Obesity has been associated with poor outcomes of asthma in cross-sectional studies but long-term effect of obesity on asthma remains unknown.
To study the effects of obesity, found at the time of diagnosis of adult-onset asthma, on 12-year prognosis by focusing on oral corticosteroid (OCS) use and respiratory-related hospital admissions.
Patients diagnosed with adult-onset asthma (n=203) were divided into three categories based on diagnostic BMI (<25, 25–29.9, ≥30 kg·m−2) and followed for 12-years as part of Seinäjoki Adult Asthma Study. Self-reported and dispensed OCS were assessed for the 12-year period. Data on hospital admissions were analysed based on medical records.
12 years after diagnosis, of the patients obese (≥30 kg·m−2) at diagnosis, 86% remained obese. During the follow-up, no difference was found in the weight gain between the BMI categories. During the 12-year follow-up, patients obese at diagnosis reported more often use of OCS courses (46.9% versus 23.1%, p=0.028), were dispensed OCS more often (81.6% versus 56.9%, p=0.014) and at higher doses (median 1350 (IQR 280–3180)mg versus 600 (0–1650)mg prednisolone, p=0.010) compared to normal-weight patients. Furthermore, obese had more often ≥1 respiratory-related hospitalisation compared to normal-weight patients (38.8% versus 16.9%, p=0.033). In multivariate logistic regression analyses, obesity predicted oral corticosteroid use and hospital admissions.
In adult-onset asthma, patients obese at diagnosis mostly remained obese at long-term and had more exacerbations and respiratory-related hospital admissions compared to normal-weight patients during 12-year follow-up. Weight loss should be a priority in their treatment to prevent this outcome.