An Intervention to Tag Findings Suspicious for Lung Cancer on Chest Computed Tomography Has Good Sensitivity and Number Needed to Diagnose

In 2015, Kaiser Permanente Northern California implemented an intervention to improve follow-up for pulmonary findings on diagnostic chest computed tomography (CT). The intervention includes tagging CT reports with the prefix “#PUL” followed by a character (0-6 or X) to track specific findings. #PUL5, indicating “suspicious for malignancy,” triggers automatic referral for multidisciplinary care review. Among patients who obtained an index chest CT exam from August 2015 to July 2017 without an exam in the previous 2 years, we computed the frequency of lung cancer diagnosis within 120 days of CT in relation to each #PUL tag. For #PUL5, we computed sensitivity, specificity, positive and negative predictive values, and number needed to diagnose. We also performed a chart review to assess why some patients diagnosed with lung cancer were not tagged #PUL5. Of the 39,409 patients with a tagged CT report, 1105 (2.8%) had a new primary lung cancer diagnosis within 120 days. Among the 2255 patients tagged #PUL5, 821 were diagnosed with lung cancer, with a sensitivity of 74% (95% confidence interval, 72%-77%). The positive predictive value was 36% (35%-38%), number needed to diagnosis was 2.7 (2.6-2.9), and specificity and negative predictive values were > 95%. Chart review identified opportunities to improve system defaults and clarify concepts. The intervention performed well but needed improvement. Automating CT reports was simple and generalizable, and enabled reduction of care gaps and system improvement.

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