BackgroundCigarette smoking has been associated with the risk of idiopathic pulmonary fibrosis (IPF). Certain comorbidities have been associated with reduced survival although some studies have indicated that current smokers have a longer survival than ex-smokers. Comorbidities in relation to smoking history have not been previously analyzed.MethodsRetrospective data was collected and patients were categorized according to gender and smoking habits. Comorbidities and medications were collected. Predictive values for mortality were identified by COX proportional hazard analyses.ResultsWe examined 45 non-smokers (53.3% female), 66 ex-smokers (9.1% female) and 17 current smokers (17.6% female) with IPF. Current smokers were younger at baseline (58.1 ± 8.74 years) compared to non-smokers (71.4 ± 8.74, p < 0.001) and ex-smokers (72.5 ±7.95, p <0.001). Median survival of non-smokers and current smokers was longer (55.0 and 52.0 months, respectively) than that of ex-smokers (36.0 months) (p=0.028 and 0.034, respectively). In age and severity adjusted analyses, smoking was not related to survival. Cardiovascular diseases (CVD) (72.7 %) were the most common comorbidities, current smokers had more chronic obstructive pulmonary disease (COPD) and lung cancer compared to ex-smokers (p<0.001). CVD, COPD and use of insulin were related to poorer survival in adjusted analyses.ConclusionsSmoking seems to influence the course of disease in IPF since current smokers developed the disease at a younger age in comparison to non-smokers and ex-smokers. No significant differences in the major comorbidities were detected between IPF patients with different smoking histories. The mechanism through which smoking influences IPF progression requires further investigation.

BackgroundIn rheumatoid arthritis-associated interstitial lung disease (RA-ILD), occurring in 10 % of patients with patients with RA, usual interstitial pattern (UIP) has shown to associate with poor prognosis but more detailed data about the course of the disease in different subtypes is limited. Our aim was to compare the disease course of patients with RA-ILD categorized into either UIP or other types of ILDs.MethodsClinical and radiological information of 59 patients with RA-ILD were re-assessed and re-classified into UIP or non-UIP groups, followed by a between-group comparison of demographic data, lung function, survival, cause of death and comorbidities.ResultsThe majority of patients (n = 35/59.3 %) showed a radiological UIP-like pattern in high resolution computed tomography. The median survival was 92 months (95 % CI 62.8–121.2) in the UIP-group and 137 months (95 % CI 31.0–243.0) in the non-UIP-group (p = 0.417). Differences in course of disease were found in the number of hospitalizations for respiratory reasons (mean 1.9 ± 2.6 in UIP vs. 0.5 ± 0.9 in non-UIP group, p = 0.004), the use of oxygen therapy (8/22.9 % UIP patients vs. 0 non-UIP patients, p = 0.016), number of deaths (23/65.7 % vs. 10/41.7 %, p = 0.046) and decline in diffusion capacity (56 ± 20.6 vs. 69 ± 20.2, p = 0.021). Dyspnea and inspiratory crackles were detected more often in the UIP group. RA-ILD was the most common primary cause of death (39.4 % of cases). Hypertension, coronary artery disease, chronic obstructive pulmonary disease, heart insufficiency, diabetes and asthma were common comorbidities. ILD preceded RA diagnosis in 13.6 % of patients.ConclusionsThe course of the disease in RA-UIP patients is different from the other RA-ILD subtypes. Several comorbidities associated commonly with RA-ILD, although ILD was the predominant primary cause of death.

Many radiological findings associate with the course of the disease of RA-ILD and could potentially be useful when planning the RA treatment or evaluating the risk of death in these patients.