When imaging adult primary care patients with acute cough, clinically relevant incidental findings on chest radiographs are uncommon, according to a study published in the November/December issue of Annals of Family Medicine.

Saskia van Vugt, MD, MSc, of University Medical Centre Utrecht, the Netherlands, and colleagues found that while incidental findings were reported in 19 percent of patients, only 3 percent had clinically relevant incidental findings.

“We found few potentially clinically relevant incidental findings that would require additional investigations; therefore, there appears to be little reason for raising thresholds for requesting chest radiographs for acute cough because of fear of revealing incidental findings,” wrote the authors.

Since incidental findings of unknown or doubtful clinical relevance can lead to unnecessary patient anxiety, expensive and potentially harmful follow-up testing and unneeded treatment, van Vugt and colleagues sought to describe incidental findings on chest radiography from a cross-sectional study in 16 European primary care networks. A total of 2,820 patients, all with acute cough, had good-quality chest radiographs, and the findings were categorized according to clinical relevance. Incidental findings included all findings apart from pneumonia and acute bronchitis. These findings might have already been known to the treating general practitioner, such as the presence of a pacemaker or a diagnosis of asthma.

While the overall rate of incidental findings was 19 percent, results showed this rate ranged from 0 percent to 36 percent based on primary care network. “We found large differences in prevalence of reported findings between primary care networks, which remained after adjustment for age, sex, and smoking status,” wrote van Vugt and colleagues. “These differences might be explained by differences in socioeconomic status, for which we had no data. Another explanation might be differences in professional routines, resulting in reporting differences.”

Of the clinically relevant findings, suspected nodules and shadow were reported in 1.8 percent of participants, and incidental findings were more common in older patients and smokers.

The authors wrote that uniformity in reporting could be improved through better agreement between radiologists and referring clinicians on clinical relevance and need for reporting of incidental findings. “Our results may inform decisions about the appropriate threshold for ordering chest radiographs in primary care, as well as in guiding clinicians in informing patients about the possibility of incidental findings when chest radiographs are ordered.”