The present study suggests that Cryptogenic organizing pneumonia (COP) has a good prognosis. However, relapse is common in COP, occurring in more than 20% of patients. Nearly 50% of relapse occurred within 12 months after diagnosis. Over 60% of relapses contributed to steroid discontinuation; approximately 30% occurred when prednisone was tapered to doses below 10 mg/d. Close follow-up is important for early detection of relapse, especially when steroids are tapered or discontinued.
Cryptogenic organizing pneumonia (COP) is a subtype of idiopathic interstitial pneumonia, characterized histologically by polypoid granulation tissue within the lumens of bronchioles and alveolar ducts without definite cause. Despite its superior overall prognosis relative to other interstitial lung diseases, frequent relapse imposes prolonged glucocorticoid exposure and substantial patient burden. Prior international studies yield inconsistent relapse predictors, while large, long-term prospective cohort data from China to guide clinical surveillance and steroid tapering remains scarce.
To fill this gap, Professor Huaping Dai's team conducted a multicenter prospective observational cohort enrolling COP patients from two respiratory institutions between March 2004 and June 2022. All diagnoses were confirmed through standardized multidisciplinary discussion (MDD) based on comprehensive integration of clinical manifestations, chest high-resolution computed tomography (HRCT) findings, bronchoalveolar lavage fluid (BALF) analysis, and pathological results of lung biopsy. Patients with incomplete clinical or imaging data and those diagnosed with secondary organizing pneumonia were excluded. A total of 268 eligible patients were prospectively followed up until October 2023, yielding a median follow-up duration of 73 months. The relevant findings were made available online in the Chinese Medical Journal on August 14, 2026.
Survival analysis revealed benign long-term prognostic profiles for COP patients, with 1-year, 3-year, 5-year, and 10-year overall survival rates of 99.6%, 97.7%, 94.5%, and 81.7%, respectively. Kaplan–Meier survival curves demonstrated no significant intergroup difference between relapsed and non-relapsed patients (P = 0.470), verifying that disease relapse exerts no adverse impact on long-term mortality. The overall disease relapse rate was 20.9%, with a median time of 12 months from diagnosis to the first disease exacerbation. Notably, 62.5% of relapses occurred following complete prednisone discontinuation, and 28.5% emerged during prednisone tapering at a daily dose below 10 mg, indicating aggressive glucocorticoid tapering and premature cessation as major contributors to COP relapse.
Multivariate Cox proportional hazards regression analysis screened three independent and clinically accessible risk factors for COP relapse: younger age (HR = 0.97), platelet count exceeding 350 × 109/L (HR = 1.89), and higher CT score (HR = 1.44). This panel of readily measurable clinical parameters supports low-cost, point-of-care risk stratification for routine clinical management.
A total of 84% of patients received standardized prednisone therapy with a median initial dose of 0.5 mg/kg/day and a median treatment duration of 8 months. The study established evidence-based, stratified glucocorticoid tapering regimens: a biweekly dose reduction of 5 mg until reaching 15–20 mg daily, slowed tapering pace for doses below 10 mg daily, and extended maintenance therapy for high-risk populations, with a total treatment course ranging from 6 to 12 months. For high-risk patients, intensified follow-up every 3 to 6 months and timely adjuvant immunosuppressive therapy are recommended to reduce relapse risk.
This study is China's one of the largest long-term prospective COP cohorts to date, supplying vital real-world East Asian clinical data. Its easily applicable risk indicators and quantified steroid-relapse correlation facilitate standardized primary care management. Limitations include single-city recruitment bias, incomplete pathological confirmation in 10% of subjects, and incomplete BAL workup for relapsers. Further nationwide multicenter validation and translational mechanistic research are warranted to clarify relapse pathogenesis. As Professor Dai emphasized, COP carries good survival outcomes; the three risk factors enable early identification of vulnerable patients, individualized steroid regimens, and intensified monitoring to reduce recurrent disease flares and cumulative glucocorticoid-related adverse events.
