Discussion
Our study suggests that intravenous MS are unequivocally cost-effective
and dominant over standard treatment in children with moderate-severe
acute asthma in emergency setting; achieving better outcomes at a lower
cost. Although the variable that exhibited a significant effect on these
results was the probability of hospitalization, MS was the dominant
strategy overall ranges of this variable analyzed.
The findings of this study constitute a new argument to include the MS
in clinical practice guidelines of pediatric asthma for treating acute
asthma exacerbations. Due to the important burden of disease generated
by asthma, especially in Colombia and other middle-income countries,
this strategy will be useful not only for decreasing the probability of
hospitalization due to acute asthma but also for decreasing associated
costs. The potential magnitude of cost savings for the health system (US
$ 448 per patient ) is no negligible if we consider that this disease
affects between 10 to 13% of children in Colombia and only 2.4% of
them meets criteria for total asthma control (26, 27)
The last version of Global Initiative for Asthma does no recommend the
use of MS for routine use in children with acute exacerbation, despite
acknowledging that there is evidence of its use and positive effects on
hospitalization rates (28).Also the Colombian Clinical Guideline for
Asthma do not recognize the MS as first line in this patients(29) . Our
study provides evidence of beneficial clinical effects of MS when added
to the standard treatment with bronchodilators, and corticosteroids in
patient with moderate-severe asthma exacerbations.
Previous economic evaluation in the UK based on evidence from a
randomized placebo-controlled multi-center trial of nebulized MgSO4 in
severe acute asthma in children found that MS had a 67.6% of
probability of being cost-effective at EUR 22.957 per QALY gained(30).
However, they only had full costing in less than 50% of cases, limiting
their conclusions. Our study is the second publication on this topic,
using a societal perspective, and made in a setting with it more limited
economic resources. The results from different countries are not easily
comparable, mainly due to many differences in prices of labor, drugs,
medical test, frequency of use of resources, adherence to clinical
guidelines, and differences in access to and provision of specialized
care instead of primary care, and payment schemes.
A very important aspect of our model is that it was robust to changing
the values of the model’s utilities and costs. MS was always the
cost-effectiveness strategy un all ranges of thresholds evaluated with a
low population EVPI. This was consistent with the finding that although
that our utilities were collected from the other population, our results
did not change when exploring the change in the ICER in the range of
values of each utility explored. The same happens with costs. Although
the resources, frequencies of use, and costs were collected from
tertiary centers, in Rionegro, and not from a national study with all
hospitals in Colombia, modifications to their values in the
sensitivity analysis also did not significantly change the ICER. These
aspects give us confidence regarding the ability to make decisions with
our results; as is always necessary for science, more studies to
replicate our results (31, 32). Our study has some limitations. The cost
data were collected retrospectively. Asthma treatment and the costs in
question, including hospital prices, did not markedly change to our
days. Furthermore, our country has been characterized by having a very
small price variation in the last 10 years, especially in health
services (20). Additionally, we use utilities extracted from the
literature and not estimated directly from our population. As was
mentioned previously, the reliability and robustness of the results were
evaluated by sensitivity analyses.
In conclusion, the MS in emergency settings was cost-effective for the
hospital treatment of an infant with asthma moderate or severe. Our
study provides evidence that should be used by decision-makers to
improve clinical practice guidelines and should be replicated to
validate their results in other middle-income countries.