Follow Up of Incidental High-Risk Pulmonary Nodules on Computed Tomography Pulmonary Angiography at Care Transitions
BACKGROUND: Computed tomography pulmonary angiography (CTPA) detects incidental findings that require follow-up. In just over 50% of cases, those incidental findings are pulmonary nodules. Fleischner guidelines recommend that patients with nodules that have a high risk of malignancy should undergo CT follow-up within 3-12 months.
OBJECTIVE: We examined the proportion of patients with pulmonary nodules requiring follow up who received repeat imaging within six weeks of the time frame recommended by the radiologist.
DESIGN: This retrospective cohort study included all patients who underwent CTPA in the emergency department and inpatient settings at three teaching hospitals in Toronto, Canada between September 1, 2014, and August 31, 2015. Natural language processing software was applied to a linked radiology information system to identify all CTPAs that contained pulmonary nodules. Using manual review and prespecified exclusion criteria, we generated a cohort with possible new lung malignancy eligible for follow-up imaging; then we reviewed available health records to determine whether follow-up had occurred.
RESULTS: Of the 1,910 CTPAs performed over the study period, 674 (35.3%) contained pulmonary nodules. Of the 259 patients with new nodules eligible for follow-up imaging, 65 received an explicit suggestion for follow-up by radiology (25.1%). Of these 65 patients, 35 (53.8%) did not receive repeat imaging within the recommended time frame. Explicit mention that follow-up was required in the discharge summary (P = .03), attending an outpatient follow-up visit (P < .001), and younger age (P = .03) were associated with receiving timely follow-up imaging.
CONCLUSIONS: Over 50% of patients with new high-risk pulmonary nodules detected incidentally on CTPA did not receive timely follow-up imaging.
© 2019 Society of Hospital Medicine
Statistical Analysis
We calculated simple descriptive statistics for all results. Mean values were compared using two-tailed t-tests, categorical groups using chi-square tests, and median values using Mann-Whitney U tests. We performed all analyses using Microsoft Excel version 16.14.1 (Redmond, Washington).
Ethics Approval
This study was approved by each institution’s research ethics board.
RESULTS
Follow Up of Incidental High-Risk Pulmonary Nodules
Of the 1910 CTPAs performed over the study period (Figure), 674 (35.3%) contained pulmonary nodules. Of the 259 patients with new pulmonary nodules eligible for follow-up imaging, 194 (74.9%) did not have an explicit suggestion for follow up by the radiologist. Ninety-five percent of radiologists (184 out of 194) provided an explanation for not recommending follow up in the radiology report; the two most common reasons were small nodule size (often described as “tiny”) and no interval change compared with the prior imaging study.2 Of the 65 patients who did receive an explicit suggestion for follow up by radiology, 35 (53.8%) did not receive repeat imaging within the recommended time frame, allowing for a six-week grace period. Of these 35 patients, 10 eventually went on to receive delayed repeat imaging. The median follow-up time for the 30 patients who received timely repeat imaging was four months (IQR 2-6 months); in contrast, the median follow-up time for the 10 patients who received delayed repeat imaging was seven months (IQR 6-8 months), P = .01.
Of the 65 patients for whom follow up was recommended, the medical record showed evidence that there was a discussion between the medical team and the patient regarding patient preference for or against follow up in 55.4% (36 out of 65) of the patients. Notably, all 36 patients showed interest in receiving follow up; no patient indicated a preference for no follow up.
Furthermore, of the 65 patients that had follow up recommended, two patients were eventually diagnosed with lung cancer (one via lung biopsy, the other via positron emission tomography imaging); both patients did not receive timely follow-up imaging. While we did not include nodule size as an exclusion criterion, not one of the 65 patients included in the final cohort had nodules larger than 3 cm.
Physician Notification
In circumstances where we could not confirm that followed up had occurred, we notified the ordering physician by e-mail. Since 10 of the 35 patients who did not receive timely follow-up imaging went on to receive delayed repeat imaging, we notified 25 physicians. Of the 25 physicians that we e-mailed, 24 acknowledged receipt of the information. Of these 24 physicians, 14 reported conducting a detailed review of the chart, from which the following additional information was obtained: one patient expired, and five physicians notified the corresponding primary care physicians (two of whom were unaware of the nodule, and subsequently arranged further follow up with the patient).
Characteristics Associated with Timely Follow Up
Explicit mention that follow up was required in the discharge summary (P = .03), attending an outpatient follow-up visit (P < .001), and younger age (P = .03) were associated with receiving timely follow up; patient sex, smoking history, history of chronic obstructive pulmonary disease, lung nodule count, recommended follow-up time, and hospital department (defined as the discharging service) were not (Table).
