GERD	gastroesophageal reflux disease
CI	confidence interval
CIP	Catastrophic Illness Patients
COPD	chronic obstructive pulmonary disease
CRS	chronic rhinosinusitis
CRSsNP	chronic rhinosinusitis without nasal polyposis
CRSwNP	chronic rhinosinusitis with nasal polyposis
DM	diabetes mellitus
HT	hypertension
HR	hazard ratio
ICD-9-CM	International Classification of Diseases, Ninth Revision, Clinical Modification
LHID2000	Longitudinal Health Insurance Database 2000
NHIRD	National Health Insurance Research Database
NSD	nasal septal deviation
RA	rheumatic arthritis
RFCIP	Registry for Catastrophic Illness Patients
SLE	systemic lupus erythematosus