The goal of this retrospective/observational study is to compare the clinical outcomes between the high-cumulative-dose group and the low- cumulative-dose group of oral/inhaled corticosteroid in the long-term management of asthma patients. The main hypothesis are:

i. High cumulative dose of corticosteroid is related to the prevalence of osteoporosis/osteoporosis in the long-term management of adult asthma.

ii. High cumulative dose of corticosteroid can affect populations that have a high-risk of osteoporosis (females over 50 years of age).

iii. High cumulative dose of corticosteroid is related to the prevalence of diabetes mellitus, hypertension, and hyperlipidemia in the long-term management of adult asthma.

iv. High cumulative dose of corticosteroid affects bone metabolism-related diagnostic tests and laboratory values and the prescription rate of bone metabolism-related medications.

A. Inclusion criteria i. Adult asthmatics (over 18 years) who have maintained inhaled corticosteroid with or without systemic corticosteroid for more than 12 months before the index date in our Medical Center.

ii. At least 1 asthma diagnosis within 1 year before the first corticosteroid exposure date by asthma specialists at Ajou University Medical Center (AUMC, Suwon, South Korea) with informed consent.

iii. A high cumulative dose is defined as the dose of corticosteroids above the mean cumulative dose of corticosteroids prescribed during 1 year.

iv. The equivalent dose will use for calculating the mean cumulative dose of each inhaled corticosteroid inhaler or systemic corticosteroid prescribed.

v. Prescriptions within 365 days from the first prescription will be assumed to be continuous, and the cohort end date will be defined as the end of the continuous drug exposure.

B. Exclusion criteria i. Patients younger than 18 years ii. Patients younger than 50 years and males in high-risk population cohorts iii. Patients with osteoporosis or osteoporosis-related major fracture outcomes (pathological fracture due to osteoporosis, closed fracture of the femur, pelvis, and vertebral column) before the index date iv. Patients with corticosteroid-related outcomes (diabetes mellitus, hypertension, hyperlipidemia) before the index date (for secondary endpoint).

Adult asthma patients that visited AUMC (Ajou University Medical Center) from 1994 to 2023