ICD-10-CM coding study: Pulmonary hypertension is frequently undercoded

Findings from a retrospective study recently published in the Journal of Cardiac Failure show that pulmonary hypertension (PH) is frequently identified but rarely coded in electronic health records (EHR).

PH, a type of high blood pressure that affects the arteries in the lungs and heart, is associated with serious complications such as heart failure and arrhythmias, according to the National Heart, Lung, and Blood Institute. To be diagnosed with PH, a patient must present with a pulmonary artery systolic pressure of greater than 36 mmHg and/or pulmonary arterial pressure of greater than 25 mmHg.

In an effort to learn more about the prevalence of PH and how consistently it’s coded in EHRs, researchers conducted a retrospective review of patients seen for outpatient treatment at the University of Pittsburgh Medical Center between January 2, 2016, to December 31, 2016. They identified charts that were coded with PH or that included the diagnostic criteria for PH. Specifically, researchers identified patient charts that included one or more of the following:

• An ICD-10-CM code for PH
• Echocardiogram results indicating a pulmonary artery systolic pressure of greater than 36 mmHg
• Right heart catherization results with a mean pulmonary arterial pressure greater than 25 mmHg

Researchers identified 11,369 patients who met one or more of these criteria. Of this sample, 9,684 patients (85%) had a pulmonary artery systolic pressure of greater than 36 mmHg and 394 patients (3%) had a pulmonary arterial pressure greater than 25 mmHg. Only 11% of the charts for patients who met one or both diagnostic criteria also included an ICD-10-CM code for PH.

To learn more about the patients’ general health and well-being, researchers also collected demographic data and two-year outcome data on the patients, including information on hospitalization and mortality rates. They found that between December 31, 2016, and December 31, 2018, 64% of patients had been hospitalized and the mortality rate for these patients was 27%.

These findings have implications for providers and coders, who may be underreporting PH, and provide a foundation for future studies on the clinical impact of identification of PH. In the discussion portion of their article, the researchers note that they intend to use these and future findings to support the implementation of a program for early identification of patients with PH.