Pleural effusions secondary to a non-malignant aetiology can represent significant morbidity and mortality. These non-malignant pleural effusions (NMPE) are common, with congestive heart failure (CHF) representing the leading cause. Despite this, there is limited data on mortality risk and the factors which influence them.
We recruited 782 consecutive patients presenting to a pleural service, between 03/2008 and 03/2015, with an undiagnosed pleural effusion. Further analysis was conducted on the 356 patients with NMPE. Pleural biochemistry, cytology, thoracic USS and chest radiograph were performed. Echocardiogram, CT scans, radiology-guided biopsy and medical thoracoscopy were undertaken as clinically indicated. Patients were followed-up for a minimum duration of 12 months with final diagnosis decided by independent review by 2 respiratory consultants.
Of the 782 patients, 356(46%) were diagnosed with a NMPE. These patients had a mean age of 68(SD17) with 69% of patients male. Cardiac, renal and liver failure patients had 1-year mortality rates of 50%, 46% and 25% respectively. Bilateral effusions (HR 3.55 CI 2.22-5.68) and transudative effusions (HR 2.78 CI 1.81-4.28) were associated with a worse prognosis in patients with NMPE, with a 57% and 43% 1-year mortality respectively.
This is the largest prospectively collected series in patients with NMPE, demonstrating that those secondary to organ dysfunction have an extremely high 1-year mortality. In addition, the presence of bilateral and transudative effusions are an indicator of increased mortality. Clinicians should be aware of these poor prognostic features and guide management accordingly.