EVALUATION OF INTERNISTS SPIROMETRIC INTERPRETATIONS

BACKGROUND: Correct interpretation of screening spirometry results is essential in making accurate clinical diagnoses and directing subseque nt pulmonary evaluation. The general internist is largely responsible for interpreting screening spirometric tests at community hospitals. H owever, reports of new guidelines for screening spirometry are infrequ ently published in the general internal medicine literature. This can lead to incorrect interpretations. We sought to evaluate whether spiro metric interpretations by a group of practicing general internists dif fered from those of two board-certified pulmonologists using guideline s published by the American Thoracic Society (ATS). METHODS: As part o f a Continuous Quality Improvement project, all available screening sp irometric tests over a 3-month period at two area community hospitals were reviewed. Only those performed on individuals age 18 or older wer e included in the analysis. Comparison was made between the interpreta tions of staff internists and those of two pulmonologists, who were bl inded to the results of all other interpretations. We analyzed 110 scr eening spirometric tests from 84 males and 26 females. The patients ra nged in age from 18 to 77 (mean 41 +/- 13 years of age). RESULTS: Ther e was 97% concordance between the two pulmonologists' interpretations. In three cases, interpretations of only one pulmonologist agreed with those of the internists. The internists and both pulmonologists agree d in 73 cases. The majority of spirometric results in this subgroup we re normal (n = 54). Both pulmonologists disagreed with internists' nom enclature in five cases, There was complete disagreement between the p ulmonologists and the internists in the other 29 cases. Using the pulm onologists' interpretations as the ''gold standard,'' the sensitivity (the internists' ability to correctly identify abnormal spirometric re sults) was 58.8% (95% confidence interval [CI] 42.2%, 73.3%), the spec ificity was 81.8% (95% CI 70.0%, 89.8%), the positive predictive value was 66.7% (95% CI 49.0%, 80.9%), and the negative predictive value wa s 76.1% (95% CI 64.3%, 85.0%). The most common inaccurate Interpretati ons made by internists were ''small airways disease'' when spirometric results were normal (n = 8); ''normal'' when a restrictive pattern wa s present (n = 6), and ''normal'' when an abnormal flow-volume loop su ggesting possible upper airway obstruction was present (n = 5) CONCLUS IONS: The spirometric interpretations of a group of general internists differed significantly from those of two board-certified pulmonologis ts using published guidelines in approximately one third of cases. Thi s may be because subspecialty guidelines are infrequently published in the general internal medicine literature. We believe that wider disse mination of these interpretative guidelines and ongoing physician educ ation would improve general internists' ability to identify patients w ho require further pulmonary evaluation.