Issues in the treatment of hypertension: current and future perspectives

The benefits of lowering elevated arterial blood pressure have been documented in many intervention trials. Initially, such studies included only patients with malignant hypertension, and very convincing improvements in the 5-year survival rate were demonstrated in several reports. Subsequent large-scale intervention studies included patients with non-malignant forms of hypertension. Again, significant improvements in cardiovascular morbidity and/or mortality were shown. Recent epidemiological data from the USA and Sweden suggest that the pattern of hypertension and its associated morbidity is changing, probably due to earlier diagnosis and treatment. The aims of this review are to describe some of the important steps that have been taken in the area of hypertension over the last few decades and to try to evaluate the status of current antihypertensive therapies. Particular emphasis will be given to discussing some of the issues and questions that are currently under investigation, for example the status of novel therapies, such as calcium channel blockers and angiotensin-converting enzyme inhibitors, and the issue of the level to which blood pressure should be lowered in order to extract the maximum benefit from antihypertensive treatment. Some of the ongoing large-scale intervention trials in hypertension will also be reviewed.

Medical and cost-economy aspects of modern antihypertensive therapy--with special reference to 2 years of clinical experience with losartan

Health economy is often addressed in terms of acquisition cost, i.e. the cost of the pill. For various reasons, mainly the stricter demands from drug regulatory agencies (increased development costs), novel agents must be expected to be more expensive than older drugs. However, if the costs of changing therapy and the costs induced by side effects and extra clinic visits are considered, the economic aspects become less of a consideration. If compliance is enhanced and better blood pressure control is achieved with the newer agents, then the therapeutic gains must be weighed against the economic aspects. Losartan, the first agent of the new class of angiotensin II receptor antagonists of the AT1 type, has been available for clinical use for more than 2 years. Losartan has proven antihypertensive effects and its safety profile in the initial controlled trials (approximately 2900 patients) and in general practice (more than 14,000 patients in Sweden) has been very good. Its effect on long-term morbidity and mortality has not yet been established but a large mortality endpoint trial is underway in hypertensive patients with cardiac hypertrophy (the LIFE trial). In heart failure, losartan has been shown to reduce 3-month mortality (the ELITE trial). Although it is too early to assess the full therapeutic benefit of losartan in relation to the total patient costs, its efficacy and low incidence of side effects has made it a useful new therapy for the treatment of hypertension.

Psychiatric morbidity in primary public health care: a multicentre investigation. Part II. Hidden morbidity and choice of treatment

A total of 1,281 patients were examined during consultation with their GP in a Nordic multicentre study focusing on the prevalence of psychiatric illness, hidden psychiatric morbidity, treatment and pathways to specialized care. The methodology and prevalence were reported in an accompanying paper. The present paper presents results concerning the variables hidden psychiatric morbidity, treatment and pathways to specialized care. The GPs detected 44% of the psychiatric cases compared with the result of a diagnostic interview (PSE). The distinction between psychosis and non-psychosis did not influence the GPs' ability to detect a mental illness. According to the GPs' assessment the majority of patients suffering from a mental disorder consulted their GP about physical complaints. The GPs treated the patients themselves, and only a limited number of cases were referred to psychiatrists or psychologists.

Glucose and insulin levels in young subjects with different maternal histories of hypertension: the Hypertension in Pregnancy Offspring Study

OBJECTIVE

To analyse whether hypertension during pregnancy is associated with early signs of impaired glucose metabolism in the offspring.

DESIGN

Longitudinal study with a 5-year follow-up.

SETTING

University Hospital, Göteborg, Sweden.

MAIN OUTCOME MEASURES

Fasting levels of glucose, insulin and C-peptide.

SUBJECTS

Thirty-six children were born to mothers with hypertension in pregnancy. The children were divided into two groups according to their mothers' blood pressure at follow-up 7-12 years after pregnancy. Nineteen children had hypertensive mothers (HT), while 17 children had normotensive mothers at follow-up (NT). A control group (C) comprised 16 children, who were born after normotensive pregnancies to mothers who remained normotensive.

RESULTS

Fasting plasma glucose was significantly higher in HT than in NT (5.2 vs. 4.9 mmol L-1; P < 0.05). In C fasting glucose was 5.1 mmol L-1. The same trend was seen for fasting insulin in HT. NT and C, respectively (6.7 vs. 4.7 vs. 5.3 microU mL-1). The C-peptide level was 1.61, 155 and 1.64 ng mL-1, respectively. Calculated insulin resistance was 1.5 in HT. 1.0 in NT and 1.2 in C.

CONCLUSIONS

It is suggested that hypertension during pregnancy may be associated with impaired glucose metabolism and elevated fasting glucose levels in the offspring during adolescence.

The Nordic Comparative Study on Sectorized Psychiatry. Part V. Contact rates, contact patterns and care level at index contact

As part of a Nordic comparative study on sectorized psychiatry in seven Nordic catchment areas, a prospective investigation of contact rates of new patients and pathways to the psychiatric services was performed. The results showed that there was more than a twofold difference between the services in the total contact rates. Regarding diagnostic groups, contact rates for neurosis were predominant in three of the services, while adjustment disorders, dependencies and personality disorders were predominant in other the services. The contact rate of functional psychosis, as well as the ratio of psychotic patients to the total contact rate were highest in two catchment areas serving inner parts of big cities. The most common way of getting into contact with the services was by self-referral, 39.4% of total referrals, followed by primary care referrals, although there were large differences between the services. Psychotic patients made contact with the services to a significantly less extent by self-referral. The majority of patients were treated in outpatient care at entry to the services, with a large variation between the services. It was also found that inpatient care at index contact was predicted by clinical characteristics-a diagnosis of psychosis and a history of former inpatient care-as well as by social characteristics-male, widowed or divorced, sick pension/old age pension.

Stent or surgery for malignant low bile duct obstruction?

The development of non-surgical techniques for the relief of malignant low bileduct obstruction has cast doubt on the best way of relieving jaundice, particularly in patients fit for surgery whose life expectancy is more than a few weeks.

We did a randomised prospective controlled trial comparing endoscopic stent insertion and surgical biliary bypass in patients with malignant low bileduct obstruction. 204 patients were randomised (surgery 103, stent 101); 3 subsequently proved to have benign disease and were excluded, leaving 101 surgical and 100 stented patients for assessment. Technical success was achieved in 94 surgical and 95 stent patients, with functional biliary decompression obtained in 92 patients in both groups. In stented patients, there was a lower procedure-related mortality (3% vs 14%, p=0.01), major complication rate (11% vs 29%, p=0.02), and median total hospital stay (20 vs 26 days, p=0.001). Recurrent jaundice occurred in 36 stented patients and 2 surgical patients. Late gastric outlet obstruction occurred in 17% of stented patients and 7% of the surgical group. Despite the early benefits of stenting there was no significant difference in overall survival between the two groups (median survival: surgical 26 weeks; stented 21 weeks; p=0.065).

Endoscopic stenting and surgery are effective palliative treatments with the former having fewer early treatment-related complications and the latter fewer late complications.

Recombinant human bile salt-stimulated lipase: an example of defective O-glycosylation of a protein produced in milk of transgenic mice

The expression of recombinant human bile salt-stimulated lipase (bssl) was targeted to the lactating mammary gland of transgenic mice. Expression of recombinant genes comprising bsslcDNA, or alternatively genomic bssl DNA, under control of regulatory elements derived from the murine whey acidic protein (wap) gene was achieved and evaluated. Constructs containing genomic bssl sequences mediated high levels (0.5-1 mg ml-1) of recombinant human BSSL in the milk. The recombinant BSSL produced was purified, biochemically characterized and compared to native BSSL and recombinant BSSL produced in mouse C127 and hamster CHO cells. Recombinant BSSL derived from transgenic mice showed a different migration and distribution after SDS-PAGE electrophoresis, lower apparent molecular mass on size-exclusion chromatography and no detectable interactions with a panel of lectins. These results indicate a significantly lower degree of O-glycosylation of recombinant BSSL in milk from transgenic mice than was found for the native enzyme or recombinant CHO- or C127 cell-produced BSSL. Despite these differences, mouse-milk-derived recombinant BSSL exhibited similar lipase activity, the same stability to low pH and similar sensitivity to elevated temperatures as the native enzyme. The observation that mouse-C127-cell-produced recombinant BSSL is heavily O-glycosylated makes species-related restrictions less attractive as an explanation for the reduced O-glycosylation.

Long-term effects of losartan on blood pressure and left ventricular structure in essential hypertension

In a 12-week, randomized, double-blind study, 24 patients with essential hypertension were given the angiotensin II antagonist losartan, or the beta-adrenoceptor blocker atenolol. Both drugs reduced blood pressure (BP) well, but losartan tended to reduce left ventricular mass (LVM) in contrast to atenolol. Following the double-blind phase 19 patients entered an open treatment period with losartan and additional treatment if BP was uncontrolled. LV structures were measured by echocardiography. The mean follow-up period was 29 +/- 2.6 (range 26-32) months. BP was reduced from 155.6 +/- 15.6/103.4 +/- 5.2 mm Hg to 131.3 +/- 10.5/82.7 +/- 3.3 mm Hg (P < 0.001). LV internal diameter was reduced (50.7 +/- 4.5 to 49.1 +/- 4.0 mm; P = 0.006), while there was an increase in interventricular septal thickness (10.2 +/- 1.1 to 11.2 +/- 1.3 mm; P = 0.001) and posterior wall thickness (10.0 +/- 0.9 to 10.6 +/- 1.1 mm; P = 0.023). Calculated LVM was not significantly altered during the follow-up period. In conclusion, losartan is effective in reducing BP during long-term treatment. No significant effect on LVM was observed, but there was an increase in LV wall thickness.

The Nordic comparative study on sectorized psychiatry. Utilization of psychiatric hospital care related to amount and allocation of resources to psychiatric services

As a part of a Nordic comparative study on sectorized psychiatry, utilization of inpatient care was related to resources and dynamic qualities of psychiatric services in seven catchment areas in four Nordic countries. One-year treated incidence cohorts were used. Each patient was followed for 1 year after first contact with the psychiatric service. Data were collected concerning number of beds and staff, number of long-term patients and turnover rate of patients in inpatient care. Findings gave some support to the earlier reports that the utilization of inpatient care is determined by the supply of available beds. Highly staffed community services did not themselves reduce the use of inpatient services, but availability of day care services seemed to reduce utilization of inpatient care among psychotic patients.

Hypertension in the elderly

TREATMENT OF ELDERLY HYPERTENSIVES: Treatment of hypertension in the elderly is nowadays an accepted and highly effective medical intervention following the positive reports on the benefits of lowering elevated arterial pressure in elderly patients. Most of the intervention studies an antihypertensive treatment in elderly patients have used diuretics or beta-blockers or the two in combination as the therapy by which blood pressure was lowered. However, from a theoretical point of view, novel therapies such as calcium antagonists could offer advantages that would translate into an even greater reduction in cardiovascular morbidity and mortality than has been obtained with the traditional antihypertensive therapies used so far. DATA ON CALCIUM ANTAGONISTS IN THE ELDERLY: Some of the studies in elderly hypertensives that are currently in progress are using calcium antagonists as one of the main therapies, e.g. the Swedish Trial in Old patients with hypertension (STOP-Hypertension)-2 study and the Systolic hypertension in Europe (Syst-Eur) study. Another source of information is a large database on nicardipine, a dihydropyridine-derived calcium antagonist, used in the treatment of elderly hypertensives.

Relationship between dose in vivo of ethylene oxide and exposure to ethene studied in exposed workers

1. In vivo doses of ethylene oxide, arising from ethene exposure, in plastic industry workers were estimated through hemoglobin adducts. The ethene exposure was assessed through person-worn monitors. The metabolic conversion of ethene to ethylene oxide was estimated from the exposure dose/in vivo dose ratio. 2. Two studies were done: In the first study hemoglobin adducts were determined in samples collected on one occasion in exposed groups and exposure doses were estimated by using exposure data from the hygienic surveillance program. The second study applies a newly developed study design with repeated blood sampling in a few persons combined with a complete personal exposure monitoring during the study period. This makes it possible to relate adduct formation with individual short-time exposure doses, which in theory should overcome the problems with exposure history dependence of the adduct level in a single blood sample. The results of the second study shows that it is possible, through the proposed method, to utilize occupational exposure situations for this kind of studies even if the exposure pattern is irregular and highly variable. Both studies show a metabolic conversion of ethene to ethylene oxide of only 0.5%, which is unexpectedly low. 3. The cancer risk associated with the ethene exposure in the highly exposed group (3.6 p.p.m. 40 h/week) is estimated by applying the radiation-dose-equivalence approach. The result of this evaluation leads to a risk corresponding to a radiation dose of 4 mSv/year which is about a factor 3 below the current dose limit for radiological work recommended by ICRP.

Structure of the human kappa-casein gene

The human kappa-casein-encoding gene, Kca, was cloned and sequenced. The structural gene consists of five exons ranging from 33 to 496 nucleotides (nt) separated by introns ranging from 1146 to 2942 nt, and extends over 8821 nt. All intron/exon splice junctions conform to the GT/AG rule. The gene organization is similar to that of the bovine gene. The 5'-flanking region contains an A + T-rich sequence; TTTAATT, close to where the TATA motif is found in most other genes, a CAAT box, and an AP-1 consensus sequence. In addition, one Alu repetitive element was found in the second intron.

The optimal blood pressure reduction

OPTIMAL BLOOD PRESSURE REDUCTION: The optimal blood pressure reduction when treating arterial hypertension is obviously the one which causes the maximum achievable prevention of hypertension-associated cardiovascular morbidity and mortality. This goal has not yet been reached by present approaches to antihypertensive treatment. Several large intervention trials in hypertension have shown that treated hypertensive patients still have an increased risk of cardiovascular morbidity and mortality in spite of receiving antihypertensive treatment. One possible explanation for this is that treated blood pressure is rarely, if ever, reduced to strictly normotensive levels. Another explanation, favored by proponents of the J-curve argument, is that excessive lowering of blood pressure may increase cardiovascular risks. DATA AVAILABLE FROM INTERVENTION TRIALS: So far, two prospective intervention trials have addressed this problem, the Swedish BBB (Treat Blood Pressure Better) study, for which results have been published, and the much larger Hypertension Optimal Treatment (HOT) study, which is still under way. Moreover, new epidemiological data from the Framingham Heart Study and the study of 50-year-old men in Gothenburg suggest that active intervention against arterial hypertension may change the pattern of blood pressure distribution in the population towards lower levels, also in untreated subjects, suggesting an additional and unexpected benefit from antihypertensive treatment.

Long-term renal preservation in essential hypertension. Angiotensin converting enzyme inhibition is superior to beta-blockade

Antihypertensive treatment is known to slow down the decline in glomerular filtration rate (GFR) with time. Angiotensin converting enzyme (ACE) inhibition has been shown to be more effective in this regard than conventional antihypertensive therapy. In a recent prospective, randomized, double blind trial in 257 patients with essential hypertension, the loss of GFR, determined with 51Cr-EDTA clearance, was significantly less with an ACE inhibitor (cilazapril) than with a beta-adrenoceptor blocker (atenolol) during the first year of treatment. However, after 2 years, the two therapies were equally effective in this regard, thereby creating doubts about the long-term superiority of ACE inhibition in this regard. In order to elucidate whether the superior renal preservation with the ACE inhibitor was a transient effect, GFR was measured after 1 more year of treatment, i.e., after 36 months. At that time, the decline in GFR was significantly smaller in the ACE inhibitor group as compared to the beta-adrenoceptor blocker group (-3.0 [-5.5, -1.0; 95% CI] v -7.0 [-9.0, -4.5; 95% CI] mL/min x 1.73 m2; P = .026). This demonstrates that in the treatment of essential hypertension ACE inhibition preserves GFR significantly better than beta-adrenoceptor blockade during long-term therapy.

The Nordic Comparative Study on Sectorized Psychiatry. III. Accessibility of psychiatric services, degree of urbanization and treated incidence

As part of a Nordic Comparative Study on Sectorized Psychiatry, accessibility of psychiatric services and degree of urbanization in seven catchment areas were related to treated incidence. One-year treated incidence cohorts were used. Accessibility was assessed according to referral practice, existence of a round the clock emergency service and geographical location of the services. Accessibility was surprisingly weakly associated with treated incidence. Easy access to the psychiatric services was not related to a high treated incidence of less severe psychiatric problems at the expense of patients suffering from severe illness. Geographical distance to the services did not predict the demand for services. A positive correlation was found between the degree of urbanization and treated incidence of psychoses but not of other diagnostic groups.

The Swedish Trial in old patients with hypertension-2 (STOP-hypertension-2): a progress report

OBJECTIVE

The Swedish Trial in Old Patients with Hypertension-2 (STOP-Hypertension-2) was designed by a project group of the Swedish Hypertension Society to test whether the "newer" treatment alternatives (ACE inhibitors and calcium antagonists) are as good as, better or less good than, the "older" ones (beta-blockers and diuretics) in terms of preventing cardiovascular morbidity and mortality in elderly hypertensives. The aim of the present paper is to report on the progress of the study.

DESIGN

Prospective, open trial with blinded end-point committee and centralized randomization (PROBE design). STOP-Hypertension-2 may be regarded as a scientific follow-up of the previously published Swedish Trial in Old Patients with Hypertension (STOP-Hypertensioon-1) (6) using the same study organization.

SUBJECTS

By the end of 1994 when recruitment was stopped, 6628 hypertensive men (34%) and women (66%) aged 70-84 (mean age 76) had been included at 312 Swedish health centres (out of approximately 850). In the whole cohort 11% are diabetics and 9% smokers. The mean total cholesterol value is 6.5 mmol/L.

RESULTS

In the whole study cohort, blood pressure was lowered from 194/98 mmHg to 167/85 mmHg after one year. At the end of 1995, 319 fatal events (all-cause mortality) had been reported, corresponding to a mortality rate of 21.3 per 1000 person-years.

CONCLUSION

In STOP-Hypertension-2, 6628 elderly hypertensive have been randomized to three different treatment regimes: beta-blocker+diuretics (the active treatment arm in STOP-Hypertension-1), ACE inhibitors, or calcium antagonists. Their average lowering of blood pressure was 27/13 mmHg and end-points have occurred at the expected rate. Thus, it should be possible to terminate STOP-Hypertension-2 within two to three years.

Major antihypertensive intervention trials conducted outside the United States

Five antihypertensive trials launched outside of the United States have been designed to address one of two vital issues. The first is whether or not there is an optimal level of blood pressure that clinicians should aim for to minimize the risk of cardiovascular disease. This has been addressed by the Swedish Behandla Blodtryck Battre (BBB) Trial and the international Hypertension Optimal Treatment (HOT) Study. The BBB Trial revealed interesting trends, but no definitive conclusions. The ongoing HOT Study will have to be completed before this particular issue can be adequately addressed. However, preliminary analysis of a subgroup study has revealed that the HOT treatment regimens are as effective in the elderly as in younger patients. The second important issue, which is the question of whether traditional antihypertensive agents are more effective than the newer agents in reducing cardiovascular risk, is the current focus of three ongoing studies. Investigators in the Captopril Prevention Project (CAPPP) are comparing captopril to beta-blocker and diuretic regimens. The purpose of the Nordic Diltiazem Study (NORDIL) is to determine if diltiazem is more effective than conventional therapy in reducing cardiovascular risk. The Swedish Trial in Old Patients with Hypertension-2 (STOP-Hypertension-2) has been designed to compare therapy with beta-blockers and diuretics to therapy with calcium antagonists and angiotension converting enzyme inhibitors. All ongoing trials should be completed in the next few years and are expected to yield valuable information that will improve current strategies for the treatment of hypertension.

Fosinopril versus enalapril in the treatment of hypertension: a double-blind study in 195 patients

The new angiotensin-converting enzyme (ACE) inhibitor fosinopril was compared with the ACE inhibitor enalapril in a multicenter (n = 11), multinational (Denmark, Finland, Iceland, Norway, and Sweden), double-blind, randomized, parallel-group 24-week study in 195 patients with mild to moderate essential hypertension [supine diastolic blood pressure, (SDBP) > or = 95 to < or = 110 mm Hg]. After discontinuing all previous antihypertensive medication, patients were entered into a placebo lead-in period of 4-6 weeks, followed by 24 weeks of randomized treatment with the active compounds administered with a double-dummy technique. The dose of fosinopril was 20 mg, which could be increased to 40 mg after 8 weeks (average 25.6 mg); that of enalapril was 10 mg, which could be increased to 20 mg after 8 weeks (average 12.9 mg). Hydrochlorothiazide 12.5 mg could be added after 16 weeks and was administered to 27% of the patients in the fosinopril group and to 30% in the enalapril group. All drugs were administered once daily. Supine systolic BP (SSBP) decreased from 157 to 143 mm Hg in the fosinopril group (p < 0.01), and from 159 to 147 mm Hg in the enalapril group (p < 0.01). SSDP decreased from 100 to 89 mm Hg in the fosinopril group (p < 0.01) and from 100 to 92 mm Hg in the enalapril group (p < 0.01). Throughout the study period, fosinopril reduced SSBP and SDBP numerically more than did enalapril, by 0-3 mm Hg. Adverse events (AE) caused withdrawal of study medication in 8 patients in the fosinopril group and in 14 patients in the enalapril group (NS). The number of reported AE was not statistically different in the two groups. Inhibition of the ACE was assessed in a subgroup of patients (n = 26, 13 in each group). Fosinopril caused a greater inhibition of ACE at the doses used in the present study, which was statistically significant. Both fosinopril and enalapril caused statistically significant reductions in BP of a similar magnitude, and both agents were well tolerated. However, fosinopril was consistently numerically slightly more effective than enalapril in reducing BP. There were fewer withdrawals due to AE (NS) in the fosinopril group, and the overall recorded AE were fewer in the fosinopril group (NS).

Characterisation of the complex of plasminogen activator inhibitor type 1 with tissue-type plasminogen activator by mass spectrometry and size-exclusion chromatography

Glycosylated human plasminogen activator inhibitor type 1 (PAI-1), produced in Chinese hamster ovary (CHO) cells, showed a variety of compounds with different molecular weights when subjected to electrospray mass spectrometry (ES-MS), owing to the heterogeneity of the carbohydrate chains. However, non-glycosylated human PAI-1, produced in E. coli, gave rise to a prominent species with a molecular weight of 42,774, consistent with the amino-acid sequence. A non-glycosylated mutant of the proteinase domain (B-chain) of tissue-type plasminogen activator (tPA) produced in C 127 cells, had a molecular weight of 28,168. Full-length, glycosylated, tPA showed a large heterogeneity in molecular mass. For a mass study, a tPA-PAI-1 complex was formed, composed of non-glycosylated PAI-1 and non-glycosylated B-chain. This complex was remarkably stable at room temperature in buffer with a neutral pH. The mass spectrum of the complex provided two main species, a peptide with a mass of 3803 and a dominating species of 67,133. These masses are consistent with a complex where PAI-1 is cleaved at the P1-P1' position. A trace of a species with a molecular mass of 70,942 was also found, corresponding to the complete, non-dissociated complex with PAI-1. Separation of the cleaved peptide, corresponding to the hydrophobic C-terminal 33 amino-acid residues of PAI-1, from the complex, was achieved by size-exclusion chromatography in the presence of 30% acetonitrile. Thus, in the complex between tPA and PAI-1, the proteins are held together by a tight covalent bond, but the C-terminal cleaved peptide of PAI-1 is only bound to the complex by hydrophobic forces. To assess whether this is specific to the tPA B-chain alone, experiments with the complex of full-length, glycosylated tPA and glycosylated PAI-1 were also performed, and it was possible to demonstrate the release of the C-terminal PAI-1 peptide by chromatography, mass spectrometry, as well as by SDS-PAGE.