Effectiveness of inhaled therapies in asthma among adults in Northern Sri Lanka, a low and middle-income country: A prospective observational study

Background Currently inhaled corticosteroids (ICS) alone, or in combined with inhaled long- acting beta2-agonist (LABA) is recommended for chronic asthma. Objective This study aimed to assess the effectiveness of inhaled therapies in a cohort of adult patients with asthma who were receiving treatment in a tertiary hospital in the Northern Sri Lanka. Methods A prospective cohort study was carried out among adult patients with asthma on inhaled medications for at least three months. Participants were followed up for six months with two follow-up interviews three months apart. Primary outcome measure was asthma control which was assessed by a locally validated asthma control patient-reported outcome measure (AC-PROM). Secondary outcome measures were use of short-acting beta2-agonists, number of nebulisations and number of hospitalisations. Chi-squared test was used to determine the significance of differences in outcome measures between the two groups. Logistic regression was performed to determine the association between asthma control and socio-demographic factors. A p-value ≤ 0.05 was considered statistically significant. Results Data from 1094 participants were analysed. Majority were females (73%) and belonged to age group >60 years (60%). Ratio between ICS monotherapy and combined therapy with ICS and LABA (ICS/LABA) was 3:1. A progressive improvement in asthma control was observed in both groups which was significant in those on ICS monotherapy (p<0.001). A significant reduction was also observed in overuse of short-acting beta2-agonist (p<0.001) and number of nebulisations (p=0.027) in participants on ICS monotherapy. No significant association between asthma control and socio-demographic factors was found in either group. Conclusions Both ICS monotherapy and ICS/LABA were effective. However, treatment package comprising regular ICS plus non-pharmacological approaches would be more realistic and cost-effective treatment strategy in the local context. Considering the low availability and current economic status of Sri Lanka, ICS/LABA could be reserved for poorly controlled asthma.