Nonspecific interstitial pneumonia: clinical associations and outcomes

Abstract

BackgroundStudies have shown that nonspecific interstitial pneumonitis (NSIP), even when initially diagnosed as an idiopathic form of the disease, might be associated with an autoimmune background that later reveals itself as an organ-specific or a systemic autoimmune disease.MethodsNSIP patients were divided into three groups. The NSIP patients who met the criteria for having a systemic autoimmune disease (SAD) were defined as the systemic autoimmune disease-associated NSIP (SAD-NSIP) group. The NSIP patients who did not meet the criteria for a systemic autoimmune disease were defined as an antibody-positive group (i-NSIP-Ab + group) if their sera were positive for autoantibodies. The NSIP patients with negative serologic tests for auto-antibodies were defined as the antibody-negative group (i-NSIP-Ab- group). The clinical characteristics were analyzed and compared among the three groups.ResultsNinety-seven NSIP patients were included. The mean age of the study population was 48 ± 11 years. The mean follow-up time was 54 ± 34 months. At the time of the surgical lung biopsies, 23/97 (23.7%) of the patients were classified as SAD-NSIP; 30/97 (30.9%) were in the i-NSIP-Ab + group; and 44/97 (45.4%) were in the i-NSIP-Ab- group. At the end of the follow-up period, three cases were diagnosed with polymyositis (one case from the i-NSIP-Ab + group, two cases from the i-NSIP-Ab- group), one with scleroderma (from the i-NSIP-Ab + group, scl-70 positive and skin biopsy) and another one with microscopic polyarteritis (from the i-NSIP-AB-group, p-ANCA and MPO positive, renal biopsy). Three cases in the i-NSIP-Ab- group were later found to be positive for autoantibodies. Due to these changes in classification, at the end of the follow-up period, the SAD-NSIP group consisted of 28/97 patients (28.9%), the i-NSIP-Ab + group of 31/97 (32.0%) and the i-NSIP-Ab- group of 38/97(39.1%). There were no significant differences in clinical manifestations, radiographic findings or pulmonary function tests among the three groups at the time of surgical lung biopsy or after reclassification after the follow-up period. SAD was an independent risk factor for the survival of the patients with NSIP after follow-up.ConclusionFollow-up is recommended because idiopathic NSIP may be the first manifestation of a systemic autoimmune disease.

Idiopathic non‐specific interstitial pneumonia

“…Initial daily doses ranging from 0.5 to 1 mg/kg of prednisone or 40–60 mg (in non‐weight‐based dosing) are most commonly reported . Typically, the initial dose is continued for 1 month prior to attempts at weaning .…”

“…74 Initial daily doses ranging from 0.5 to 1 mg/kg of prednisone or 40-60 mg (in non-weight-based dosing) are most commonly reported. 12,30,74,79 Typically, the initial dose is continued for 1 month prior to attempts at weaning. 12,30 Average treatment length reported by Park et al specifically for iNSIP was 17.4 ± 12.1 months.…”

Factors affecting treatment outcome in patients with idiopathic nonspecific interstitial pneumonia: a nationwide cohort study

“…They suggested that sero-positivity of ANA could be an early manifestation of systemic diseases associated with a poor outcome of NSIP. Xu et al [ 19 ] also showed that systemic autoimmune disease was significantly associated with increased mortality in NSIP patients ( p = 0.023). Felicio et al [ 20 ] reported a higher production of collagen and elastic fibers in NSIP with collagen vascular disease than in iNSIP; in a cohort of 41 NSIP patients, an increase in elastic fibers >1.5% was a significant risk factor for poor outcome ( p = 0.01).…”

Nonspecific Interstitial Pneumonia

“…6,10,11,14,15,60 However, other symptoms including fevers and constitutional symptoms such as fatigue and weight loss may occur. 7,10,14,27,60,61 Physical examination findings such as digital clubbing (0-40%) and fine inspiratory crepitations can be present but do not discriminate NSIP from other forms of ILD. 8,10,62 A thorough clinical examination remains important, as findings such as a skin rash or Raynaud's phenomena can add impetus for the clinician to further investigate for an underlying etiology, such as an occult CTD.…”