The predictive value of provisional clinical diagnosis in the evaluation of respiratory disorders

Background: Many non-pulmonary physicians in hospital and family care pract ice base the diagnosis of pulmonary disorders on clinical impressions made from the history and physical examination. Experience has shown that relyin g on these parameters alone is not adequate, since this may result in missi ng a significant number of diseases, or in the unnecessary treatment of oth ers. This study set out to compare the sensitivity, specificity and positiv e predictive value of the clinical assessment (provisional clinical diagnos is or PCD) with the combined clinical assessment and other investigations, including pulmonary function test (PFT). Patients and Methods: One thousand and fifteen (1015) patients referred for PFT to the pulmonary function laboratory of a teaching hospital were invol ved in the study. The referring physicians were asked to fill a specially p repared form giving details of the patients' history and clinical assessmen t. The PFT was performed using an Erich-Jager Master Lab. Results: Analysis of the final diagnosis revealed that only 51% of patients with a pre-evaluation diagnosis of asthma were actually confirmed to have asthma after further tests. Similar findings of 59% and 52% of patients wit h chronic obstructive pulmonary disease (COPD) and pulmonary fibrosis were observed, respectively. The positive predictive value of PCD for asthma and lung fibrosis was 64.1% and 61.9%, respectively, while that for CORD was 7 4.2%. Conclusion: This study showed conclusively that the predictive value of pro visional clinical diagnosis in the evaluation of pulmonary disorders is usu ally inadequate, and needs to be augmented with additional simple investiga tions such as PFT, in order to establish a more accurate diagnosis.