Discussion
Our study suggests that FeNO-SC achieving better outcomes at a lower
cost over standard treatment without FeNO in children with mild to
moderate allergic asthma. These better outcomes are due to reductions in
the probabilities of asthma exacerbation and sub-optimal control of the
disease, with the consequent increase of patients well controlled. The
magnitude of annual cost savings for the health system (US$ 118 per
patient ) is no negligible if we consider that this disease affects
between 10 to 13% of children and only 2.4% of them meet the criteria
for total asthma control in Colombia. The findings constitute a new
argument to include the FeNO-SC in clinical practice guidelines of
pediatric asthma.
Our findings are in line with previous studies in the literature
evaluating the economic value of FeNO of inserting FeNO monitoring into
asthma management, some of them enrolling pediatric patients.
Beerthuizen et al. assessed the cost-effectiveness of web-based monthly
monitoring and of 4-monthly monitoring of FeNO as compared with standard
care. The economic evaluation was performed alongside a multicentre RCT
with a 1-year follow-up, and included 272 children aged between 4 and 18
years of age. The FeNO-based strategy had 83% chance of being most
cost-effective at \euro40 000/QALY from a societal perspective (18).
Berg et al. assessed the cost-effectiveness of FeNO measurement with
NIOX MINO in the diagnosis of asthma and in optimizing asthma management
using the expected reimbursement price of the device. In this study, the
use of FeNO measurement in treatment decisions was less costly than
asthma management based on standard guidelines (while in mild to severe
patients, asthma management with FeNO measurement instead of standard
guidelines resulted in cost-savings of \euro30 per patient and year,
in more severe population, management with FeNO measurement would save
costs of \euro160 per patient) and provided similar health benefits
(7). Brooks et al. examined the impact of FeNO monitoring on the
cost-effectiveness of asthma management compared with management without
FeNO. FeNO in conjunction with current standard of care guidelines had
decreased expected per-patient annual expenditure (US$2,228) and
increased expected per-patient annual QALYs (0.844) compared with
current standard of care alone (US$2,637 and 0.767)(9). Price et al.
determined the cost-effectiveness of FeNO measurement using a hand-held
monitor (NIOX MINO), at a reimbursement price of £23, for asthma
diagnosis and management in the UK. Asthma management using FeNO
measurement instead of lung function testing resulted in annual
cost-savings of £341 and 0.06 QALYs gained for patients with mild to
severe asthma and cost-savings of £554 and 0.004 QALYs gained for those
with moderate to severe asthma(19). Sabatelli et al. evaluated the
cost-effectiveness and budget impact of FeNO monitoring for management
of adult asthma in Spain over a 1-year period. Adding FeNO to standard
asthma care saved \euro62.53 per patient-year and improved QALYs by
0.026 per patient-year. The budget impact analysis revealed a potential
net yearly saving of \euro129 million if FeNO monitoring had been used
in primary care settings in Spain.8 Similarly, Harnan et al. assessed
the cost-effectiveness of the hand-held electrochemical devices NIOX
MINO® (Aerocrine, Solna, Sweden), NIOX VERO® (Aerocrine) and NO breath®
(Bedfont Scientific, Maidstone, UK) for the diagnosis and management of
asthma. The de novo management model indicated that the ICER of
guidelines plus FeNO monitoring using NO breath compared with guidelines
alone in children is expected to be approximately £45,200 per QALY
gained, concluding that FeNO-guided management has the potential to be
cost-effective, although this is largely dependent on the duration of
effect(10)
The last version of the Global Initiative for Asthma refers to children
“ FeNO-guided treatment significantly reduces exacerbation rates
compared with guidelines-based treatment (Evidence A). However, further
studies are needed to identify the populations most likely to benefit
from FeNO-guided treatment, and the optimal frequency of FeNO
monitoring”(2). However, in the references that support this statement
included only RCTs and not economic evaluations were revised. The
dynamics between clinical research in the effectiveness and research of
efficiency of the allocation of health resources must be coordinated,
synchronous of the moment to make a recommendation from individual to
public health level. It is clear the complexity of the transferability
of economics evaluations, but this situation highlights the need to
assess the health technologies in the clinical guidelines no only
evaluating effectiveness or safety but also review economical topics to
increase the level of recommendation in clinical guidelines.
A very important aspect of our model is that it was robust to changing
the values of the model’s utilities, probabilities, and costs using
oneway and probabilistic sensibility analysis of a Markov model. FeNO-SC
was always the cost-effectiveness strategy in all ranges of values of
utilities, probabilities, and costs. Even more, FeNO-SC was always the
cost-effectiveness strategy in all ranges of thresholds evaluated with a
low population EVPI. These findings in the sensibility analysis have
cardinal importance in our study because many of the inputs were
extracted from literature, which all were hospital-based and undertaken
in affluent countries; also allow decision making with an estimated
degree of uncertainty in each cost parameter or QALYs per strategy.
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 (14). 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 FeNO-SC was cost-effective for 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.