Alpine altitude climate treatment (AACT) may help people with asthma that remains severe despite maximum guideline-adherent treatment, according to a position paper by the European Academy of Allergy and Clinical Immunology (EAACI).
“AACT improves various outcomes such as asthma control and quality of life, exacerbation rate and hospitalizations, oral corticosteroid reduction, lung function parameters, upper airways symptoms, and exercise tolerance in adults and children,” lead author Karin B. Fieten, PhD, of the Swiss Institute of Allergy and Asthma Research (SIAF) at the University of Zurich in Davos Wolfgang, Switzerland, and her colleagues write.
"AACT can be considered as a natural treatment," they add. "Based on the available observational studies and expert opinion, AACT is a therapy for those asthma patients who, despite all the advances in medical science, still cannot achieve optimal control of their complex condition and therefore run the risk of falling into a downward spiral of loss of physical and mental health."
AACT integrates the physical benefits of moderate altitude, favorable environment, and personalized inpatient multidisciplinary pulmonary rehabilitation, they write.
As reported in Allergy, Fieten and her colleagues used the standard medical research databases to review the literature on physical characteristics of altitude, environmental characteristics of the alpine climate, and immunological and clinical outcomes.
They focused on studies of treatment provided in Europe. Although several observational studies described AACT in adults and children with severe or uncontrolled asthma, the authors write, randomized trials or studies with a control group studying the effectiveness of AACT are lacking. So they took an expert-based consensus approach and developed position statements, including those below.
Long History of Observed Benefits
For over a century, AACT has helped treat patients with asthma and other pulmonary diseases at altitude clinics. Most of the clinics are located in the Alps at between 1200 and 2500 meters (3937 and 8202 feet) above sea level, where hypoxia does not greatly stress the body.
The lower barometric pressure, inspiratory oxygen pressure, and air density, along with the relatively low temperature and humidity, and the increased ultraviolet radiation, induce immunologic and physiologic adaptation responses. And at higher elevations, house dust mites, pollen, fungi, air pollution, and other aeroallergens are reduced.
AACT may contribute to clinical improvement in asthma control and quality of life, fewer exacerbations and hospitalizations, less need for oral corticosteroids, decreased airway hyperresponsiveness, along with improved lung function and exercise tolerance, and better sinonasal outcomes.
At moderate altitudes, type 2 inflammation appears to be reduced in patients with allergic asthma. Altitude also appears to restore the suppressive and regulatory phenotype of regulatory T cells (Tregs) in all asthma phenotypes. And less exposure to allergens appears to lead to significantly less antigen-induced basophil histamine release, total immunoglobulin E (IgE), and specific IgE.
"The specific effectiveness of AACT may lie in the observed rapid decrease in inflammation, either because of fewer environmental triggers in the alpine climate or physical altitude climate factors and their immunomodulatory effects, or because of other yet unknown mechanisms," the authors write.
In line with international guidelines that recommend a stepwise multidisciplinary asthma management approach for optimal disease control, most AACT programs involve extensive patient assessment, psychological and behavioral interventions, exercise programs, patient education, and personalized action plans patients can follow after the treatment ends.
A Natural Treatment That Targets Biological Pathways
Anuradha Ray, PhD, professor of medicine and immunology and endowed chair in lung immunology at the University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, told Medscape Medical News that "the authors propose AACT as a natural therapeutic option for the treatment of poorly managed asthma that can suppress disease-associated inflammatory pathways."
"The authors propose that suppression of asthma-promoting type 2 inflammation combined with reduction in Tregs with inflammatory phenotype to those with suppressive phenotype together may help in AACT-induced asthma control and improved quality of life," she said in an email.
"One limitation noted by the authors is the lack of studies that included randomized controlled trials comparing AACT to other pulmonary rehabilitation programs," added Ray, who was not involved in developing the position paper.
"Another is the lack of understanding of molecular mechanisms that cause immunomodulation toward a better outcome," she said. The duration of the beneficial effect of AACT on asthma is also unknown."
Richard A. Lee, MD, associate clinical professor specializing in critical care medicine and pulmonary disease at the University of California, Irvine, called this paper "an excellent review of the known mechanisms and observed benefits of AACT."
"The authors acknowledge that future well-designed randomized trials will be necessary to further corroborate the effects of ACCT on clinical outcomes and to identify underlying molecular mechanisms of AACT as well as which asthma phenotypes will benefit most from the treatment," he said in an email.
"In the absence of randomized trials assessing the effectiveness of AACT, the authors provide an expert-based consensus describing AACT as a suitable treatment option that can be considered for patients who cannot achieve optimal control of asthma despite maximum treatment according to guidelines," added Lee, who also was not involved in developing the paper.
The authors recommend further related research.
Fieten, Ray, and Lee report no relevant financial relationships. Several coauthors report financial relationships with the pharmaceutical industry.
Allergy. Published online February 3, 2022. Full text.