Chest
Volume 149, Issue 1, January 2016, Pages 201-208
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Original Research: Diffuse Lung Disease
Clinical Characteristics of Connective Tissue Disease-Associated Interstitial Lung Disease in 1,044 Chinese Patients

https://doi.org/10.1378/chest.15-1145Get rights and content

Background

Because the prevalence of connective tissue disease (CTD)-associated interstitial lung disease (ILD; CTD-ILD) in China is unknown, we wanted to analyze the clinical characteristics of this disease in Chinese patients.

Methods

The medical records of patients who received a diagnosis of ILD and treated in Shanghai Pulmonary Hospital from January 1999 to January 2013 were reviewed. Based on the records, patients who also received a diagnosis of CTD were identified, and their records of follow-up examinations for a minimum of 12 months until the end of December 2013 were reviewed.

Results

Of the 2,678 patients who received a diagnosis of ILD, 1,798 (67%) were identified as having CTD-ILD; 299 (11.2%) had idiopathic pulmonary fibrosis (IPF). Complete clinical data were available for 1,044 patients with CTD-ILD and 178 with IPF. We found that 332 of the 1,044 patients with CTD-ILD (32%) did not receive an accurate diagnosis at the initial hospital admission, 195 (18.7%) of the 1,044 patients showed persistent negative test results for autoantibodies, and 262 (25.1%) of the 1,044 patients had negative autoantibodies at the initial hospital admission and then became positive at follow-up examinations. Of the 288 patients who had confirmed CTD-ILD, 41 (14%) showed pulmonary symptoms as the initial clinical manifestation (PSIM) and 247 (86%) showed extrapulmonary symptoms as the initial clinical manifestation (EPSIM). For the 756 patients who had undifferentiated CTD-ILD, the proportion of PSIM and EPSIM was 44% and 56%, respectively. For patients who presented with PSIM, 23 who had confirmed CTD-ILD (56%) and 216 who had unconfirmed CTD-ILD (65%) did not receive an accurate diagnosis at the initial visit but were ultimately diagnosed at subsequent follow-up examinations.

Conclusions

Patients with CTD-ILD do not receive an accurate diagnosis at the initial hospital admission possibly because of negative serologic test results for autoantibodies and the absence of obvious extrapulmonary symptoms. Thus, patients with ILD should be examined for extrapulmonary symptoms and tested for autoantibodies at follow-up examinations.

Section snippets

Patients

A total of 2,678 patients were identified who received a diagnosis of ILD at Shanghai Pulmonary Hospital between January 1999 and January 2013; among them, 1,798 patients received a diagnosis of CTD-ILD. In total, 1,044 patients who received a diagnosis of CTD-ILD were followed up until December 31, 2013, and had complete clinical data including medical history, test results for pulmonary function and serum autoantibodies, and records of treatment and prognosis. Of the 2,678 patients, 299

Results

Complete clinical data were available for 1,044 patients with CTD-ILD and 178 with IPF. Table 2 lists the demographics of these patients. Most patients with CTD-ILD had UCTD-ILD (72.4%). The average age, sex ratio (man/woman), and proportion of smokers for patients with different types of clinical presentation of CTD-ILD were similar (Table 2). For the 178 patients with IPF, the ratio of men to women was 13.8:1; 87.6% were smokers (Table 2).

Discussion

Pulmonary complications are common in patients with CTD. ILD is sometimes the initial clinical manifestation of CTD,19, 20, 21 whereas some patients with CTD have no respiratory symptoms but exhibit abnormal chest HR CT scans.22 In this retrospective study, patients with CTD-ILD accounted for 1,798 of 2,678 (67.1%) of total patients with ILD. In contrast, previous studies showed that the prevalence of CTD-ILD in patients with ILD varied from 12.4% to 34%.23 The discrepancy might be because only

Conclusion

Our findings suggest that patients with CTD-ILD often received an inaccurate diagnosis at the initial hospital admission, possibly because of the absence of obvious extrapulmonary symptoms and negative test results for serologic autoantibodies. Thus, we believe that patients with ILD should be examined for extrapulmonary signs and symptoms and tested for autoantibodies during follow-up examinations.

Acknowledgments

Author contributions: Y. H. had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Y. H., L.-S. W., Y. W, and H.-P. L. were involved in the conception, hypothesis, and design of the study; Y. H., L.-S. W., and Y.-R. W. selected the patients and acquired the samples; S.-S. D., Y. Z., Q.-H. L., Y.-L. S., F. Z., L. S., Y.-K. D., X. H., and N. L. acquired the data; Y. H., L.-S. W., Y.-R. W., and H.-P. L. analyzed

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    Drs Hu, Wang, and Wei contributed equally to this manuscript.

    FUNDING/SUPPORT: This study was funded by the National Science Foundation of China [Grants 91442103, 81170011, 81200045, 81570057 and 81500052], the Science and Technology Commission of Shanghai Municipality [Grants 12DJ1400103, 124119a9000, 12DZ1942500, and 12411950105], the Health Bureau Program of Shanghai Municipality [Grants SHDC12014120 and 2013SY047], and Tongji University [Grant 1511219020].

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