Effect of intermittent systemic corticosteroid on bone metabolism in bronchial asthma patients

The purpose of this study was to assess the effect on bone mineral density (BMD) of systemic corticosteroid (SCS) intermittently administered for rescue from asthmatic exacerbation. Through digital image processing and calculation of four other indices, BMD was compared in groups of asthmatic patients receiving inhaled corticosteroid (ICS) alone or ICS plus intermittent SCS. We defined SCS as intermittent administration of the equivalent of 1 mg/day prednisolone in the management of asthma exacerbations during the previous 1 year. Serum NTX, a bone resorption marker, was significantly higher (p = 0.02) in the SCS group than the ICS group. SCS had no effect on BMD, although the frequency of patients at "high-risk" for osteoporosis according to the Female Osteoporosis Self-assessment Tool for Asia (FOSTA) tended to be higher in the SCS group (35%) than in the ICS (28%) or control (10%) group. Because patients in the ICS group already had impaired respiratory function due to repeated asthma exacerbations, it was difficult to determine whether it was asthma itself or SCS that is the risk factor for osteoporosis. In addition, the response of biochemical markers of bone turnover to intermittent SCS remains unclear and likely differs from that elicited by high-dose, short-term, or continuous SCS. That said, relatively low-dose intermittent administration of SCS raised levels of bone resorption markers, which likely reflects altered bone metabolism. Taken together, these findings suggest that, without consideration of its effects on bone, SCS administration should be avoided.