Blood Pressure Control in Treated Hypertensive Patients in Daily Practice of Latvian Family Physicians

Inga Stukena1, Daiva Asta Apanavičienė2, Guntis Bahs1, Andrejs Kalvelis1, Vilnis Dzerve3, Baiba Ansmite4, Oskars Kalejs1, 5, Aivars Lejnieks1, 4 1Department of Internal Medicine, Riga Stradins University, Latvia, 2Sanofi-Aventis Lietuva, Vilnius, Lithuania, 3Research Institute of Cardiology, University of Latvia, Riga, Latvia, 4Department of Internal Medicine, Riga Eastern Clinical University Hospital, Latvia, 5Department of Internal Medicine, P. Stradins University Hospital, Riga, Latvia


Introduction
Using the currently recommended criteria for the diagnosis of arterial hypertension (AH) (mean systolic blood pressure [SBP] of ≥140 mm Hg or mean diastolic blood pressure [DBP] of ≥90 mm Hg or use of antihypertensive medication), the overall prevalence of hypertension in adults in the United States in 1999-2000 was 27% for men and 30% for women (1).National surveys indicate that the prevalence of hypertension in many countries is as high or higher as identifi ed in the United States.Recent estimates suggest that approximately 1 billion adults have hypertension, with the highest prevalence being noted in Eastern Europe and the Latin American/Caribbean region (2).The prevalence of hypertension is 41.8% and 40.5% in Latvian urban and rural populations, respectively (3).
The Seventh Report of the Joint National Com-mittee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure has recognized AH as a major risk factor for cardiovascular (CV) diseases (1).Persistent high BP increases the risk of coronary heart disease, stroke, peripheral artery disease, and heart failure (4).Clinical trials have demonstrated that a reduction in SBP by 5 mm Hg can reduce stroke mortality by 14%, coronary heart disease mortality by 9%, and overall mortality by 7%.Antihypertensive therapy has also been associated with a mean 35% to 40% reduction in stroke incidence, a 20% to 25% reduction in myocardial infarction, and a greater than 50% reduction in heart failure (5).Despite advances in understanding of the pathophysiology of hypertension, a wide range of effective antihypertensive drugs, and evidence-based national and international guidelines for the management of hypertension, BP control is still far from optimal in many countries.The results of epidemiologic studies revealed that even in the countries with advanced economy, only half of all hypertensive patients were treated and only 15% to 20% were controlled to target BP level (6).The reasons for inadequate BP control are complex and arise from a combination of factors related to poor patient adherence to therapy and the way that physicians treat hypertension (noncompliance with the current guidelines, avoidance of combined therapy and nonpharmacologic measures) (7)(8)(9)(10).
The main objective of this study was to evaluate BP control level in treated hypertensive patients in Latvia.We also aimed to compare the patients with controlled and uncontrolled BP in terms of their clinical characteristics, prescribed medications, and recommendations for further treatment.

Materials and Methods
The protocol of the study was reviewed and approved by the Latvian Independent Ethics Committee for the Investigation of Drugs and Pharmaceutical Products.The study was conducted in accordance with the recommendations adopted by the 18th World Medical Assembly (Helsinki, 1964) and all applicable amendments.This was a cross-sectional study.In order to ensure that the data refl ect BP control of patients living in urban as well as rural areas, randomly selected family physicians throughout Latvia were asked to participate in the study.A total of 73 family physicians agreed to take part in the study.The regions covered included Aizkraukle, Bauska, Cesis, Daugavpils, Dobele, Jelgava, Kuldiga, Lapmezciems, Liepaja, Limbazi, Ludza, Ogre, Rezekne, Riga, Skrun da, Saldus, Talsi, Tukums, Valmiera, and Vents pils.Every physician had to include at least 6 patients.Every third patient with the diagnosis of hypertension who visited the family physicians on a working day for any reason was asked to take part in the study.In case this patient did not meet the inclusion criteria or refused to participate, the next patient was offered to take part.
A total of 455 patients were recruited between March 2009 and June 2009.The subjects included in the study were 18-80 years old who had a diagnosis of essential AH and had been treated with antihypertensive drugs for at least 1 year.All the patients provided written informed consent.The following exclusion criteria were applied: known secondary hypertension, pregnancy, required hospitalization, and factors that may infl uence the accuracy of BP measurements (i.e., fever, alcohol or drug addiction, anxiety, restlessness, etc.).
For each patient, the family physician registered the following data into a standardized case report form during a single visit: age, gender, weight, height, waist circumference, duration of AH, concomitant diseases and risk factors, previous antihyperten-sive treatment, BP, and heart rate.Demographic and medical data were retrieved from patients' fi les, while anthropometric parameters (height, weight, and waist circumference) and blood pressure were measured during the study visit.Height (cm) and weight (kg) was measured with indoor clothing and without shoes.BMI was defi ned as measured weight in kilograms divided by squared height in meters.The waist circumference (cm) was measured at the level of the umbilicus with the participant standing and breathing normally.BP was measured in a seated position after a 5-minute rest using a calibrated mechanical aneroid sphygmomanometer (manufacturer Rudo lf Riester GmbH, model Big Ben®).Two measurements were performed.If results of SBP and/or DBP differed by 10 mm Hg or more, the third BP measurement was performed.The mean of 2 or 3 readings was recorded into a case report form.Heart rate (heartbeats per 1 minute) was also measured in a seated position after a 5-minute rest.
Family physicians indicated patients' target BP according their CV risk and assessed if target BP (<140/90 mm Hg in low and moderate added CV risk or <135/85-125/75 mm Hg in high and very high risk) was achieved.Stratifi cation of CV risk was performed according to the criteria by the ESH/ ESC guidelines for the management of arterial hypertension (11) and the Latvian guidelines for hypertension management (12).The stratifi cation was based on records in patients' fi les about risk factors: • Age >55 years for men and >65 years for women; According to the above referred guidelines (11,12), the low added CV risk group comprised patients with the following: 1) normal BP (DBP/SBP, 80-84/120-129 mm Hg) or high normal BP (DBP/ SBP, 85-89/130-139 mm Hg) plus 1-2 risk factors; or 2) grade 1 hypertension (DBP/SBP, 90-99/140-159 mm Hg) alone.The moderate added CV risk group comprised patients with the following: 1) normal BP plus ≥3 risk factors or the metabolic syndrome or subclinical organ damage or diabetes; or 2) grade 1 hypertension plus 1-2 risk factors; or 3) grade 2 hypertension (DBP/SBP, 100-109/160-179 mm Hg) with or without 1-2 risk factors.The high added CV risk group included patients with the following: 1) high normal BP or grade 1-2 hypertension plus ≥3 risk factors or the metabolic syndrome or subclinical organ damage or diabetes; or 2) grade 3 hypertension (DBP/SBP, ≥110/≥180 mm Hg) alone.The very high added CV risk group consisted of patients with the following: 1) established CV or renal disease; or 2) grade 3 hypertension plus 1-3 risk factors or the metabolic syndrome or subclinical organ damage or diabetes.
The main parameter to be evaluated was BP control.BP was considered as controlled if the target BP was achieved according to the assessment of the family physicians and as uncontrolled if the target BP was not achieved.
The descriptive statistics was applied for data analysis.The χ 2 test or Fisher exact test was used to assess the difference between categorical data.The Student t test was applied to test the difference between continuous normally distributed data or the Wilcoxon signed rank test if the data were not normally distributed.Statistical tests were interpreted at the 5% signifi cance level (two-tailed).Following initial descriptive statistics, multiple logistic regression analysis was used to identify variables that predicted the likelihood of reaching target BP.A forward stepwise procedure was used for the addition of individual variables to build the model.Differences were considered statistically signifi cant in the fi nal model with a P value of <0.05.Statistical software SAS 9.1.2was used for statistical data analysis.

Results
A total of 455 patients with essential AH were enrolled into the study.There were 137 men (30.1%) and 318 women (69.9%) among the study participants.The mean age of the patients was 62.6 years (SD, 9.7; range, 33 to 80 years).The mean duration of hypertension in the study population was 11.1 years (SD, 8.2).
One hundred ninety-six patients (43.1%) were classifi ed as having low or moderate added risk, while 259 patients (56.9%) were considered as having high or very high added risk.The proportion of men with high or very high added risk was higher than that of women (67.2% and 52.5%, respectively; P<0.05).
Nearly half (46.2%) of the study patients attained their target BP according to the assessment of family physicians.The proportion of patients with effectively controlled BP was almost 2-fold greater in the group of low or moderate risk in comparison with the group of high or very high added risk (61.7% vs. 34.4%,P<0.0001).BP was controlled (<140/90 mm Hg) in 161 patients (35.4%) as assessed by BP measurements performed during the study visit.The mean BP was similar among patients with different added CV risk (143.2±19.6/85.9±9.9 mm Hg and 144.1±18.5/86.3±10.1 mm Hg in patients with low or moderate risk and high or very high risk, respectively).
In total, 317 patients (69.7%) had at least one concomitant disease.The most frequent comorbid conditions were heart failure, coronary heart disease, and diabetes, each present in more than 30% of patients.The proportion of patients without any concomitant disease in the group of controlled BP was higher than that in the group of uncontrolled BP (35.7% vs. 25.7%).A total of 439 patients (96.3%) had at least one risk factor, with abdominal obesity and dyslipidemia being most prevalent.Among the patients with uncontrolled BP, there were more patients with multiple risk factors (89.4% vs. 80.0%,P<0.05).This group had more patients with metabolic syndrome, dyslipidemia, or abdominal obesity (Table 1).
The results of the fi nal multivariate analysis showed 3 signifi cant predictors of reaching the target BP.Compared with the patients classifi ed as having high or very high added risk, those with low or moderate added risk had a greater chance of reaching targeted BP (odds ratio [OR], 2.42; 95% confi dence interval [CI], 1.73 to 3.39).Lower odds of reaching target BP were associated with the diagnosis of the metabolic syndrome (OR, 0.67; 95% CI, 0.45 to 0.99) or dyslipidemia (OR, 0.59; 95% CI, 0.42 to 0.82).
Current pharmacologic management of hypertension was similar in the patients who attained their target BP and those who did not attained their target BP, except the patients with uncontrolled BP who were treated with DHP calcium channel blockers more frequently.
Overall, on the day of study visit, family physicians did not change treatment for 173 patients (38.0%); this decision was more common among patients with controlled BP.For the remaining patients, pharmacological treatment was changed.The majority of patients (N=214, 47.0%) were advised a single treatment correction.Sixty-one patients (13.4%) were offered to change 2 treatment recommendations, while 7 patients (1.5%) were offered 3 changes in their current treatment.An addition of a drug from another class, an increase in a single drug dose, and change of drug class were the more frequent decisions (Table 2).

Discussion
This study discloses the BP control among patients receiving pharmacologic antihypertensive  Epidemiologic studies carried out in the United States, Canada, and Europe have shown that BP control is inadequate despite pharmacological treatment.In different countries, the percentage of treated hypertensive patients who achieved the recommended BP targets of <140/90 mm Hg was shown to range from 8.3% to 42% (13-23).The rate of hypertension control that was observed in our study population was similar to that observed in another recent Lithuanian study with a similar design.In that study, 45.4% of treated hypertensive patients achieved target BP levels, and the rate of BP control was signifi cantly higher in a group of low and moderate added CV risk than in high and very high added risk group (62.9% vs. 26.3%)(24).In contrast, available published studies from Latvia reported much lower BP control rate (6.4%-17.6%)(3,25).The actual reason for such signifi cant differences between countries in BP control rates is not clear, but most likely it is related to methodological differences used in the studies.
A high proportion (90.8%) of patients treated with two or more antihypertensive drugs in the study population shows that Latvian family physicians follow the current national and international guidelines.The widespread use of combined treatment may at least partially explain the relatively high rate of BP control in the study population.However, despite the fact that almost all patients with high or very high added CV risk received combined antihypertensive treatment (91.4%),only one-third of them achieved the target BP.One of the reasons may be the more stringent target BP for patients with high or very high risk (<135/85-125/75 mm Hg).According to the published data from other countries, 30%-60% of hypertensive patients receive monotherapy (15-21, 23, 26, 27).BP control rate in patients receiving monotherapy in Latvia was very low and ranged from 3.8% in patients receiving diuretics to 12.5% in those treated with beta-blockers (3).No information about the proportion of patients receiving monotherapy was provided in this  (12,29).Physicians usually consider the patient nonadherence to pharmacologic and nonpharmacologic treatment as the main barrier to successful hypertension management (6).Information about patient adherence within the framework of this study was not collected; however, other authors reported that only half of Latvian patients (48% in city and 49.7% in village) regularly take prescribed antihypertensive drugs (25).
While interpreting the reasons for relatively high BP control rate found in this study, the possibility of selection bias cannot be excluded, i.e., physicians might be more inclined to enroll patients with better-controlled BP.In order to minimize the selection bias, every third hypertensive patient who visited the family physicians on a working day for any reason was asked to take part in the study.
The comparison of patients' characteristics revealed that diabetes, metabolic syndrome, dyslipidemia, and abdominal obesity were more frequent among patients with uncontrolled BP.Multivariate logistic regression analysis showed that patients with the metabolic syndrome or dyslipidemia had lower odds of attaining BP target.
As expected, patients with uncontrolled BP were more often recommended to correct the pharmacologic antihypertensive treatment.The most popular decisions were an addition of a drug from another class, an increase in a single drug dose, and change of drug class.Very few patients (7.4%) who did not achieve the target BP were not recommended any treatment recommendations.

Conclusions
In the present sample of treated hypertensive patients, the rate of blood pressure control was less than 50% and was even worse in patients with high or very high added CV risk (34.4%).Since the overwhelming majority of patients with uncontrolled blood pressure received the combination therapy and most of them were recommended some treatment modifi cations, other unidentifi ed reasons in this study may interfere with the management of hypertension especially among high-risk patients.

Table 1 .
Clinical Characteristics of Patients With Controlled or Uncontrolled Blood Pressure

Table 2 .
(28)ent Antihypertensive Treatment and Recommendations for Further Treatment in Patients With Controlled or Uncontrolled Blood Pressure article.Monotherapy even at maximal doses effectively controls BP in less than 50% of hypertensive patients(28); thus, combination therapy is needed for the majority of hypertensive patients.Combination therapy is more effective, and guidelines for the management of hypertension declare the combinations of low dose antihypertensive drugs as a fi rstchoice treatment in patients with high or very high added CV risk Values are number (percentage).BP, blood pressure; ACE, angiotensin-converting enzyme; DHP, dihydropyridine.*P<0.05.