Bone Mineral Density in Subjects with Mild Asthma
Bone Mineral Density in Subjects with Mild Asthma
Abstract & commentary
Synopsis: This current report found that there was no change in bone mineral density over 2 years in patients with mild asthma who were taking inhaled cortico-steroids vs. noncorticosteroid treatment. Furthermore, asthma control was better in patients taking inhaled corticosteroids.
Source: Tattersfield AE, et al. Thorax. 2001;56:272-278.
The development of osteoporosis is a major concern with oral corticosteroids.1 Whether inhaled corticosteroids (ICS) significantly affect bone density is not clear. ICS are clearly beneficial in patients with moderate to severe asthma. They are absorbed to some extent and although systemic effects are less than with oral steroids, potential long-term adverse effects have to be considered when considering risks and benefits of their use in mild asthma.
Tattersfield and associates performed a prospective, randomized, open trial in 19 centers in France, New Zealand, and the United Kingdom. Patients with mild asthma were randomized to receive either inhaled budesonide at a median daily dose of 389 mcg, inhaled beclomethasone dipropionate at a median daily dose of 499 mcg, or noncorticosteroid (nonICS) treatment for 2 years. After initial assessment and screening, subjects were seen in the clinic every 4 weeks for the first 3 months and then every 3 months.
There were no significant differences in the change in the mean bone mineral density between the 3 groups. There was no difference in markers of bone metabolism between budesonide and the nonICS group. However, the beclomethasone group had lower osteocalcin levels than the nonICS group (104 vs 141; P < .05). The beclomethasone group also had higher urinary deoxypyridinoline levels than the budesonide group (105 vs 92) and higher urinary pyridinoline levels than the budesonide group (101 vs 90; P < .05). In subjects taking ICS, the mean dose of ICS correlated with the fall in bone mineral density over 2 years at the lumbar spine (P < .01) but not at the femoral neck. To investigate whether asthma severity might be contributing to bone mineral density by requiring more doses of corticosteroids, FEV1 was added to the prediction model. Little change, however, was observed in the regression coefficient when FEV1 was added as compared to without FEV1 (-0.80 vs -0.82; P = .016) and the findings remained statistically significant. Asthma control was better in patients treated with ICS as determined by reduction in day-time and night-time symptoms and in rescue bronchodilator use. The increase in morning peak flow was more rapid and more marked in subjects receiving ICS, with a mean increase in morning peak flow of 48, 36, and 20 L/min in the budesonide group, beclomethasone group, and the nonICS group, respectively. The change in FEV1 followed a similar pattern with an early increase in the 2 groups receiving ICS.
COMMENT BY DAVID OST, MD, & AAMIR AWAN, MD
ICS are clearly beneficial in patients with moderate to severe asthma. The extent to which the ICS affect bone metabolism and bone density is less clear since the few prospective studies in asthma patients have been small and most cross-sectional studies have not controlled adequately for the prior use of oral corticosteroids.2,3 In the current study, participants had mild asthma, were taking beta-2 agonists only, and had not used corticosteroid treatment by any route during the previous 3 months.
Although no significant differences were observed in bone mineral density in the 3 groups, there was a relationship between the dose of ICS and the fall in bone mineral density over 2 years at the lumbar spine but not at the femoral neck. This could be explained by a direct effect of corticosteroids on bone or an indirect effect due to asthma severity since patients with lower peak flow and FEV1 might have been taking higher doses of inhaled corticosteroids. However, when adjusted for FEV1, there was no significant change in the relationship between ICS and bone mineral density, with a regression coefficient without adjustment for FEV1 of -0.82 and after adjusting for FEV1 of -0.80 (P = .016). Asthma was better controlled in the ICS group, with patients in the nonICS group taking twice as many courses of oral corticosteroids than patients in the ICS group.
On analyzing the data, some caution is needed in interpreting the results. Bone mineral density can be influenced by many factors like menopause and change in weight and smoking, although these did not differ between the 3 groups at baseline. More patients in the nonICS group discontinued the study and this may have introduced bias. These findings would also be influenced by the type of treatment selected for the nonICS group.
Dr. Awan is a Fellow in Pulmonary and Critical Care Medicine, North Shore University Hospital, Manhasset, NY.
References
1. Smith R. Thorax. 1990;45:573-578.
2. Geddes DM. Thorax. 1992;47:404-407.
3. Herrala JT, et al. Am J Resp Crit Care Med. 1995; 151:A374.
Subscribe Now for Access
You have reached your article limit for the month. We hope you found our articles both enjoyable and insightful. For information on new subscriptions, product trials, alternative billing arrangements or group and site discounts please call 800-688-2421. We look forward to having you as a long-term member of the Relias Media community.