Mineral water inhalations for bronchial asthma: a meta-analysis

Bronchial asthma (BA) is a common disease that contributes significantly to the incidence rate and death rate worldwide. A widespread treatment method is the use of inhalations of mineral waters, with conflicting information about their effectiveness. Purpose of the study was to assess the generalized effect power of the course of inhalations of mineral waters on the disease progress in patients with BA. A search of randomized clinical studies in data bases Pubmed, EMBASE, ELibrary, MedPilot amd CyberLeninka, according to PRISMA strategy, published between 1986 and July 2021. Standardized difference of mean values and their 95% of CI were employed for calculation using the random effects model. The meta-analysis drawing on 1266 sources included 14 studies, with 2 of them being randomized controlled clinical studies, including the results of the treatment of 525 patients. All 14 articles contain a conclusion that the inhalation of mineral water has a positive effect on the course of the disease in patients with BA. The analysis demonstrated that the group of patients after mineral water inhalations, compared with the control group, showed improvement of forced expiratory volume (FEV1), expressed both in % of the norm and in liters. The standardized difference of mean values FEV1 (%) (Hedge's g) was 8.2 (95% CI: 5.87 - 10.59; 100%), FEV1 values (liter.) (Hedge's g) was 0.69 (95% CI: -0.33-1.05). A significant heterogeneity of the results of individual studies was found (Q=124.96; tau2 = 14.55, I2 = 69.13%, p<0.0001 and Q=2.35; tau2 = 0, I2 = 0%, p<0.0001). Patients with mild, moderate, and hormone-dependent BA with a controlled and partially controlled disease course, after mineral water inhalations, compared with the control group, demonstrated a statistically significant decrease in the frequency and intensity of the cardinal symptoms of BA and improvement of FEV1.