Diagnostic accuracy of nitroglycerine as a 'test of treatment' for cardiac chest pain: a systematic review

To determine the accuracy of using nitroglycerine as a 'test of treatment' in the diagnosis of cardiac chest pain we undertook a systematic review of studies of diagnostic accuracy. Databases searched included PubMed, Cochrane Database, Google Scholar, Science Citation Index, EMBASE and manual searching of bibliographies of known primary and review articles. Studies were included if sublingual nitroglycerine was the index test, its effect on the patient's pain score was recorded and the reference test was performed on at least 80% of patients. The data from the five papers were used to form 2×2 contingency tables. Five eligible studies were found, all in the acute setting (although one paper collected its data in the follow-up setting, all patients had acute presentations). The sensitivity ranged from 35% to 92% and the specificity from 12% to 63%. However, in all but one paper the Youden indices were close to zero suggesting that the response to nitroglycerine is not useful as a diagnostic test. The combined sensitivity was 0.52 (95% CI 0.48 to 0.56) and combined specificity was 0.49 (95% CI 0.46 to 0.52). The diagnostic OR from the combined studies was 1.2 (95% CI 0.97 to 1.5), which is not significantly different from 1. In the acute setting, nitroglycerine is not a reliable test of treatment for use in the diagnosis of coronary artery disease. However, further studies are needed to determine the diagnostic accuracy of nitroglycerine for recurrent exertional chest pain.

Development and validation of decision rules to guide frequency of monitoring CD4 cell count in HIV-1 infection before starting antiretroviral therapy

Background

Although CD4 cell count monitoring is used to decide when to start antiretroviral therapy in patients with HIV-1 infection, there are no evidence-based recommendations regarding its optimal frequency. It is common practice to monitor every 3 to 6 months, often coupled with viral load monitoring. We developed rules to guide frequency of CD4 cell count monitoring in HIV infection before starting antiretroviral therapy, which we validated retrospectively in patients from the Swiss HIV Cohort Study.

Methodology/Principal Findings

We built up two prediction rules (“Snap-shot rule” for a single sample and “Track-shot rule” for multiple determinations) based on a systematic review of published longitudinal analyses of CD4 cell count trajectories. We applied the rules in 2608 untreated patients to classify their 18 061 CD4 counts as either justifiable or superfluous, according to their prior ≥5% or <5% chance of meeting predetermined thresholds for starting treatment. The percentage of measurements that both rules falsely deemed superfluous never exceeded 5%. Superfluous CD4 determinations represented 4%, 11%, and 39% of all actual determinations for treatment thresholds of 500, 350, and 200×10⁶/L, respectively. The Track-shot rule was only marginally superior to the Snap-shot rule. Both rules lose usefulness for CD4 counts coming near to treatment threshold.

Conclusions/Significance

Frequent CD4 count monitoring of patients with CD4 counts well above the threshold for initiating therapy is unlikely to identify patients who require therapy. It appears sufficient to measure CD4 cell count 1 year after a count >650 for a threshold of 200, >900 for 350, or >1150 for 500×10⁶/L, respectively. When CD4 counts fall below these limits, increased monitoring frequency becomes advisable. These rules offer guidance for efficient CD4 monitoring, particularly in resource-limited settings.

Effects of fenofibrate on renal function in patients with type 2 diabetes mellitus: the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) Study

AIMS/HYPOTHESIS

Fenofibrate caused an acute, sustained plasma creatinine increase in the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) and Action to Control Cardiovascular Risk in Diabetes (ACCORD) studies. We assessed fenofibrate's renal effects overall and in a FIELD washout sub-study.

METHODS

Type 2 diabetic patients (n = 9,795) aged 50 to 75 years were randomly assigned to fenofibrate (n = 4,895) or placebo (n = 4,900) for 5 years, after 6 weeks fenofibrate run-in. Albuminuria (urinary albumin/creatinine ratio measured at baseline, year 2 and close-out) and estimated GFR, measured four to six monthly according to the Modification of Diet in Renal Disease Study, were pre-specified endpoints. Plasma creatinine was re-measured 8 weeks after treatment cessation at close-out (washout sub-study, n = 661). Analysis was by intention-to-treat.

RESULTS

During fenofibrate run-in, plasma creatinine increased by 10.0 μmol/l (p < 0.001), but quickly reversed on placebo assignment. It remained higher on fenofibrate than on placebo, but the chronic rise was slower (1.62 vs 1.89 μmol/l annually, p = 0.01), with less estimated GFR loss (1.19 vs 2.03 ml min(-1) 1.73 m(-2) annually, p < 0.001). After washout, estimated GFR had fallen less from baseline on fenofibrate (1.9 ml min(-1) 1.73 m(-2), p = 0.065) than on placebo (6.9 ml min(-1) 1.73 m(-2), p < 0.001), sparing 5.0 ml min(-1) 1.73 m(-2) (95% CI 2.3-7.7, p < 0.001). Greater preservation of estimated GFR with fenofibrate was observed with baseline hypertriacylglycerolaemia (n = 169 vs 491 without) alone, or combined with low HDL-cholesterol (n = 140 vs 520 without) and reductions of ≥ 0.48 mmol/l in triacylglycerol over the active run-in period (pre-randomisation) (n = 356 vs 303 without). Fenofibrate reduced urine albumin concentrations and hence albumin/creatinine ratio by 24% vs 11% (p < 0.001; mean difference 14% [95% CI 9-18]; p < 0.001), with 14% less progression and 18% more albuminuria regression (p < 0.001) than in participants on placebo. End-stage renal event frequency was similar (n = 21 vs 26, p = 0.48).

CONCLUSIONS/INTERPRETATION

Fenofibrate reduced albuminuria and slowed estimated GFR loss over 5 years, despite initially and reversibly increasing plasma creatinine. Fenofibrate may delay albuminuria and GFR impairment in type 2 diabetes patients. Confirmatory studies are merited.

TRIAL REGISTRATION

ISRCTN64783481.

A1C to detect diabetes in healthy adults: when should we recheck?

OBJECTIVE

To evaluate the optimal interval for rechecking A1C levels below the diagnostic threshold of 6.5% for healthy adults.

RESEARCH DESIGN AND METHODS

This was a retrospective cohort study. Participants were 16,313 apparently healthy Japanese adults not taking glucose-lowering medications at baseline. Annual A1C measures from 2005 to 2008 at the Center for Preventive Medicine, a community teaching hospital in Japan, estimated cumulative incidence of diabetes.

RESULTS

Mean age (+/-SD) of participants was 49.7 +/- 12.3 years, and 53% were male. Mean A1C at baseline was 5.4 +/- 0.5%. At 3 years, for those with A1C at baseline of <5.0%, 5.0-5.4%, 5.5-5.9%, and 6.0-6.4%, cumulative incidence (95% CI) was 0.05% (0.001-0.3), 0.05% (0.01-0.11), 1.2% (0.9-1.6), and 20% (18-23), respectively.

CONCLUSIONS

In those with an A1C <6.0%, rescreening at intervals shorter than 3 years identifies few individuals (approximately <or=1%) with an A1C >or=6.5%.

Can we rely on the best trial? A comparison of individual trials and systematic reviews

Background

The ideal evidence to answer a question about the effectiveness of treatment is a systematic review. However, for many clinical questions a systematic review will not be available, or may not be up to date. One option could be to use the evidence from an individual trial to answer the question?

Methods

We assessed how often (a) the estimated effect and (b) the p-value in the most precise single trial in a meta-analysis agreed with the whole meta-analysis. For a random sample of 200 completed Cochrane Reviews (January, 2005) we identified a primary outcome and extracted: the number of trials, the statistical weight of the most precise trial, the estimate and confidence interval for both the highest weighted trial and the meta-analysis overall. We calculated the p-value for the most precise trial and meta-analysis.

Results

Of 200 reviews, only 132 provided a meta-analysis of 2 or more trials, with a further 35 effect estimates based on single trials. The average number of trials was 7.3, with the most precise trial contributing, on average, 51% of the statistical weight to the summary estimate from the whole meta-analysis. The estimates of effect from the most precise trial and the overall meta-analyses were highly correlated (rank correlation of 0.90).

There was an 81% agreement in statistical conclusions. Results from the most precise trial were statistically significant in 60 of the 167 evaluable reviews, with 55 of the corresponding systematic reviews also being statistically significant. The five discrepant results were not strikingly different with respect to their estimates of effect, but showed considerable statistical heterogeneity between trials in these meta-analyses. However, among the 101 cases in which the most precise trial was not statistically significant, the corresponding meta-analyses yielded 31 statistically significant results.

Conclusions

Single most precise trials provided similar estimates of effects to those of the meta-analyses to which they contributed, and statistically significant results are generally in agreement. However, "negative" results were less reliable, as may be expected from single underpowered trials. For systematic reviewers we suggest that: (1) key trial(s) in a review deserve greater attention (2) systematic reviewers should check agreement of the most precise trial and the meta analysis. For clinicians using trials we suggest that when a meta-analysis is not available, a focus on the most precise trial is reasonable provided it is adequately powered.

Tonsillectomy or adeno-tonsillectomy versus non-surgical treatment for chronic/recurrent acute tonsillitis

BACKGROUND

Surgical removal of the tonsils, with or without adenoidectomy (adeno-/tonsillectomy), is a common ENT operation but the indications for surgery are controversial.

OBJECTIVES

To determine the effects of tonsillectomy, with and without adenoidectomy, in patients with chronic/recurrent acute tonsillitis.

SEARCH STRATEGY

The Cochrane Ear, Nose and Throat Disorders Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2008, issue 2), MEDLINE (1966 to 2008), EMBASE (1974 to 2008), bibliographies, and additional sources were searched for published and unpublished trials. The date of the last search was 11 April 2008.

SELECTION CRITERIA

Randomised controlled trials comparing tonsillectomy, with or without adenoidectomy, with non-surgical treatment in adults and children with chronic/recurrent acute tonsillitis. We included trials which used reduction in the number and severity of tonsillitis and sore throat as main outcome measures.

DATA COLLECTION AND ANALYSIS

Two authors applied the inclusion/exclusion criteria independently.

MAIN RESULTS

This review includes five studies: four undertaken in children (719 participants) and one in adults (70 participants). Good information about the effects of tonsillectomy is only available for children and for effects in the first year following surgery.Children were divided into two subgroups: those who are severely affected (based on specific criteria which are often referred to as the 'Paradise criteria') and those less severely affected.For more severely affected children adeno-/tonsillectomy will avoid three unpredictable episodes of any type of sore throat, including one episode of moderate or severe sore throat in the next year. The cost of this is a predictable episode of pain in the immediate postoperative period.Less severely affected children may never have had another severe sore throat anyway and the chance of them so doing is modestly reduced by adeno-/tonsillectomy. For them, surgery will mean having an average of two rather than three unpredictable episodes of any type of sore throat. The cost of this reduction is one inevitable and predictable episode of postoperative pain. The 'average' patient will have 17 rather than 22 sore throat days but some of these 17 days (between five and seven) will be in the immediate postoperative period. Whilst the concept of the 'average' patient is attractive, in practice, wide variability is likely.One reason why the impact of surgery is so modest, is that many untreated patients get better spontaneously. There is a trade-off for the physician and patient who must weigh up a number of different uncertainties: what proportion of my throat symptoms are attributable to my tonsils, and will I get better without any treatment? Similarly, the potential 'benefit' of surgery must be weighed against the risks of the procedure.

AUTHORS' CONCLUSIONS

Adeno-/tonsillectomy is effective in reducing the number of episodes of sore throat and days with sore throats in children, the gain being more marked in those most severely affected. The size of the effect is modest, but there may be a benefit to knowing the precise timing of one episode of pain lasting several days - it occurs immediately after surgery as a direct consequence of it.It is clear that some children get better without any surgery, and that whilst removing the tonsils will always prevent 'tonsillitis', the impact of the procedure on 'sore throats' due to pharyngitis is much less predictable.

WITHDRAWN: Advice on low-fat diets for obesity

BACKGROUND

Overweight and obesity are global health problems contributing to an ever increasing noncommunicable disease burden. Calorie restriction can achieve short-term weight loss but the weight loss has not been shown to be sustainable in the long-term. An alternative approach to calorie restriction is to lower the fat content of the diet. However, the long-term effects of fat-restricted diets on weight loss have not been established.

OBJECTIVES

To assess the effects of advice on low-fat diets as a means of achieving sustained weight loss, using all available randomised clinical trials. This review focused primarily on participants who were overweight or clinically obese and were dieting for the purpose of weight reduction. Since we were particularly interested in the ability of participants to sustain weight loss over a longer period of time, we focused on studies of 'free living' men and women who were given dietary advice rather than provision of food or money to purchase food.

SEARCH STRATEGY

We searched the Cochrane Controlled Trials Register (Cochrane Library Issue 2, 2001), MEDLINE (up to February 2002), and EMBASE (up to February 2002). We also searched the Science Citation Index (up to January 2001) and bibliographies of studies identified. Date of latest search: February 2002.

SELECTION CRITERIA

Trials were included if they fulfilled the following criteria: 1) they were randomised controlled clinical trials of low-fat diets versus other weight-reducing diets, 2) the primary purpose of the study was weight loss, 3) participants were followed for at least six months, 4) the study participants were adults (18 years or older) who were overweight or obese (BMI >25 kg/m2) at baseline. Studies including pregnant women or patients with serious medical conditions were excluded. Two people independently applied the inclusion criteria to the studies identified. Disagreement was resolved by discussion or by intervention of a third party.

DATA COLLECTION AND ANALYSIS

Data were extracted by three independent reviewers and meta-analysis performed using a random effects model. Weighted mean differences of weight loss were calculated for treatment and control groups at 6, 12 and 18 months.

MAIN RESULTS

Four studies were included at the six month follow-up, five studies at the 12 month follow-up and three studies at the 18 month follow-up. There was no significant difference in weight loss between the two groups at six months (WMD 1.7 kg, 95% CI -1.4 to 4.8 kg). The weighted sum of weight loss in the low fat group was -5.08 kg (95% CI -5.9 to -4.3 kg) and in the control group was -6.5 kg, (95% CI -7.3 to -5.7 kg). There was no significant difference in weight loss between the two groups at 12 months (WMD 1.1 kg, 95% CI -1.6 to 3.8 kg). The weighted sum of weight loss in the low fat group was -2.3 kg (95% CI -3.2 to -1.4 kg) and in the control group was -3.4 kg (95% CI -4.2 to -2.6 kg). There was no significant difference in weight loss between the two groups at 18 months (WMD 3.7 kg, 95% CI - 1.8 to 9.2). The weighted sum of weight loss in the control group was -2.3 kg (95% CI -3.5 to -1.2 kg) and in the low fat group there was a weight gain of 0.1 kg (95% CI -0.8 to 1 kg). There was significant heterogeneity in the results for weight loss at six months and 12 months. Apart from one study which showed a slight but statistically significant difference in total cholesterol in the low fat group at one year follow-up, there were no significant differences between the dietary groups for other outcome measures such as serum lipids, blood pressure and fasting plasma glucose. Studies measuring other factors such as perceived wellness and quality of life reported conflicting results.

AUTHORS' CONCLUSIONS

The review suggests that fat-restricted diets are no better than calorie restricted diets in achieving long term weight loss in overweight or obese people. Overall, participants lost slightly more weight on the control diets but this was not significantly different from the weight loss achieved through dietary fat restriction and was so small as to be clinically insignificant.

Antibiotic therapy to prevent the development of asymptomatic middle ear effusion in children with acute otitis media: a meta-analysis of individual patient data

OBJECTIVES

To determine predictors of the development of asymptomatic middle ear effusion (MEE) in children with acute otitis media (AOM) and to assess the effect of antibiotic therapy in preventing the development of MEE in these children.

DATA SOURCES

A systematic literature search was performed using PubMed, EMBASE, the Cochrane databases, and the proceedings of international otitis media symposia.

STUDY SELECTION

A trial was selected if the allocation of participants to treatment was randomized, children aged 0 to 12 years with AOM were included, the comparison was between antibiotic therapy and placebo or no (antibiotic) treatment, and MEE at 1 month was measured.

DATA EXTRACTION

Data from 5 randomized controlled trials were included in the meta-analysis of individual patient data (1328 children aged 6 months to 12 years). We identified independent predictors of the development of asymptomatic MEE and studied whether these children benefited more from antibiotic therapy than children with a lower risk. The primary outcome was MEE (defined as a type B tympanogram) at 1 month.

DATA SYNTHESIS

The overall relative risk of antibiotic therapy in preventing the development of asymptomatic MEE after 1 month was 0.9 (95% confidence interval, 0.8-1.0; P =.19). Independent predictors of the development of asymptomatic MEE were age younger than 2 years and recurrent AOM. No statistically significant interaction effects with treatment were found.

CONCLUSION

Because of a marginal effect of antibiotic therapy on the development of asymptomatic MEE and the known negative effects of prescribing antibiotics, including the development of antibiotic resistance and adverse effects, we do not recommend prescribing antibiotics to prevent MEE.

Monitoring cholesterol levels: measurement error or true change?

BACKGROUND

Cholesterol level monitoring is a common clinical activity, but the optimal monitoring interval is unknown and practice varies.

OBJECTIVE

To estimate, in patients receiving cholesterol-lowering medication, the variation in initial response to treatment, the long-term drift from initial response, and the detectability of long-term changes in on-treatment cholesterol level ("signal") given short-term, within-person variation ("noise").

DESIGN

Analysis of cholesterol measurement data in the LIPID (Long-Term Intervention with Pravastatin in Ischaemic Disease) study.

SETTING

Randomized, placebo-controlled trial in Australia and New Zealand (June 1990 to May 1997).

PATIENTS

9014 patients with past coronary heart disease who were randomly assigned to receive pravastatin or placebo.

MEASUREMENTS

Serial cholesterol concentrations at randomization, 6 months, and 12 months, and then annually to 5 years.

RESULTS

Both the placebo and pravastatin groups showed small increases in within-person variability over time. The estimated within-person SD increased from 0.40 mmol/L (15 mg/dL) (coefficient of variation, 7%) to 0.60 mmol/L (23 mg/dL) (coefficient of variation, 11%), but it took almost 4 years for the long-term variation to exceed the short-term variation. This slow increase in variation and the modest increase in mean cholesterol level, about 2% per year, suggest that most of the variation in the study is due to short-term biological and analytic variability. Our calculations suggest that, for patients with levels that are 0.5 mmol/L or more (> or =19 mg/dL) under target, monitoring is likely to detect many more false-positive results than true-positive results for at least the first 3 years after treatment has commenced.

LIMITATIONS

Patients may respond differently to agents other than pravastatin. Future values for nonadherent patients were imputed.

CONCLUSION

The signal-noise ratio in cholesterol level monitoring is weak. The signal of a small increase in cholesterol level is difficult to detect against the background of a short-term variability of 7%. In annual rechecks in adherent patients, many apparent increases in cholesterol level may be false positive. Independent of the office visit schedule, the interval for monitoring patients who are receiving stable cholesterol-lowering treatment could be lengthened.

A systematic review of analytical methods used to study subgroups in (individual patient data) meta-analyses

OBJECTIVES

To determine whether individual patient data meta-analyses (IPDMA) are used to perform subgroup analyses and to study whether the analytical methods regarding subgroup analyses differ between IPDMA and conventional meta-analyses (CMA).

STUDY DESIGN AND SETTING

IPDMA were identified with a comprehensive literature search, subsequently, CMA on similar research questions were traced. Methods for studying subgroups were compared for IPDMA and CMA that were matched with respect to domain, type of treatment, and outcome measure.

RESULTS

Of all 171 identified IPDMA and 102 CMA, 80% and 45% presented subgroup analyses, respectively. For 35 IPDMA and 37 "matched" CMA, subgroup analytic methods could be compared. The number of performed subgroup analyses did not differ between IPDMA and CMA. Both IPDMA and CMA often do not report adequate information on methods of analyses. Interaction tests were often not performed in IPDMA (69%) and individual patient data was often not directly modelled (74%).

CONCLUSION

Many IPDMA performed subgroup analyses, but overall treatment effects were more emphasized than subgroup effects. To study subgroups, a wide variety of analytical methods was used in both IPDMA and CMA. In general, the use and reporting of appropriate methods for subgroup analyses should be promoted. Recommendations for improvement of methods of analyses are provided.

Antibiotics for sore throat

BACKGROUND

Sore throat is a very common reason for people to present for medical care. Although it remits spontaneously, primary care doctors commonly prescribe antibiotics for it.

OBJECTIVES

To assess the benefits of antibiotics for sore throat.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) and the Database of Abstracts of Reviews of Effects (DARE) (The Cochrane Library, Issue 1, 2006), MEDLINE (January 1966 to March 2006) and EMBASE (January 1990 to December 2005).

SELECTION CRITERIA

Trials of antibiotic against control with either measures of the typical symptoms (throat soreness, headache or fever), or suppurative or non-suppurative complications of sore throat.

DATA COLLECTION AND ANALYSIS

Potential studies were screened independently by two authors for inclusion, with differences in opinion resolved by discussion. Data were then independently extracted from studies selected by inclusion by two authors. Researchers from three studies were contacted for additional information.

MAIN RESULTS

There were 27 studies with 2835 cases of sore throat. 1. Non-suppurative complications: There was a trend for antibiotics to protect against acute glomerulonephritis, but there were insufficient cases to be sure. Several studies found antibiotics reduced acute rheumatic fever by more than two thirds (relative risk (RR) 0.22; 95% CI 0.02 to 2.08). 2. Suppurative complications: Antibiotics reduced the incidence of acute otitis media (RR 0.30; 95% CI 0.15 to 0.58); of acute sinusitis (RR 0.48; 95% CI 0.08 to 2.76); and of quinsy (peritonsillar abscess) compared to those taking placebo (RR 0.15; 95% CI 0.05 to 0.47). 3.

SYMPTOMS

Throat soreness and fever were reduced by antibiotics by about one half. The greatest difference was seen at about 3 to 4 days (when the symptoms of about 50% of untreated patients had settled). By one week about 90% of treated and untreated patients were symptom-free. The overall number need to treat to prevent one sore throat at day 3 was just under six (95% CI 4.9 to 7.0); at week 1 it was 21 (95% CI 13.2 to 47.9). 4. Subgroup analyses of symptom reduction: Analysis by: age; blind versus unblinded; or use of antipyretics, found no significant differences. Analysis of results of throat swabs showed that antibiotics were more effective against symptoms at day 3, RR 0.58 (95% CI 0.48 to 0.71) if the swabs were positive for Streptococcus, compared to RR 0.78 (95% CI 0.63 to 0.97) if negative. Similarly at week 1, RRs 0.29 (95% CI 0.12 to 0.70) for positive, and 0.73 (95% CI 0.50 to 1.07) for negative swabs.

AUTHORS' CONCLUSIONS

Antibiotics confer relative benefits in the treatment of sore throat. However, the absolute benefits are modest. Protecting sore throat sufferers against suppurative and non-suppurative complications in modern Western society can only be achieved by treating many with antibiotics, most of whom will derive no benefit. In emerging economies (where rates of acute rheumatic fever are high, for example), the number needed to treat may be much lower for antibiotics to be considered effective. Antibiotics shorten the duration of symptoms by about sixteen hours overall.

Identifying studies for systematic reviews of diagnostic tests was difficult due to the poor sensitivity and precision of methodologic filters and the lack of information in the abstract

BACKGROUND AND OBJECTIVES

Methods to identify studies for systematic reviews of diagnostic accuracy are less well developed than for reviews of intervention studies. This study assessed (1) the sensitivity and precision of five published search strategies and (2) the reliability and accuracy of reviewers screening the results of the search strategy.

METHODS

We compared the results of the search filters with the studies included in two systematic reviews, and assessed the interobserver reliability of two reviewers screening the list of articles generated by a search strategy.

RESULTS

In the first review, the search strategy published by van der Weijden had the greatest sensitivity, and in the second, four search strategies had 100% sensitivity. There was "substantial" agreement between two reviewers, but in the first review each reviewer working on their own would have missed one paper eligible for inclusion in the review. Ascertainment intersection techniques indicate that it is unlikely that further papers have been missed in the screening process.

CONCLUSION

Published search strategies may miss papers for reviews of diagnostic test accuracy. Papers are not easily identified as studies of diagnostic test accuracy, and the lack of information in the abstract makes it difficult to assess the eligibility for inclusion in a systematic review.

Do individualized medication effectiveness tests (n-of-1 trials) change clinical decisions about which drugs to use for osteoarthritis and chronic pain?

To assess the impact of individualized medication effectiveness tests (IMETs, or n-of-1 trials), on patients' short-term decision making about medications for chronic pain. Survey evaluation of patients undergoing a double-blind, crossover comparison of drug versus placebo, drug versus drug, or drug versus drug combination using paracetamol and ibuprofen in 3 pairs of treatment periods, randomized within pairs. General practice patients (supplemented by a few from 2 tertiary pain clinics) with either chronic pain (> or =3 months), or osteoarthritis (with pain for > or =1 month) severe enough to warrant consideration of long-term nonsteroidal antiinflammatory drug (NSAID) use but for whom there was doubt about the efficacy of NSAID or alternative. Pain and stiffness in sites nominated by the patient, global pain, use of escape analgesia, and side effects. Of 116 IMETs started, 71 were completed. Drug management changed for 46 of 71 (65%). The most common change was to add paracetamol or to substitute the NSAID or COX-2 inhibitor with paracetamol (25 of 71 patients and 54% of changes). Of the 37 who were using NSAIDs or COX-2 inhibitors before the IMET, 12 (32%) ceased these afterward. Paracetamol was as effective or more effective than ibuprofen in 37 (68%) of the 54 IMETs directly comparing these drugs. IMETs provide useful information for clinical decisions. Paracetamol continues to be useful for patients with chronic pain whose optimal drug choice is in doubt. Our results provide a new (individual) perspective on the well-known recommendation for paracetamol as first-line treatment for chronic pain and demonstrate that it is feasible to provide IMETs nationally by mail and telephone.

A systematic review of the diagnostic accuracy of natriuretic peptides for heart failure

BACKGROUND

The diagnosis of heart failure is difficult, with both overdiagnosis and underdiagnosis occurring commonly in practice. Natriuretic peptides have been proposed as a possible test for assisting diagnosis. We assessed the diagnostic accuracy of brain natriuretic peptide (BNP), including a comparison with atrial natriuretic peptide (ANP).

METHODS

Electronic searches were conducted of MEDLINE and EMBASE from January 1994 to December 2002 and handsearches of reference lists of included studies. We included studies that assessed the diagnostic accuracy of BNP against echocardiographic or clinical criteria or that compared the diagnostic accuracy of BNP with ANP. Two reviewers assessed studies for inclusion and quality and extracted the relevant data. A meta-analysis was performed by pooling the diagnostic odds ratios for studies that used a common reference standard.

RESULTS

Twenty studies were included. For the 8 studies (n = 4086) that measured BNP against the criterion of left ventricular ejection fraction of 40% or less (or equivalent), the pooled diagnostic odds ratio was 11.6 (95% confidence interval, 8.4-16.1). The pooled diagnostic odds ratio was greater, 30.9 (95% confidence interval, 27.0-35.4), in the 7 studies (n = 2374) that measured BNP against clinical criteria (generally a consensus view using all other clinical information). The diagnostic odds ratio was similar in studies conducted in general practice and in hospital settings. Three studies compared BNP with N-terminal-ANP, a precursor form of ANP, and pooling of the results of these studies showed BNP to be a more accurate marker of heart failure than NT-ANP.

CONCLUSIONS

Brain natriuretic peptide is an accurate marker of heart failure. Use of a cutoff value of 15 pmol/L achieves high sensitivity, and BNP values below this exclude heart failure in patients in whom disease is suspected. As the diagnostic odds ratio for BNP is greater when assessed against clinical criteria than against left ejection fraction alone, BNP may also be detecting patients with "diastolic" heart failure.

Resting injured limbs delays recovery: a systematic review

OBJECTIVES

Rest is commonly used as primary treatment, rather than just palliation, for injured limbs. We searched the literature for evidence of benefit or harm from immobilization or mobilization of acute limb injury in adults.

DATA SOURCES

We systematically searched for and retrieved randomized controlled trials (RCTs) of mobilization or rest for treatment of acute limb injuries, in Medline (1966-2002), EMBASE, Web of Science, and the Cochrane library, in all languages.

REVIEW METHODS

We examined patient-centered outcomes (pain, swelling, and cost), functional outcomes (range of motion, days lost from work) and complications of treatment.

RESULTS

Forty-nine trials of immobilization for soft tissue injuries and fractures of both upper and lower limbs were identified (3366 patients). All studies reported either no difference between rest and early mobilization protocols, or found in favor of early mobilization. Reported benefits of mobilization included earlier return to work; decreased pain, swelling, and stiffness; and a greater preserved range of joint motion. Early mobilization caused no increased complications, deformity or residual symptoms.

CONCLUSIONS

We should not assume any benefit for immobilization after acute upper or lower limb injuries in adults. Rest appears to be overused as a treatment. More trials are needed to identify optimal programs for early mobilization.

Valerian does not appear to reduce symptoms for patients with chronic insomnia in general practice using a series of randomised n-of-1 trials

OBJECTIVE

To investigate the effectiveness of valerian for the management of chronic insomnia in general practice.

DESIGN

Valerian versus placebo in a series of n-of-1 trials, in Queensland, Australia.

RESULTS

Of 42 enrolled patients, 24 (57%) had sufficient data for inclusion into the n-of-1 analysis. Response to valerian was fair for 23 (96%) participants evaluating their "energy level in the previous day" but poor or modest for all 24 (100%) participants' response to "total sleep time" and for 23 (96%) participants' response to "number of night awakenings" and "morning refreshment". As a group, the proportion of treatment successes ranged from 0.35 (95% CI 0.23, 0.47) to 0.55 (95% CI 0.43, 0.67) for the six elicited outcome sleep variables. There was no significant difference in the number (P=0.06), distribution (P=1.00) or severity (P=0.46) of side effects between valerian and placebo treatments.

CONCLUSIONS

Valerian was not shown to be appreciably better than placebo in promoting sleep or sleep-related factors for any individual patient or for all patients as a group.

Towards complete and accurate reporting of studies of diagnostic accuracy: the STARD initiative

OBJECTIVE

Our aim was to improve the accuracy and completeness of reporting of studies of diagnostic accuracy in order to allow readers to assess the potential for bias in a study and to evaluate the generalizability of its results.

METHODS

The Standards for Reporting of Diagnostic Accuracy (STARD) steering committee searched the literature to identify publications on the appropriate conduct and reporting of diagnostic studies and extracted potential items into an extensive list. Researchers, editors and members of professional organizations shortened this list during a 2-day consensus meeting with the goal of developing a checklist and a generic flow diagram for studies of diagnostic accuracy.

RESULTS

The search for published guidelines about diagnostic research yielded 33 previously published checklists, from which we extracted a list of 75 potential items. At the consensus meeting, participants shortened the list to a 25-item checklist, by using evidence whenever available. A prototype of a flow diagram provides information about the method of recruitment of patients, the order of test execution and the numbers of patients undergoing the test under evaluation and/or the reference standard.

CONCLUSIONS

Evaluation of research depends on complete and accurate reporting. If medical journals adopt the checklist and the flow diagram, the quality of reporting of studies of diagnostic accuracy should improve, to the advantage of clinicians, researchers, reviewers, journals and the public.

Prolotherapy injections, saline injections, and exercises for chronic low-back pain: a randomized trial

OBJECTIVES

To assess the efficacy of a prolotherapy injection and exercise protocol in the treatment of chronic nonspecific low back pain.

DESIGN

Randomized controlled trial with two-by-two factorial design, triple-blinded for injection status, and single-blinded for exercise status.

SETTING

General practice.

PARTICIPANTS

One hundred ten participants with nonspecific low-back pain of average 14 years duration were randomized to have repeated prolotherapy (20% glucose/0.2% lignocaine) or normal saline injections into tender lumbo-pelvic ligaments and randomized to perform either flexion/extension exercises or normal activity over 6 months.

MAIN OUTCOME MEASURES

Pain intensity (VAS) and disability scores (Roland-Morris) at 2.5, 4, 6, 12, and 24 months.

RESULTS

Follow-up was achieved in 96% at 12 months and 80% at 2 years. Ligament injections, with exercises and with normal activity, resulted in significant and sustained reductions in pain and disability throughout the trial, but no attributable effect was found for prolotherapy injections over saline injections or for exercises over normal activity. At 12 months, the proportions achieving more than 50% reduction in pain from baseline by injection group were glucose-lignocaine: 0.46 versus saline: 0.36. By activity group these proportions were exercise: 0.41 versus normal activity: 0.39. Corresponding proportions for >50% reduction in disability were glucose-lignocaine: 0.42 versus saline 0.36 and exercise: 0.36 versus normal activity: 0.38. There were no between group differences in any of the above measures.

CONCLUSIONS

In chronic nonspecific low-back pain, significant and sustained reductions in pain and disability occur with ligament injections, irrespective of the solution injected or the concurrent use of exercises.