected 436 registered since registration became mandatory (2004). DATA EXTRACTION Pairs of reviewers working independently collected study characteristics and determined the outcomes measured and their type (physiological outcomes, surrogate outcomes thought to reflect an increased risk for patient-important outcomes, and patient-important outcomes). RESULTS Of the 436 registered RCTs included in this analysis, 24 (6%) had not started enrollment, 109 (25%) were actively enrolling, and 303 (69%) had completed enrollment. Primary outcomes were patient-important outcomes in only 78 of 436 RCTs (18%; 95% confidence interval [CI], 14%-22%), physiological and laboratory outcomes in 69 of 436 (16%; 95% CI, 13%-20%), and surrogate outcomes in 268 of 436 (61%; 95% CI, 57%-66%). Patient-important outcomes were reported as primary or secondary outcomes in 201 of 436 (46%; 95% CI, 41%-51%). In multivariate analysis, large trials (odds ratio [OR], 1.10; 95% CI, 1.02-1.19 for every additional 100 patients) and trials of longer duration (OR, 1.03; 95% CI, 1.01-1.06 for every additional 30 days) were more likely while parallel design RCTs (OR, 0.15; 95% CI, 0.05-0.44) and type 2 diabetes trials (OR, 0.23; 95% CI, 0.09-0.61) were less likely to assess patient-important outcomes as a primary outcome. CONCLUSION In this sample of registered ongoing RCTs in diabetes, only 18% included patient-important outcomes as primary outcomes.

Antiandrogens for the Treatment of Hirsutism: A Systematic Review and Metaanalyses of Randomized Controlled Trials

CONTEXT The relative efficacy of antiandrogens for the treatment of hirsutism remains unclear. OBJECTIVE We performed a systematic review and metaanalyses of randomized controlled trials (RCTs) evaluating the effect of antiandrogens on hirsutism. DATA SOURCES We used librarian-designed search strategies for MEDLINE, EMBASE, and Cochrane CENTRAL (up to May 2006), review of reference lists, and contact with hirsutism experts to identify eligible RCTs. STUDY SELECTION Eligible studies were RCTs of at least 6 months of antiandrogen use in women with hirsutism. Reviewers, with acceptable chance-adjusted agreement (kappa = 0.72), independently assessed eligibility. DATA EXTRACTION Reviewers used structured forms to assess and collect methodological quality (allocation concealment, blinding, and loss to follow-up) and study data. DATA SYNTHESIS Of 348 candidate studies, 12 were eligible (18 comparisons). Their methodological quality was low. Random-effects metaanalyses showed that compared with placebo, antiandrogens reduce Ferriman-Gallwey scores by 3.9 [95% confidence interval (CI), 2.3-5.4; inconsistency (I(2)) = 0%]. When compared with metformin, spironolactone reduced hirsutism scores by 1.3 (CI, 0.03-2.6) and flutamide by 5.0 (CI, 3.0-7.0; I(2) = 0%). For these interventions, two to five women need to receive treatment for one to notice improvement. Spironolactone or finasteride in combination with contraceptives (1.7; CI, 0.1-3.3; I(2) = 0%) or flutamide with metformin (4.6; CI, 1.3-7.9; I(2) = 40%) appear superior to monotherapy with contraceptives and metformin, respectively. Only three RCTs reported patient self-assessments of hirsutism. CONCLUSIONS Weak evidence suggests antiandrogens are mildly effective agents for the treatment of hirsutism.

Insulin sensitizers for the treatment of hirsutism: A systematic review and metaanalyses of randomized controlled trials

CONTEXT Insulin sensitizers, including metformin and thiazolidinediones (TZDs), improve hyperinsulinemia and reproductive dysfunctions in some women with hyperandrogenism. The extent to which these agents improve hirsutism remains unclear. OBJECTIVE Our objective was to conduct a systematic review and metaanalyses of randomized controlled trials of metformin or TZDs for the treatment of hirsutism. DATA SOURCES We searched the following databases: MEDLINE, EMBASE, and Cochrane CENTRAL (up to May 2006). Review of reference lists and contact with hirsutism experts further identified candidate trials. STUDY SELECTION Reviewers working independently and in duplicate, with acceptable chance-adjusted agreement (kappa = 0.72), determined trial eligibility. Eligible trials randomly assigned women with hirsutism to at least 6 months of insulin sensitizers or control and measured hirsutism outcomes. DATA EXTRACTION Reviewers working independently and in duplicate determined the methodological quality of trials and collected data on patient characteristics, interventions, and outcomes. DATA SYNTHESIS Of 348 candidate studies, 16 trials (22 comparisons) were eligible. The methodological quality of these trials was low. Random-effects metaanalyses showed a small decrease in Ferriman-Gallwey scores in women treated with insulin sensitizers compared with placebo [pooled weighted mean difference (WMD) of -1.5; 95% confidence interval (CI), -2.8 to -0.2; inconsistency (I(2)) = 75%]. There was no significant difference between insulin sensitizers and oral contraceptives (WMD of -0.5; CI, -5.0, 3.9; I(2) = 79%). Metformin was inferior to both spironolactone (WMD of 1.3; CI, 0.03, 2.6) and flutamide (WMD of 5.0; CI, 3.0, 7.0; I(2) = 0%). CONCLUSIONS Imprecise and inconsistent evidence of low to very low quality suggests that insulin sensitizers provide limited or no important benefit for women with hirsutism.

Effect of perioperative insulin infusion on surgical morbidity and mortality: systematic review and meta-analysis of randomized trials

OBJECTIVE To conduct a systematic review and meta-analysis of randomized controlled trials (RCTs) to evaluate the effect of perioperative insulin infusion on outcomes important to patients. PATIENTS AND METHODS We used 6 search strategies including an electronic database search of MEDLINE, EMBASE, and Cochrane CENTRAL, from their inception up to May 1, 2006, and included RCTs of perioperative insulin infusion (with or without glucose targets) measuring outcomes in patients undergoing any surgery. Pairs of reviewers working independently assessed the methodological quality and characteristics of included trials and abstracted data on perioperative outcomes (ie, outcomes that occurred during hospitalization or within 30 days of surgery). RESULTS We identified 34 eligible trials. In the 14 trials that assessed mortality, there were 68 deaths among 2192 patients randomized to insulin infusion compared with 98 deaths among 2163 patients randomized to control therapy (random-effects pooled relative risk, 0.69; 95% confidence interval [CI], 0.51-0.94; 99% CI, 0.46-1.04; I2, 0%; 95% CI, 0.0%-47.4%). Hypoglycemia increased in the intensively treated group (20 trials, 119/1470 patients in insulin infusion vs 48/1476 patients in control group; relative risk, 2.07; 95% CI, 1.29-3.32; 99% CI, 1.09-3.88; I2, 31.5%; 95% CI, 0.0%-59.0%). No significant effect was seen in any other outcomes. The available mortality data represent only 40% of the optimal information size required to reliably detect a plausible treatment effect; potential methodological and reporting biases weaken inferences. CONCLUSION Perioperative insulin infusion may reduce mortality but increases hypoglycemia in patients who are undergoing surgery; however, mortality results require confirmation in large and rigorous RCTs.

Autogenous versus prosthetic vascular access for hemodialysis: a systematic review and meta-analysis.

OBJECTIVES The autogenous arteriovenous access for chronic hemodialysis is recommended over the prosthetic access because of its longer lifespan. However, more than half of the United States dialysis patients receive a prosthetic access. We conducted a systematic review to summarize the best available evidence comparing the two accesses types in terms of patient-important outcomes. METHODS We searched electronic databases (MEDLINE, EMBASE, Cochrane CENTRAL, Web of Science and SCOPUS) and included randomized controlled trials and controlled cohort studies. We pooled data for each outcome using a random effects model to estimate the relative risk (RR) and its associated 95% confidence interval (CI). We estimated inconsistency caused by true differences between studies using the I(2) statistic. RESULTS Eighty-three studies, of which 80 were nonrandomized, met eligibility criteria. Compared with the prosthetic access, the autogenous access was associated with a significant reduction in the risk of death (RR, 0.76; 95% CI, 0.67-0.86; I(2) = 48%, 27 studies) and access infection (RR, 0.18; 95% CI, 0.11-0.31; I(2) = 93%, 43 studies), and a nonsignificant reduction in the risk of postoperative complications (hematoma, bleeding, pseudoaneurysm and steal syndrome, RR 0.73; 95% CI, 0.48-1.16; I(2) = 65%, 31 studies) and length of hospitalization (pooled weighted mean difference -3.8 days; 95% CI, -7.8 to 0.2; P = .06). The autogenous access also had better primary and secondary patency at 12 and 36 months. CONCLUSION Low-quality evidence from inconsistent studies with limited protection against bias shows that autogenous access for chronic hemodialysis is superior to prosthetic access.

Endarterectomy vs stenting for carotid artery stenosis: A systematic review and meta-analysis

OBJECTIVES The relative efficacy and safety of endarterectomy and stenting in patients with carotid stenosis remain unclear. In this review we synthesize the available evidence derived from randomized controlled trials (RCTs) that compared the two procedures in terms of the risks of death, stroke (disabling and nondisabling), and nonfatal myocardial infarction. METHODS We searched for RCTs in MEDLINE, EMBASE, Current Contents, and Cochrane CENTRAL; expert files, and bibliographies of included articles. Two reviewers, working independently, determined trial eligibility and extracted descriptive, methodologic, and outcome data from each eligible RCT. Random-effects meta-analysis was used to assess relative and absolute risks and the I(2) statistic was used to assess heterogeneity of treatment effect among trials. RESULTS Ten RCTs with 3182 participants proved eligible. At 30 days and compared with endarterectomy, carotid stenting was associated with a nonsignificant reduction in the risk of death (relative risk [RR], 0.61; 95% confidence interval [CI], 0.27-1.37; I(2) = 0%), a nonsignificant reduction in the risk of nonfatal myocardial infarction (RR, 0.43; 95% CI 0.17-1.11; I(2) = 0%), and a nonsignificant increase in the risk of any stroke (RR, 1.29; 95% CI, 0.73-2.26; I(2) = 40%) and major/disabling stroke (RR, 1.06; 95% CI, 0.32-3.52; I(2) = 45%). If one considers the two procedures equivalent if the absolute difference in events is <2%, these results provide moderate-quality evidence for equivalence with respect to death (risk difference [RD] -0.40, 95% CI -1.02 to 0.40) and nonfatal myocardial infarction (RD, -0.70; 95% CI -1.90 to 0.50), but because of much wider CI, only low-quality evidence of equivalence in stroke (RD, 1.00; 95% CI, -1.00 to 3.10). CONCLUSION In RCTs, carotid stenting and carotid endarterectomy seem equivalent in terms of death and nonfatal myocardial infarction. Although the impact on stroke remains unestablished, results are consistent with a clinically important increase in stroke risk with stenting, an intervention that aims at reducing the risk of stroke.

Systematic reviewers commonly contact study authors but do so with limited rigor

OBJECTIVES Author contact can enhance the quality of systematic reviews. We conducted a systematic review of the practice of author contact in recently published systematic reviews to characterize its prevalence, quality, and results. STUDY DESIGN AND SETTING Eligible studies were systematic reviews of efficacy published in 2005-2006 in the 25 journals with the highest impact factor publishing systematic reviews in clinical medicine and the Cochrane Library, identified by searching MEDLINE, EMBASE, and the Cochrane Library. Two researchers determined whether and why reviewers contacted authors. To assess the accuracy of the abstracted data, we surveyed reviewers by e-mail. RESULTS Forty-six (50%) of the 93 eligible systematic reviews published in top journals and 46 (85%) of the 54 eligible Cochrane reviews reported contacting authors of eligible studies. Requests were made most commonly for missing information: 40 (76%) clinical medicine reviews and 45 (98%) Cochrane reviews. One hundred and nine of 147 (74%) reviewers responded to the survey, and reported a higher rate of author contact than apparent from the published record. CONCLUSION Although common, author contact is not a universal feature of systematic reviews published in top journals and the Cochrane Library. The conduct and reporting of author contact purpose, procedures, and results require improvement.

Surveillance of arteriovenous hemodialysis access: A systematic review and meta-analysis

OBJECTIVES Hemodialysis centers regularly survey arteriovenous (AV) accesses for signs of dysfunction. In this review, we synthesize the available evidence to determine to what extent proactive vascular access monitoring affects the incidence of AV access thrombosis and abandonment compared with clinical monitoring. METHODS We searched electronic databases (MEDLINE, EMBASE, Cochrane CENTRAL, Web of Science, and SCOPUS) and sought references from experts, bibliographies of included trials, and articles that cited included studies. Two reviewers independently assessed trial quality and extracted data. We used random effects meta-analysis to estimate the pooled relative risk (RR) and 95% confidence interval (CI) across studies and conducted subgroup analyses to explain heterogeneity. The I(2) statistic was used to assess heterogeneity of treatment effect among trials. RESULTS Nine studies (1363 patients) compared a strategy of surveillance vs clinical monitoring. A vascular intervention to maintain or restore patency was provided to both groups if needed. Surveillance followed by intervention led to a nonsignificant reduction of the risk of access thrombosis (RR, 0.82; 95% CI, 0.58-1.16; I(2) = 37%) and access abandonment (RR, 0.80; 95% CI, 0.51-1.25; I(2) = 60%). Three studies (207 patients) compared the effect of vascular interventions vs observation in patients with abnormal surveillance result. Vascular interventions after an abnormal AV access surveillance led to a significant reduction of the risk of access thrombosis (RR, 0.53; 95% CI, 0.36-0.76) and a nonsignificant reduction of the risk of access abandonment (RR, 0.76; 95% CI, 0.43-1.37). CONCLUSION Very low quality evidence yielding imprecise results suggests a potentially beneficial effect of AV access surveillance followed by interventions to restore patency. This inference, however, is weak and will require randomized trials of AV access surveillance vs clinical monitoring for rejection or confirmation.

Choice of data extraction tools for systematic reviews depends on resources and review complexity

OBJECTIVE To assist investigators planning, coordinating, and conducting systematic reviews in the selection of data-extraction tools for conducting systematic reviews. STUDY DESIGN AND SETTING We constructed an initial table listing available data-collection tools and reflecting our experience with these tools and their performance. An international group of experts iteratively reviewed the table and reflected on the performance of the tools until no new insights and consensus resulted. RESULTS Several tools are available to manage data in systematic reviews, including paper and pencil, spreadsheets, web-based surveys, electronic databases, and web-based specialized software. Each tool offers benefits and drawbacks: specialized web-based software is well suited in most ways, but is associated with higher setup costs. Other approaches vary in their setup costs and difficulty, training requirements, portability and accessibility, versatility, progress tracking, and the ability to manage, present, store, and retrieve data. CONCLUSION Available funding, number and location of reviewers, data needs, and the complexity of the project should govern the selection of a data-extraction tool when conducting systematic reviews.

Immunotherapeutic agents in type 1 diabetes: a systematic review and meta-analysis of randomized trials

Objective  Although recent trial results of anti‐CD3 therapy are promising, there have been conflicting results of various immunotherapeutic agents used in patients with type 1 diabetes. We conducted a systematic review and meta‐analysis to determine the efficacy of nonantigen‐based immunotherapeutic approaches for preservation of beta‐cell function in patients with type 1 diabetes.