An open-label study of chronic polyethylene glycol laxative use in chronic constipation

BACKGROUND

Polyethylene glycol 3350 (MiraLAX, Braintree Laboratories Inc., Braintree, MA, USA) is approved for the short-term treatment of occasional constipation.

AIM

To extend the safety data of polyethylene glycol used for chronic treatment of chronic constipation.

METHODS

Study subjects who met defined criteria for chronic constipation were enrolled in this open-labelled, single-treatment multi-centre study to receive polyethylene glycol laxative as a single daily dose of 17 g for 12 months. Subjects returned to their study centres after 2, 4, 6, 9 and 12 months of treatment where blood and urine samples were collected and adverse events were reviewed. At each visit, subjects were queried for ROME constipation criteria and they rated their overall improvement using a global efficacy scale.

RESULTS

311 patients including 117, age 65 and older, were enrolled and received treatment at one of 50 centres. One hundred and eighty-four completed all 12 months of treatment. With respect to the 'Global Efficacy Assessment', depending on the month of observation, 80-88% of enrolled patients, and 84-94% of the elderly, were treated successfully. Similar results were obtained from secondary efficacy measures that assessed individual ROME constipation criteria at each visit. The response to treatment was durable over time. Over the 1-year course of study representing 218 patient-years at the labelled dose, medication-associated adverse effects were gastrointestinal complaints of diarrhoea, loose stool, flatulence and nausea. These effects were generally mild or moderate in severity. There were no clinically significant changes in haematology or blood chemistry, particularly electrolytes, for the study population as a whole or the elderly group.

CONCLUSIONS

Polyethylene glycol laxative is safe and effective for treating constipation in adult and elderly patients for periods up to 12 months, with no evidence of tachyphylaxis.

Reporting of the Role of the Expert Searcher in Cochrane Reviews

Introduction - This study applied the principles of evidence based information practice to clarify the role of information specialists and librarians in the preparation of Cochrane systematic reviews and to determine whether information specialists impact the quality of searching in Cochrane systematic reviews. Objectives - This research project sought to determine how the contribution of the person responsible for searching in the preparation of Cochrane systematic reviews was reported; whether the contribution was recognized through authorship or acknowledgement; the qualifications of the searcher; and the association between the type of contributorship and characteristics of the search strategy, assessability, and the presence of certain types of errors. Methods - Data sources: The Cochrane Database of Systematic Reviews, The Cochrane Library 3 (2002). Inclusion criteria: The study included systematic reviews that met the following criteria: one or more sections of the Cochrane Highly Sensitive Search Strategy were utilised, primary studies were either randomised controlled trials (RCTs) or quasi-RCTs, and included and excluded studies were clearly identified. Data extraction: Two librarians assessed the searches for errors, establishing consensus on discordant ratings. Results - Of the 169 reviews screened for this project, 105 met all eligibility criteria. Authors fulfilled the searching role in 41.9% of reviews studied, acknowledged persons or groups in 13.3%, a combination in 9.5%, and the role was not reported in 35.2% of reviews. For the 78 reviews in which meta-analyses were performed, the positions of those responsible for statistical decisions were examined for comparative purposes. The statistical role was performed by an author in 47.4% of cases and unreported in the same number of cases. Insufficient analyzable data was obtained regarding professional qualifications (3/105 for searching, 2/78 for statistical decisions). Search quality was assessed for 66 searches across 74 reviews. In general, it was more possible to assess the search quality when the searcher role was reported. An association was found between the reporting of searcher role and the presence of a consequential error. There was no association between the number of consequential errors and how the contribution of the searcher was reported. Conclusions - Qualifications of the persons responsible for searching and statistical decision-making were poorly reported in Cochrane reviews, but more complete role reporting is associated with greater assessability of searches and fewer substantive errors in search strategies.

Errors in search strategies were identified by type and frequency

OBJECTIVE

Errors in the electronic search strategy of a systematic review may undermine the integrity of the evidence base used in the review. We studied the frequency and types of errors in reviews published by the Cochrane Collaboration.

STUDY DESIGN AND SETTING

Data sources were MEDLINE searches from reviews in the Cochrane Library, Issue 3, 2002. To be eligible, systematic reviews must have been of randomized or quasi-randomized controlled trials, reported included and excluded studies, and used one or more sections of the Cochrane Collaboration's Highly Sensitive Search Strategy. MEDLINE search strategies not reported in enough detail to be assessed or that were duplicates of a search strategy already assessed for the study were excluded. Two librarians assessed eligibility and scored the eligible electronic search strategies for 11 possible errors. Dual review with consensus was used.

RESULTS

Of 105 MEDLINE search strategies examined, 63 were assessed; 31 were excluded because they were inadequately reported, and 11 were duplicates of assessed search strategies. Most (90.5%) of the assessed search strategies contained > or =1 errors (median 2, interquartile range [IQR] 1.0-3.0). Errors that could potentially lower recall of relevant studies were found in 82.5% (median 1, IQR 1.0-2.0) and inconsequential errors (to the evidence base) were found in 60.3% (median 1, IQR 0.0-1.0) of the search strategies. The most common search errors were missed MeSH terms (44.4%), unwarranted explosion of MeSH terms (38.1%), and irrelevant MeSH or free text terms (28.6%). Missed spelling variants, combining MeSH and free text terms in the same line, and failure to tailor the search strategy for other databases occurred with equal frequency (20.6%). Logical operator error occurred in 19.0% of searches.

CONCLUSION

When the MEDLINE search strategy used in a systematic review is reported in enough detail to allow assessment, errors are commonly revealed. Additional peer review steps are needed to ensure search quality and freedom from errors.

Canada urgently needs a national network of libraries to access evidence

Canadian health professionals and their patients are deprived of important evidence to guide health and healthcare decisions, ensure quality and avoid unnecessary deaths because, unlike other developed countries, Canada does not have a national medical library as can be found in the United States' National Library of Medicine and the United Kingdom's National Health Service.

Knowledge for knowledge translation: the role of the Cochrane Collaboration

Knowledge-translation (KT) activities, including continuing education, should be informed by the totality of available research evidence. Systematic reviews are a generic methodology used to synthesize evidence from a broad range of research methods addressing different questions. Over the past decade, there has been a dramatic increase in the availability of systematic reviews that could support KT activities. However, the conduct of systematic reviews is technically challenging, and it is not surprising that the quality of available reviews is variable. In addition, unless attempts are made to update systematic reviews, they rapidly become out of date. The Cochrane Collaboration is a unique, worldwide, not-for-profit organization that aims to help people make well-informed decisions about all forms of health care by preparing, maintaining, and promoting the accessibility of systematic reviews of the effects of health care interventions. Globally, over 13, 000 consumers, clinicians, policymakers, and researchers are involved with The Cochrane Collaboration and have to date produced over 2, 500 systematic reviews that can be used to inform KT activities. The Cochrane Collaboration publishes its reviews quarterly in The Cochrane Library. Cochrane reviews have been used to develop a number of KT-derivative products for professionals, consumers, and policymakers. Whereas most Cochrane Review groups focus on specific clinical areas, the Cochrane Effective Practice and Organisation of Care Group undertakes reviews of interventions to improve health care delivery and health care systems, including reviews of different KT activities. We summarize the activities of The Cochrane Collaboration and how these can contribute to KT activities.

Systematic reviews need systematic searchers

PURPOSE

This paper will provide a description of the methods, skills, and knowledge of expert searchers working on systematic review teams.

BRIEF DESCRIPTION

Systematic reviews and meta-analyses are very important to health care practitioners, who need to keep abreast of the medical literature and make informed decisions. Searching is a critical part of conducting these systematic reviews, as errors made in the search process potentially result in a biased or otherwise incomplete evidence base for the review. Searches for systematic reviews need to be constructed to maximize recall and deal effectively with a number of potentially biasing factors. Librarians who conduct the searches for systematic reviews must be experts.

DISCUSSION/CONCLUSION

Expert searchers need to understand the specifics about data structure and functions of bibliographic and specialized databases, as well as the technical and methodological issues of searching. Search methodology must be based on research about retrieval practices, and it is vital that expert searchers keep informed about, advocate for, and, moreover, conduct research in information retrieval. Expert searchers are an important part of the systematic review team, crucial throughout the review process-from the development of the proposal and research question to publication.

Impact of informed consent requirements on cardiac arrest research in the United States: exception from consent or from research?

INTRODUCTION

Research in patients with life-threatening illness such as cardiac arrest is challenging since they can not consent. The Food and Drug Administration addressed research under emergency conditions by publishing new criteria for exception from informed consent in 1996. We systematically reviewed randomized trials over a 10-year period to assess the impact of these regulations.

METHODS

Case-control study of published trials for cardiac arrest (cases) and atrial fibrillation (controls.) Studies were identified by using structured searches of MEDLINE and EMBASE from 1992 to 2002. Included were studies using random allocation in humans with cardiac arrest or atrial fibrillation prior to enrollment. Excluded were duplicate publications. Number of American trials, foreign trials and proportion of trials of American origin were compared by using regression analysis. Changes in cardiac arrest versus atrial fibrillation trials were calculated as risk differences.

RESULTS

Of 4982 identified cardiac arrest studies, 57 (1.1%) were randomized trials. The number of American cardiac arrest trials decreased by 15% (95% CI: 8, 22%) annually (P = 0.05). The proportion of cardiac arrest trials of American origin decreased by 16% (95% CI: 10, 22%) annually (P = 0.006). Of 5596 identified atrial fibrillation studies, 197 trials (3.5%) were randomized trials. The risk difference between cardiac arrest versus atrial fibrillation trials being of American origin decreased significantly (annual difference -5.8% (95% CI: -10, -0.1%), P = 0.03).

INTERPRETATION

Fewer American cardiac arrest trials were published during the last decade, when federal consent requirements changed. Regulatory requirements for clinical trials may inhibit improvements in care and threaten public health.

Association of autistic spectrum disorder and the measles, mumps, and rubella vaccine: a systematic review of current epidemiological evidence

OBJECTIVE

To systematically review the evidence for and against the existence of an association between autistic spectrum disorder (ASD) and the measles, mumps, and rubella (MMR) vaccine.

STUDY DESIGN

We conducted a systematic review of the medical literature to identify all controlled epidemiological articles examining for an association between ASD and the MMR vaccine. We extracted data from the articles on the characteristics and objectives of the study as well as evidence of an association.

RESULTS

Twelve articles met the inclusion criteria. One study found no difference in the rates of ASD and the MMR vaccine in children who were vaccinated and those who were not. Six studies examined for evidence of an increase in ASD associated with an increase in the MMR vaccine coverage, none of which showed evidence of an association. Four studies examined if a variant form of ASD was associated with the MMR vaccine, none of which showed evidence of an association. Eight studies attempted to determine if there was a temporal association between developing ASD and receiving the MMR vaccine. Of these, 1 study identified an increase in parental concern in the 6-month period following vaccination with MMR in one of its analyses. The results of all other studies showed no association between ASD and the MMR vaccine.

CONCLUSIONS

The current literature does not suggest an association between ASD and the MMR vaccine; however, limited epidemiological evidence exists to rule out a link between a rare variant form of ASD and the MMR vaccine. Given the real risks of not vaccinating and that the risks and existence of variant ASD remain theoretical, current policies should continue to advocate the use of the MMR vaccine.

Teaching evidence-based complementary and alternative medicine: 5. Interpreting the results of a study on therapy and applying them to a patient

Practicing evidence-based complementary and alternative medicine (CAM) requires that practitioners develop an ability to understand and appropriately apply the results of published studies addressing questions related to their clinical practice. This paper describes a process by which CAM practitioners can interpret the results of studies evaluating therapeutic interventions and then determine if they can apply these results to their patients. We describe a process for interpreting the results of a study on therapy that involves determining the estimate of the magnitude of the therapy's effect and determining the precision of this estimate. We then describe a process for determining whether the results of a study on therapy can be applied to a given patient that involves determining the extent to which patients in the study differ from the patient being treated and determining if the study addressed all outcomes of interest.

Teaching evidence-based complementary and alternative medicine: 3. Asking the questions and identifying the information

Practicing evidence-based complementary and alternative medicine (EBCAM) requires skills in accessing current valid literature on clinical queries. This requires searching a variety of sources within a broad scope of scientific disciplines. This daunting task requires effective skills for accessing information from both print and electronic sources. This paper identifies the progression from question formulation through to searching and acquiring the valid information. In the evolving information age, complementary and alternative medicine (CAM) practitioners require informational databases and knowledge of search terminology. This paper suggests practical strategies for successful database searches in support of EBCAM.

Do silicone breast implants cause rheumatologic disorders? A systematic review for a court-appointed national science panel

OBJECTIVE

To assist in evaluating expert testimony and scientific evidence presented in law suits brought against silicone breast implant manufacturers, a US District Court Order established a National Science Panel to assess whether existing studies provide scientific evidence of an association between silicone breast implants and systemic classic/accepted connective disease, atypical connective disease, and certain signs and symptoms identified by plaintiffs in the law suits. Local disorders potentially associated with these implants were not addressed in this review. Therefore, we performed a systematic review of published studies on the association between silicone breast implants and systemic connective tissue disorders.

METHODS

Data from relevant studies (human cohort, case-control, or cross-sectional studies with > or = 10 participants and appropriate controls) were identified through literature searches of Medline, Current Contents, HealthStar, Biological Abstracts, EMBase, Toxline, and Dissertation Abstracts. Two independent reviewers, using standard collection forms, extracted data from the included studies. Adjusted relative risks (RRs) in cohort studies and odds ratios (ORs) in case-control and cross-sectional studies were reported if provided; otherwise, unadjusted RRs and ORs were calculated.

RESULTS

Twenty-four studies meeting inclusion criteria were identified. No association was evident between breast implants and any established or atypical connective tissue disorder. There was discordance among studies in reports of arthralgias, lymphadenopathy, myalgias, sicca symptoms, skin changes, and stiffness.

CONCLUSION

The panel found no evidence to support expert testimony suggesting an association between silicone breast implants and connective diseases. Discordance for symptoms may reflect differences in symptoms included in various categories, the small number of cases, and the effect of having single subjects with > 1 symptom represented in analyses of each symptom reported. The process presented here is an early example of the use of independent scientific panels to help courts clarify scientific evidence in legal proceedings.

The prevention of chronic NSAID induced upper gastrointestinal toxicity: a Cochrane collaboration metaanalysis of randomized controlled trials

OBJECTIVE

To review the effectiveness of common interventions for the prevention of nonsteroidal antiinflammatory drug (NSAID) induced upper gastrointestinal (GI) toxicity.

METHODS

Randomized controlled clinical trials (RCT) of prostaglandin analogs, H2-receptor antagonists (H2RA), or proton pump inhibitors (PPI) for the prevention of chronic NSAID induced upper GI toxicity were identified through electronic databases, the Cochrane control trials register, conference proceedings, and by contacting content experts and companies. Outcome measures investigated were endoscopic ulcers, ulcer complications, symptoms, overall dropouts, dropouts due to symptoms, and study quality.

RESULTS

Thirty-four RCT met the inclusion criteria. All doses of misoprostol significantly reduced the risk of endoscopic ulcers. Misoprostol 800 microg/day was superior to 400 microg/day for the prevention of endoscopic gastric ulcers (RR 0.18, RR 0.38, respectively; p = 0.0055). A dose-response relationship was not seen with duodenal ulcers. Misoprostol caused diarrhea at all doses, although significantly more at 800 than 400 microg/day (p = 0.0012). Misoprostol was the only prophylactic agent documented to reduce ulcer complications. Standard doses of H2RA were effective at reducing the risk of endoscopic duodenal (RR 0.24, 95% CI 0.10-0.57) but not gastric ulcers (RR 0.73, 95% CI 0.50-1.09). Both double dose H2RA and PPI were effective at reducing the risk of endoscopic duodenal and gastric ulcers (RR 0.44, 95% CI 0.26-0.74 and RR 0.37, 95% CI 0.27-0.51, respectively, for gastric ulcer) and were better tolerated than misoprostol.

CONCLUSION

Misoprostol, PPI, and double dose H2RA are effective in preventing chronic NSAID related endoscopic gastric and duodenal ulcers. Lower doses of misoprostol are less effective and are still associated with diarrhea. Only misoprostol 800 microg/day has been directly shown to reduce the risk of ulcer complications.

The effect of clinical pathway implementation on total hospital costs for thyroidectomy and parathyroidectomy patients

Clinical pathways have long been used to guide the delivery of patient care in varied practice settings. There is little information in the literature to document the effectiveness of pathway implementation in general surgical populations. This study reports the effect of clinical pathway implementation in two general surgical patient groups, thyroidectomy and parathyroidectomy. Clinical pathways were implemented to serve patients undergoing thyroidectomy and parathyroidectomy surgery. The effects of both clinical pathways on total hospital costs, length of hospitalization, variances, and outcomes were collected and evaluated from July 1998 through July 1999. These data were compared to data from the previous year. The average length of stay for parathyroidectomy patients decreased from 2.4 to 1.5 days (P = 0.26) for pathway patients as compared to prepathway patients. The average cost per case decreased from $5071 to $4291 (P = 0.50) for parathyroidectomy pathway versus prepathway patients. The average length of stay decrease for thyroidectomy patients was 1.4 to 1.2 (P = 0.16) for the pathway to prepathway comparison. The average cost per case decrease was minor at $4117 to $4111. Pharmacy costs and laboratory utilization were effectively reduced. Perioperative costs rose dramatically during this period, operating room/central sterile supply cost per case rose 12 per cent, anesthesia supply cost per case rose 15 per cent, and surgical pathology costs increased 110 per cent overall for both patient groups. Clinical pathway implementation has allowed us to reduce or maintain total hospital costs in the face of rising perioperative costs. We conclude that implementation of these clinical pathways has allowed us to improve consistency with which we deliver care while maintaining the quality of patient outcomes and reducing the costs of care and length of hospital stay.

Finger position for chest compressions in cardiac arrest in infants

OBJECTIVE

To determine whether the recommended method of locating finger position for chest compression in infant cardiac arrest can cause pressure on the abdomen or xiphisternum.

DESIGN

The length from the inter-nipple line to the xiphisternum was calculated in 30 infants. These lengths were compared with the finger position achieved by 30 adults, using the recommended method, on templates of infant chests.

RESULTS

The mean infant lower sternal length was 2.3 cm (95% CI 1.6). The mean distance covered by the adults fingers was 4.4 cm (95% CI 0.9).

CONCLUSION

If any infant in this study had chest compressions performed by any of the adults, using the recommended method, pressure would be exerted on the xiphisternum or abdomen. We suggest changing the method of locating finger position, to one using sternal anatomy.

Prevention of chronic NSAID induced upper gastrointestinal toxicity

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) are important agents in the management of arthritic and inflammatory conditions, and are among the most frequently prescribed medications in North America and Europe. However, there is overwhelming evidence linking these agents to a variety of gastrointestinal (GI) toxicities.

OBJECTIVES

To review the effectiveness of common interventions for the prevention of NSAID induced upper GI toxicity.

SEARCH STRATEGY

A literature search was conducted, according to the Cochrane methodology for identification of randomized controlled trials in electronic databases, including MEDLINE from 1966 to January 2000, Current Contents for 6 months prior to January 2000, Embase to Febuary 1999, and a search of the Cochrane Controlled Trials Register from 1973 to 1999. Recent conference proceedings were reviewed and content experts and companies were contacted.

SELECTION CRITERIA

Randomized controlled clinical trials (RCTs) of prostaglandin analogues (PA), H2-receptor antagonists (H2RA) or proton pump inhibitors (PPI) for the prevention of chronic NSAID induced upper GI toxicity were included.

DATA COLLECTION AND ANALYSIS

Two independent reviewers extracted data regarding population characteristics, study design, methodological quality and number of patients with endoscopic ulcers, ulcer complications, symptoms, overall drop-outs, drop outs due to symptoms. Dichotomous data was pooled using Revman V3.1. Heterogeneity was evaluated using a chi square test.

MAIN RESULTS

Thirty-three RCTs met the inclusion criteria. All doses of misoprostol significantly reduced the risk of endoscopic ulcers. Misoprostol 800 ug/day was superior to 400 ug/day for the prevention of endoscopic gastric ulcers (RR=0.18, and RR=0. 38 respectively, p=0.0055). A dose response relationship was not seen with duodenal ulcers. Misoprostol caused diarrhea at all doses, although significantly more at 800ug/day than 400ug/day (p=0.0012). Misoprostol was the only prophylactic agent documented to reduce ulcer complications. Standard doses of H2RAs were effective at reducing the risk of endoscopic duodenal (RR=0.24; 95% CI: 0.10-0. 57) but not gastric ulcers(RR=0.73; 95% CI:0.50-1.09). Both double dose H2RAs and PPIs were effective at reducing the risk of endoscopic duodenal and gastric ulcers (RR=0.44; 95% CI:0.26-0.74 and RR=0.37;95% CI;0.27-0.51 respectively for gastric ulcer), and were better tolerated than misoprostol.

REVIEWER'S CONCLUSIONS

Misoprostol, PPIs, and double dose H2RAs are effective at preventing chronic NSAID related endoscopic gastric and duodenal ulcers. Lower doses of misoprostol are less effective and are still associated with diarrhea. Only Misoprostol 800ug/day has been directly shown to reduce the risk of ulcer complications.