title: Respiratory impairment and COPD hospitalisation in older persons: a competing risk analysis.
abstract: The aim of the present study was to evaluate, among older persons, the association between respiratory impairment and hospitalisation for chronic obstructive pulmonary disease (COPD), based on spirometric Z-scores, i.e. the LMS (lambda, mu, sigma) method, and a competing risk approach. Using data on 3,563 white participants aged 65-80 yrs (from the Cardiovascular Health Study) we evaluated the association of LMS-defined respiratory impairment with the incident of COPD hospitalisation and the competing outcome of death without COPD hospitalisation, over a 5-yr period. Respiratory impairment included airflow limitation (mild, moderate or severe) and restrictive pattern. Over a 5-yr period, 276 (7.7%) participants had a COPD hospitalisation incident, whereas 296 (8.3%) died without COPD hospitalisation. The risk of COPD hospitalisation was elevated more than two-fold in LMS-defined mild and moderate airflow limitation and restrictive pattern (adjusted HR (95% CI): 2.25 (1.25-4.05), 2.54 (1.53- 4.22) and 2.65 (1.82-3.86), respectively), and more than eight-fold in LMS-defined severe airflow limitation (adjusted HR (95% CI) 8.33 (6.24-11.12)). Conversely, only LMS-defined restrictive-pattern was associated with the competing outcome of death without COPD hospitalisation (adjusted HR (95% CI) 1.68 (1.22-2.32)). In older white persons, LMS-defined respiratory impairment is strongly associated with an increased risk of COPD hospitalisation. These results support the LMS method as a basis for defining respiratory impairment in older persons.
authors.affiliation: Clinical Epidemiology Research Center, VA Connecticut Healthcare System, 950 Campbell Ave, Mailcode 151B, West Haven, CT, USA. carlos.fragoso@yale.edu
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Vaz Fragoso
authors.forename: John
authors.initials: J
authors.lastname: Concato
authors.forename: Gail
authors.initials: G
authors.lastname: McAvay
authors.forename: Peter H
authors.initials: PH
authors.lastname: Van Ness
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Gill
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D016016:Proportional Hazards Models; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000453:epidemiology / Q000401:mortality; D012131:Respiratory Insufficiency / Q000209:etiology* / Q000401:mortality; D018570:Risk Assessment; D013147:Spirometry