Compelling evidence from meta-epidemiological studies demonstrates overestimation of effects in randomized trials that fail to optimize randomization and blind patients and outcome assessors.

OBJECTIVES: To investigate the impact of potential risk of bias elements on effect estimates in randomized trials. STUDY DESIGN AND SETTING: We conducted a systematic survey of meta-epidemiological studies examining the influence of potential risk of bias elements on effect estimates in randomized trials. We included only meta-epidemiological studies that either preserved the clustering of trials within meta-analyses (compared effect estimates between trials with and without the potential risk of bias element within each meta-analysis, then combined across meta-analyses; between-trial comparisons), or preserved the clustering of substudies within trials (compared effect estimates between substudies with and without the element, then combined across trials; within-trial comparisons). Separately for studies based on between- and within-trial comparisons, we extracted ratios of odds ratios (RORs) from each study and combined them using a random-effects model. We made overall inferences and assessed certainty of evidence based on Grading of Recommendations, Assessment, development, and Evaluation and Instrument to assess the Credibility of Effect Modification Analyses. RESULTS: Forty-one meta-epidemiological studies (34 of between-, 7 of within-trial comparisons) proved eligible. Inadequate random sequence generation (ROR 0.94, 95% confidence interval [CI] 0.90-0.97) and allocation concealment (ROR 0.92, 95% CI 0.88-0.97) probably lead to effect overestimation (moderate certainty). Lack of patients blinding probably overestimates effects for patient-reported outcomes (ROR 0.36, 95% CI 0.28-0.48; moderate certainty). Lack of blinding of outcome assessors results in effect overestimation for subjective outcomes (ROR 0.69, 95% CI 0.51-0.93; high certainty). The impact of patients or outcome assessors blinding on other outcomes, and the impact of blinding of health-care providers, data collectors, or data analysts, remain uncertain. Trials stopped early for benefit probably overestimate effects (moderate certainty). Trials with imbalanced cointerventions may overestimate effects, while trials with missing outcome data may underestimate effects (low certainty). Influence of baseline imbalance, compliance, selective reporting, and intention-to-treat analysis remain uncertain. CONCLUSION: Failure to ensure random sequence generation or adequate allocation concealment probably results in modest overestimates of effects. Lack of patients blinding probably leads to substantial overestimates of effects for patient-reported outcomes. Lack of blinding of outcome assessors results in substantial effect overestimation for subjective outcomes. For other elements, though evidence for consistent systematic overestimate of effect remains limited, failure to implement these safeguards may still introduce important bias.

Is Acetaminophen Beneficial in Patients With Cancer Pain Who are on Strong Opioids? A Randomized Controlled Trial.

CONTEXT: Pain is common among cancer patients. The evidence recommends using strong opioids in moderate to severe cancer pain. No conclusive evidence supports the effectiveness of adding acetaminophen to patients with cancer pain who are already using this regime. OBJECTIVES: To assess the analgesic efficacy of acetaminophen in hospitalized cancer patients with moderate to severe pain receiving strong opioids. METHODS: In this randomized blinded clinical trial, hospitalized cancer patients with moderate or severe acute pain managed with strong opioids were randomized to acetaminophen or placebo. The primary outcome was pain intensity difference between baseline and 48 hours using the Visual Numeric Rating Scales (VNRS). Secondary outcomes included change in morphine equivalent daily dose (MEDD), and patients' perception of improved pain control. RESULTS: Among 112 randomized patients, 56 patients received placebo, 56 acetaminophen. Mean (standard deviation [SD]) decrease in pain intensity (VNRS) at 48 hours were 2.7 (2.5) and 2.3 (2.3), respectively (95% Confidence Interval (CI) [-0.49; 1.32]; P = 0.37). Mean (SD) change in MEDD was 13.9 (33.0) mg/day and 22.4 (57.7), respectively (95% CI [-9.24; 26.1]; P = 0.35). The proportion of patients perceiving pain control improvement after 48 hours was 82% in the placebo and 80% in the acetaminophen arms (P = 0.81). CONCLUSION: Among patients with cancer pain on strong opioid regime, acetaminophen may not improve pain control, or decrease total opioid use. These results add to the current evidence available suggesting not to use acetaminophen as an adjuvant for advanced cancer patients with moderate to severe cancer pain who are on strong opioids.

Instruments assessing risk of bias of randomized trials frequently included items that are not addressing risk of bias issues.

OBJECTIVES: To establish whether items included in instruments published in the last decade assessing risk of bias of randomized controlled trials (RCTs) are indeed addressing risk of bias. STUDY DESIGN AND SETTING: We searched Medline, Embase, Web of Science, and Scopus from 2010 to October 2021 for instruments assessing risk of bias of RCTs. By extracting items and summarizing their essential content, we generated an item list. Items that two reviewers agreed clearly did not address risk of bias were excluded. We included the remaining items in a survey in which 13 experts judged the issue each item is addressing: risk of bias, applicability, random error, reporting quality, or none of the above. RESULTS: Seventeen eligible instruments included 127 unique items. After excluding 61 items deemed as clearly not addressing risk of bias, the item classification survey included 66 items, of which the majority of respondents deemed 20 items (30.3%) as addressing risk of bias; the majority deemed 11 (16.7%) as not addressing risk of bias; and there proved substantial disagreement for 35 (53.0%) items. CONCLUSION: Existing risk of bias instruments frequently include items that do not address risk of bias. For many items, experts disagree on whether or not they are addressing risk of bias.

Randomized double-blind controlled trial to assess the efficacy of intravenous acetaminophen associated with strong opioids in the treatment of acute pain in adult cancer patients: study protocol.

BACKGROUND: Cancer pain is one of the most frequent and relevant symptoms in cancer patients and impacts on patient's quality of life. International and local standards recommend as an initial strategy the use of an analgesic scheme composed of strong opioids associated with adjuvants such as acetaminophen, based upon the assumption that combining drugs could have a better analgesic effect, could allow lowering opioid dosing, and could prevent the occurrence of adverse effects of opioids. However, there is uncertainty about the impact of acetaminophen as an adjuvant in patients who use strong opioids for moderate to severe pain management in cancer patients. The aim of this study is to assess the efficacy and safety of intravenous acetaminophen associated with strong opioids in hospitalized adult cancer patients who have moderate to severe cancer-related pain. METHODS: We will perform a randomized double-blinded controlled study comparing intravenous acetaminophen 1 g 4 times a day versus placebo for 48 h as an adjuvant to strong opioids. We will assess pain intensity as a primary outcome, using the verbal numerical rating scale (VNRS, I0 to 10 scale with higher scores meaning higher pain intensity), and we will compare the mean difference in pain intensity between baseline and 48 h among the placebo and intervention groups. We estimate that a decrease of 1 point in the VNRS would be clinically significant. Assuming a standard deviation in pain intensity of 1.7 points, an alpha of 0.025, and a power of 0.8, we estimate a sample size of 112 patients, with 56 patients in each arm. Secondary outcomes include the difference in total opioid use between baseline and at 48 h among the groups, and adverse effects such as drowsiness, constipation, nausea, and vomiting would be evaluated. DISCUSSION: The randomized, double-blind, placebo-controlled design is the best strategy to assess the efficacy of acetaminophen as an adjuvant in adult cancer patients with moderate to severe pain who are receiving strong opioids. We expect to contribute to national and international guidelines with these results. TRIAL REGISTRATION: Clinicaltrials.gov NCT04779567 . Registered on March 3, 2021. Retrospectively registered.

Antimicrobial lock solutions for preventing catheter-related infections in haemodialysis.

BACKGROUND: Patients undergoing haemodialysis (HD) through a central venous catheter (CVC) are exposed to several risks, being a catheter-related infection (CRI) and a CVC lumen thrombosis among the most serious. Standard of care regarding CVCs includes their sealing with heparin lock solutions to prevent catheter lumen thrombosis. Other lock solutions to prevent CRI, such as antimicrobial lock solutions, have proven useful with antibiotics solutions, but not as yet for non-antibiotic antimicrobial solutions. Furthermore, it is uncertain if these solutions have a negative effect on thrombosis incidence. OBJECTIVES: To assess the efficacy and safety of antimicrobial (antibiotic, non-antibiotic, or both) catheter lock solutions for preventing CRI in participants undergoing HD with a CVC. SEARCH METHODS: We searched the Cochrane Kidney and Transplant Specialised Register up to 18 December 2017 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal, and ClinicalTrials.gov. SELECTION CRITERIA: We included all randomised or quasi-randomised control trials (RCTs) comparing antimicrobial (antibiotic and non-antibiotic) lock solutions to standard lock solutions, in participants using a CVC for HD, without language restriction. DATA COLLECTION AND ANALYSIS: Two authors independently assessed studies for eligibility, and two additional authors assessed for risk of bias and extracted data. We expressed results as rate ratios (RR) per 1000 catheter-days or 1000 dialysis sessions with 95% confidence intervals (CI). Statistical analyses were performed using the random-effects model. MAIN RESULTS: Thirty-nine studies, enrolling 4216 participants, were included in this review, however only 30 studies, involving 3392 participants, contained enough data to be meta-analysed. Risk of bias was low or unclear for most domains in the majority of the included studies.Studies compared antimicrobial lock solutions (antibiotic and non-antibiotic) to standard sealing solutions (usually heparin) of the CVC for HD. Fifteen studies used antibiotic lock solutions, 21 used non-antibiotic antimicrobial lock solutions, and 4 used both (antibiotic and non-antibiotic) lock solutions. Studies reported the incidence of CRI, catheter thrombosis, or both.Antimicrobial lock solutions probably reduces CRI per 1000 catheter-days (27 studies: RR 0.38, 95% CI 0.27 to 0.53; I2 = 54%; low certainty evidence), however antimicrobial lock solutions probably makes little or no difference to the risk of thrombosis per 1000 catheter days (14 studies: RR 0.79, 95% CI 0.52 to 1.22; I2 = 83%; very low certainty evidence). Subgroup analysis of antibiotic and the combination of both lock solutions showed that both probably reduced CRI per 1000 catheter-days (13 studies: RR 0.30, 95% CI: 0.22 to 0.42; I2 = 47%) and risk of thrombosis per 1000 catheter-days (4 studies: RR 0.26, 95% CI: 0.14 to 0.49; I2 = 0%), respectively. Non-antibiotic antimicrobial lock solutions probably reduced CRI per 1000 catheter-days for tunnelled CVC (9 studies: RR 0.60, 95% CI 0.40 to 0.91) but probably made little or no difference with non-tunnelled CVC (4 studies: RR 0.93, 95% CI 0.48 to 1.81). Subgroup analyses showed that antibiotic (5 studies: RR 0.76, 95% CI 0.42 to 1.38), non-antibiotic (8 studies: RR 0.85, 95% CI 0.44 to 1.66), and the combination of both lock solutions (3 studies: RR 0.63, 95% CI 0.22 to 1.81) made little or no difference to thrombosis per 1000 catheter-days compared to control lock solutions. AUTHORS' CONCLUSIONS: Antibiotic antimicrobial and combined (antibiotic-non antibiotic) lock solutions decreased the incidence of CRI compared to control lock solutions, whereas non-antibiotic lock solutions reduce CRI only for tunnelled CVC. The effect on thrombosis incidence is uncertain for all antimicrobial lock solutions. Our confidence in the evidence is low and very low; therefore, better-designed studies are needed to confirm the efficacy and safety of antimicrobial lock solutions.

Amiodarone versus other pharmacological interventions for prevention of sudden cardiac death.

BACKGROUND: Sudden cardiac death (SCD) is one of the main causes of cardiac death. There are two main strategies to prevent it: managing cardiovascular risk factors and reducing the risk of ventricular arrhythmias. Implantable cardiac defibrillators (ICDs) constitute the standard therapy for both primary and secondary prevention; however, they are not widely available in settings with limited resources. The antiarrhythmic amiodarone has been proposed as an alternative to ICD. OBJECTIVES: To evaluate the effectiveness of amiodarone for primary or secondary prevention in SCD compared with placebo or no intervention or any other antiarrhythmic drugs in participants at high risk (primary prevention) or who have recovered from a cardiac arrest or a syncope due to Ventricular Tachycardia/Ventricular Fibrillation, or VT/VF (secondary prevention). SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (OVID), EMBASE (OVID), CINAHL (EBSCO) and LILACS on 26 March 2015. We reviewed reference lists of included studies and selected reviews on the topic, contacted authors of included studies, screened relevant meetings and searched in registers for ongoing trials. We applied no language restrictions. SELECTION CRITERIA: Randomised and quasi-randomised trials assessing the efficacy of amiodarone versus placebo, no intervention, or other antiarrhythmics in adults. For primary prevention we considered participants at high risk for SCD. For secondary prevention we considered participants recovered from cardiac arrest or syncope due to ventricular arrhythmias. DATA COLLECTION AND ANALYSIS: Two authors independently assessed the trials for inclusion and extracted relevant data. We contacted trial authors for missing data. We performed meta-analyses using a random-effects model. We calculated risk ratios (RR) for dichotomous outcomes with 95% confidence intervals (CIs). Three studies included more than one comparison. MAIN RESULTS: We included 24 studies (9,997 participants). Seventeen studies evaluated amiodarone for primary prevention and six for secondary prevention. Only three studies used an ICD concomitantly with amiodarone for the comparison (all of them for secondary prevention).For primary prevention, amiodarone compared to placebo or no intervention (17 studies, 8383 participants) reduced SCD (RR 0.76; 95% CI 0.66 to 0.88), cardiac mortality (RR 0.86; 95% CI 0.77 to 0.96) and all-cause mortality (RR 0.88; 95% CI 0.78 to 1.00). The quality of the evidence was low.Compared to other antiarrhythmics (three studies, 540 participants), amiodarone reduced SCD (RR 0.44; 95% CI 0.19 to 1.00), cardiac mortality (RR 0.41; 95% CI 0.20 to 0.86) and all-cause mortality (RR 0.37; 95% CI 0.18 to 0.76). The quality of the evidence was moderate.For secondary prevention, amiodarone compared to placebo or no intervention (two studies, 440 participants) appeared to increase the risk of SCD (RR 4.32; 95% CI 0.87 to 21.49) and all-cause mortality (RR 3.05; 1.33 to 7.01). However, the quality of the evidence was very low. Compared to other antiarrhythmics (four studies, 839 participants) amiodarone appeared to increase the risk of SCD (RR 1.40; 95% CI 0.56 to 3.52; very low quality of evidence), but there was no effect in all-cause mortality (RR 1.03; 95% CI 0.75 to 1.42; low quality evidence).Amiodarone was associated with an increase in pulmonary and thyroid adverse events. AUTHORS' CONCLUSIONS: There is low to moderate quality evidence that amiodarone reduces SCD, cardiac and all-cause mortality when compared to placebo or no intervention for primary prevention, and its effects are superior to other antiarrhythmics.It is uncertain if amiodarone reduces or increases SCD and mortality for secondary prevention because the quality of the evidence was very low.

Comparison of different regimens of proton pump inhibitors for acute peptic ulcer bleeding.

BACKGROUND: Treatment with proton pump inhibitors (PPIs) improves clinical outcomes in patients with peptic ulcer bleeding. However, the optimal dose and route of administration of PPIs remains controversial. OBJECTIVES: To evaluate the efficacy of different regimens of PPIs in the management of acute peptic ulcer bleeding using evidence from direct comparison randomized controlled trials (RCTs).We specifically intended to assess the differential effect of the dose and route of administration of PPI on mortality, rebleeding, surgical intervention, further endoscopic haemostatic treatment (EHT), length of hospital stay, transfusion requirements and adverse events. SEARCH METHODS: We searched CENTRAL (in The Cochrane Library 2010, Issue 3), MEDLINE and EMBASE (from inception to September 2010) and proceedings of major gastroenterology meetings (January 2000 to September 2010), without language restrictions. Original investigators were contacted to request missing data. SELECTION CRITERIA: RCTs that compared at least two different regimens of the same or a different PPI in patients with acute peptic ulcer bleeding, diagnosed endoscopically. DATA COLLECTION AND ANALYSIS: Two reviewers independently selected studies, extracted data and assessed risk of bias. We synthesized data using the Mantel-Haenszel random-effects method and performed multivariate meta-regression with random permutations based on Monte Carlo simulation. We measured heterogeneity with the I² statistic and Cochrane Q test and assessed publication bias with funnel plots and Egger's test. We graded the overall quality of evidence using the GRADE approach. MAIN RESULTS: Twenty two RCTs were included; risk of bias was high in 17 and unclear in 5. The main analysis included 13 studies (1716 patients) comparing "high" dose regimens (72-hour cumulative dose > 600 mg of intravenous PPI) to other doses; there was no significant heterogeneity for any clinical outcome. We found low quality evidence that did not exclude a potential reduction or increase in mortality, rebleeding, surgical interventions or endoscopic haemostatic treatment (EHT) with "high" dose regimens. For mortality, pooled risk ratio (RR) was 0.85 (95% confidence interval (CI) 0.47 to 1.54); pooled risk difference (RD) was 0 more deaths per 100 patients treated with "high" dose (95% CI from 1 fewer to 2 more deaths per 100 treated). For rebleeding, pooled RR was 1.27 (95% CI 0.96 to 1.67); pooled RD was 2 more rebleeding events per 100 patients treated with "high" dose (95% CI from 0 fewer to 5 more rebleeding events per 100 treated). For surgical interventions, pooled RR was 1.33 (95% CI 0.63 to 2.77); pooled RD was 1 more surgical intervention per 100 patients treated with "high" dose (95% CI from 1 fewer to 2 more surgical interventions per 100 treated). For further EHT, pooled RR was 1.39 (95% CI 0.88 to 2.18), pooled RD was 2 more events per 100 patients treated with "high" dose PPI (95% CI from 1 fewer to 5 more events per 100 treated). We found moderate quality evidence suggesting no important difference between the two regimens with regards to length of hospital stay (mean difference (MD) 0.26 days; 95% CI -0.08 to 0.6 days) or blood transfusion requirements (MD 0.05 units; 95% CI -0.21 to 0.3 units). There was visual and statistical evidence of "inverse" publication bias for mortality (missing small studies with favourable outcomes for "high" dose), but not for any other outcome. The results were similar for all subgroup analyses (according to risk of bias, geographical location, route of administration for non-"high" dose regimens, continuous infusion vs. bolus administration for intravenous non-"high" regimens group), sensitivity analyses (restriction to patients who had EHT for high risk stigmata, use of different dose thresholds for comparative regimens) and post hoc analyses (inclusion of all studies (N = 22) that compared at least two PPI regimens with different cumulative 72 hour doses; restriction of the previous analysis to patients who had EHT for high risk stigmata). Meta-regression analysis did not show any statistically significant associations between treatment effect (for the outcomes of mortality, rebleeding and surgical intervention) and the three study-level factors that were assessed (geographical location (Asia versus not Asia), route of PPI administration (intravenous versus oral), within-study ratio among the 72-hour cumulative doses of the two PPI regimens). AUTHORS' CONCLUSIONS: There is insufficient evidence for concluding superiority, inferiority or equivalence of high dose PPI treatment over lower doses in peptic ulcer bleeding.

Non-hormonal interventions for hot flushes in women with a history of breast cancer.

BACKGROUND: Hot flushes are common in women with a history of breast cancer. Hormonal therapies are known to reduce these symptoms but are not recommended in women with a history of breast cancer due to their potential adverse effects. The efficacy of non-hormonal therapies is still uncertain. OBJECTIVES: To assess the efficacy of non-hormonal therapies in reducing hot flushes in women with a history of breast cancer. SEARCH STRATEGY: We searched the Cochrane Breast Cancer Group Specialised Register, CENTRAL (The Cochrane Library), MEDLINE, EMBASE, LILACS, CINAHL, PsycINFO (August 2008) and WHO ICTRP Search Portal. We handsearched reference lists of reviews and included articles, reviewed conference proceedings and contacted experts. SELECTION CRITERIA: Randomized controlled trials (RCTs) comparing non-hormonal therapies with placebo or no therapy for reducing hot flushes in women with a history of breast cancer. DATA COLLECTION AND ANALYSIS: Two authors independently selected potentially relevant studies, decided upon their inclusion and extracted data on participant characteristics, interventions, outcomes and the risk of bias of included studies. MAIN RESULTS: Sixteen RCTs met our inclusion criteria. We included six studies on selective serotonin (SSRI) and serotonin-norepinephrine (SNRI) reuptake inhibitors, two on clonidine, one on gabapentin, two each on relaxation therapy and homeopathy, and one each on vitamin E, magnetic devices and acupuncture. The risk of bias of most studies was rated as low or moderate. Data on continuous outcomes were presented inconsistently among studies, which precluded the possibility of pooling the results. Three pharmacological treatments (SSRIs and SNRIs, clonidine and gabapentin) reduced the number and severity of hot flushes. One study assessing vitamin E did not show any beneficial effect. One of two studies on relaxation therapy showed a significant benefit. None of the other non-pharmacological therapies had a significant benefit. Side-effects were inconsistently reported. AUTHORS' CONCLUSIONS: Clonidine, SSRIs and SNRIs, gabapentin and relaxation therapy showed a mild to moderate effect on reducing hot flushes in women with a history of breast cancer.

How to teach evidence-based medicine to teachers: reflections from a workshop experience.

RATIONALE, AIMS AND OBJECTIVES: To summarize 20-year experience of conducting a workshop designed for educators who wish to improve their teaching skills of evidence based medicine (EBM). The goal is to provide tips for educators interested in replicating this educational model. METHODS: Qualitative description of factors associated with the success of the workshop. RESULTS: The factors considered by instructors to be most helpful are: the small group interactive design, role-play and simulation of real world learning environments, a mentorship model and high educator to learner ratio. CONCLUSIONS: Although this experience is observational and does not represent high quality evidence, certain attributes in the design of EBM workshops may lead to better dissemination of EBM concepts. Educators may consider empirically applying some of these attributes and testing their efficacy in comparative studies.

Actinomycosis: a great pretender. Case reports of unusual presentations and a review of the literature.

Actinomycosis is a rare, chronic disease caused by a group of anaerobic Gram-positive bacteria that normally colonize the mouth, colon, and urogenital tract. Infection involving the cervicofacial area is the most common clinical presentation, followed by pelvic region and thoracic involvement. Due to its propensity to mimic many other diseases and its wide variety of symptoms, clinicians should be aware of its multiple presentations and its ability to be a 'great pretender'. We describe herein three cases of unusual presentation: an inferior caval vein syndrome, an acute cholecystitis, and an acute cardiac tamponade. We review the literature on its epidemiology, clinical presentation, diagnosis, treatment, and prognosis.

[Consensus: Rational approach towards the patient with cancer, fever and neutropenia]. / Consenso: Manejo racional del paciente con cáncer, neutropenia y fiebre.

The severity and duration of post chemotherapy neutropenia were recognized during the 1960s as main predisposing factors for infections in cancer patients. At the beginning of the 70's a standard management approach for all febrile neutropenia (FN) episodes was proposed, based on hospitalization and intravenous empirical broad spectrum antibiotic therapy. Widespread use of this approach resulted in a significant reduction in mortality attributable to bacterial infections. During the last 10 to 15 years, reappraisal of this standard approach has been done by several research groups who question the benefit of treating all FN patients similarly without taking in to consideration differences in severity of the FN episodes. This reappraisal has led during the 1990s to the development of the concept of high and low risk FN episodes that has been the base for the adoption of selective therapies based on the risk categorization of the individual patient. The Chilean Infectious Diseases Society called upon two government National Programs responsible for the appropriate distribution of chemotherapeutic drugs to all pediatric and adults cancer patients within the public health system, and upon the Chilean Hematology Society for the development of a Consensus on Diagnosis, Treatment and Prevention of Infections during FN Episodes in Cancer patients. The need for this Consensus is based on two main aspects: the new approaches proposed during the past year for management of these episodes, and the increasing population of cancer patients receiving improved chemotherapeutic agents that has increased there survival possibilities as well as there possibility to suffer a FN episode. The topics discussed in this document are based on an updated systematic and analytic review of the medical literature including epidemiology, laboratory diagnostics, risk categorization, treatment and prophylaxis. National data was included when available in order to provide the healthcare personnel that take care of these patients with best evidence based recommendations adjusted to the Chilean reality.

Effectiveness of amiodarone for conversion of atrial fibrillation to sinus rhythm: a meta-analysis.

BACKGROUND: Although clinicians sometimes choose amiodarone to convert atrial fibrillation (AF) to sinus rhythm, no current and comprehensive systematic review has summarized its effectiveness. OBJECTIVE: To review the effectiveness of amiodarone in converting AF to sinus rhythm over a 4-week period. METHODS: Two reviewers conducted a systematic search for randomized trials in databases, complemented by hand searches and contact with experts. Selected trials compared amiodarone with placebo, digoxin, or calcium channel blockers for conversion of AF to sinus rhythm. Reviewers evaluated the methodology and extracted data from each primary study. RESULTS: Twenty-one studies met eligibility criteria. Duration of AF proved to be a source of heterogeneity, leading to 2 analyses. The relative risk (RR) for achieving sinus rhythm was 4.33 (95% confidence interval [CI], 2.76-6.77) for trials with mean AF duration of greater than 48 hours and 1.40 (95% CI, 1.25-1.57) for those with AF of 48 hours or less. The risk differences for these 2 groups were 27% and 26%, respectively, yielding a number needed to treat of 4 for both groups. The low control event rate among trials with long duration of AF, compared with that of trials with a duration of 48 hours or less, explained the difference in the RR for conversion. We found that the size of the left atrium, presence of cardiovascular disease, and protocols of amiodarone administration did not influence the magnitude of effect. Serious adverse events were infrequent. CONCLUSIONS: Amiodarone is effective for converting AF to sinus rhythm in a wide range of patients. Although use of amiodarone is apparently safe, safety data are too scarce for definitive conclusions.

Estudio de sobrevida de los pacientes adultos mayores en unidades de cuidado intensivo: ¿deben ingresar? / Survival of elderly patients in intensive care units: should they be admitted?

We retrospectively analyzed the mortality of 443 patients older than 65 years old, admitted to an intensive care unit between 1993 and 1994. The mortality was compared with that of 334 younger patients admitted in the same period. Severity of disease was determined using admission APACHE II score. Older patients had a higher admission APACHE score than younger subjects (18.4+- and 14.5+-8.7 respectively, p 0.01). Mortality during the intensive care unit stay was similar in older and younger patients (18.5 and 14.4 per cent, respectively). Hospital mortality was also similar (22.4 and 25.9 per cent respectively). Older patients had a higher frequency of chronic diseases and degree of functional impairment. Mortality rates for different diseases were also similar in older and younger patients. Older age was not associated with a higher mortality during intensive care unit stay. Prognosis is determined by the admission severity score and the number of concomitant chronic diseases