Daytime hypercapnia in adult patients with obstructive sleep apnea syndrome in France, before initiating nocturnal nasal continuous positive airway pressure therapy.

CONTEXT: Daytime hypercapnia in patients with obstructive sleep apnea syndrome (OSAS) has a highly variable prevalence in the published studies, and is usually thought to be the consequence of an associated disease, COPD, or severe obesity. STUDY OBJECTIVES: To assess the prevalence of daytime hypercapnia in a very large population of adult patients with OSAS, free of associated COPD, and with a wide range of body mass index (BMI), and to evaluate the relationship between daytime hypercapnia and the severity of obesity and obesity-related impairment in lung function. DESIGN: Retrospective analysis of prospectively collected data. METHODS: The database of the observatory of a national nonprofit network for home treatment of patients with chronic respiratory insufficiency (Association Nationale pour le Traitement a Domicile de l'Insuffisance Respiratoire Chronique) was used. Collected data at treatment initiation were age, apnea-hypopnea index, BMI, FEV(1), vital capacity (VC), and arterial blood gases. The study included 1,141 adult patients with OSAS treated in France with nocturnal nasal continuous positive airway pressure (CPAP), FEV(1) >/= 80% predicted, FEV(1)/VC >/= 70%, and absence of restrictive respiratory disease other than related to obesity. RESULTS: The prevalence of daytime hypercapnia (Paco(2) >/= 45 mm Hg) before initiating CPAP therapy was 11% in the whole study population. The prevalence of daytime hypercapnia was 7.2% (27 of 377 patients) with BMI < 30, 9.8% (58 of 590 patients) with BMI from 30 to 40, and 23.6% (41 of 174 patients) with BMI > 40. Patients with daytime hypercapnia had significantly higher BMI values and significantly lower VC, FEV(1), and Pao(2) values than the normocapnic patients. Stepwise multiple regression showed that Pao(2), BMI, and either VC or FEV(1) were the best predictors of hypercapnia, but these variables explained only 9% of the variance in Paco(2) levels. CONCLUSION: Daytime hypercapnia was observed in > 1 of 10 patients with OSAS needing CPAP therapy and free of COPD, and was related to the severity of obesity and obesity-related impairment in lung function. However, other mechanisms than obesity are probably involved in the pathogenesis of daytime hypercapnia in OSAS.

Prognostic value of the hematocrit in patients with severe COPD receiving long-term oxygen therapy.

BACKGROUND: Although traditionally associated with polycythemia, COPD has a systemic inflammatory component that could interfere with erythropoiesis. This study describes the distribution and prognostic value of the hematocrit in patients with severe COPD receiving long-term oxygen therapy (LTOT). METHODS: A total of 2,524 patients with COPD, FEV1/vital capacity (VC) < 70%, FEV1 < 80% of predicted, and Pa(O2) < 7.3 kPa in whom a hematocrit was available at entry was identified between 1980 and 1999 in the French Association Nationale pour le Traitement à Domicile de l'Insuffisance Respiratoire chronic respiratory insufficiency and home-care database (male/female ratio, 5/1; mean +/- SD age, 68 +/- 10 years for men, and 70 +/- 10 years for women). Correlations between hematocrit, demographic data, and pulmonary function data were examined. A multivariate Cox proportional hazard regression was performed to identify prognostic factors. RESULTS: Mean hematocrit was 45.9 +/- 7.0% in men and 43.9 +/- 6.0% in women (< 39% in 12.6% of men, and < 36% in 8.2% of women) according to the World Health Organization definition of anemia. Hematocrit was negatively correlated with age (r = - 0.245) and FEV1/VC (r = - 0.068) and was positively correlated with Pa(CO2) (r = 0.161) and body mass index (r = 0.127). Multivariate analysis found hematocrit to be an independent predictor of survival, hospital admission rate, and cumulative duration of hospitalization. The 3-year survival was 24% (95% confidence interval, 16 to 33%) when the hematocrit was < 35%, and 70% (63 to 76%) when the hematocrit was > or = 55%. CONCLUSIONS: A low hematocrit is not uncommon in LTOT/COPD patients. Hematocrit is negatively associated with mortality and morbidity. Whether the association is causative or not and whether or not corrective measures are warranted remain to be determined.

Prognostic value of nutritional depletion in patients with COPD treated by long-term oxygen therapy: data from the ANTADIR observatory.

BACKGROUND: An association between weight depletion and mortality has been demonstrated in patients with COPD, but the prognostic influence of malnutrition has not been evaluated in patients with the most severe COPD treated with home long-term oxygen therapy (LTOT). STUDY OBJECTIVE: To analyze the prognostic value of nutritional depletion in patients with COPD receiving LTOT with respect to survival and hospitalization rate. DESIGN: Analysis of a national database (Observatory of Association Nationale pour le Traitement a Domicile de l'Insuffisance Respiratoire Chronique [ANTADIR]). SETTING: The national nonprofit network for home treatment of patients with chronic respiratory insufficiency (ANTADIR) founded in France in the 1980s. PATIENTS: A total of 4,088 patients with a diagnosis of chronic bronchitis or emphysema, FEV(1)/vital capacity ratio < 60%, PaO(2) < 8 kPa, and treatment with LTOT between 1984 and 1993. MEASUREMENTS AND RESULTS: The prevalence of malnutrition, as defined by a body mass index (BMI) < 20, was 23% in men and 30% in women. BMI was significantly correlated with FEV(1) and FEV(1)/VC. The mean follow-up duration was 7.5 years. The 5-year survival rates were 24%, 34%, 44%, and 59%, respectively, for patients with BMIs < 20, 20 to 24, 25 to 29, and > or = 30. Multivariate analysis using the Cox model demonstrated that the effect of BMI on survival was independent of age, FEV(1), PaO(2), and sex. Lower BMI was the most powerful predictor of duration and rate of hospitalization, independently of blood gas levels and respiratory function. The mean (+/- SD) annual time spent in the hospital was 29.6 +/- 40.4 days for patients with a BMI < 20 vs 17.5 +/- 30.1 days for patients with a BMI > 30. CONCLUSION: This study showed that nutritional depletion is an independent risk factor for mortality and hospitalization in patients with COPD receiving LTOT. The best prognosis was observed in overweight and obese patients.

Cardiovascular risk factors in men and women with obstructive sleep apnoea syndrome.

UNLABELLED: We wished to evaluate the prevalence of cardiovascular (CV) risk factors in patients with obstructive sleep apnoea syndrome (OSAS) before initiation of continuous positive airway pressure (CPAP), and without any declared or diagnosed pre-existing CV disorder. We wanted to compare the prevalence of these CV risk factors between men and women in an observational study. A questionnaire concerning CV risk factors was submitted to the patients, by a respiratory home-care technician at the time of installation of the CPAP treatment. PATIENTS: The study population consisted of 1117 patients; 834 men, 283 women. RESULTS: The prevalence of arterial hypertension (HT), diabetes, obesity, active smoking, hyperlipidemia and family history of coronary heart disease was 54.1%, 22.8%, 65.8%, 18.3%, 33.8% and 20%, respectively. Women had significantly more HT (62.1 vs 51.4%), diabetes (29.9 vs 20.4%), obesity (77 vs 62%) and family history of coronary disease (25.1 vs 18.2%). The prevalence of active smoking was significantly higher in men (20.4 vs 12%). The prevalence of hyperlipidemia was not different between men and women (34.5 vs 31.8%). Stepwise logistic regression showed that HT and diabetes were both independently associated with BMI and age, while diabetes and not HT was independently associated with female gender. The prevalence of classical CV risk factors was very high in this population with OSAS requiring CPAP, especially in women. There is thus a very elevated CV risk level independent of that directly related to OSAS. It is important to screen for and treat classical CV risk factors in this population.

Evaluation of the tuberculin skin test and the interferon-gamma release assay for TB screening in French healthcare workers.

INTRODUCTION: Using French cut-offs for the Tuberculin Skin Test (TST), results of the TST were compared with the results of an Interferon-gamma Release Assay (IGRA) in Healthcare Workers (HCW) after contact to AFB-positive TB patients. METHODS: Between May 2006 and May 2007, a total of 148 HCWs of the University Hospital in Nantes, France were tested simultaneously with IGRA und TST. A TST was considered to indicate recent latent TB infection (LTBI) if an increase of >10 mm or if TST >/= 15 mm for those with no previous TST result was observed. For those with a positive TST, chest X-ray was performed and preventive chemotherapy was offered. RESULTS: All HCWs were BCG-vaccinated. The IGRA was positive in 18.9% and TST >/= 10 mm was observed in 65.5%. A recent LTBI was believed to be highly probable in 30.4% following TST. Agreement between IGRA and TST was low (kappa 0.041). In 10 (16.7%) out of 60 HCWs who needed chest X-ray following TST the IGRA was positive. In 9 (20%) out of 45 HCWs to whom preventive chemotherapy was offered following TST the IGRA was positive. Of those considered TST-negative following the French guidelines, 20.5% were IGRA-positive. In a two-step strategy - positive TST verified by IGRA - 18 out of 28 (64.3%) IGRA-positive HCWs would not have been detected using French guidelines for TST interpretation. CONCLUSION: The introduction of IGRA in contact tracings of BCG-vaccinated HCWs reduces X-rays and preventive chemotherapies. Increasing the cut-off for a positive TST does not seem to be helpful to overcome the effect of BCG vaccination on TST.