Short-term growth and bone turnover in children with persistent asthma during inhaled steroid therapy

ABSTRACT

Although the change in therapy of bronchial asthma towards inhaled corticosteroids [ICS] is supported by both pathophysiological findings and efficacy data, its safety is often questioned. Many pediatricians are still concerned about the potential adverse effects of long-term treatment with inhaled corticosteroids, particularly on growth. As a result, this class of medication remains underused in children in many countries. The objective of this study is to compare the formation and degradation markers of bone turnover in asthmatic children who are using inhaled fluticasone propionate [FP]. The present study included 45 asthmatic children, of the age group 6-12 years, They were divided into two groups Group 1 26 patient with mild to moderate persistent asthma, receiving FP via pressurized metered dose inhalers [pMDI] at dosages equal to or below 200 mcg/day and Group II 19 patients with moderate to severe persistent asthma, receiving FP at doses above 200 mcg/day. The study also included 14 healthy, nonatopic, non-asthmatic children as controls. All asthmatic children were subjected to full medical history taking, symptom score calculation, thorough clinical examination, anthropometric measurements, Peak expiratory flow rate [PEFR] monitoring as well as pulmonary function testing before and after treatment, laboratory investigations including CBC with absolute eosinophilic count [AEC] calculation and total serum IgE once, serum calcium, phosphorous, alkaline phosphatase. Carboxy terminal of procollagen I [PICP] and Carboxy terminal telopeptide of type I collagen [ICTP] by radioimmunoassay as markers for bone formation and degradation respectively, before and after treatment with inhaled FP for 6 months. PICP and ICTP were also assessed once in controls. The results of the present work demonstrated a statistically significant decrease in asthma symptom score in both groups, as well as improvement of all asthma symptoms. A statistically significant increase in mean weight and height was observed in both groups that was within the normal percentiles. However, no statistically significant increase in mean body mass index [BMI] was demonstrated in either group. As regards pulmonary functions, a statistically significant increase in mean Forced expiratory volume in the first second [FEV[1]] Forced expiratory volume in the first second/Forced vital capacity [FEV[1]/FVC] and Forced expiratory flow through the midportion of the FVC [FEF[25-75]] was detected after treatment. No statistically significant difference between pre-and post-treatment mean values of serum calcium, phosphorous, and alkaline phosphatase was demonstrated. However, a statistically significant decrease was observed in post-treatment mean values of both PICP and ICTP as compared to pretreatment values with a significant positive correlation between both analytes implying a decrease in rate of bone turnover. No suppression of statural growth should occur in asthmatic children treated with inhaled FP if used at the conventional doses tailored to disease severity. A slowing down of bone turnover rate may occur, which is coupled for both formation and degradation markers. PICP and ICTP are sensitive markers that might be early indicators for potential growth suppression