Comorbidities and mortality in hypercapnic obese under domiciliary noninvasive ventilation.
BACKGROUND
The higher mortality rate in untreated patients with obesity-associated hypoventilation is a strong rationale for long-term noninvasive ventilation (NIV). The impacts of comorbidities, medications and NIV compliance on survival of these patients remain largely unexplored.


METHODS
Observational cohort of hypercapnic obese patients initiated on NIV between March 2003 and July 2008. Survival curves were estimated by the Kaplan-Meier method. Anthropometric measurements, pulmonary function, blood gases, nocturnal SpO(2) indices, comorbidities, medications, conditions of NIV initiation and NIV compliance were used as covariates. Univariate and multivariate Cox models allowed to assess predictive factors of mortality.


RESULTS
One hundred and seven patients (56% women), in whom NIV was initiated in acute (36%) or chronic conditions, were followed during 43±14 months. The 1, 2, 3 years survival rates were 99%, 94%, and 89%, respectively. In univariate analysis, death was associated with older age (>61 years), low FEV1 (<66% predicted value), male gender, BMI×time, concomitant COPD, NIV initiation in acute condition, use of inhaled corticosteroids, ß-blockers, nonthiazide diuretics, angiotensin-converting enzyme inhibitors and combination of cardiovascular drugs (one diuretic and at least one other cardiovascular agent). In multivariate analysis, combination of cardiovascular agents was the only factor independently associated with higher risk of death (HR = 5.3; 95% CI 1.18; 23.9). Female gender was associated with lower risk of death.


CONCLUSIONS
Cardiovascular comorbidities represent the main factor predicting mortality in patient with obesity-associated hypoventilation treated by NIV. In this population, NIV should be associated with a combination of treatment modalities to reduce cardiovascular risk.
INSERM U 1042, HP2 Laboratory, Université Joseph Fourier, Faculté de Médecine, Grenoble, France. j.borel@agiradom.com
Jean-Christian
JC
Borel
Benoit
B
Burel
Renaud
R
Tamisier
Sonia
S
Dias-Domingos
Jean-Philippe
JP
Baguet
Patrick
P
Levy
Jean-Louis
JL
Pepin
D002423:Cause of Death; D015897:Comorbidity; D005260:Female; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume; D005602:France / Q000453:epidemiology; D006699:Home Care Services / Q000706:statistics & numerical data; D006801:Humans; D006935:Hypercapnia / Q000150:complications* / Q000401:mortality* / Q000503:physiopathology; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D063087:Noninvasive Ventilation; D009765:Obesity / Q000150:complications* / Q000401:mortality*; D016016:Proportional Hazards Models; D012307:Risk Factors