A review of the true methodological quality of nutritional support trials conducted in the critically ill: time for improvement

Insulin-euglycemia therapy in acute aluminum phosphide poisoning: a randomized clinical trial

Introduction: Aluminum phosphide is a pesticide that is used in developing countries. Aluminum phosphide poisoning has a high mortality rate and there is no known antidote. This study aimed to evaluate the safety and efficacy of insulin-euglycemia therapy in the management of patients with acute aluminum phosphide poisoning.Methods: This trial was prospectively registered in the Pan African Clinical Trials Registry (PACTR202008534546951). A total of 108 patients were randomly allocated to two groups. The intervention group received insulin-euglycemia therapy in addition to standard treatment (norepinephrine and supportive care); the control group received standard treatment plus placebo. The main outcome measures were survival, blood pressure, and laboratory investigations.Results: The two groups had similar baseline parameters. Insulin-euglycemia therapy was associated with a significant reduction in mortality compared with that in the control group (64.8 percent and 96.3 percent, respectively; P value <0.001). Patients randomized to insulin-euglycemia also required lower doses of vasopressors (median was 7 mg versus 26 mg in control group; P value 0.006) and fewer patients needed intubation (61.1 percent versus 81.5 percent in the control group; P value 0.019). Insulin-euglycemia therapy significantly improved blood pressure (systolic, diastolic, and mean arterial pressure) (median at 6h post-admission was 80 mmHg, 55 mmHg and 65 mmHg compared with 20 mmHg, 10 mmHg and 13 mmHg in the control group respectively; P value <0.001) and bicarbonate and lactate concentrations.Conclusion: Insulin-euglycemia therapy appears to be a safe and effective treatment option for patients with aluminum phosphide poisoning. Vasopressor only therapy was associated with very poor outcomes in acute aluminum phosphide poisoning.

Essential Amino Acid Profile in Parenteral Nutrition Mixtures: Does It Meet Needs?

BACKGROUND AND AIMS

The study compares the essential amino acid (EAA) composition of different parenteral nutrition (PN) mixtures with whey protein EAA profile and the theoretical daily EAA requirements (set by WHO/FAO/UNU or IAAO method). According to the individual EAA profile, the potential effect of several PN mixtures was evaluated on the skeletal muscle mass (SMM) of patients on home PN.

METHODS

Eight AA solutions and fifteen complete PN mixtures were considered. Twenty-nine clinically stable patients with short bowel syndrome on home total PN were retrospectively evaluated. SMM was estimated by bioelectrical impedance analysis.

RESULTS

The prescribed doses of EAA that showed a significant increase in home PN patients muscle mass were considerably greater than the theoretical ones, showing an EAA profile similar to whey protein. At the daily dose of 1 g of total AA s/kg body weight (BW), the considered PN mixtures mostly failed to improve SMM. Only prescribed doses which included more than 0.25 g/kg BW of total BCAA with at least 0.10 g/kg BW leucine, 0.08 g/kg BW isoleucine, and 0.06 g/kg BW methionine showed a significant increase in SMM.

CONCLUSIONS

The theoretical daily requirement for each EAA was met by all considered PN solutions when the prescribed daily dose of total AAs was set at 1 g/kg BW. Nevertheless, our data suggest that only an increase in total BCAA, also richer in single AA leucine, isoleucine, and methionine, is associated with the maintenance and/or increase of SMM. According to these preliminary observations, we support the prescription of an EAA composition of PN mixtures close to that of whey protein for the preservation of SMM in patients on long-term total PN.

A practice change initiative to improve the provision of enteral nutrition to intensive care patients

AIM

To describe a practice change initiative that improved the provision of enteral nutrition (EN) to patients in a New Zealand tertiary intensive care unit (ICU).

METHODS

The project reviewed and summarized EN literature, amended local policy, and an evidence-based EN delivery algorithm was developed. The EN practice change initiative was implemented and evaluated. Data was collected and analyzed in a pre-audit (2009) and a post-audit (2013).

RESULTS

Comparison of the pre-audit (N = 25) and the post-audit (N = 40) data demonstrated improvements in three areas of EN delivery. The commencement of early EN within 24 h of admission was evident for a large proportion of patients in both 2009 and 2013 audits. There was a large reduction in time between the two audits for both ICU admission to achievement of EN goal rate (M = 57·71 h versus M = 33·79 h, p = 0·006) and also for EN commencement to achievement of EN goal rate (M = 31·65 h versus M = 10·15 h, p = 0·000). The volume of prescribed EN delivered on days 2, 4 and 6 was greater in the 2013 audit in comparison to the 2009 audit. Staff compliance with adhering to the EN policy and algorithm improved from 46% in 2009, to 95% in 2013.

CONCLUSIONS

The practice change has significantly improved the practice delivery of EN for patients in the local ICU resulting in optimal care.

RELEVANCE TO CLINICAL PRACTICE

Malnutrition is highly prevalent among intensive care patients. Strategies and initiatives that improve the delivery of enteral nutrition to the critical care population is therefore vitally important. This article describing such an initiative is thus highly relevant to all health care professionals delivering enteral nutrition in intensive and critical care units.

The clinical role of glutamine supplementation in patients with multiple trauma: a narrative review

Glutamine is considered an essential amino acid during stress and critical illness. Parenteral glutamine supplementation in critically ill patients has been shown to improve survival rate and minimise infectious complications, costs and hospital length-of-stay. However, glutamine supplementation in patients receiving enteral nutrition and the best method of administration are still controversial. The purpose of this article is to provide a narrative review of the current evidence and trials of enteral and parenteral glutamine supplementation in multiple trauma patients. A search in PubMed and EMBASE was conducted and relevant papers that investigated the effect of enteral or parenteral glutamine supplementation in patients with multiple trauma were reviewed. Although recent nutritional guidelines recommend that glutamine supplementation should be considered in these patients, further well-designed trials are required to provide a confirmed conclusion. Due to the inconclusive results of enteral glutamine supplementation trials in patients receiving enteral nutrition, future trials should focus on intravenous glutamine supplementation in patients requiring enteral nutrition and on major clinical outcome measures (e.g. mortality rate, infectious complications).

Is there a difference in bloodstream infections in critically ill patients associated with ready-to-use versus compounded parenteral nutrition?

BACKGROUND & AIMS

Parenteral nutrition is widely used in critically ill patients receiving nutritional support. Several previous studies associated the use of parenteral nutrition with the development of bloodstream infections. This study compared bloodstream infections in critical care patients receiving parenteral nutrition (PN) prepared via conventional compounding versus premixed multichamber bags.

METHODS

Records in the Premier Perspective™ database for all in patients ≥ 18 years of age, with a minimum 3-day intensive care unit stay, who received PN between 2005 and 2007 were analyzed (n = 15,328). Statistical analysis of data, grouped according to preparation method, compared differences in both observed bloodstream infection rates and adjusted rates, using logistic regression to examine the impact of hospital and patient baseline characteristics.

RESULTS

Patients receiving compounded parenteral nutrition had longer intensive care unit stays (11.3 vs. 9.1 days) and longer hospital stays (22.6 vs. 19.4 days); both P < .001. After adjusting for baseline differences, the probability for bloodstream infections was 19% higher when using compounded parenteral nutrition vs. multichamber bags (29.6 vs. 24.9%; odd ratio = 1.29; 95% confidence interval = 1.06-1.59).

CONCLUSION

In this retrospective review of a large patient database the adjusted probability of bloodstream infection was significantly lower in patients receiving multichamber bags than compounded parenteral nutrition. These findings need to be investigated further in high quality observational studies and prospective clinical trials.

Failure to report protocol violations in clinical trials: a threat to internal validity?

Background

Excessive protocol violations (PV), which can be defined as preventable mistakes in study conduct, may result in patient harm and introduce errors into a clinical trial's results leading to flawed trial conclusions.

The purpose of this project was to gain a better understanding of reported PVs, to describe current practice with regards to the use of methods for the reduction of PVs and to investigate relationships between clinical trial characteristics and PVs.

Methods

We reviewed 80 clinical trials conducted across a broad range of medical specialties published in four major general medical journals (The Lancet, NEJM, JAMA, BMJ). Eligible papers were identified using a PubMed search. For each included trial, two authors independently abstracted information on trial characteristics, PV reporting and PV rates and interventions used to reduce PVs. PVs were categorised into one of five distinct types: enrolment, randomisation, study intervention, patient compliance and data collection errors. Associations between PVs and study characteristics were investigated using logistic regression.

Results

Eighty clinical trials (20 from each journal) were identified from 101 consecutive PubMed abstracts. The median number of participants was 701 (range: 20 to 162, 367) and the median number of participating sites was 15 (range: 1 to 701). Nineteen percent (15/80) of included trials were single centre trials. The median study duration was 24 months (range: 5.81 - 127 months) and 74% (59/80) of included trials were primarily academic funded.

Thirty two percent (26/80) of included trials failed to provide explicit reporting of any type of PV and none (0/80) of the trials provided explicit reporting of all five types of PVs. Larger clinical trials (more patients, more sites, longer duration, more complex management structure) were more likely to have more complete reporting of PV's.

Only 9% (7/80) of trials reported the use of a specific study method to prevent PVs. Use of a run-in phase was the only method reported.

Conclusions

PVs are under-reported. Although the CONSORT statement provides guidance on the reporting of PVs, reporting requirements are not explicit for all types of PVs. As a first step towards improved reporting by authors, we recommend the CONSORT statement highlight the importance of PVs by making reporting requirements more explicit.

Randomized trials in critical care nutrition: look how far we've come! (and where do we go from here?)

BACKGROUND

The purpose of this methodological review is to quantify and qualify critical care nutrition randomized controlled trials (RCTs) that inform our practice, to evaluate their strengths and limitations, and to recommend strategies for improving the design of future trials in this area.

METHODS

The literature was systematically reviewed to find all RCTs published between 1980 and December 2008 that evaluated nutrition interventions in critical care. Data were abstracted on the nature and quality of included RCTs.

RESULTS

A total of 207 RCTs met the inclusion criteria. Of these, 170 (82.1%) were single-center, and 37 (17.9%) were multicenter. The largest number of trials evaluated intensive insulin therapy (n = 25), arginine-supplemented diets (n = 22), and supplemental parenteral glutamine (n = 17). The first RCTs were published in 1983 (n = 2), and the mean sample size was 39.0. In 2008, there were 26 RCTs, each enrolling an average of 237.1 patients. Excluding 2 cluster RCTs, 62 of 205 (30.2%) trials had concealed randomization, 125 of 205 (61.0%) reported on intention-to-treat analyses, and 69 of 205 (33.7%) had a double-blinded intervention; 18 of 205 (8.8%) studies reported on all 3 design characteristics. Currently, 60 critical care nutrition RCTs (18 multicenter trials) are registered on clinical trials registries.

CONCLUSIONS

The future of clinical critical care nutrition research is promising, with more trials of increasing sample size being conducted. Robust trial methodology, transparent reporting, and the development of research networks will help to further advance this important field.

Developing research programs in clinical and translational nutrition

Most clinicians believe that nutrition support therapy improves outcome in hospitalized patients. Unfortunately, few patients receive optimal nutrition management. A lack of strong, well-designed research studies may prevent the medical/surgical community from fully embracing the practice. More quality research is needed. This article discusses 3 potential strategies to improve research activity in clinical nutrition: increase funding of nutrition research, foster young physician training in nutrition and research, and attract nutrition researchers to our national nutrition society meetings. The best chance for this process to succeed is for the national nutrition societies to partner with medical and surgical subspecialty societies to develop larger scale clinical and translational research programs.

Early enteral nutrition reduces mortality in trauma patients requiring intensive care: a meta-analysis of randomised controlled trials

INTRODUCTION

To determine whether the provision of early standard enteral nutrition (EN) confers treatment benefits to adult trauma patients who require intensive care.

MATERIALS AND METHODS

MEDLINE and EMBASE were searched. Hand citation review of retrieved guidelines and systematic reviews was undertaken and academic and industry experts were contacted. Methodologically sound randomised controlled trials (RCTs) conducted in adult trauma patients requiring intensive care that compared the delivery of standard EN, provided within 24 h of injury, to standard care were included.The primary analysis was conducted on clinically meaningful patient-oriented outcomes, which included mortality, functional status and quality of life. Secondary analyses considered vomiting/regurgitation, pneumonia, bacteraemia, sepsis and multiple organ dysfunction syndrome. Meta-analysis was conducted using an analytical method known to minimise bias in the presence of sparse events. The impact of heterogeneity was assessed using the I2 metric.

RESULTS

Three RCTs with 126 participants were found to be free from major flaws and were included in the primary analysis. The provision of early EN was associated with a significant reduction in mortality(OR = 0.20, 95% confidence interval 0.04–0.91, I2 = 0). No other outcomes could be pooled. A sensitivity analysis and a confirmatory analysis conducted using a different analytical method confirmed the presence of a mortality reduction.

CONCLUSION

Although the detection of a statistically significant reduction in mortality is promising,overall trial quality was low and trial size was small. The results of this meta-analysis should be confirmed by the conduct of a large multi-center trial.

Amino acid composition in parenteral nutrition: what is the evidence?

PURPOSE OF REVIEW

Complete parenteral nutrition solutions contain mixed amino acid products providing all nine essential amino acids and a varying composition of nonessential amino acids. Relatively little rigorous comparative efficacy research on altered parenteral nutrition amino acid composition has been published in recent years.

RECENT FINDINGS

Limited data from randomized, double-blind, adequately powered clinical trials to define optimal doses of total or individual amino acids in parenteral nutrition are available. An exception is the growing number of studies on the efficacy of glutamine supplementation of parenteral nutrition or given as a single parenteral agent. Parenteral glutamine appears to confer benefit in selected patients; however, additional data to define optimal glutamine dosing and the patient subgroups who may most benefit from this amino acid are needed. Although some promising studies have been published, little data are available in the current era of nutrition support on the clinical efficacy of altered doses of arginine, branched chain amino acids, cysteine, or taurine supplementation of parenteral nutrition.

SUMMARY

Despite routine use of parenteral nutrition, surprisingly little clinical efficacy data are available to guide total or specific amino acid dosing in adult and pediatric patients requiring this therapy. This warrants increased attention by the research community and funding agencies to better define optimal amino acid administration strategies in patient subgroups requiring parenteral nutrition.

Improvement of quality of reporting in randomised controlled trials to prevent hypotension after spinal anaesthesia for caesarean section

Hypotension is a frequent complication of spinal anaesthesia for caesarean section and can threaten the well-being of the unborn child. Numerous randomised controlled trials (RCTs) dealt with measures to prevent hypotension. The aim of this study was to determine the reporting quality of RCTs using the Consolidated Standards of Reporting Trials (CONSORT) statement since low quality can lend false credibility to a study and overestimate the effect of an intervention. We performed a systematic literature search in PubMed to identify relevant RCTs in a pre-CONSORT period (1990-1994) and a post-CONSORT period (2004-2008). A comparative evaluation was done between the two periods, and the trials were assessed for compliance with each of the 22 CONSORT items. A total of 37 RCTs was identified. The CONSORT score increased significantly (p < 0.05) from 66.7% (±12.5%) in the pre-CONSORT period to 87.4% (±6.9%) in the post-CONSORT period. A statistically significant improvement was found for eight items, including randomization, blinding and intention-to-treat analysis. The CONSORT score in the post-CONSORT era was fairly good, also in comparison to other medical fields. In the post-CONSORT era, reporting of important items improved, in particular in the domains that are crucial to avoid bias and to improve internal validity. Use of CONSORT should be encouraged in order to keep or even improve the reporting quality.

Reporting randomised clinical trials of analgesics after traumatic or orthopaedic surgery is inadequate: a systematic review

BACKGROUND

Several randomised clinical trials (RCTs) of analgesics in postoperative pain after traumatic or orthopaedic surgery (TOS) have been published, but no studies have assessed the quality of these reports. We aimed to examine the quality of reporting RCTs on analgesics for postoperative pain after TOS.

METHODS

Reports of RCTs assessing analgesics in postoperative pain after TOS were systematically searched from electronic databases. The quality of reports was assessed using the CONSORT checklist (scoring range from 0 to 22). The quality was considered poor when scoring was 12 or lesser. The publication year and the impact factor of journals were recorded.

RESULTS

A total of 92 reports of RCTs were identified and 69 (75%) scored 12 or lesser in CONSORT checklist (range 5-17). The mean (SD) CONSORT score of all reports was 10.6 (2.7). Missing CONSORT items included primary and secondary outcome measures (11%), the specific objectives and hypothesis definition (12%), the sample size calculation (12%), the dates defining the periods of recruitment (12%), the discussion of external validity of findings (14%), the allocation sequence generation (24%), and the interpretation of potential bias or imprecision of results (25%). There was a little improvement in CONSORT scores over time (r = 0.62; p < 0.001) and with impact factor of journals (r = 0.30; p < 0.001).

CONCLUSION

Quality of reporting RCTs on analgesics after TOS is poor. Reporting of those RCTs should be improved according to methodological standard checklists in the next years.

Early enteral nutrition, provided within 24 h of injury or intensive care unit admission, significantly reduces mortality in critically ill patients: a meta-analysis of randomised controlled trials

PURPOSE

To determine whether the provision of early standard enteral nutrition (EN) confers treatment benefits to critically ill patients.

METHODS

Medline and EMBASE were searched. Hand citation review of retrieved guidelines and systematic reviews were undertaken, and academic and industry experts were contacted. Methodologically sound randomised controlled trials (RCTs) conducted in critically ill patient populations that compared the delivery of standard EN, provided within 24 h of intensive care unit (ICU) admission or injury, to standard care were included. The primary analysis was conducted on clinically meaningful patient-oriented outcomes. Secondary analyses considered vomiting/regurgitation, pneumonia, bacteraemia, sepsis and multiple organ dysfunction syndrome. Meta-analyses were conducted using the odds ratio (OR) metric and a fixed effects model. The impact of heterogeneity was assessed using the I (2) metric.

RESULTS

Six RCTs with 234 participants were analysed. The provision of early EN was associated with a significant reduction in mortality [OR = 0.34, 95% confidence interval (CI) 0.14-0.85] and pneumonia (OR = 0.31, 95% CI 0.12-0.78). There were no other significant differences in outcomes. A sensitivity analysis and a simulation exercise confirmed the presence of a mortality reduction.

CONCLUSION

Although the detection of a statistically significant reduction in mortality is promising, overall trial quality was low, trial size was small, and the findings may be restricted to the patient groups enrolled into included trials. The results of this meta-analysis should be confirmed by the conduct of a large multi-centre trial enrolling diverse critically ill patient groups.

Parenteral nutrition in the critically ill patient

A 67-year-old woman with type 2 diabetes mellitus undergoes extensive resection of the small bowel and right colon with a jejunostomy and colostomy because of mesenteric ischemia. In the surgical intensive care unit, severe systemic inflammatory response syndrome with possible sepsis develops. The patient is treated with volume resuscitation, vasopressor support, mechanical ventilation, broad-spectrum antibiotics, and intravenous insulin infusion. Low-dose tube feedings are initiated postoperatively through a nasogastric tube. However, these feedings are discontinued after the development of escalating vasopressor requirements, worsening abdominal distention, and increased gastric residual volume, along with an episode of emesis. The hospital nutritional-support service is consulted for feeding recommendations. A discussion with the patient's family reveals that during the previous 6 months, she lost approximately 15% of her usual body weight and decreased her food intake because of abdominal pain associated with eating. Her preoperative body weight was 51 kg (112 lb), or 90% of her ideal body weight. The physical examination reveals mild wasting of skeletal muscle and fat. Blood tests show hypomagnesemia, hypophosphatemia, and normal hepatic and renal function. Central venous parenteral nutrition is recommended.

Symposium 4: Hot topics in parenteral nutrition Current evidence and ongoing trials on the use of glutamine in critically-ill patients and patients undergoing surgery

The amino acid glutamine has numerous important roles including particularly antioxidant defence, immune function, the inflammatory response, acid–base balance and N economy. The present systematic review of randomised controlled trials of nutrition support with glutamine up to August 2008 has found that parenteral glutamine in critical illness is associated with a non-significant reduction in mortality (risk ratio 0·71 (95% CI 0·49, 1·03)) and may reduce infections. However, poor study quality and the possibility of publication bias mean that these results should be interpreted with caution. There is no evidence to suggest that glutamine is harmful in terms of organ failure and parenteral glutamine may reduce the development of organ failure.

Evidence-based nutrition support in the intensive care unit: an update on reported trial quality

PURPOSE OF REVIEW

Meta-epidemiological reviews report that trials of nutritional support in critical illness rarely fulfil basic quality requirements, with overall quality rated as 'worse than poor'. This update reviews recently published trials to determine whether current evidence meets or exceeds basic quality requirements.

RECENT FINDINGS

Although recent trials were significantly more likely to report blinding, there is a concerning trend towards a decrease in overall trial quality. Many recent trials fail to report the use of 'any' of three key validity criteria: use of blinding, presentation of intention-to-treat analysis and the maintenance allocation concealment.

SUMMARY

Future researchers must improve the quality with which trials are conducted and reported. Submitting a clinical trial to an approved registry prior to enrolling patients provides transparency of conduct. Investigators must ensure that an intention-to-treat analysis is reported, especially when a subset efficacy analysis is presented, even if the intention-to-treat analysis requires imputing missing data values. Investigators also need to improve reporting details concerning allocation concealment and blinding. Finally, until investigators, editors and reviewers embrace these measures, we strongly recommend that readers should become familiar with the appropriate evidence-based medicine users' guides so that they can base clinical decisions on valid studies.

Feeding the injured intestine: enteral nutrition in the critically ill patient

PURPOSE OF REVIEW

The utilization of enteral nutrition in critically ill patients is frequently suboptimal. This may be due, in part, to ongoing controversies regarding appropriate use of enteral support, but there are also perceived barriers to its use even when there is good evidence that it can be given. This review was undertaken to outline some of these controversies and barriers to use of enteral nutrition in the ICU.

RECENT FINDINGS

Although the advantages of enteral nutrition may have been overstated, it remains preferable to parenteral nutrition for support of critically ill patients. Early initiation of enteral support is a reasonable approach. Many patients with perceived contraindications to enteral therapy are actually good candidates for its use. Frequent interruptions in enteral nutrition lead to suboptimal nutrient delivery, but might be overcome by use of specific protocols emphasizing safe and effective utilization of enteral support.

SUMMARY

Use of enteral nutritional support is recommended for critically ill patients requiring specialized nutritional support. Barriers to its use could be overcome by better educating providers about indications for use and by developing methods to avoid undue interruption of therapy.

Early nutrition support in critical care: a European perspective

PURPOSE OF REVIEW

Today, early nutrition support is considered standard care in most ICUs. The recommended method is the enteral route, although there is only minor evidence for this. Often inadequate delivery of energy and a cumulative energy deficit are implied. The purpose of this paper is to evaluate the indication for early enteral nutrition or immunonutrition and to discuss the application of additional parenteral nutrition.

RECENT FINDINGS

The indication for early enteral nutrition is also supported by guidelines for enteral nutrition recently published by the European Society for Clinical Nutrition and Metabolism. Some more recent results strengthen the indication for a special formula in acute respiratory distress syndrome and septic patients. A recent metaanalysis has shown that parenteral nutrition is superior to delayed enteral nutrition. Additional parenteral nutrition thus seems to be the way to avoid cumulative energy deficit associated with insufficient or no enteral nutrition.

SUMMARY

Early enteral nutrition is recommended for critically ill patients, with special formulas indicated in specific subgroups of patients. If enteral nutrition is insufficient or fails, parenteral nutrition should be instituted, respecting the often reduced demand for exogenous substrates in critically ill patients.

Early enteral nutrition in the critically ill: do we need more evidence or better evidence?

PURPOSE OF REVIEW

Nutritional support of the critically ill is accepted as a standard of care. Recommendations for early enteral nutrition are based on reasonable evidence but only 50% of eligible patients receive enteral nutrition within 48 h of admission to the intensive care unit. The purpose of this review is to determine how recent developments advance the current state of knowledge.

RECENT FINDINGS

The benefits of early enteral nutrition are supported by two recent evidence-based guidelines initiatives. Early (< 48 h after intensive care unit admission) enteral nutrition may decrease hospital discharge mortality by 8-12% (grade B+ evidence-based recommendation). Five recent level II clinical trials, two of which contain major methodological flaws, are consistent with this recommendation.

SUMMARY

Higher levels of evidence, demonstrating benefit to a patient-oriented outcome, are more likely to change practice. The addition of more level II trials to a meta-analysis composed of level II trials may not convince clinicians to change practice. A level I trial (equivalent to a phase III Food and Drug Administration licensing trial) is required to convince more clinicians to provide early enteral nutrition. A level I trial would also provide an important opportunity to validate changes in disease-oriented outcomes (measures of nutritional status) against improvements in patient-oriented outcomes.

Does the CONSORT checklist improve the quality of reports of randomised controlled trials? A systematic review

OBJECTIVE

To determine whether the adoption of the CONSORT checklist is associated with improvement in the quality of reporting of randomised controlled trials (RCTs).

DATA SOURCES

MEDLINE, EMBASE, Cochrane CENTRAL, and reference lists of included studies and of experts were searched to identify eligible studies published between 1996 and 2005.

STUDY SELECTION

Studies were eligible if they (a) compared CONSORT-adopting and non-adopting journals after the publication of CONSORT, (b) compared CONSORT adopters before and after publication of CONSORT, or (c) a combination of (a) and (b). Outcomes examined included reports for any of the 22 items on the CONSORT checklist or overall trial quality.

DATA SYNTHESIS

1128 studies were retrieved, of which 248 were considered possibly relevant. Eight studies were included in the review. CONSORT adopters had significantly better reporting of the method of sequence generation (risk ratio [RR], 1.67; 95% CI, 1.19-2.33), allocation concealment (RR, 1.66; 95% CI, 1.37-2.00) and overall number of CONSORT items than non-adopters (standardised mean difference, 0.83; 95% CI, 0.46-1.19). CONSORT adoption had less effect on reporting of participant flow (RR, 1.14; 95% CI, 0.89-1.46) and blinding of participants (RR, 1.09; 95% CI, 0.84-1.43) or data analysts (RR, 5.44; 95% CI, 0.73-36.87). In studies examining CONSORT-adopting journals before and after the publication of CONSORT, description of the method of sequence generation (RR, 2.78; 95% CI, 1.78-4.33), participant flow (RR, 8.06; 95% CI, 4.10-15.83), and total CONSORT items (standardised mean difference, 3.67 items; 95% CI, 2.09-5.25) were improved after adoption of CONSORT by the journal.

CONCLUSIONS

Journal adoption of CONSORT is associated with improved reporting of RCTs.

A comparison of early gastric and post-pyloric feeding in critically ill patients: a meta-analysis

OBJECTIVE

To investigate the potential beneficial and adverse effects of early post-pyloric feeding compared with gastric feeding in critically ill adult patients with no evidence of impaired gastric emptying.

DESIGN

Randomised controlled studies comparing gastric and post-pyloric feeding in critically ill adult patients from Cochrane Controlled Trial Register (2005 issue 3), EMBASE and MEDLINE databases (1966 to 1 October 2005) without any language restriction were included. Two reviewers reviewed the quality of the studies and performed data extraction independently.

MEASUREMENTS AND RESULTS

Eleven randomised controlled studies with a total of 637 critically ill adult patients were considered. The mortality (relative risk [RR] 1.01, 95% CI 0.76-1.36, p=0.93; I2=0%) and risk of aspiration or pneumonia (RR 1.28, 95% CI 0.91-1.80, p=0.15; I2=0%) were not significantly different between patients treated with gastric or post-pyloric feeding. The effect of post-pyloric feeding on the risk of pneumonia or aspiration was similar when studies were stratified into those with and those without the use of concurrent gastric decompression (RR ratio 0.95, 95% CI 0.48-1.91, p=0.89). The risk of diarrhoea and the length of intensive care unit stay (weighted mean difference in days -1.46, 95% CI -3.74 to 0.82, p=0.21; I2=24.6%) were not statistically different. The gastric feeding group had a much lower risk of experiencing feeding tube placement difficulties or blockage (0 vs 9.6%, RR 0.13, 95% CI 0.04-0.44, p=0.001; I2=0%).

CONCLUSIONS

Early use of post-pyloric feeding instead of gastric feeding in critically ill adult patients with no evidence of impaired gastric emptying was not associated with significant clinical benefits.

Randomization and allocation concealment: a practical guide for researchers

Although the randomized controlled trial is the most important tool currently available to objectively assess the impact of new treatments, the act of randomization itself is often poorly conducted and incompletely reported. The primary purpose of randomizing patients into treatment arms is to prevent researchers, clinicians, and patients from predicting, and thus influencing, which patients will receive which treatments. This important source of bias can be eliminated by concealing the upcoming allocation sequence from researchers and participants. Although there are many approaches to randomization that are known to effectively conceal the randomization sequence, the use of sequentially numbered, opaque sealed envelopes (SNOSE) is both cheap and effective. The purpose of this tutorial is to describe a step-by-step process for the preparation of SNOSE. We will outline how to prepare SNOSE to preserve allocation concealment in a trial that (a) uses unrestricted (simple) randomization, (b) stratifies randomization on one factor, (c) uses permuted blocks and, and (d) is conducted at more than 1 study site.

Parenteral vs. enteral nutrition in the critically ill patient: a meta-analysis of trials using the intention to treat principle

OBJECTIVE

Controversy surrounds the use of parenteral nutrition in critical illness. Previous overviews used composite scales to identify high-quality trials, which may mask important differences in true methodological quality. Using a component-based approach this meta-analysis investigated the effect of trial quality on overall conclusions reached when standard enteral nutrition is compared to standard parenteral nutrition in critically ill patients.

METHODS

An extensive literature search was undertaken to identify all eligible trials. We retrieved 465 publications, and 11 qualified for inclusion. Nine trials presented complete follow-up, allowing the conduct of an intention to treat analysis.

RESULTS

Aggregation revealed a mortality benefit in favour of parenteral nutrition, with no heterogeneity. A priori specified subgroup analysis demonstrated the presence of a potentially important treatment-subgroup interaction between studies of parenteral vs. early enteral nutrition compared to parenteral vs. late enteral. Six trials with complete follow-up reported infectious complications. Infectious complications were increased with parenteral use. The I(2) measure of heterogeneity was 37.7%.

CONCLUSIONS

Intention to treat trials demonstrated reduced mortality associated with parenteral nutrition use. A priori subgroup analysis attributed this reduction to trials comparing parenteral to delayed enteral nutrition. Despite an association with increased infectious complications, a grade B+ evidence-based recommendation (level II trials, no heterogeneity) can be generated for parenteral nutrition use in patients in whom enteral nutrition cannot be initiated within 24 h of ICU admission or injury.