Background Inflammatory myopathies including the Antisynthetase syndrome (ASS) is often complicated by interstitial lung disease (ILD), with impact on morbidity and mortality (1). There is increasing focus on the ILD component of the ASS, but knowledge about long term pulmonary outcome is still limited.
Objectives To perform a longitudinal assessment of pulmonary function tests (PFT) in a well-defined cohort of ASS-patients with long term follow up.
Methods The ASS-cohort at Oslo University Hospital includes 97 patients diagnosed from 1994-2011. Serial PFT data available for retrospective analyses were available in 94 of these patients. PFT measurements included Forced Vital Capacity (FVC), Forced Expiratory Volume in one second (FEV1) and diffusing capacity of the lung for Carbon monoxide (DLCO). PFT data were captured by systematic review of patient charts from symptom onset to study end (at December 31st 2014) or time of death. The earliest PFT identified was defined as the baseline PFT and the examination closest to study end or the time of death was defined as the follow-up PFT. The study was approved by the regional committee of health and medical research ethics in South-East Norway. Paired samples T-test and independent T-test were used to evaluate statistical significance (p<0.05).
Results The study cohort included 65 female and 29 male ASS patients (77 anti Jo-1, 7 anti-PL-7 and 10 anti-PL-12) with median age at diagnosis of 49 years. At the end of the study period 62 of the patients were alive and 32 (34%) had died. At the time of the follow-up PFT, 90/94 patients were on immunosuppressive therapy. The median time from baseline to follow up PFT was 61 months, but differed between the living and deceased subsets (Table). In the total cohort, there were no significant differences in PFT values from baseline to follow-up; FVC -0.008 (p<0.933), FEV1 0.061 (p<0.369) and DLCO -0.312 (p<0.208). Subset analyses showed that the deceased patients, except for FVC at baseline, had consistently lower PFT values than the living patients (Table).We also observed a reduction in mean FVC and FEV1 values from baseline to follow-up in the deceased group, but not in the living group (Table).
Conclusions In this study, on 94 ASS patients, we found no significant differences in pulmonary function parameters during a median follow up time of 61 months. These data indicate that pulmonary function may be rather stable in treated ASS-patients. The patients who died during the observation period had lower PFT values than the patients who survived, supporting the notion that PFTs have prognostic value in the ASS. Further analyses are required to fully evaluate the described data set.
Marie I et al. Short-term and long-term outcome of interstitial lung disease in polymyositis and dermatomyositis: a series of 107 patients. Arthritis Rheum Nov;63(11):3439-47
Disclosure of Interest None declared