ZERIFIN, ISRAEL-- Inhaled cortico-steroids reduce asthma mortality, new data suggest. Michael Goldman, MD, Yitzhak Katz, MD, and colleagues[1] at the Assaf Harofeh Medical Center in Zerifin, Israel, examined asthma mortality rates before and after inhaled corticosteroids became widely used in Israel and found that asthma deaths dropped as use of inhaled corticosteroids increased.

"The basic question we were asking in this study was, 'what was the trend of asthma mortality?'" Dr. Katz said. "We found that asthma mortality declined from 1991 to 1995." This decrease corresponded with an increase in the sale of inhaled corticosteroids and could not be explained by a drop in asthma prevalence or severity, he added.

Using data from Israel's Department of National Health Statistics, Goldman et al compared the asthma mortality rate in Israel from 1991 to 1995 with that of the previous decade. The researchers also examined data on the use of inhaled corticosteroids and ß₂-agonists. Inhaled corticosteroids became available in Israel in the late 1970s, but their use did not become widespread until the early 1990s. Goldman et al found that mean yearly sales of these drugs (based on units equivalent to a 50-µg canister of beclomethasone dipropionate) increased from 21.70 per 100,000 population in 1982 to 190.45 per 100,000 population in 1995. During the same period, annual asthma mortality in the 5- to 34-year-old population dropped from a mean of 0.393 per 100,000 in the years 1981 to 1990 to 0.202 per 100,000 in the period from 1991 to 1995 (P < .05).

The decrease in asthma mortality did not appear to reflect a decline in asthma prevalence or severity, Dr. Katz noted, because average yearly sales of inhaled ß₂-agonists, typically used as "rescue" inhalers during asthma attacks, were actually slightly higher in the years 1991 to 1995 than in the 1980s. Instead, the improvement in outcome was likely due to better control of inflammation through use of inhaled corticosteroids, Dr. Katz told RESPIRATORY REVIEWS. This study supports the shift in asthma treatment over the past decade from controlling bronchospasm to reducing inflammation.

Asthma deaths also decreased among those age 35 to 64 years, but the change did not reach statistical significance. Dr. Katz suggested that this may have had several causes, including a higher incidence of chronic obstructive pulmonary disease in the older population and a decreased likelihood that asthma was accurately listed as a cause of death. The decrease in mortality was also not significant when the whole 5- to 64-year-old population was considered together; however, a strong negative correlation between decreased asthma mortality and increased sales of inhaled corticosteroids in the entire cohort was found. According to Dr. Katz, this negative correlation suggests "that there was a direct relationship between these two events."

Goldman et al noted that they could not prove that increased use of inhaled corticosteroids was the only factor responsible for the decreased mortality rate. Nevertheless, they concluded, "The ability to demonstrate a statistically significant reduction in asthma mortality … that correlated with a statistically significant change in therapeutic management is encouraging."

--Janis Kelly

Reference
1. Goldman M, Rachmiel M, Gendler L, Katz Y. Decrease in asthma mortality rate in Israel from 1991-1995: is it related to increased use of inhaled corticosteroids? J Allergy Clin Immunol. 2000;105:71-74.