Журнал «Здоровье ребенка» 4 (47) 2013

Juvenile rheumatoid arthritis (JRA) is the most common rheumatic disease in childhood.

Despite the fact that children with JRA have predisposing factors for development of arterial hypertension (endothelial dysfunction, increased arterial stiffness, systemic glucocorticoid use), problem of blood pressure (BP) pathological changes in this group is not clearly understood.

Arterial hypertension is very good recognizing factor of atherosclerosis and cardiovascular morbidity even in the absence of other traditional cardiovascular risk factors (I. P. Katerenchuk et al., 2008; V. G. Maidannik et al., 2008).

Increased BP in children is associated with increased risk of coronary artery calcification in older age (L.T. Mahoney, T.L. Burns et al., 1996). Systolic blood pressure above 110 mmHg in children is associated with the development of lipid spots in the right coronary artery and abdominal aorta (H.C. McGill Jr. et al., 2000). Arterial hypertension in childhood causes development of endothelial dysfunction, vascular wall remodeling and increase of arterial stiffness (V. G. Maidannik et al., 2008).  Thickening of intima-media in the common carotid artery is more than 8 mm in half of children primary hypertension.

The prevalence of hypertension in adult patients with rheumatoid arthritis (RA) is about 52-73%. It is characterized by lower efficiency of antihypertensive therapy and BP control in contrast with hypertensive patients without arthritis (Panoulas V. F., Metsios G. S. and coauthors, 2008). O. Halyutina, M.A. Stanislavchuk  have found that high risk of coronary events in patients with RA depends on diastolic BP and pulsed BP (2007). Shilkina N. P. et al. showed the following results of ABPM in patients with RA : decrease of physiological BP reduction at night, increase in the number of "non-dipper" and variability in contrast with the control group (2010).

There is a small number of studies devoted to the problem of arterial hypertension in children with JRA. Significant increase in mean systolic BP was found in children with juvenile idiopathic arthritis compared to healthy controls: 120 mmHg in children with arthritis vs. 111 mmHg in healthy children (Glowinska-Olszewska B. et al., 2011).

No data can be found in the scientific literature concerning the results of the office and daily blood pressure in children with JRA. 

The aim of our research was to study BP characteristic in children with JIA as an important factor of cardiovascular pathology.

Materials and methods: 31 patients were examined during 2011-2012 years. The average age of the group was 12.25 ± 3.07 years. Mean disease duration was 3.45 ± 3.53 years. Polyarthritis was observed in 15 (48.8%) children, oligoarthritis in 12 (38.7%), systemic form JRA in 4 (12.5%). High activity was observed in 5 (16.1%) cases, moderate in 9 (29%), low in 17 (54.9%). One girl had positive rheumatoid factor.

The systemic glucocorticosteroids (GCS) were subscribed to 21 (67.7%) patients. The average dose of GCS was 9 mg / kg/d, the mean duration of GCS treatment was 1.7 years with a maximum duration 2.5 years, 10 children received pulse- therapy of methylprednisolone at different stages of treatment (at first observation and during exacerbations).

The control group consisted of 20 healthy children similar by age.

Measurement of office BP on different limbs, ambulatory monitoring of BP (ABPM), calculating ankle-brachial index (ABI) were performed. Interpretation of the office BP data was performed with regard to the age and height as it is recommended by Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents (2004). ABPM results were compared with the physical activity of patients, presence of nocturnal sleep disturbances during the diagnostic procedure. For correct estimation of ABPM results we used guidelines of ANA Ambulatory Blood Pressure Monitoring in Children and Adolescents: Recommendations for Standard Assessment: A Scientific Statement From the American Heart Association Atherosclerosis, Hypertension, and Obesity in Youth Committee of the Council on Cardiovascular Disease in the Young and the Council for High Blood Pressure Research (2008).

Statistical analysis included χ-criterion, t- criterion, correlation coefficient.

Results: In children with JRA mean office systolic BP (SBP) was 112±1.47, diastolic BP (DBP) 66.9±1.7, pulsed BP 44.5±1.88 vs 104±1.68, 63.6±2.12 and 45.6±2.12 in healthy children. A significant increase in SBP was revealed in patients compared with healthy children (p = 0.007).

After comparing of the received results to height, gender and age BP level under 90^th percentile was observed in 2 children and 95th percentiles in 5 children (p=0.022) with JIA.

In 6 children asymmetry in SBP between the two arms for more than 10% (p = 0.036) was revealed. In one patient asymmetry of diastolic blood pressure was observed. The difference in the values ​​of pulsed pressure on the upper extremities was observed in 14 patients (41.2%) compared to 4 (20%) healthy children.

Ambulatory Blood Pressure Monitoring (ABPM) data was: mean daily SBP 116.36±1.9, mean daily DBP 66.39±1.24, mean daily SBP 121 ±1.99, mean daily DBP 71 ± 1.58 in children with JIA vs mean daily SBP 108.3±1.22, mean daily DBP 61.35±0.78 and mean daily SBP 113.5 ± 1.34, mean daily DBP 66.4±0.72 in healthy children. In children with JRA significant increase of average SBP and DBP (p <0.05) were observed. But we found no significant difference in the levels of morning, day and night BP in children with JRA compared to the control group. Increase in mean values of pressure-time index and significant decrease in SBP day index in children with JRA were also observed.

Pathologicaly increased pressure-time index and pressure-square index were observed in 12 patients (p=0.012). In the main group 19 children were «dippers», 11 − «non-dippers» (p=0.012), 1 «night-piker» vs 19 «dippers» and 1«non-dipper» in health children. Arterial hypertension was diagnosed in 7(22.58%) JIA children (p=0.02).

The abnormal increase of blood pressure during ABPM was noted in 12 children (37.5%) (p = 0.0015). Hypertension was observed in 7 (21.85%) (p = 0.022) patients with JRA.

The ABI in children with JRA was 1.18 ± 0.016. No significant difference between the clinical types of JRA was found. It was 1.163 ± 0.013 in group of polyarthritis and 1.207 ± 0.03 and oligoarthritis, 1.19 ± 0.01 in systemic form. In healthy children ABI was 1.35 ± 0.011 (p <0.05). The significant difference of the value of ABI in children with different degree of arthritis activity was also found: 1.17 ± 0.02 during the III degree, 1.163 ± 0.0108 − II degree (p <0.05) and 1,15 ± 0,09 − I degree.

Age(r = 0.57), diseases duration (r = 0.5), GC time use (r = 0.42) influence on blood pressure in JRA patients. No significant influence of height, CRP level, currently GC dose, autonomic nervous system on blood pressure was detected. Due to formation of short stature BP in children with JIA depends on age, despite healthy children, whose BP depends on both age and height.

Conclusion: children with JRA have more significant increase of office blood pressure and its daily characteristics. Blood pressure levels in children with JRA are more determined by age than height. Duration of GCS therapy has more influence on parameters of blood pressure than current GCS dose.