Effects of smoking, gender and occupational exposure on the risk of severe pulmonary fibrosis: a population-based case-control study.

OBJECTIVES: To estimate the effects of smoking, gender and occupational exposure on the risk of developing severe pulmonary fibrosis (PF), including dose-response and interaction effects. METHODS: National case-control study of 171 patients (cases) who had started a long-term oxygen therapy for PF in Sweden between February 1997 and April 2000, and 719 random control participants from the general population. Of these cases, 137 had probable idiopathic PF (IPF). The ORs for smoking, gender and occupational exposure were estimated using Mantel-Haenszel analysis and conditional logistic regression, controlling for age and year of diagnosis. RESULTS: The adverse effect of smoking was amplified by male gender and occupational exposure, OR 4.6 (95% CI 2.1 to 10.3) for PF, and OR 3.0 (1.3 to 6.5) for IPF, compared with in non-exposed women. Higher cumulative smoking exposure was linearly associated with increased risks. Compared with smoking less than 10 pack-years, smoking ≥20 pack-years was associated with increased risk of PF and IPF, OR 2.6 (1.4 to 4.9) and OR 2.5 (1.3 to 5.0), respectively. CONCLUSIONS: Smoking has a dose-related association with increased risk of severe PF. Men with a history of smoking and occupational exposure is a particular risk group for developing severe PF.

A model of quality assessment in patients on long-term oxygen therapy.

BACKGROUND: The difficulty of implementing guidelines for long-term oxygen therapy (LTOT) has been recognized. We performed this analysis to evaluate the impact of a national quality assurance register on the quality of LTOT and to suggest indicators with levels for excellent quality LTOT. METHODS: Based on national register data on Swedish LTOT patients in 1987-2005, we measured nine quality indicators and the achievement levels of the participating counties in fulfilling these treatment criteria. RESULTS: There were improvements in the following eight quality indicators: access to LTOT, PaO(2) < or = 7.3 kPa without oxygen, no current smoking, low number of thoracic deformity patients without concomitant home mechanical ventilation, >16 h of oxygen/day, mobile oxygen equipment, reassessment of hypoxemia when LTOT was not started in a stable state of chronic obstructive pulmonary disease (COPD) and avoidance of continuous oral glucocorticosteroids in COPD. There was decline in the quality indicator PaO(2) > 8 kPa on oxygen. After improvements, three criteria were fulfilled by > or = 80% of the counties in 2004-2005. CONCLUSIONS: We found improvements in eight of nine quality indicators. We suggest these indicators with levels for excellent quality for use in quality assurance of LTOT based on our results.

Occupational exposure and severe pulmonary fibrosis.

BACKGROUND: External agents, especially metal and wood dust, are believed to be risk factors for development of idiopathic pulmonary fibrosis (IPF). The aim of this case-control study was to investigate which occupational exposure types are associated with development of severe pulmonary fibrosis (PF), and especially IPF. METHODS: An extensive postal questionnaire including 30 specific items regarding occupational exposure was completed by 181 patients with severe PF and respiratory failure reported to the Swedish Oxygen Register, among whom 140 were judged as having IPF. The questionnaire was also completed by 757 control subjects. We stratified data for age, sex and smoking and calculated odds ratios (ORs). RESULTS: We found increased risk for IPF in men with exposure to birch dust (OR 2.7, 95% confidence interval (95% CI) 1.30-5.65) and hardwood dust (OR 2.7, 95% CI 1.14-6.52). Men also had slightly increased ORs associated with birds. We did not find any increased risk in association with metal dust exposure. CONCLUSION: Exposure for birch and hardwood dust may contribute to the risk for IPF in men.

Survival and future need of long-term oxygen therapy for chronic obstructive pulmonary disease--gender differences.

We aimed to study trends in gender-related differences in incidence, and prevalence for long-term oxygen therapy due to chronic obstructive pulmonary disease. Another aim was to study survival after onset of oxygen therapy. Prospectively followed were 5689 Swedish patients, who were prescribed oxygen therapy because of chronic obstructive pulmonary disease from 1987 to 2000. The annual incidence of women starting oxygen therapy increased more rapidly than that in men. In 2000, 7.6 per 100,000 women started treatment compared with 7.1 in men. The frequency of ever smoking in Sweden in the age group receiving oxygen, i.e. age 65-84 years, was 36.4% in women and 65.0% in men, indicating that women ran a higher risk of developing an oxygen-requiring chronic hypoxaemia. An increase in women requiring oxygen therapy is predicted due to the increase in smoking frequency in young and middle-aged women and it is estimated that about 70% of Swedish patients on oxygen in 2026 will be women, with an estimated prevalence of 61 per 100,000. In conclusion, the incidence and prevalence for long-term oxygen therapy increases more rapidly among women than in men. This is probably due to the increased frequency of smoking in women compared with men and a higher susceptibility to develop severe hypoxaemia in women. The survival is better in women with long-term oxygen therapy than in men.

Survival of patients with kyphoscoliosis receiving mechanical ventilation or oxygen at home.

BACKGROUND: Home mechanical ventilation (HMV) and long-term oxygen therapy (LTOT) are the two treatment alternatives when treating respiratory insufficiency in patients with kyphoscoliosis. We aimed to study the effect on survival with regard to HMV or LTOT alone in patients with respiratory insufficiency due to kyphoscoliosis. METHODS: Swedish patients with nonparalytic kyphoscoliosis (ie, scoliosis not related to neuromuscular disorders) who started LTOT or HMV between 1996 and 2004 were followed up prospectively until February 14, 2006, with death as the primary outcome. Treatment modality, arterial blood gas levels, the presence of concomitant respiratory diseases, and age were recorded at the onset of treatment. No patient was lost to follow-up. RESULTS: One hundred patients received HMV, and 144 patients received oxygen therapy alone. Patients treated with HMV experienced better survival, even when adjusting for age, gender, concomitant respiratory diseases, and blood gas levels, with a hazard ratio of 0.30 (95% confidence interval, 0.18 to 0.51). CONCLUSION: The survival of patients with kyphoscoliosis receiving HMV was better than that of patients treated with LTOT alone. We suggest HMV and not oxygen therapy alone as the primary therapy for patients with respiratory failure due to kyphoscoliosis, regardless of gender, age, and the occurrence of concomitant respiratory diseases.