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PubMed1994

If there is gold in the labeling index hills, are we digging in the right place?

Surrogate endpoint biomarkers (SEBs) are a necessary tool for cancer chemoprevention studies. However, the efficiency gain from using an SEB is purchased at a price. SEBs need to go through a developmental process, in which their behavior is understood in detail, before they can be used broadly in chemoprevention work. Examples of problems that need to be overcome are presented for labeling indices of cell proliferation. Since literature-based meta-analyses are not feasible for SEBs, a data archive is proposed in order to strengthen the development phase by pooling data across studies.

Anticarcinogenic Agents↗

PubMed1994

[Adjuvant systemic treatment of primary breast cancer].

Systemic adjuvant therapy has improved the prognosis of patients with primary breast cancer. Meta-analyses have demonstrated that approximately 1/4 of deaths can be avoided among younger women treated with multiple cytotoxic drug regimens and among older women treated with tamoxifen. However, with the treatments available today many aspects related to the optimal therapy, taking into account the physical, psychological and socio-economic consequences are still open. This review discusses some of the major open questions related to the effectiveness of the adjuvant systemic therapy in terms of its ability to reduce recurrence rate and mortality.

Breast Neoplasms↗

PubMed1994

[Cancer risk under hormone therapy].

Estrogens are not carcinogenic. They create however a milieu, which generally stimulates cell division and growth of the target organs, also in cases of existing early neoplastic changes. This growth stimulating effect is dependent on dose and duration of the estrogen effects. Low doses exert no significant influence, medium doses are stimulating, high doses inhibit carcinoma growth, if the tumor is hormone responsive. Cyclic application of a progestogen stops proliferation and induces the specific function of the target tissue. This influence is mediated through a reduction of the number of estrogen receptors, a stimulation of the transformation of estradiol to estrone, a decrease of intracellular metabolism and a reduction of blood perfusion of the target organs. Progestogens therefore act generally preventive against cancer development at the genital organs and probably also on the breast. They should therefore principally be given together with estrogens for at least 10, optimal 12 to 14 days at month. Whether the compromise to give a progestogen only every three or six month will be acting equally carcinoma preventive as the monthly medication, ist not known. In woman bearing risk factors - except proliferative mastopathy - an estrogen-progestogen substitution seems not to increase the inherent risk, rather to reduce it. However nevertheless the manifestation of genital and breast cancer occurs preponderately in women at risk. Familial-genetic immunologic, metabolic factors, weight, race, nutrition, chronic inflammation, regeneration, old age and other risks seem equally or even more important than hormonal factors. Women, who receive a long time estrogen-progestogen substitution, have a lower risk to develop endometrial and ovarian cancer. This is probably also true for mammary and colon cancer. Meta-analyses of all studies could not show so far an increased risk for mammary cancer in estrogen-progestogen substituted postmenopausal women. Women, who receive a postmenopausal long during estrogen-progestogen substitution show statistically a better prognosis of their genital and mammary cancers, if they occur, than unsubstituted controls. Following treated cervical, endometrial and ovarian cancer a strictly indicated estrogen-progestogen substitution is possible without causing drawbacks. The so far valid contraindication against estrogens in post-carcinoma patients does not longer exist. Positive influences on cure rates and survival have been described. In cases of estrogen-progestogen negative receptor mammary cancer cases a substitution is also possible. In all other cases hormones can be given after five years recidive free survival. It is recommended to prescribe not too high doses of estrogens and to combine them with an effective progestogen.(ABSTRACT TRUNCATED AT 400 WORDS)

Breast Neoplasms↗

PubMed1994

[Pharmacological control of heart rate].

Heart rate, an important risk factor of coronary mortality, is highly correlated with numerous anthropometric and biochemical variables: height, body weight and hyperlipidemia; it varies, furthermore, with smoking and age and can be modified during pharmacotherapy for hypertension. From meta-analyses on different cardiovascular treatments, given after coronary events, only the efficacy of drugs significantly reducing heart rate is borne out (beta-blockers with sympathomimetic activity, or calcium-antagonists with a prevalent vasodilatory action do not provide a protective effect). Among calcium-antagonists, while the mechanism of action is similar at the cell level (delay of opening of voltage-operated slow channels), the distribution of activity within the vascular system varies markedly. Dihydropyridines (e.g., nifedipine) exert a dominant peripheral effect, with consequent vasodilation, whereas phenylalkylamines (verapamil) have both peripheral vasorelaxant and cardiac negative chronotropic activity, because of a reduced sinus node action potential. A relative tachycardia may occur with dihydropyridines, secondary to the activation of baroreceptors; the compensatory heart mechanism operated by verapamil antagonizes this reflex tachycardia. The activity of verapamil on the atrioventricular conduction allows both a slowing of functional recovery of the channel in hyperexcitable conditions (supraventricular tachycardia), and, moreover, increased diastolic intervals, with consequent improvement of coronary flow. New molecules can selectively reduce the sinus node activity without exerting other effects (hypotensive, anti-arrhythmic). From a comparative evaluation of these molecules with verapamil, it clearly emerges how this latter can provide a more acceptable pharmacodynamic profile, both for the hypotensive activity, and also for the control of reflex tachycardia, with a consequently improvement of coronary flow.

Adrenergic beta-Antagonists↗

PubMed1994

[Benefits and costs of early detection and treatment of hypercholesterolemia].

Hypercholesterolemia is the epidemiologically most relevant parameter of hyperlipoproteinemia 1) for its high prevalence of almost 40% > = 250 mg/dl in the adult German population (30-65 years) and 2) because of a relative risk of 3 and more for coronary heart disease. An estimate of the cost to benefit relation of early diagnosis and therapy requires epidemiological, clinical, and economic analysis. A synopsis of the present scientific discussion leads to more restricted recommendations for treatment than before, i.e., limited to males aged 40-65, of high cardiovascular risk and cholesterol of at least > = 250 mg/dl. An even more conservative approach especially with regard to screening programs is not justified yet. However, careful monitoring of forthcoming trials and meta-analyses is mandated. The costs for an indicated cholesterol-lowering medication are not extreme, but there are large differences between different drugs on the German market. Overtreatment of the aged population occurs together with undertreatment of hypercholesterolemic men of medium age.

Adult↗

PubMed1995

[Phase III studies of combined chemotherapy and radiation in locally advanced non-small-cell lung cancer and limited small-cell lung cancer].

Large phase III studies for lung cancer are reviewed. In an effort to improve survival results in locally advanced inoperable non-small-cell lung cancer (NSCLC), several studies have documented survival advantage for cisplatin + vinka alkaloid followed by radiotherapy (RT) when compared with RT alone. In SCLC, meta-analyses show that thoracic radiotherapy moderately improves survival in patients who are treated with combination chemotherapy. The optimum combination of chemotherapy and radiotherapy needs to be established.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1994

Gastric alkalinization does not increase the risk of pneumonia in critically ill patients.

Nosocomial pneumonia remains an important determinant of hospital-acquired morbidity and mortality. Although therapy designed to prevent stress-induced gastritis has been effective at relieving upper gastrointestinal (GI) bleeding, the use of agents (histamine-2 receptor antagonists, antacids) that raise gastric pH have also been implicated as increasing the incidence of nosocomial pneumonia. Examination of two recently published meta-analyses investigating the role of gastric pH and nosocomial pneumonia and several individual studies show that raising gastric pH does not increase the incidence of nosocomial pneumonia. Importantly, those clinical trials that purport to show that raising gastric pH increases the incidence of nosocomial pneumonia have not been blinded studies and have failed to control for sites of enteral feeding and volume. Taken together, analysis of several clinical trials finds no compelling evidence for the concept that gastric alkalization increases the evidence of nosocomial pneumonia. Given the methodological flaws incurred in several previous studies, the optimal approach for preventing nosocomial pneumonia while preventing stress gastritis-induced upper (GI) bleeding remains to be identified.

Antacids↗

PubMed1993

Indications for selective decontamination of the digestive tract.

Controversy exists as to the utility of selective decontamination of the digestive tract (SDD) as a method of infection prevention in critically ill patients. A number of prospective randomly controlled studies and 2 meta-analyses have shown a statistically significant protective effective of SDD against nosocomial infection. Most other SDD trials have shown reductions in nosocomial infections, but these reductions have not been statistically significant. Nearly all SDD studies have shown a less clear mortality benefit, and in no trial has cost-effectiveness been critically evaluated. Side effects of SDD have been limited. Despite nearly a decade of use at some institutions, reports of antimicrobic resistance evolving with SDD and causing disease are infrequent. At this time, SDD cannot be recommended for all intensive care patients in all clinical settings. SDD may be an effective infection prevention method in intensive care units in which there is a high rate of nosocomial pneumonia and/or other infections and in the postoperative period of orthotopic liver transplantation. SDD may also be useful to eliminate resistant gram-negative bacilli colonizing patients who are at high risk for infection sequelae. When SDD is used, periodic surveillance for the emergence of resistant microorganisms is imperative.

Anti-Bacterial Agents↗

PubMed1994

Effect of physician reminders on preventive care: meta-analysis of randomized clinical trials.

The objective of this study was to assess the clinical value of the physician reminder, an information intervention, in increasing compliance for selected preventive health care measures. Meta-analysis was used to combine the quantitative evidence from randomized controlled clinical trials meeting the eligibility criteria. The trials included in this meta-analysis were conducted in a family or internal medicine clinic. Physician reminders were used in the trials to influence utilization and compliance of preventive health care activities. The use of physician reminders for preventive health care activities resulted in a homogeneous effect for the subcategories of cervical cancer screening (test for heterogeneity X2(2) = 4.122, non-significant) and tetanus immunization (test for heterogeneity X2(2) = 3.139, non-significant). Similarly, the odds ratio from the combination of evidence from the three cervical cancer screening trials was significant (1.180, 95 percent CI: 1.020 to 1.339). The resulting odds ratio from the combination of evidence from the three tetanus immunization trials was significant (2.819, 95 percent CI: 2.664 to 2.975). The results of the meta-analyses for cervical cancer screening and tetanus immunizations indicate that physician reminders are an effective information intervention and can improve compliance for these two preventive health care procedures. Based on the results of this meta-analysis, further trials testing the effect of physician reminders on tetanus immunization would be unnecessary and probably unethical.

Female↗

PubMed1994

Meta-analysis of hydroxyethylrutosides in the treatment of chronic venous insufficiency.

The efficacy of O-(beta-hydroxyethyl)-rutosides (HR) in chronic venous insufficiency (CVI) was assessed by using a meta-analysis on the basis of randomized trials. Analyzed parameters were clinical symptoms related to CVI, i.e. pain of the legs, nocturnal cramps, tired legs, swelling sensations and restless legs. The treatments had to be administered for at least 4 weeks and the average HR dose chosen was 1000 mg/day. On a total of 21 evaluated trials, 15 were selected that included 1973 patients. The placebo-treated group showed a significant (p < 0.01) improvement of patients (i.e., disappearance of the symptoms) as follows: pain 27%, cramps 26%, tired legs 22%, swelling 35% and restless legs 26%. Compared to placebo, the mean additional improvement in favour of HR was 11% for pains, 12% for cramps, 12% for restless legs, 14% for swelling and 24% for tired legs. All these improvements were significant (p < 0.01). The results were robust and stood up to the treatment effect to all meta-analyses across subgroups of randomized clinical trials. In conclusion, this meta-analysis shows that, despite the high response rate to placebo therapy, the effect of HR therapy is significantly superior in the treatment of symptoms related to CVI.

Adult↗

PubMedDate not supplied

Meta-analysis in the evaluation of treatment for streptococcal pharyngitis: a review.

Penicillin has been first-line therapy for the treatment of streptococcal pharyngitis for more than 40 years. Since the 1980s, there have been a number of reports suggesting that bacteriologic failure rates with penicillin may be rising. A number of alternative therapies have been proposed, including oral cephalosporins. To evaluate the efficacy of these agents, two meta-analyses have recently been performed. In the meta-analysis performed by Pichichero and Margolis, oral cephalosporins were reported to achieve a significantly greater bacteriologic cure rate than penicillin (92% with cephalosporins vs 84% with penicillin, P < 0.0001) when results from 19 studies were analyzed. A separate meta-analysis performed by Deeter et al reported that the oral cephalosporin cefadroxil monohydrate achieved significantly greater bacteriologic cure rates (94.8% cefadroxil vs 87.5% penicillin, P < 0.05) than oral penicillin when 9 trials in 1406 patients with streptococcal pharyngitis were analyzed. A review of 65 studies of the use of penicillin for the treatment of streptococcal pharyngitis has shown that bacteriologic failure rates in the period 1980 to 1993 were approximately 12% to 13%, slightly but not significantly greater than during the period 1953 through 1979. Oral cephalosporins such as cefadroxil monohydrate provide reasonable alternatives for the treatment of streptococcal pharyngitis.

Administration, Oral↗

PubMed1994

[Research in psychotherapy].

Psychotherapy is an empirical discipline and is therefore open to exact investigations which is one of the prerequisites of its further development. The beginnings of exact research are associated with the names of H. J. Eysenck and C. R. Rogers. The contemporary research based frequently on the generic model of psychotherapy whose authors are D. E. Orlinsky and K. J. Howard is concerned in particular with the effectiveness of psychotherapy; it compares the action of different procedures, deals with differentiated indications and "mechanisms" inducing changes. The most frequent research strategies are an experimental approach, comparative (correlating) research and intensive research strategy. The most important source of information on research are meta-analyses which make it possible to summarize and compare an unlimited amount of mutually independent investigations. The hitherto most extensive meta-analytic processing of research projects was implemented in the Institute of Psychology of Bern University headed by K. Graw. It was revealed among others that psychotherapy exerts a very differentiated action and that in neurotic patients and patients with personality disorders cognitive behavioural psychotherapy, Rogers psychotherapy and psychoanalytic psychotherapy, cca 100 sessions, proves definitely effective. Close to the criterium of objectively effective psychotherapy is also shape psychotherapy and systematically oriented family therapy. In the Czech Republic research is conducted on a small scale but the work is demanding as regards methods and is of a high standard. Exact research of the psychotherapeutic process and therapeutic results contributes to the gradual shaping of a psychotherapeutic model which is internally differentiated and which integrates verified findings of various psychotherapeutic schools and trends.

Humans↗

PubMed1994

[From clinical trials to routine treatment. General aspects of clinical trials in cardiovascular diseases].

The first of two articles deals with general aspects of clinical cardiological research: hard end points -mortality and morbidity-in relation to intermediate end points, power of clinical studies, multicentre studies, meta-analyses, and the relationship between the trial population and the total patient population. The article takes up the kind of problems that are addressed in clinical research, and the relationship between the medical profession and the pharmaceutical industry. The author discusses the situation as regards clinical research in Norway, and emphasizes the need for greater efforts in this field.

Cardiovascular Diseases↗

PubMed1993

A study to determine the efficacy and safety of tenoxicam versus piroxicam, diclofenac and indomethacin in patients with osteoarthritis: a meta-analysis.

OBJECTIVE: To obtain a better quantitative and qualitative estimate of the effect of tenoxicam (Tx) compared to piroxicam (Px), diclofenac (Dcl) and indomethacin (Ind) in the treatment of osteoarthritis (OA). METHODS: Relevant studies were identified using computerized Medline search, manual search of cited references and correspondence with investigators, colleagues and the manufacturer of Tx. Once the studies were selected and chosen on the basis of predetermined methodologic criteria, the required data were extracted by 2 authors, independently. Eighteen studies met the required eligibility criteria. Meta-analyses were undertaken on 12 studies of Tx vs Px, 3 studies of Tx vs Dcl, and 2 studies of Tx vs Ind. Efficacy was measured in 2 ways: (1) physician global rating scale and (2) pain scale. Safety was measured in 3 ways: (1) physician global rating scale, (2) number of patients with adverse events, and (3) dropouts due to adverse events. RESULTS: The following findings of the meta-analysis were statistically significant: In Tx vs Px comparisons, efficacy-(1), safety-(1) and safety-(3) were all better with Tx; in Tx vs Ind comparisons, safety-(1) and safety-(2) were better with Tx. All other findings showed no statistically significant differences between Tx and the comparison drug. CONCLUSIONS: Compared to Px, Tx performs better on physician assessment of efficacy and tolerability, but the other comparisons remain inconclusive. Compared to Dcl, there appears not to be a difference. Compared to Ind, Tx is safer.

Aged↗

PubMed1994

Meta-analysis in dental research: a paradigm for performance and interpretation.

Applications of meta-analysis have begun to appear with some regularity in the dental research literature. Recently, a meta-analysis played a high-profile role in the ongoing academic debate concerning the relative anticaries efficacy of dentifrices containing fluoride as sodium fluoride and as sodium monofluorophosphate, engendering a controversy concerning the methodology employed. This has given rise to the need for a careful consideration of the principles involved in the meta-analytic process to provide a basis of understanding upon which such controversies may be resolved. The present report endeavors to meet this need by enumerating the steps involved in a meta-analysis, and contrasting them with the analogous steps in the more widely-understood "usual" inferential process, bringing to light both the similarities and differences between these two types of analyses. Within this context, the conflicting meta-analyses associated with the current controversy are discussed and compared, and the source of the difference between them is readily identified. This process reaffirms the need for close collaboration between statisticians and other scientists in the performance of a meta-analysis, and the value of such close collaboration in the evaluation and interpretation of a meta-analysis performed by others, as well.

Dental Caries↗

PubMedDate not supplied

[Hypercholesterolemia: to treat or not to treat? That is the question].

Numerous epidemiological studies have confirmed the positive correlation of elevated serum cholesterol levels to increased coronary risk. Clinical and angiographical trials have shown that modification of hypercholesterolaemia by diet or drugs can lower cardiovascular morbidity and mortality. No good evidence exists that lowering serum cholesterol is harmful. In some meta-analyses enhancing statistical power, total mortality appears to be decreased in primary prevention trials if hypercholesterolaemia is sufficiently reduced. Current guidelines for cholesterol modification should include the primary prevention with identification of individuals at high risk, combined with population information, and the secondary prevention for the patients with symptomatic coronary heart disease.

Age Factors↗

PubMedDate not supplied

1992 Bonica Lecture. Advances in chronic pain management since gate control.

OBJECTIVE: Two pain treatment systems that developed soon after the publication of the gate theory are probably a direct result of its publication: neuraxial opiate administration and electrical stimulation of the spinal cord and peripheral nerves and receptors. Although the use of these modalities has become widespread in managing chronic pain, there is disagreement about their long-term efficacy. This presentation will attempt to review the data regarding the mechanisms of action of these modalities and their efficacy in treating chronic pain of malignant and nonmalignant origin. DATA SOURCES: Data were derived almost entirely from original articles reporting experimental data from both animal and human studies and from series of patients undergoing treatment with the modalities reviewed. STUDY SELECTION: Where possible, controlled studies were selected. However, much of the available data regarding treatment results are uncontrolled. DATA EXTRACTION AND SYNTHESIS: Selected data from studies that were felt to be reasonably well conducted are presented or summarized. Because of the lack of control groups in many of the clinical trials, meta-analyses were not carried out. CONCLUSIONS: Long-term spinal opiate administration has been shown to be more effective than systemic opiates in some patients with cancer pain, but often must be combined with local anesthetics to provide satisfactory pain relief. Loss of effect over time is a significant problem. Since the identification of spinal opiate receptors and the introduction of spinally administered narcotics, a number of other receptors that are important in both sensitization and suppression of pain projection systems have been characterized. Agonists and antagonists to many of these receptors are being developed, and a few are available for clinical trials. Long-term electrical stimulation of the spinal cord produces substantial analgesia below the stimulated spinal segments in some patients with chronic pain. Although initial results are usually encouraging, long-term efficacy may be disappointing. It is postulated that analgesia associated with spinal stimulation is associated with both stimulation of large fiber ascending tracts and blockade of spinothalamic pathways. Transcutaneous electrical nerve stimulation (TENS) has come into widespread use in managing chronic pain and has had limited trials in cancer pain patients. It is well accepted by patients and physicians, but clinical studies of long-term efficacy have yielded variable results. The analgesic action is probably the result of both large afferent fiber activation and blockade of peripheral nociceptors.

Adrenergic alpha-Agonists↗

PubMed1993

[Antihypertensive treatment and left ventricular hypertrophy].

Left ventricular hypertrophy in arterial hypertension can be considered as an adaptive response of the heart to the increased afterload, in order to reduce wall stress; however, cardiac hypertrophy can also represent the first step toward a pathological process that leads to the development of congestive heart failure. Epidemiological studies have documented that left ventricular hypertrophy in essential hypertension represents an independent risk factor for cardiovascular morbidity and mortality. The possibility of reversing, or even preventing, left ventricular hypertrophy through a reduction in elevated blood pressure values and modification of some other pathogenetic factors should represent a major therapeutic need in the treatment of hypertensive patients. It has been demonstrated that different classes of antihypertensive drugs do not have the same effect in reducing left ventricular mass, probably because beyond control of blood pressure, the pharmacological interference with adrenergic system, the renin-angiotensin-aldosterone system or other growth factors can influence the development and the reduction of cardiac hypertrophy. Two recent meta-analyses of the principal regression studies have shown that ACE-inhibitors, followed by calcium antagonists and drugs capable of reducing sympathetic nervous system activity, are more effective in decreasing left ventricular mass. The results of experimental and clinical studies have demonstrated that the reversal of cardiac hypertrophy is associated with an improvement of the functional consequences of an increased left ventricular mass. Further studies are needed in order to verify whether the reversal of left ventricular hypertrophy per se increases survival in essential hypertensive patients.

Adaptation, Physiological↗