[Description of long-term stays, based on PMSI data, in hospital specializing in short-term stays]

OBJECTIVE

In a context of organization of care where the budget of hospitals is a function of the number and of the severity of the in-patients and not of the duration of stay, stays of long duration (SLD) in short-stay hospitals represent a problem of both medical and administrative management. To identify the characteristics of long-duration stays.

METHODS

The data used in this retrospective study were drawn from the Standardized Discharge Summaries of the year 1997 of a University Hospital of the Paris area (France). A stay of long duration (SLD) was defined in an arbitrary way as a stay exceeding 30 days. The stays of long duration (> 30 days) were subdivided in "long stays" (from 31 to 60 days) and "very long stays" (more than 60 days).

RESULTS

The SLDs represent 3.7% of the discharge summaries of our hospital, among them, 40% are medical DRGs and 60% surgical DRGs. The patients in SLD more often come from other structures of care than the patients having a short duration stay of (SDS) coming mainly from their residence and were also hospitalised in several different units during their stay. Patients having a long stay were more often classified in DRGs outside the principal activity of this hospital (i.e. cardiovascular diseases).

CONCLUSION

This first approach suggests that a set of simple descriptive variables (pre-existing and acquired co-morbidity, admission in surgical ward, multi-unit stay...) makes it possible to identify the patients likely to have a long duration stay. Simple variables added to the current hospital minimum medical record would make it possible to consider a predictive approach.

Comparison of nurse- and physician-determined clinic blood pressure levels in patients referred to a hypertension clinic: implications for subsequent management

BACKGROUND

When measuring BP, the physician induces a transient pressor response triggered by an alarm reaction. This 'white-coat effect' can influence therapeutic decisions. Whether it depends on the characteristics of the physician has not been evaluated.

OBJECTIVE

To assess the 'white-coat effect' induced by several physicians in a large sample of patients, using the blood pressure measured by trained nurses as a reference.

SETTING

Referral hypertension clinic.

METHODS

Patients were selected for the study if they had been referred for the first time to the clinic and if they had had their supine systolic/diastolic blood pressure measured by a trained nurse (mean of the last two of three measurements taken every 1 min by an oscillometric device) and a physician (auscultatory method using a standard mercury sphygmomanometer). Physicians were included in the study provided they had seen at least 25 patients during the study period. The between-physician difference was assessed using linear regression analysis. Physician blood pressure was the dependent and nurse blood pressure was the independent variable.

RESULTS

From 1 January 1997 to 15 September 1997, 1062 patients (50% male, aged 52 +/- 14 years), seen by 10 physicians (26-187 patients per physician) and one nurse were included for analysis. The mean systolic/diastolic blood pressure for physicians was 162 +/- 27/ 97 +/- 15 mmHg and that for the nurse was 155 +/- 24/ 88 +/- 14 mmHg. The nurse-physician differences were -6 mmHg (range -67 to +66) for systolic and -8 mmHg (-44 to +31) for diastolic blood pressures. Major differences were observed between individual physicians. Intercepts of the physician blood pressure versus nurse blood pressure relationship ranged from 0.1 -60.7 mmHg for systolic and from 13.3-55.3 mmHg for diastolic pressures. The slopes of this relationship differed less between physicians for systolic (0.72-1) than for diastolic pressures (0.56-0.97). There was no difference between the patients seen by physicians in patients' age, sex, tobacco consumption, anti-hypertensive treatment or target-organ damage.

CONCLUSION

Large between-physician differences exist in the magnitude of the white-coat effect that cannot be explained by patient characteristics. Physicians should therefore not make any decisions based on blood pressure measured manually during a first encounter.

Association between high von willebrand factor levels and the Thr789Ala vWF gene polymorphism but not with nephropathy in type I diabetes. The GENEDIAB Study Group and the DESIR Study Group

BACKGROUND

A genetic susceptibility for diabetic kidney disease is suspected since diabetic nephropathy occurs in only 30 to 40% of type I diabetic patients. As elevated von Willebrand factor (vWF) plasma concentrations have been reported to precede the development of microalbuminuria in type I diabetes, we addressed a possible implication of vWF as a genetic determinant for diabetic nephropathy.

METHODS

Three known vWF gene polymorphisms were genotyped in a group of 493 type I diabetic subjects, all showing proliferative retinopathy, but with various stages of renal involvement, which ranged from no microalbuminuria, despite a mean duration of diabetes of 31 years, to advanced nephropathy (GENEDIAB Study): Thr789Ala (Rsa I), M-/M+ (Msp I) (intron 19), and Ala1381Thr (Hph I). Plasma vWF and factor VIII (F VIII) levels were also measured in this population.

RESULTS

Plasma vWF and F VIII levels were increased in diabetic subjects with nephropathy (P < 0.001) or with coronary heart disease (CHD; P < 0.001), but there was no interaction of both conditions on plasma levels. The Msp I polymorphism (M-/M+) was weakly associated with nephropathy (P = 0. 04), but this association was not more significant when other risk factors were used in a logistic regression analysis. The vWF Thr789Ala polymorphism was associated with CHD (P = 0.002) and with plasma vWF levels. Logistic regression analysis indicated an independent and codominant effect of the Thr789Ala polymorphism on CHD, but not on nephropathy, with a maximal risk for Ala/Ala homozygotes (OR = 4.2, 95% CI, 1.8 to 9.9, P = 0.0008).

CONCLUSION

It is unlikely that polymorphisms in the vWF gene contribute to the risk for nephropathy in type I diabetic patients. However, the Thr789Ala polymorphism might affect the risk for CHD in this population through modulation of plasma vWF levels.

Determinants of elevated urinary albumin in the 4,937 type 2 diabetic subjects recruited for the DIABHYCAR Study in Western Europe and North Africa

OBJECTIVE

Whether ACE inhibition is useful for type 2 diabetic patients with micro- and macroalbuminuria remains unknown. The Non-Insulin-Dependent Diabetes, Hypertension, Microalbuminuria, Cardiovascular Events and Ramipril (DIABHYCAR) Study was set up to address this issue through a multicenter double-blind parallel placebo-controlled > or = 3-year trial in Europe and North Africa. In this article, we report the characteristics of the randomized patients.

RESEARCH DESIGN AND METHODS

The main selection criteria were as follows: men or women aged > or = 50 years with type 2 diabetes treated with oral antidiabetic drugs, with or without hypertension, with a plasma creatinine level < 150 mumol/l, and with persistent micro- or macroalbuminuria, as assessed centrally by two successive urine samples containing a urinary albumin concentration > or = 20 mg/l. Patient characteristics were studied by comparing patients who were randomized to those who were not, taking their geographical origin into account.

RESULTS

There were 25,455 patients screened for urinary albumin (20,296 from France, 918 from Germany, 1,019 from Northwest Europe, 969 from Central Europe, 959 from Mediterranean Europe, and 1,294 from North Africa). Of these patients, 4,937 were randomized. Compared with the nonrandomized patients, the randomized patients were older, more often men, more obese, had higher systolic/diastolic blood pressure and plasma glucose, smoked more tobacco, drank more alcohol, and had complications more frequently. Using a logistic regression analysis, all the above-mentioned items appeared as independent determinants for randomization into the study, with the exception of alcohol intake. The contribution of each item varied slightly from one geographical origin to another.

CONCLUSIONS

The physical, biological, and behavioral characteristics create a poor renal and cardiovascular prognosis for the type 2 diabetic patients randomized to the DIABHYCAR Study because of micro- and macroalbuminuria. Testing the usefulness of ACE inhibition for the type 2 diabetic patients with microalbuminuria seems feasible through the DIABHYCAR Study.

[The problem of therapeutic efficacy indices. 3. Comparison of the indices and their use]

Efficacy indices do not contain the same information although they are all combinations of the same two quantities. Therefore, one should choose the proper index. Actually, none is entirely appropriate. Each more or less meets the specifications, depending on the underlying effect model for the therapy considered. However, one can say that the absolute benefit is more appropriate from the patient's point of view, the relative from the scientific point of view and the number of patients to treat from the policy maker's point of view. Nevertheless, this classification needs to be considered with caution. Finally, it emerges from the review that none is fully relevant to express the efficacy of a therapy, even in the most suitable condition, the acute illness.

The use of the personalized estimate of death probabilities for medical decision making

Data coming from the French national statistics on the cause of deaths are used to calculate the probabilities of death from pathologies. These probabilities are calculated according to age, sex, and place of residence of the patient to "personalize" the estimate. This individual prediction of the risk of death is proposed for pathologies for which the feasibility and the utility of prevention measures had been demonstrated. Relative risks of death according to the socioprofessional category, which are coming from the scientific literature, are used to adjust the probabilities of death as a function of the patient socioprofessional category. The aim of this work is to guide a scientist toward a prevention strategy according to the age and characteristics of patient. The use of computers by the scientists will make possible the diffusion of such tool of prediction to improve a personalized prevention.

Is it Possible to Differentiate between Angiotensin II Type 1 (AT1) Receptor Blockers in Normotensive Volunteers?

Variability of blood pressure responses to inhibition of the renin-angiotensin system is influenced by factors inherent in the patient, such as renin status, and by drug-specific factors, such as pharmacokinetics. The pharmacokinetic-pharmacodynamic interactions of two doses of candesartan cilexetil, which is an ester prodrug of the insurmountable angiotensin II type 1 (AT 1 ) receptor blocker candesartan, were compared with those of the standard dose of losartan in normotensive volunteers whose renin status was controlled by mild sodium depletion. In a double-blind, placebo-controlled crossover study, the effects of single oral doses of candesartan cilexetil, 8 mg and 16 mg, and losartan, 50 mg, were compared for 24 h in 16 healthy individuals pretreated with a single 40-mg dose of furosemide. Mean blood pressure was recorded by repeated measurements using the oscillometric method. In addition, measurements were made of plasma active renin, angiotensin I and angiotensin II, and plasma levels of candesartan and EXP-3174, the active metabolites of candesartan cilexetil and losartan, respectively, were determined by high-performance liquid chromatography and correlated to pharmacodynamic changes. The large interindividual variability of EXP-3174 levels in subjects who received losartan revealed a significant correlation between active renin and peak drug levels ( r = 0.77, n = 16, p < 0.01). Such a correlation was not found within either group of individuals who received candesartan cilexetil, because of lower interindividual pharmacokinetic variability. A dose-response relationship was found between plasma renin and candesartan when both doses of candesartan cilexetil were analysed. The pharmacodynamic effects of a single oral dose of candesartan cilexetil, 16 mg, were superior to those of candesartan cilexetil, 8 mg, and losartan, 50 mg (see Table). This conclusion has been confirmed by the results of a parallel-group, dose-determination study performed in hypertensive patients. The less variable pharmacokinetic-pharmacodynamic interaction for candesartan cilexetil than for losartan could account for the smooth 24-h reduction in blood-pressure found in patients treated with candesartan cilexetil. These results suggest not only that AT 1 -receptor antagonists can be differentiated, but that they will not be equally useful in clinical practice where, in contrast to clinical research, clear evidence is more difficult to obtain because of variability in renin status.

Models to predict cardiovascular risk: comparison of CART, multilayer perceptron and logistic regression

The estimate of a multivariate risk is now required in guidelines for cardiovascular prevention. Limitations of existing statistical risk models lead to explore machine-learning methods. This study evaluates the implementation and performance of a decision tree (CART) and a multilayer perceptron (MLP) to predict cardiovascular risk from real data. The study population was randomly splitted in a learning set (n = 10,296) and a test set (n = 5,148). CART and the MLP were implemented at their best performance on the learning set and applied on the test set and compared to a logistic model. Implementation, explicative and discriminative performance criteria are considered, based on ROC analysis. Areas under ROC curves and their 95% confidence interval are 0.78 (0.75-0.81), 0.78 (0.75-0.80) and 0.76 (0.73-0.79) respectively for logistic regression, MLP and CART. Given their implementation and explicative characteristics, these methods can complement existing statistical models and contribute to the interpretation of risk.

Using semantic distance for the efficient coding of medical concepts

OBJECTIVE

To use the notion of semantic distance to find the nearest neighbors of a medical concept in a controlled vocabulary.

MATERIAL AND METHOD

392 concepts from the cardiovascular chapter of the ICD-10 were projected on the axes of SNOMED III. Distances were measured on each axis and the resulting distance was found using a Lp norm.

RESULTS

The distance between a set of ischemic diseases and a set of non-ischemic diseases was significant (p < 0.0001). Our method was validated by finding the k nearest neighbors of ten different diagnoses from the ICD-10 cardiovascular chapter.

DISCUSSION

The availability of SNOMED-RT should improve our method. Several more steps are necessary to provide an ideal coding tool.

Interobserver variability in the interpretation of renal digital subtraction angiography

OBJECTIVE

Our purpose was to analyze interobserver variability in the interpretation of renal digital subtraction angiography and to describe the main factors associated with observer discrepancies.

MATERIALS AND METHODS

Forty-nine cases of unilateral atheromatous renal artery stenosis of more than 60% were quantified first by local investigators in a multicenter study and then by five other radiologists. Differences between radiologists for the minimum diameter (Dmin), the reference diameter (Dref), and the percentage of stenosis of the renal arteries were analyzed. Interpretations by the local investigators were then compared with the gold standard, defined as the mean for the five radiologists.

RESULTS

The average SD for estimation of all renal artery stenoses by all radiologists was 7% for stenosis percentage, 0.5 mm for Dmin, and 0.7 mm for Dref. Main discrepancies occurred more frequently in cases of weakly opacified renal artery stenosis and poststenotic dilatation. The observations of local investigators disagreed by more than two SDs (14%) with the gold standard for 11 of 49 cases (22%).

CONCLUSION

The accuracy of digital subtraction angiography in renal artery interpretations is poor because of variations in evaluating both Dmin and Dref. Precise and reproducible methods for quantification of renal artery stenosis are required.

[Arterial hypertension and cerebrovascular accident: the need for improved prevention strategies]

It is well demonstrated that the antihypertensive treatment is effective, particularly for the primary prevention of stroke. However, benefits of treatment are rather small in certain groups of patients. The explicit assessment of absolute cardiovascular risks and likely treatment benefits in patients with hypertension can usefully guide treatment decisions and provide a more rational basis for initiating therapy than blood pressure levels alone. This approach highlights the generally greater cardiovascular risk and potential treatment benefits in older compared with younger hypertensive patients. Some specific questions remain still unanswered. Evidence is accumulating concerning protective effect of antihypertensive treatment against dementia. Trials are in progress to investigate the effect of treatment on stroke incidence in hypertensive patients over the age of 80 years. Finally, despite the worldwide use of calcium antagonists and converting enzyme inhibitors, solid evidence of their safety and efficacy compared with the references drugs (beta-blockers and diuretics) is still lacking.

Intracerebral calcification in systemic sclerosis

BACKGROUND AND PURPOSE

Advanced cerebrovascular wall calcification was recently observed at autopsy in 2 patients with systemic sclerosis. To further investigate this issue, we conducted a prospective CT study of scleroderma patients to detect intracerebral calcification.

METHODS

Thirty-seven consecutive patients with systemic sclerosis underwent unenhanced brain CT. Images were blindly interpreted, together with those of 2 age-matched (+/-1 year) and sex-matched control subjects per patient.

RESULTS

Intracerebral calcification was found in 12 patients (32.4%) and 7 controls (9.5%) (P=0.006). Among the patients, intracerebral calcification was associated with the duration of Raynaud's phenomenon (P=0.005) and not with age (P=0.086).

CONCLUSIONS

Intracerebral calcification is closely associated with scleroderma, which suggests that scleroderma causes primary cerebrovascular changes.

[Do the long-term results of carotid surgery influence the status of the contralateral carotid artery?]

AIM

The main cause of long-term death and disability of patients undergoing carotid artery surgery is coronary artery disease. To identify the prognostic value of the status of the contralateral artery, we studied the course of 224 patients operated consecutively on one or both carotid arteries in the same institution between 1985 and 1995.

PATIENTS AND METHODS

The 224 patients were divided into three groups: group I (n = 56) having an occluded contralateral carotid artery; group II (n = 56) in which both carotids were operated on; and, group III (n = 112) having a normal contralateral carotid artery. The clinical status of all patients was ascertained by one of us for all patients except one. This study concerned also the course of 40 patients (group R) belonging to the three groups, who had during the follow-up period a coronary and/or a peripheral vascular intervention with a preoperative coronarography.

RESULTS

The median follow-up was 62.8, 78 and 65 months for groups I, II and III, respectively. Actuarial survival rates were 67%, 73%, 72.5% at 5 years, and 39%, 51.5% and 42% at 10 years, for group I, II and III respectively. Actuarial stroke-free rates were 96%, 100%, 91% at 5 years, and 96%, 100% and 78.5% at 10 years for group I, II and III respectively. Actuarial cardiac death rates were 26%, 23%, 19% at 5 years, and 49%, 42% and 37% at 10 years for group I, II and III, respectively. None of the differences between the three groups regarding these three different end-points was significant. The group R fatal or non-fatal cardiac event-free rates at 5 and 10 years were 88% and 53% respectively. When compared with the rates of other patients (without revascularization): 68% and 25.5% at 5 and 10 years, the results were almost significant (P = 0.07). Average age for group R patients was significantly lower (65 vs. 69 years, P < 0.05). Using Cox's model, age alone emerged as a factor influencing survival (P = 0.07) but not revascularization (P = 0.13).

CONCLUSION

The status of the contralateral artery does not influence the long-term prognosis of patients undergoing carotid artery surgery. A periodic cardiological and vascular follow-up of these patients tends to improve their survival.

[Outline of the problem of indices of therapeutic efficacy. 4. Expression of efficacy when the underlying illness is incurable. Study Group for the Indices of Efficacy]

In chronic illness, when death or a non-fatal event can occur at any time, the current efficacy indices are no longer appropriate to express the effect of the treatment on the potential therapeutic objectives. The inappropriateness is not dependent on the effect model. Clues for solutions are proposed.

[Audit of the treatment of arterial hypertension in specialized consultation]

The objective of the study was to estimate the control of elevated blood pressure (BP) among patients regularly followed-up and to analyse physicians attitudes in patients having uncontrolled BP. Two hundred and fifty-eight consecutive patients (mean age 56 years, 58% of males) with essential hypertension attending the outpatient department of a specialised hypertension clinic, having at least a 6-month follow-up at the clinic and at least 3 prior visits, were included in the study. Twelve different physicians were in charge of these patients. Data were collected [1] from the structured computerised record called ARTEMIS and [2] from a structured questionnaire filled up by the physician after each visit, where he/she explained the reasons for his/her decisions. BP was measured by a nurse using an automatic device (oscillometric method) and then by a physician using a mercury sphygmomanometer. During follow-up, mean physician's BP fell from 179/107 to 148/91 mmHg and mean nurse BP fell from 164/96 to 143/83 mmHg. Percentages of patients having a controlled hypertension (BP < 140/90 mmHg) were 27% (physician's BP) and 45% (nurse BP). Physicians did not modify treatment in 59% of patients among whom they measured a BP > or = 140/90 mmHg. The 3 main reasons given by physicians for not modifying treatment were: BP controlled when using other BP measurement methods (nurse, home or ambulatory BP), 44%; BP control considered as satisfactory, 29%; systolic hypertension in the elderly, 8%. The person (physician or nurse) who measures BP and the measurement method have dramatic consequences on BP control level. Reasons for not modifying treatment in uncontrolled patients (physician's BP > or = 140/90 mmHg) were based on opinions rather than evidence, for example when isolated systolic hypertension in the elderly is concerned.

Maximal thickness of the normal human pericardium assessed by electron-beam computed tomography

The purpose of this study was to determine the maximal value of normal pericardial thickness with an electron-beam computed tomography unit allowing fast scan times of 100 ms to reduce cardiac motion artifacts. Electron-beam computed tomography was performed in 260 patients with hypercholesterolemia and/or hypertension, as these pathologies have no effect on pericardial thickness. The pixel size was 0.5 mm. Measurements could be performed in front of the right ventricle, the right atrioventricular groove, the right atrium, the left ventricle, and the interventricular groove. Maximal thickness of normal pericardium was defined at the 95th percentile. Inter-observer and intra-observer reproducibility studies were assessed from additional CT scans by the Bland and Altman method [24]. The maximal thickness of the normal pericardium was 2 mm for 95 % of cases. For the reproducibility studies, there was no significant relationship between the inter-observer and intra-observer measurements, but all pericardial thickness measurements were </= 1.6 mm. Using electron-beam computed tomography, which assists in decreasing substantially cardiac motion artifacts, the threshold of detection of thickened pericardium is statistically established as being 2 mm for 95 % of the patients with hypercholesterolemia and/or hypertension. However, the spatial resolution available prevents a reproducible measure of the real thickness of thin pericardium.

Computer-adjusted dosage of anticoagulant therapy improves the quality of anticoagulation

OBJECTIVE

Risks and benefits of anticoagulant therapy depend directly of the quality of anticoagulation. We performed a meta-analysis of published randomized trials to assess the overall effectiveness of computer-based prescription systems on the quality of anticoagulation.

DESIGN

Randomized controlled trials were identified through electronic searches of the Medline database (1966-1997) and systematic analyses of the references of articles. Two investigators selected relevant papers and summarized data from the studies.

METHODS

The outcome variable was the proportion of days within the target range of anticoagulation. A pooled estimate of the common odds ratio of being in the target range and its confidence interval was obtained by the Mantel-Haenszel method.

RESULTS

Seven trials having included 1217 patients were identified. Computer systems were based on a pharmacokinetic-pharmacodynamic model and a bayesian prediction method. Most of them concerned the oral anticoagulant warfarin. The global odds ratio of being in the target range was 1.58 [95% CI: 1.34-1.86], thus meaning that the use of a computer for anticoagulation optimization increased by 58% the proportion of visits where patients were appropriately treated. The proportion of clinical events was too low for allowing a summary analysis.

CONCLUSION

Evidence from randomized controlled trials supports the effectiveness of computer-aided anticoagulant prescription. Diffusion of these systems in ambulatory care could increase the benefit/risk ratio of anticoagulant treatment at a low cost.

Can echocardiography identify mildly hypertensive patients at high risk, left untreated based on current guidelines?

OBJECTIVE

To determine whether the decision to treat uncomplicated mild hypertension with drugs, in accordance with the World Health Organization - International Society of Hypertension (WHO/ISH) guidelines based on a series of blood pressure (BP) measurements over 6 months, resulted in the treatment of patients at high risk on the basis of echocardiography.

METHODS

One hundred and eighteen patients with mild hypertension (diastolic blood pressure 90-105 mm Hg and/or systolic blood pressure 140-180 mm Hg) were examined by echocardiography at inclusion and followed up for 6 months by a single physician unaware of the echographic results.

RESULTS

Drug treatment was given to 48 patients, and 70 remained untreated. Treated patients had higher echographic indices than untreated patients (all P<0.05): left ventricular (LV) mass/body surface area (83.0+/-15.6 versus 75.3+/-14.8 g/m2), inter-ventricular septal thickness (9.7+/-1.7 versus 8.5+/-1.3 mm), LV posterior wall thickness (8.4+/-1.1 versus 7.8+/-1.1 mm), relative wall thickness (0.37+/-0.06 versus 0.34+/-0.06). LV geometry was normal in 98 patients, and 20 had LV concentric remodelling. The 10-year coronary disease risk (Framingham equation) was higher in the 20 patients with concentric remodelling than in those with normal LV geometry (10.4 versus 4.2%; P<0.005). Nine of these 20 patients were still untreated at the end of the 6-month follow-up period.

CONCLUSION

Rigorous application of the WHO/ISH clinical guidelines in a group of mild hypertensive patients led to the treatment of patients with slightly higher LV mass and more concentric LV geometry than were found in those not treated. However, a high-risk subgroup, with concentric remodelling, was not identified and left untreated.

[The problem of therapeutic efficacy indices. 2. Description of the indices]

The four indices for a binary outcome or therapeutic objective are: the odds ratio, the relative risk, the absolute benefit and the number of patients to treat. For a continuous outcome, the effect size is the best choice. The odds ratio approximates the relative risk. The difference may be large in some instances. The number of patients to treat is the reciprocal of the absolute benefit. Although they are built on the same two quantities, they are not interchangeable and should not be considered in the same way. Moreover, their meaning is not straightforward and they can be misused.

[Current aspects of arterial hypertension. Prognostic value of self-monitoring blood pressure measurements in aged hypertensive patients: a SHEAF study protocol]

HOW TO MEASURE BLOOD PRESSURE: Studies conducted in large series have established the prognostic value of blood pressure measured by conventional methods. This measurement technique has however a certain number of limitations and alternative systems have been proposed, including self-monitoring methods. A preliminary study suggested that the prognostic value of self-monitoring blood pressure measurements would be superior to those obtained with conventional methods. These findings require confirmation. A LARGE SCALE STUDY: The primary objective of the SHEAF study is to determine the prognostic value of self-monitoring blood pressure measurements in terms of cardiovascular mortality in a population of hypertensive elderly subjects living in France. The study protocol projects to include 5,000 hypertensive patients, whether treated or not, aged 60 and over. Baseline pressures are to be measured by a physician using a mercury sphygmomanometer (3 successive measurements at 2 visits) and by the participants using a self-monitoring device in their home (3 measurements in the morning and evening for 4 consecutive days). The patients will be followed for 3 years and all cardiovascular events will be recorded, including: death, myocardial infarction, cerebral vascular events, transitory ischemic events, hospitalization for angina, episodes of angina, heart failure, angioplasy or coronary bypass. The results of this large-scale epidemiology study should be available in 2002. METHODOLOGICAL PRECAUTIONS: The SHEAF study will analyze the patient's usual blood pressures, whatever the treatment at study inclusion, rather than blood pressures observed after treatment withdrawal. Efforts will be made to limit the number of drop-outs.

Pharmacokinetic-pharmacodynamic interactions of candesartan cilexetil and losartan

BACKGROUND

The variability of the blood pressure response to blockade of the angiotensin II type 1 receptor is influenced by renin status and pharmacokinetics and pharmacokinetic-pharmacodynamic interactions.

OBJECTIVE

To compare the pharmacokinetic-pharmacodynamic interactions of two doses of an ester prodrug of a noncompetitive angiotensin II type 1 receptor antagonist, candesartan cilexetil, at 8 and 16 mg, with those of the reference angiotenisn II type 1 receptor blocker, losartan, at the standard dose (50 mg), in a human model that controls renin status.

DESIGN AND METHODS

In a double-blind placebo-controlled crossover study, we compared the effects on renin and mean blood pressure over 24 h of single oral doses of candesartan cilexetil at 8 and 16 mg and losartan at 50 mg in 16 sodium-depleted normotensive subjects.

RESULTS

The area under the curve (0-24 h) for plasma active renin did not differ significantly between 8 mg candesartan cilexetil and 50 mg losartan, but was significantly higher for 16 than for 8 mg candesartan cilexetil or for 50 mg losartan. The area under the curve (0-24 h) for the fall in mean blood pressure with 16 mg candesartan cilexetil (-197 +/- 96 mmHg/h) was significantly greater than that for placebo (-112 +/- 81 mmHg/h; P< 0.05) but the difference was not statistically significant compared with either 8 mg candesartan cilexetil (-158 +/- 95 mmHg/h) or 50 mg losartan (-144 +/- 66 mmHg/h). The area under the curve (0-24 h) for the fall in mean blood pressure did not significantly differ between 8 mg candesartan cilexetil, 50 mg losartan and placebo. The area under the curve (0-24 h) for plasma active renin was significantly correlated to that for plasma levels of the active metabolite of losartan, EXP 3174 (r = 0.65, n = 16, P< 0.01). No such correlation was detected for each single dose of candesartan cilexetil but a dose-response relationship was present when both doses were combined.

CONCLUSIONS

The pharmacodynamic effects of a single oral dose of 16 mg candesartan cilexetil are greater than those of 50 mg losartan and 8 mg candesartan cilexetil. The variability in the pharmacokinetic-pharmacodynamic interaction is less pronounced for candesartan than for EXP 3174, which could result in reduced variability of the blood pressure effects in patients.

Renal changes on hyperglycemia and angiotensin-converting enzyme in type 1 diabetes

Hyperglycemia causes capillary vasodilation and high glomerular capillary hydraulic pressure, which lead to glomerulosclerosis and hypertension in type 1 diabetic subjects. The insertion/deletion (I/D) polymorphism of the angiotensin I-converting enzyme (ACE) gene can modulate risk of nephropathy due to hyperglycemia, and the II genotype (producing low plasma ACE concentrations and probably reduced renal angiotensin II generation and kinin inactivation) may protect against diabetic nephropathy. We tested the possible interaction between ACE I/D polymorphism and uncontrolled type 1 diabetes by measuring glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) during normoglycemia ( approximately 5 mmol/L) and hyperglycemia ( approximately 15 mmol/L) in 9 normoalbuminuric, normotensive type 1 diabetic subjects with the II genotype and 18 matched controls with the ID or DD genotype. Baseline GFR (145+/-22 mL/min per 1.73 m2) and ERPF (636+/-69 mL/min per 1.73 m2) of II subjects declined by 8+/-10% and 10+/-9%, respectively, during hyperglycemia; whereas baseline GFR (138+/-16 mL/min per 1.73 m2) and ERPF (607+/-93 mL/min per 1.73 m2) increased by 4+/-7% and 6+/-11%, respectively, in ID and DD subjects (II versus ID or DD subjects: P=0.0007 and P=0.0005, for GFR and ERPF, respectively). The changes in renal hemodynamics of subjects carrying 1 or 2 D alleles were compatible, with a mainly preglomerular vasodilation induced by hyperglycemia, proportional to plasma ACE concentration (P=0.024); this was not observed in subjects with the II genotype. Thus, type 1 diabetic individuals with the II genotype are resistant to glomerular changes induced by hyperglycemia, providing a basis for their reduced risk of nephropathy.

[The problem of therapeutic efficacy indices. 1. Elements of the problem]

Efficacy indices measure the efficacy of therapies. They derive, by definition, from two quantities, the basal or control risk of event, Rc, observed in the control group, and the on-treatment risk, Rt, observed in the treated group. In clinical trials and meta-analyses, each is an unbiased measure of efficacy. Although they are a combination of frequencies, these indices are used in clinical practice to predict the benefit in treated patients. Their relevance to express efficacy depends on the type of clinical condition, and is better for acute diseases than for chronic diseases. In order to be useful for prescribers, they should meet certain specifications. In addition, they should be considered in the more general framework of effect models.