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PubMed1996

Controversies: synthetic or natural surfactant treatment for respiratory distress syndrome? The case for synthetic surfactant.

The choice of surfactant for prophylactic or "rescue" treatment of RDS is dependent on a number of different considerations: a) Randomised controlled trials have shown that natural and synthetic surfactants increase survival whether used prophylactically or as rescue. No statistically significant difference in mortality has been shown when the two types of surfactant have been compared in randomised trials. b) Possible adverse effects of surfactant treatment include: (i) Intraventricular haemorrhage (IVH). Two randomised trials of natural surfactant have shown a significant increase in IVH with natural surfactant treatment. In meta-analyses, IVH has not been significantly reduced despite decreased mortality. Acute changes in cerebral haemodynamics and EEG have been demonstrated following natural surfactant administration. These changes are less marked or absent with synthetic surfactant. (ii) The antigenicity of animal surfactant has not been shown to have clinical consequences. (iii) Prions are infectious particle (resistant to some sterilising techniques) which are responsible for slow encephalopathies, some of which have crossed species barriers. Contamination of bovine surfactant with prion particles from nervous tissue has been a theoretical concern. Synthetic surfactant has no risk of prion contamination. (iv) One natural surfactant has been shown to contain platelet activating factor (PAF). Synthetic surfactants can be made with greater chemical purity. c) Natural surfactants improve oxygenation faster than do synthetic surfactants. A rapid effect is not necessarily better with respect to later outcomes. d) Synthetic surfactant preparations are generally cheaper per dose than natural surfactant preparations. Synthetic surfactant treatment increases survival with less concern about adverse effects and generally lower cost per dose than natural surfactant.

Cerebrovascular Circulation↗

PubMed1996

Infection and prematurity: evidence-based approaches.

The real cost savings arising from effectively preventing or treating preterm birth ascribable to prevalent reproductive tract infections are demonstrated in the lives of children saved from premature death and personal, biologic and economic impairment. Three meta-analyses demonstrate neonatal and maternal benefits from adjunctive antibiotic treatment of mothers suffering preterm premature rupture of membranes. The effects of adjunctive antibiotic treatment of women with preterm labor are inconsistent, but single-agent regimens using erythromycin and clindamycin are effective and provide coverage for group B streptococcus. Providers and payers now have evidence-based, clinically proven and cost-saving opportunities to prevent important numbers of preterm births, as well as preventing individual children suffering from being 'born too soon'.

Anti-Bacterial Agents↗

PubMed1996

Who needs antiplatelet therapy?

A series of overviews or meta-analyses of randomized clinical trials prepared by the Antiplatelet Trialists' Collaboration were published in the British Medical Journal in January 1994. They demonstrated that prolonged courses of medium-dose aspirin were very effective at preventing both fatal and non-fatal myocardial infarction and stroke in patients at high risk of occlusive vascular disease. The aim of this review is to provide the general practitioner with a practical guide to the use of aspirin in patients at high and low risk of occlusive vascular disease and to discuss appropriate dosages and contraindications to treatment in the light of all the recent evidence.

Aspirin↗

PubMed1996

Random versus nonrandom assignment in controlled experiments: do you get the same answer?

Psychotherapy meta-analyses commonly combine results from controlled experiments that use random and nonrandom assignment without examining whether the 2 methods give the same answer. Results from this article call this practice into question. With the use of outcome studies of marital and family therapy, 64 experiments using random assignment yielded consistently higher mean post-test effects and less variable posttest effects than 36 studies using nonrandom assignment. This difference was reduced by about half by taking into account various covariates, especially pretest effect size levels and various characteristics of control groups. The importance of this finding depends on (a) whether one is discussing meta-analysis or primary experiments, (b) how precise an answer is desired, and (c) whether some adjustment to the data from studies using nonrandom assignment is possible. It is concluded that studies using nonrandom assignment may produce acceptable approximations to results from randomized experiments under some circumstances but that reliance on results from randomized experiments as the gold standard is still well founded.

Family Therapy↗

PubMed1996

[Large trials in the secondary prevention of stroke].

To date, no drug has been demonstrated as efficacious in the treatment of acute ischemic stroke. Therefore, primary and secondary prevention play a fundamental role. Besides adequate control of risk factors, trials and meta-analyses have demonstrated that both medical and surgical therapy are effective in secondary prevention of stroke. In patients with atherothrombotic transient ischemic attack (TIA) or minor stroke and carotid stenosis > 70%, surgical therapy (endarterectomy) is the treatment of choice, while antiplatelet drugs are the elective treatment in the case of stenosis < 70%. Acetylsalicylic acid is the first choice medical treatment, but the optimal dosage is still a matter of debate. Ticlopidine has an efficacy similar to that of aspirin, but shows a certain number of side effects; recently a European study has shown the efficacy of dipyridamole, and the superiority of the combination dipyridamole-aspirin vs low-dose aspirin. In the secondary prevention of cardioembolic stroke, oral anticoagulants have higher efficacy than antiplatelet drugs, at least in selected groups of patients.

Anticoagulants↗

PubMed1996

Renal protection and angiotensin converting enzyme inhibition in microalbuminuric type I and type II diabetic patients.

BACKGROUND: Many studies have emphasized the role of antihypertensive drugs and in particular angiotension converting enzyme (ACE) inhibitors in the retardation of diabetic nephropathy. Although these studies have focused predominantly on patients with overt proteinuria, more recently a number of investigators have explored the role of ACE inhibitors in both type I and type II diabetic patients with an earlier phase of diabetic renal disease known as microalbuminuria. These agents are now being considered as renoprotective agents not only in hypertensive patients but also in those with 'normal' blood pressure. Initially, studies in type I diabetic patients showed that ACE inhibition was effective in retarding the increase in albuminuria which was observed in placebo treated groups. More recently, several multi-centre placebo controlled studies have been performed suggesting that prolonged treatment not only reduced albuminuria but also preserved renal function. The role of ACE inhibition in microalbuminuric type II diabetic patients is less well characterised although several studies have recently described beneficial effects of ACE inhibition on albuminuria and possibly on renal function. REVIEW: Although ACE inhibitors have been clearly shown to reduce urinary albumin excretion in diabetic patients, the issue as to whether they confer a specific benefit over other classes of antihypertensive agents remains controversial. Several meta-analyses have suggested that ACE inhibitors are more potent at decreasing albuminuria or proteinuria than other antihypertensive agents, for a given reduction in blood pressure. The Melbourne Diabetic Nephropathy Study Group has instituted a study which is placebo-controlled and is confined to normotensive type I and type II diabetic patients. The ACE inhibitor perindopril has been compared not only with placebo but also with the dihydropyridine calcium channel blocker, nifedipine. Preliminary analysis reveals that after 12 and 24 months of treatment, perindopril is more effective in reducing albuminuria than placebo or nifedipine. CONCLUSION: ACE inhibitors are a promising class of antihypertensive agents in diabetic patients with microalbuminuria. These drugs should be considered as first line agents in such patients, even in the absence of systemic hypertension.

Albuminuria↗

PubMed1997

Health outcomes associated with antihypertensive therapies used as first-line agents. A systematic review and meta-analysis.

OBJECTIVE: To review the scientific evidence concerning the safety and efficacy of various antihypertensive therapies used as first-line agents and evaluated in terms of major disease end points. DATA SOURCES: MEDLINE searches and previous meta-analyses for 1980 to 1995. DATA SELECTION: We selected long-term studies that assessed major disease end points as an outcome. For the meta-analysis, we chose placebo-controlled randomized trials. For randomized trials using surrogate end points such as blood pressure, we selected the largest studies that evaluated multiple drugs. Where clinical trial evidence was lacking, we relied on information from observational studies. DATA SYNTHESIS: Diuretics and beta-blockers have been evaluated in 18 long-term randomized trials. Compared with placebo, beta-blocker therapy was effective in preventing stroke (relative risk [RR], 0.71; 95% confidence interval [CI], 0.59-0.86) and congestive heart failure (RR, 0.58; 95% CI, 0.40-0.84). The findings were similar for high-dose diuretic therapy (for stroke, RR, 0.49; 95% CI, 0.39-0.62; and for congestive heart failure, RR, 0.17; 95% CI, 0.07-0.41). Low-dose diuretic therapy prevented not only stroke (RR, 0.66; 95% CI, 0.55-0.78) and congestive heart failure (RR, 0.58; 95% CI, 0.44-0.76) but also coronary disease (RR, 0.72; 95% CI, 0.61-0.85) and total mortality (RR, 0.90; 95% CI, 0.81-0.99). Although calcium channel blockers and angiotensin-converting enzyme (ACE) inhibitors reduce blood pressure in hypertensive patients, the clinical trial evidence in terms of health outcomes is meager. For several short-acting dihydropyridine calcium channel blockers, the available evidence suggests the possibility of harm. Whether the long-acting formulations and the nondihydropyridine calcium channel blockers are safe and prevent major cardiovascular events in patients with hypertension remains untested and therefore unknown. CONCLUSION: Until the results of large long-term clinical trials evaluating the effects of calcium channel blockers and ACE inhibitors on cardiovascular disease incidence are completed, the available scientific evidence provides strong support for the current national guidelines, which recommend diuretics and beta-blockers as firstline agents and low-dose therapy for all antihypertensive agents.

Adrenergic beta-Antagonists↗

PubMed1997

[Behavior and cognitive treatments for insomnia. An alternative to pharmacotherapy].

OBJECTIVE: To familiarize family physicians with cognitive and behavioural treatments for insomnia. DATA SOURCES: MEDLINE was searched from 1983 to 1995 and Psychlit from 1974 to 1995 using the key words "behaviour therapy," "cognitive therapy," "phototherapy," and "insomnia." STUDY SELECTION: We chose randomized trials and meta-analyses on the treatment of insomnia. Information was extracted on time-lag before sleep, frequency and duration of wakeful periods during the night, consumption of hynotics, and subjects' own assessment of their sleep before and after treatment. SYNTHESIS: The most effective interventions were relaxation training, sleep restriction, and stimulus control. Practising good sleeping habits was only somewhat effective and should always be used in conjunction with other interventions. CONCLUSION: Stimulus control for insomnia has been demonstrated to be effective when used by primary care physicians. Other nonpharmacologic treatments should be evaluated in a similar manner.

Behavior Therapy↗

PubMed1997

Cognitive-behavioral therapy for panic disorder: current status.

Controlled clinical trials evaluating cognitive-behavioral approaches for panic disorder are rapidly accumulating. In the aggregate, these studies suggest substantial efficacy for cognitive-behavioral approaches in both the short and long term. Summaries and meta-analyses of these results are briefly described, but new evidence is also presented indicating that, in this chronic condition, patients continue to experience some exacerbations and remissions over the long term. Current attempts to evaluate combination psychosocial and pharmacologic approaches are described as well as the beginnings of efforts to develop more powerful treatments for panic disorder with or without agoraphobia.

Alprazolam↗

PubMed1997

Updated results of the trials of screening mammography.

Most analysts agree that screening women for breast cancer can reduce the death rate by at least 25% to 30%. In 1993 the National Cancer Institute created a great deal of confusion among women and their physicians by withdrawing support for screening women aged 40 to 49 years. The controversy arose as a result of the inappropriate and scientifically insupportable analysis of data from the early results from the randomized controlled trials of screening. Despite that the trials were not designed to evaluate women aged 40 to 49 years as a separate subgroup and that they lacked the statistical power to permit legitimate analysis of this subgroup, women aged 40 to 49 years were analyzed separately, and erroneous conclusions were drawn. In an effort to justify these conclusions, other data have been analyzed improperly to try to suggest that significant screening parameters change at menopause or at the age of 50, whereas the facts do not support any abrupt change. There are no parameters such as breast density, cancer detection rate, or positive predictive value that change abruptly at age 50 or any other age. With longer follow-up of the screening trial data and the commensurately greater statistical power, the most recent meta-analyses provide statistically significant proof that screening can reduce the death rate from breast cancer for women aged 40 to 49 years by at least 24%.

Adult↗

PubMed1997

[Acute lumbar disk displacement with nerve root compression. Indications for peridural steroid injection].

The rationale and indication, but also the efficacy and limitation of lumbar epidural corticosteroid injection in patients suffering from acute lumbosacral radicular pain are explained. Epidural administration of corticosteroids with longterm effect and bupivacaine by a translumbar approach in patients suffering from acute low back pain and sciatica causes an immediate, persistent pain relief and a more prompt regression of nerve root compression compared to patients just treated by bed rest and analgesics. The state of the art is based on recent meta-analyses and the understanding of the pathophysiology of discal hernia which includes inflammation. Contemporary concepts and data from recent reviews are summarized to elucidate current recommendations and suggestions for the management of patients with acute sciatica. The postulate of an application performed by an experienced anaesthesiologist is stressed. Advantages of this invasive form of therapy include reduction of addictive analgesic drugs, decreased time of absolute immobilisation, respectively strict bed rest, and of hospitalisation.

Acute Disease↗

PubMed1996

Clinical studies of effects of nitrogen oxides in healthy and asthmatic subjects.

Traffic and cooking and heating using unventilated gas appliances are the major sources for environmental exposures to nitrogen oxides. The nitrogen oxides of importance for health effects are nitrogen dioxide (NO2), and maybe the two derivatives nitric and nitrous acid (HNO3 and HNO2). Due to this, human exposure studies on NO2 have been performed intensively during the last decades. Nitric oxide (NO) is quantitatively the major pollutant, but is not very toxic and may even be used in treatment of certain conditions of respiratory insufficience. Major lung function effects shown in humans are a decrease in the forced expiratory volume in the first second (FEV1), increased specific airway resistance (SRaw), and increased responsiveness in bronchial provocation tests. Studies have been performed primarily on healthy and asthmatic subjects, but only asthmatic subjects show these reactions at levels relevant to exposures found in indoor and outdoor environments. Other effects found in animal studies and epidemiological studies like decreased mucociliary function, increased susceptibility to infections have not been proven in humans and are therefore still on debate. Human studies have furthermore shown that antioxidants like vitamin C and E may prevent effects of NO2, which is explained by that the mechanism of NO2-action is the oxidation of airway phospholipids. A large inconsistency in the results of the studies makes it very difficult to conclude about dose-response relationships and about no observed effect levels (NOEL). Single study observations and results of meta-analyses have indicated a biphasic dose-response relationship. However, such a relationship is hard to explain and need to be investigated further. Several other explanations, e.g. the limited statistical power of the studies, may exist and will be discussed.

Asthma↗

PubMedDate not supplied

[Nifedipine and coronary insufficiency: reasons for controversy].

Meta-analyses of Furberg's original data (after correction of two minor errors) were performed using six different methods. Only three of them gave significant results at p < 0.05. The sensitivity analysis showed that taking into account some of the criticisms applied to the original meta-analysis did not change the results. When all the criticisms were considered together, the 95 per cent confidence interval of the odds ratio for mortality was [0.96; 1.31] instead of [1.06; 1.37] originally (p = 0.14 and p = 0.03 respectively), and the dose excess mortality relationship stressed by Furberg disappeared. When the selection of the studies to be entered in a meta-analysis is not straightforward, a sensitivity analysis should be performed.

Angina Pectoris↗

PubMedDate not supplied

Paradise regained: insights into coronary heart disease prevention from recent clinical trials and basic research.

Many of the uncertainties regarding the place of lipid lowering in the prevention of coronary heart disease have recently been resolved. Some of the newer findings are reviewed, and the scope for a revised clinical approach examined. The results of trials of lipid lowering, based on clinical end-points and particularly on angiographic end-points, and their meta-analyses are discussed. The close relation between coronary-angiographic and clinical outcomes is reviewed in relation to recent advances in understanding of the underlying arterial pathology, and possible underlying mechanisms are proposed. The variables predictive of progression of coronary artery disease, including nutrient intake, are examined. The management of hyperlipidaemia requires that treatment and therapeutic goals are consonant with the patient's cardiovascular risk; for this purpose, clinical and biochemical assessment of risk may be enhanced by angiographic and non-invasive methods to detect potentially-infarctogenic atherosclerotic lesions.

Anticholesteremic Agents↗

PubMed1997

The drug trials that have influenced our clinical practice in acute ischaemic stroke.

With the possible exception of aspirin, there are still no drug treatments which have been found to be so effective in randomised controlled trials, and meta-analyses of such trials, that they should be used routinely in acute ischaemic stroke. The evidence on thrombolysis is tantalising but with only about 3500 randomised patients in all the trials put together it is too early to say how, and for whom, this promising treatment should be used, particularly bearing in mind the risk of intracranial haemorrhage; the evidence so far is enough to persuade us to enter our patients into further large trials of thrombolysis but it is not enough to justify this treatment in our routine clinical practice.

Fibrinolytic Agents↗

PubMed1997

Reductase inhibitor monotherapy and stroke prevention.

BACKGROUND: Epidemiologic evidence and meta-analyses of data from early clinical trials suggest that lowering the levels of cholesterol does not reduce the events of stroke. These analyses have not included more recent clinical trials using reductase inhibitors. OBJECTIVE: To conduct a meta-analysis of the effect of reducing cholesterol levels on stroke in all reported clinical trials of primary (n = 4) and secondary (n = 8) prevention of coronary heart disease that used reductase inhibitor monotherapy and provided information on incident stroke. RESULTS: Analysis of combined data from primary and secondary prevention trials showed a highly statistically significant reduction of stroke associated with the use of reductase inhibitor monotherapy (27% reduction in stroke; P = .001). Analysis of secondary prevention trials alone disclosed a similar statistically significant effect (32% reduction in stroke; P = .001). A smaller nonsignificant reduction in stroke was noted in the primary prevention trials (15% reduction in stroke; P = .48). CONCLUSIONS: Reductase inhibitors now in use for lowering cholesterol levels are more potent and have fewer side effects than the cholesterol-lowering agents previously available. They appear to reduce stroke, most notably in patients with prevalent coronary artery disease, which may be partly due to the effects of lowering the levels of cholesterol on the progression and plaque stability of extracranial carotid atherosclerosis or the marked reduction of incident coronary heart disease associated with treatment.

Adult↗

PubMed1996

[Chemotherapy for non-small cell lung cancer].

The combination of cisplatin and either a vinca alkaloid or etoposide is one of the most effective chemotherapeutic regimens for non-small cell lung cancer. Meta-analyses of clinical trials in which cisplatin-based combination chemotherapy was compared with supportive care in patients with non-resectable non-small cell lung cancer showed that the chemotherapy reduced mortality. In the last decade, new agents, including vinorelbine, edatrexate, paclitaxel, docetaxel, irinotecan, topotecan and gemcitabine, have shown promise in the treatment of non-small cell lung cancer, and new agents combined with platinum compounds have reached the level of phase III testing. Randomized studies in which radiotherapy alone was compared with radiotherapy and cisplatin-based combination chemotherapy in patients with stage III disease showed that combined treatment can prolong survival and improve long-term outcome in patients with locally advanced non-small cell lung cancer. Recently, new agents combined with radiotherapy have been tested. Regimens in which platinum compounds are combined with new agents hold promise for more successful treatment of this disease.

Antineoplastic Agents, Phytogenic↗

PubMed1997

Diagnosis and treatment of gastrointestinal bleeding secondary to portal hypertension. American College of Gastroenterology Practice Parameters Committee.

UNLABELLED: Guidelines for clinical practice are intended to suggest preferable approaches to particular medical problems as established by interpretation and collation of scientifically valid research, derived from extensive review of published literature. When data are not available that will withstand objective scrutiny, a recommendation may be made based on a consensus of experts. Guidelines are intended to apply to the clinical situation for all physicians without regard to specialty. Guidelines are intended to be flexible, not necessarily indicating the only acceptable approach, and should be distinguished from standards of care, which are inflexible and rarely violated. Given the wide range of choices in any health care problem, the physician should select the course best suited to the individual patient and the clinical situation presented. These guidelines are developed under the auspices of the American College of Gastroenterology and its practice parameters committee. These guidelines are also approved by the governing boards of American College of Gastroenterology and Practice Parameters Committee. Expert opinion is solicited from the outset for the document. Guidelines are reviewed in depth by the committee, with participation from experienced clinicians and others in related fields. The final recommendations are based on the data available at the time of the production of the document and may be updated with pertinent scientific developments at a later time. The following guidelines are intended for adults and not for pediatric patients. OBJECTIVE: To develop practice guidelines for the management of gastrointestinal bleeding in adult patients with cirrhosis and portal hypertension. METHOD: Randomized controlled trials published through October of 1993 were evaluated by members of the American College of Gastroenterology Practice Parameters Committee. Each paper was reviewed by three members of the committee and rated for quality of design by predetermined criteria. Meta-analysis of the studies for each treatment were evaluated for both outcome and quality of design and formed the basis for recommendations for treatment. Randomized controlled trials published between October of 1993 and August of 1995 have been added to update and modify the recommendations. The reader is referred to an excellent article by D'Amico et al. (The treatment of portal hypertension: A meta-analytic review. Hepatology 1995;22:332-354), which presents most of the meta-analyses reviewed by this committee. CONCLUSIONS: Once esophageal varices have been established by endoscopy as the site of bleeding, either sclerotherapy or endoscopic variceal ligation should be performed to control the bleeding episodes. Concomitant use of vasoactive drugs lowers portal pressure, potentially offers the endoscopist a clearer field in which to work, and is the only noninvasive treatment for nonesophagogastric variceal sites of bleeding related to portal hypertension. For patients failing medical therapy, the transjugular intrahepatic portasystemic shunt procedure is a reasonable alternative to an emergency surgically created shunt. Nonselective beta-adrenergic blockers are the only proven therapy for prevention of first variceal hemorrhage. Both nonselective beta-adrenergic blockers and endoscopic variceal ligation (which has replaced sclerotherapy for this indication) are effective in reducing the risk of recurrent variceal bleeding. For patients failing these approaches, selective or total shunts or, in selected patients, liver transplantation are appropriate rescue procedures.

Acute Disease↗