REPLY
Effect of Inhaled Steroids on the Course of Asthma
Constance P. van Schayck;
Edward Dompeling; and
Hans Folgering
15 November 1993 | Volume 119 Issue 10 | Pages 1051-1052
IN RESPONSE:
To determine whether inhaled corticosteroid treatment prevents the accelerated decline in FEV1 observed during bronchodilator therapy alone, patients must be observed during a prolonged bronchodilator treatment period with and without inhaled steroids. This was not done in the study by Kerstjens and colleagues [1], a randomized controlled trial of bronchodilator therapy with or without inhaled corticosteroids. Kerstjens and associates reported that patients who used only the ß2-agonist had an FEV1 decline of 64 mL per year and that the patients who used the combination of the ß2-agonist and the inhaled steroid had an FEV1 decline of 33 mL per year. It would have been interesting to follow the patients who received the ß2-agonist alone after the addition of an inhaled steroid.
As to the difference between prebronchodilator and postbronchodilator FEV1 slope, the redrawn Figure in which the postbronchodilator FEV1 values are included is interesting. We agree that no difference was seen between the postbronchodilator value before and during corticosteroid therapy, and even a nonsignificant opposite trend ( –98 mL/year compared with –120 mL/year) resulted in the paradoxical extrapolation. We observed a significant improvement, however, in postbronchodilator FEV1 during the first 6 months of treatment (+105 mL/year), which seemed to occur only in patients with asthma (+201 mL/year) and not in patients with COPD (–5 mL/year).
We agree completely that the effects of steroid treatment were much more pronounced during prebronchodilator treatment than during postbronchodilator treatment. Indeed, this study proved that the prebronchodilator slope did not indicate an irreversible change in lung function: The steep average prebronchodilator decline of 320 mL during the 2-year bronchodilator treatment period was followed by an increase of 229 mL during the first 6 months of steroid treatment, indicating that at least 72% of this loss seems to be reversible. However, to some extent, this was true for the postbronchodilator change: The average postbronchodilator decline of 196 mL during the 2-year bronchodilator treatment period was followed by an increase of 53 mL during the first 6 months of steroid treatment, indicating that at least 27% of this loss seems to be reversible.
Apart from theoretical considerations, thus far, only the prebronchodilator FEV1 slope has been shown to be a predictor of asthma mortality [2]. We are not aware of any studies that investigated the postbronchodilator FEV1 slope as an indicator of disease severity.
Finally, we should emphasize that extrapolations of observations made during only 2 to 4 years should be interpreted with extreme caution. As we mentioned [3], these extrapolations are a simplification. It can be questioned whether a linear model (as used in the extrapolations of ourselves and in this drawn figure) is adequate to predict the course of lung function over 10 to 20 years.
1. Kerstjens HA, Brand PLP, Hughes MD, Robinson NJ, Postma DS, Sluiter HL, et al. A comparison of bronchodilator therapy with or without inhaled corticosteroid therapy for obstructive airways disease. N Engl J Med. 1992; 327:1413-9.
2. Burrows B, Bloom JW, Traver GA, Cline MG. The course and prognosis of different forms of chronic airways obstruction in a sample from the general population. N Engl J Med. 1987; 317:1309-14.
3. Dompeling E, van Schayck CP, van Grunsven P, van Herwaarden CL, Akkersmans R, Molema J, et al. Slowing the deterioration of asthma and chronic obstructive pulmonary disease observed during bronchodilator therapy by adding inhaled corticosteroids. Ann Intern Med. 1993; 118:770-8.
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