topeeng.gif (8416 bytes)

[ Scientific Activity - Actividad Científica ] [ Brief Communications - Temas Libres ]

Hypertension. Risk Stratification

Dr. Jorge Pastor Did Núñez

"Raúl Gómez García" Educational Policlinic Hospital
Havana City. Cuba

Introduction
Objectives
Methods
Results
Discussion
Conclusions

 

Introduction. The cardiovascular risk in patients with high blood pressure (HBP) is determined not only by tensional figures that we observe or detect isolated or maintained, but also by the target organ disease (TOD), or other risk factors, such as smoking, dyslipidemia, diabetes, etc. Therefore, the Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure (JNC VI) [1] has established that based on the goal studies bases-analysis, these factors modify in an independent way, the onset of a subsequent cardiovascular disease. Consequently, it orientates the exploration of this possibility during a routinary evaluation of the patients wiht hypertension (i.e., medical history, physical examination, and laboratory test). Based on this concept and on the average level of blood pressure (BP) [2], the JNC VI recommends a new system for the patient categorization in the Risk Groups, that enables the physician in charge to get a practical guide for therapeutic decision.

However, after an automated extensive revision of the national and international medical literature, we concluded that there is not a previous experience on the item neither an available paper that could approach it.

Objetives. To classify the patients according to the risk groups and describe the therapeutic behavior performed according to the recommendations of the JNC VI.

Methods. A number of 1412 hypertensive patients registered in the Work Basic Group no. 2 at "Raúl Gómez García" Educational Policlinic Hospital of Havana City, were subjected to a research protocol during the 1996 - 1998 period. This research included: estimate average tensional figures, identification of mayor risk factors, TOD and cardiovascular disease and undergoing treatment.

The patients were classified on the basis of the previous elements considering the tensional figures and risk groups. In a number of 39 patients from the total, the research protocol could not be completed concerning some of the phases, so they were not included in the final results of the 1373 patient group.

The average systolic and diastolic arterial BP estimated, was performed on the basis of 6 evaluations of tensional figures, based on the standardized method protocol, measuring technique of arterial tension, occasionally at the patients' home or in the physician's office at different hours [1,3].

In order to identify the Mayor Risk Factors, each patient was studied so as to detect any possibility of cardiovascular risk recommended by the JNC VI.

The TOD and/or cardiovascular disease was considered positive once it could be identified conclusively: Heart Disease, Cerebrum Vascular Disease or episodes of Transitory Cerebral Isquemia, Nefrophaty, Periphery Arterial Disease, or Retinopathy [1,4].

The Treatment type defined is in two variants: pharmacological and not pharmacological [3]. We do not observe the indications, but the practical application of the measures in lifestyle modification (MOD), and drug therapy.

Patient classification according to tensional figure Stages in agreement with the recommendations of the JNC VI was performed from the average values of systolic and diastolic BP.

Patient classification according to Risk Groups was performed by the JNC VI considering the BP figures, the studied risk factors, TOD and/or Cardiovascular Heart Disease and Diabetes Mellitus.

These risk groups embraces 990 patients of the studied, (exluding those with optimal, or normal figures), which are distributed in the tables of the therapeutic behavior, following the recommendations of the JNC VI.

The previous processes described were performed under an automated procedure with a program support applied to the databases of the patients whose structure echoes the defined intents. For the statistic process, the Epi Info programs version 6.03 endorsed by the Atlanta's Center for Disease Control & Prevention (CDC) was used.

Results. Figure 1 represents the classification of the 1373 valuable patients in the different categories of BP, recommended by the JNC VI. Analyzing the current control criterion (BP < 140/90), that encloses categories of optimal BP, normal and high-normal, we could observe that 56.9% of the patients have acceptable tensional values or that minor risk. However, we must underline that the stratificables tensional categories in the risk groups (BP high-normal and hypertension in any of its stages), involves the 72.1% of the over-all cases.

img002.gif (74953 bytes)

Patient distribution according to tensional figures and risk groups, are exposed on Table 1. From the total of 990 stratificable cases, 456 are in the risk group B (46.0%) and 514 in the risk group C (51.9%). These two groups gather 970 patients; that is, a 97.9% of the cases.

The relation between tensional figures and the risk groups (p=0.00465413) can be seen on Table 1. BP stages high-normal (40.2%) and hypertension stage I (50.0%) are predominant and they reach the 90.2% of the stratificable over-all cases.

img003.gif (84925 bytes)

In group A, 60% of the patients are classified as normal, while in risk group B and C, the hypertension stage I is the most frequent. It is significant to point out that the 45.2% and 35.0% of the patients in risk group B and C show figures of BP high-normal.

At this point, it is convenient to focus the therapeutic intervention in the different stages of BP underlying those that will be exposed separately, but always respecting the general format proposed by the JNC VI (see Annex 1).

Table 2 shows those patients with BP high-normal (p=0.00030097). It is precisely in this stage where MOD can be more beneficial, especially in-groups A and B. Nevertheless, only the 50.0% and the 14.9% of the cases in those groups, the practice in some of its forms is an intervention behavior. On the contrary, the 18.4% in group B only takes antihypertensive drugs.

img004.gif (84946 bytes)

Patients in hypertension stage I are stratified in Table 3 (p=0.00011824). On examining group A we verify that the 12.5% only uses the MOD. It is remarkable that this group is selected for a long-term treatment of this type for 1 year. If in the course of time, an adequate adjustment of tensional figures in not achieved, we would add a drug therapy, recommending a variant in the treatment up to 6 months for group B that equally shows a 20.3% insufficiency of it.

img005.gif (84898 bytes)

The 97 patients stratified in stages II and III of arterial hypertension are shown in Table 4. Only in high BP figures (as in a reduced number cases) and adequate therapeutic behavior is performed.

img006.gif (84815 bytes)

Discussion. The close relation that maintains systolic and diastolic pressures and the cardiovascular risk is strong, continuos, graded, consistent, independent, predictive and etiologically significant for all patients with or without coronary heart disease [5,6]. For this reason, in spite of the adult HBP classification that is somehow arbitrary, it is useful for general physicians in order to decide the patient treatment, considering a group of factors that include the current level of BP [1].

The First National Inquiry of Risk Factors and Preventive Activities in Cuba evidenced that, from the total number of hypertensive patients detected, only a 60.8% were known as such, and of these, only the 45.2% were controlled. The reported control figures have change substantially according to the authors, geographic zones and employed methods considering (20% for the 73.1% and even higher) [7]. In the majority of them, the values are untimely and not comparable with the methodologic criterion assumed in this paper.

img007.gif (84819 bytes)

Concerning the matter, we consider important to state the significance of patients who are regularly considered as controled or in stage I, because of the fact that they do not show alarming figures and so do not receive the adequate assistance on the physician's part that could a morbidity probability or complication associated to a number of reasons if there is no preventive approach based on the risk groups.

According to MOD, which is a low cost treatment, and of minimun risk, we consider important to emphasize that besides having the capacity to acting preventively on the onset of symptomatic HBP, it has been demonstrated to be effective in decreasing tensional figures, and that it can reduce an important cardiovascular risk factor group [8]. Although de MOD itself does not solve HBP control, it can reduce the number and the necessary antihypertensive drug dosage.

Conclusions. To approach the subject or item of risk factor by de JNC VI to the studied cases, it is clear that a significant patient proportion in the risk groups B (45.2%) and C (35.0%), show figures of rated BP as high-normal. Even though when it becomes comfortable to adapt general patterns of behavior concerning BP figures, we should not obviate a possible risk of cardiovascular disease and so it ought to be the main preoccupation of the physician in charge.

The obtained results clearly confirm that in spite of its innocuity and low cost, the non-pharmacological measures of control are little used in the risk groups where they can be more efficient.

Top

 Reference

1. Joint National Commitee on Detection, Evaluation, and Treatment of High Blood Pressure. Sixth report of Joint National Commitee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI). Arch Intern Med 1997;157:2413-46.
2. Kannel WB, Blood pressure as a cardiovascular risk factor: prevention and treatment. JAMA 1996;275:1571-76.
3. Dueñas Herrera, A; Hipertensión arterial. Su control en el nivel primario de salud. Rev Cubana Med Gen Integral 1992;8(3):195-213.
4. National Institutes of Health. National Heart, Lugn and Blood Institute, Joint National Commitee on Detection, Evaluation, and Treatment of High Blood Pressure. The Fifth Report of Joint National Commitee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC V). NIH Publication No. 93-1088. March 1994.
5. Stamler J. Blood pressure and high blood pressure: aspects of risk. Hypertension 1991;18(Suppl I):I-95-I-107.
6. Flack JM, Nealton J, Grimm R Jr. For the multiple risk factor Intervention Trial Research Group. Blood pressure and mortality among men with prior myocardial infaction. Circulation 1995;92:2437-45.
7. Macías Castro, I. Epidemiología de la hipertensión arterial. Acta Méd 1997;7(1):15-24.
8. Appel LJ, Moore TJ, Obarzaneck E. for the DASH Collaborative Research Group. A clinical trial of the effects of dietary patterns on blood pressure. N. Engl J Med. 1997;336:1117-24.
9. Neaton JD, Grimn RH Jr, Prineas RJ. For the Treatment of Mild Hypertension Study Research Group. Treatment of mild Hypertension Study: final results. JAMA 1993;270:713-24.

 

Questions, contributions and commentaries to the Authors: send an e-mail message (up to 15 lines, without attachments) to hbp-pcvc@pcvc.sminter.com.ar , written either in English, Spanish, or Portuguese.

Top


© CETIFAC
Bioengineering
UNER

Update
31-Oct-1999