Unfavourable outcome of glucocorticoid treatment in suspected idiopathic pulmonary fibrosis

Background and objective The diagnostic classification of ‘possible idiopathic pulmonary fibrosis (posIPF)’ is characterized by a radiological pattern of inconsistent usual interstitial pneumonia (UIP) on high‐resolution computed tomography (HRCT) scan and a UIP pattern in surgical lung biopsy (SLB). The evidence base to guide treatment for patients with posIPF is lacking; the clinician must choose between observation, treatment with immunomodulatory agents or anti‐fibrotic agents. Methods To evaluate outcomes of immunomodulatory treatment, a multicentre cohort of 59 posIPF patients treated with prednisone was analysed retrospectively. Prednisone starting dose was 0.5 mg/kg/day and tapered to 0.15 mg/day/kg over 6 months. Outcome measures were forced vital capacity (FVC) and serious adverse events (SAE), defined as death or hospital admissions. Results The majority of prednisone‐treated posIPF patients were non‐responders (68%) with a decrease in FVC >5% or death within 6 months from baseline; 90% of patients with radiographical presence of honeycombing were non‐responders. In contrast, six out of seven patients with focal desquamative interstitial pneumonia‐like reaction in the SLB who had stopped smoking for <5 years ago were responders to prednisone, demonstrating <5% FVC decline. The mean decline of FVC was 8.7% (95% CI: 3.1–14.3%) before treatment and 20% (95% CI: 9.4–31.1%) after treatment ( P  = 0.018) in the 32 patients with available FVC data. Twelve SAE occurred within the first 3 months on prednisone (at dosage >0.3 mg/kg/day), including five deaths. Conclusion Patients with posIPF demonstrated an accelerated FVC decline and a substantial number of SAE on steroid therapy.