Benign pleural effusions in long-standing diabetes mellitus

We studied intractable pleural effusions in five patients with long-standing diabetes mellitus and an additional 40 patients with left ventricular systolic dysfunction to determine whether the frequency of pleural effusions is increased in diabetic patients and, if so, the relation of pleural effusions to left ventricular dysfunction. In our initial observations, effusions were benign, were not always associated with congestive heart failure (CHF), and reaccumulated following thoracentesis. Effusions associated with CHF persisted despite medical treatment and improvement of CHF. In our study of 40 patients with similar degrees of left ventricular dysfunction, the incidence of pleural effusions in diabetic patients was 83 percent and in our nondiabetic patients was 14 percent (p less than 0.001). We conclude that pleural effusions occur more commonly in diabetic than nondiabetic patients and may be related to left ventricular dysfunction and possibly other factors leading to increased effusion.