Inflammatory lung disease a potential risk factor for onset of idiopathic inflammatory myopathies: results from a pilot study

Abstract

ObjectivesTo assess the association between inflammatory lung disease and the risk of developing idiopathic inflammatory myopathies.MethodsA population-based case–control study was conducted. Adult myositis cases, identified from the Swedish inpatient registry (diagnosed between 1995 and 1997), and randomly selected controls matched to cases on the date of birth, gender and residency, were asked to fill out a questionnaire with questions on lifestyle, environmental exposures and health. Eventually, 100 cases and 402 controls responded to the questionnaire and were included in the analyses. Exposure was defined as self-reported preceding inflammatory lung diseases (pneumonia, tuberculosis or sarcoidosis). The association between the exposure and risk of developing myositis was evaluated by calculating OR together with 95% CIs in logistic regressions.Results42 (42%) cases and 112 (28%) controls reported preceding inflammatory lung disease. Median duration between inflammatory lung disease and first symptom of myositis was 30 years. We observed a significant association between self-reported history of lung disease at study inclusion and diagnosis of myositis (crude OR=1.8 (1.1 to 2.9); smoking adjusted OR=1.9 (1.2 to 3.1)). We further identified a modestly increased, yet non-significant, association between preceding inflammatory lung disease (prior to index year) and diagnosis of myositis (smoking adjusted OR=1.6 (0.9 to 2.8)). The association was more pronounced among the cases of myositis with concurrent interstitial lung disease (OR=3.8 (1.0 to 14.5)).ConclusionsPatients with preceding inflammatory lung disease tend to have an increased risk of developing myositis compared to those without. The effect was more pronounced among patients with myositis with concurrent interstitial lung disease. Thus inflammatory lung disease may constitute a risk factor for myositis.

Mortality in idiopathic inflammatory myopathy: results from a Swedish nationwide population-based cohort study

“…The validity of the ICD codes used for IIM has been tested in the same underlying study population as included in the current study, and it indicates high validity of the ICD codes used to identify IIM (positive predictive value of >85 and sensitivity of >85% for all ICD codes except those indicating sIBM) 25. In addition, there are two previously published papers: one Swedish,26 partly using the same study population as presented here, and one Canadian,27 also using administrative data, where using ICD codes to identify IIM was found to have a sensitivity of 88%,  specificity of 96%27 and a positive predictive value of 85% 26. In the present study, only visits at IIM specialist clinics (rheumatology, internal medicine, dermatology and neurology) were included in the identification algorithm (which is presented in Svensson et al 25).…”

Infections and respiratory tract disease as risk factors for idiopathic inflammatory myopathies: a population-based case–control study

“…Respiratory inflammatory exposures were found to be associated with IIM in a recent study15 but it only included three specific respiratory outcomes (sarcoidosis, pneumonia and tuberculosis) while our study includes a wider range of respiratory tract diseases. Their identification of IIM using hospitalisation data only likely led to the inclusion of more severe cases of IIM.…”

Acute Coronary Syndrome in Idiopathic Inflammatory Myopathies: A Population-based Study

“…The adult (≥ 18 yrs) incident IIM cohort was identified from the NPR using the International Classification of Diseases, 10th revision (ICD-10) codes for IIM (juvenile DM M33.0, DM M33.1, PM M33.2, 33.9, and IBM G72.4). The IIM case definition used in this study was used in previous publications and showed a positive predictive value (PPV) and a sensitivity of > 85% for all ICD codes except IBM 16,17 . Based on this algorithm, to be included in our cohort an individual was required to have (1) ≥ 2 visits indexed with an IIM diagnosis by a specialist (dermatologist, internist, neurologist, or rheumatologist); (2) an initial visit between 2002 and 2011; and (3) a followup visit within 1 year listing an IIM code.…”