[The evidence (in) the evidence-based medicine]. / Die Evidenz (in) der Evidence-Based Medicine.

Evidence-based medicine is a new approach to improve the transfer process of knowledge from research to medical practice. The assumption that only results of randomized controlled studies are evident is true for many but by far not for all clinical problems. As is demonstrated from one historical and many recent examples, there exists another but equally stringent method of proof which is based on an implicit historical comparison. This kind of evidence still has to be defined exactly in order to protect it from misuse by alternative medicine. The statement that only 20% of methods used in conventional medicine are [corrected] evidence-based cannot be substantiated. Methods and importance of meta-analyses are critically discussed as well as the meaning of the term publication bias. The new documentation- and information techniques will improve some steps in the transfer process. At the end it will be crucial whether the last step, the improvement of rationality in patient care, will be successful. This evidence still has to be demonstrated.

Angioplasty of renal arteries: a report of ten year's experience.

Report of PTA of renal arteries in 288 patients. Primary results show good to optimal dilatation of the arteries (60.6% to 78.6%). One third of all cases achieved optimal blood pressures. In about 40% antihypertensive drugs had to be administered, in about 30% blood pressure remained unchanged although PTA was effective. PTA of renal arteries is the best method of treating renal hypertension, also because of the low rate of complications.

[General insecurity, "false" and "real" security: arguments for the routine study of hospital patients for anti-HIV]. / Allgemeine Unsicherheit, "falsche" und "echte" Sicherheit: Argumente für die routinemässige Untersuchung von Krankenhauspatienten auf anti-HIV.

HIV infection has become an important risk for medical personal. Use of sufficient preventive measures with all patients and patient materials is time consuming, expensive and impracticable. In the present epidemiological situation anti-HIV testing of all hospital patients will give correct information on the presence or absence of HIV infection for 999 of 1000 patients. In addition to the increased safety of medical personal, testing will have several other advantages, some for the HIV infected persons: (1) In patients with HIV-related diseases time consuming delays in diagnosing the disease can be avoided. An earlier start of therapy will improve prognosis. (2) In HIV-infected persons a therapy can be chosen which exerts the least stress to the immune system. This may delay manifestation or progression of HIV-related diseases. (3) By medical surveillance of HIV-infected persons prophylaxis and immediate therapy of opportunistic infections is possible, which may prolong survival time. (4) Counselling of persons previously unaware of their HIV infection will slow down spread of HIV in the population. (5) Missing data on prevalence and incidence of HIV infection in different geographical areas will be available. Apart from the considerable cost reduction by reducing the use of extensive preventive measures to less than 10% of patients, routine screening of all patients is already economic if testing of 10,000 patients will prevent one single new infection by counselling of people with previously unknown HIV infection.

Alpha- and beta-adrenoceptors in hypertension. II. Platelet alpha 2- and lymphocyte beta 2-adrenoceptors in children of parents with essential hypertension. A model for the pathogenesis of the genetically determined hypertension.

To study whether changes in alpha- and beta-adrenoceptors in human essential hypertension (EHT) might be genetically determined, we assessed platelet alpha 2- and lymphocyte beta 2-adrenoceptor density in 48 normotensive children of normotensive parents (NT) and in 41 normotensive children with one EHT-parent. Both groups did not differ in age, body weight and height, blood pressure, heart rate, plasma catecholamine levels, plasma renin activity (PRA), and lymphocyte beta 2-adrenoceptor density. Platelet alpha 2-adrenoceptor density, however, was in EHT-children significantly higher than in NT-children. In NT-children, platelet alpha 2-adrenoceptors were significantly, inversely correlated with PRA, indicating that they might mirror renal alpha 2-adrenoceptors which inhibitorily regulate renin release. In contrast, in EHT-children PRA was not at all related to platelet alpha 2-adrenoceptors, suggesting an early (even in the normotensive stage) disturbance of the alpha 2-adrenoceptor-mediated regulation in renin release. From these results and those obtained in the experimental rat models of acquired hypertension, a model for the pathogenesis of the genetically determined hypertension is proposed in which a very early step in the development of hypertension is a genetically determined increase in renal alpha-adrenoceptors that causes enhanced sodium retention. This initiates a chain of events that finally results in increased peripheral vascular resistance and, hence, blood pressure. On the other hand, beta-adrenoceptor changes seem to be secondary phenomena due to the elevation in blood pressure.

Intraperitoneal heparin in peritoneal dialysis and its effect on fibrinopeptide A in plasma and dialysate.

In 6 patients on continuous ambulatory peritoneal dialysis we investigated the inhibition of intraperitoneal fibrin formation by heparin. A continuous addition of 500 U of heparin per liter dialysate was used for 52 h. In plasma no heparin activity could be detected, even 52 h after intraperitoneal administration of heparin. The fibrin formation was determined by fibrinopeptide A, a thrombin-induced split product of fibrinogen. In patients under regular continuous ambulatory peritoneal dialysis we determined the fibrinopeptide A concentrations in plasma. The values were comparable with the fibrinopeptide A concentrations measured in disseminated intravascular coagulopathy. They decreased during intraperitoneal administration of heparin from 63.2 +/- 11.8 to 4.9 +/- 1.7 ng/ml. The fibrinopeptide A concentration in the 4-hour intraperitoneal dialysate (155.8 +/- 15.7 ng/ml) decreased after heparin administration to 8.5 +/- 2.0 ng/ml and was always higher than in plasma. We conclude that 500 U heparin per liter dialysate prevents the intraperitoneal fibrin formation. The low antithrombin III concentration (0.44 +/- 0.13 mg/dl) in protein-poor dialysate seems to be sufficient to inhibit the thrombin activity after acceleration by heparin.

Changing prescription patterns: impact on costs.

The cost of treating hypertension is high. In the Federal Republic of Germany the total sales of antihypertensive compounds increased, from 1981 to 1984, from 1075 million to 1525 million DM per year, corresponding to 7.4 and 9.1%, respectively, of total drug expenditure. Economists have calculated that about two-thirds of this increase is caused by structural changes within the market, i.e. changing prescription patterns. The proportion of prescribed daily doses of reserpine combinations dropped from 52 to 34% whereas that of most other compounds increased. The approximate daily costs of treatment vary from 0.5 DM (reserpine combinations) to 2.5 DM [angiotensin converting enzyme, (ACE) inhibitors], but the decline of the cheaper compounds and their substitution by newer and more expensive drugs has resulted in additional costs of 309-328 million DM. The higher prices of the new drugs should be justified by greater benefits compared with conventional compounds. Assessment of new antihypertensive drugs should include potency, efficacy, number and quality of adverse effects, and impact on quality of life. The evaluation should be performed separately for mild and for more severe forms of hypertension. Some advantages or drawbacks of the newer drugs may be important for small subgroups only.

Urinary enzyme excretion after a single dose of phenacetin and paracetamol (acetaminophen) during antidiuresis and during water diuresis.

2 g phenacetin or paracetamol in a single oral dose were administered to five healthy persons under the conditions of antidiuresis and subsequent water diuresis. Excretion of the brush border enzyme GGT, the cytoplasm enzyme LDH, and the lysosomal enzymes, NAG and GAL, was analysed before, during and after ingestion of the analgesics. Increased excretion of LDH and GGT indicated a similar moderate damage of the tubular epithelia after phenacetin and paracetamol. The state of diuresis appeared to have no influence.

Intraperitoneal fibrin-formation and its inhibition in CAPD.

The intraperitoneal fibrin formation and its inhibition by intraperitoneal heparin (5000 U) was investigated in six patients on CAPD. The intraperitoneal heparin concentration decreased linearily from 1.78 U/ml to 1.13 U/ml during a 4-hour dwell time. The antithrombin III-concentration increased to 0.56 +/- 0.1 mg/dl, reaching 1.87% of normal plasma values. The antithrombin III-portion of total protein was 0.62% in plasma and 0.79% in dialysate. The fibrinopeptide A-concentration, a specific product of thrombin action on fibrinogen was 37.1 +/- 11.8 ng/ml in plasma (normal range: less than 2.5 ng/ml) and 153.4 +/- 16.8 ng/ml in dialysate during regular CAPD. After the addition of 5000 U heparin the fibrinopeptide A-concentration in dialysate decreased to 11.6 +/- 2.6 ng/ml during a 4-hour dwell time. In vitro experiments showed no remarkable inhibition of fibrin formation by heparin without antithrombin III in dialysate. We suggest that the fibrinopeptide A is produced intraperitoneally and the antithrombin III-concentration in dialysate is sufficient to inhibit the fibrin formation after acceleration by heparin.