Study Identifies Thousands of Potential Diagnosis Errors Among Patients With COPD

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Researchers found that thousands of patients with chronic obstructive pulmonary disease (COPD) did not follow the traditional trajectory associated with the disease, suggesting a possible incorrect diagnosis.

Thousands of patients could be at risk of having been mis- or overdiagnosed with chronic obstructive pulmonary disease (COPD), according to a recent study published in npj Digital Medicine.

“We have created a method that intelligently can improve the quality of routine care data in a national patient registry. In this case, the method does not just correct administrative errors that lead to diagnoses being wrongly recorded. Using longitudinal disease histories, we point at errors that likely stem from incomplete work-up or less robust human examination,” the investigators said.

Although there are methods for identifying undiagnosed individuals, the only available method to determine cases of misdiagnosis or overdiagnosis is through manual evaluation of patients, health records, or autopsies.

To determine whether patients are at risk of a mis- or overdiagnosis, the investigators used the Danish National Patient Registry. They detected statistically significant patterns of time-ordered, directional disease co-occurrences associated with COPD disease trajectory. The investigators noted that their method could be used to detect mis- and overdiagnosis rates in other disease populations.

They defined overdiagnosis as when a diagnosis is correct, in the sense that the condition exists, but will cause more harm than benefit for the patient. Misdiagnosis was defined as an incorrect diagnosis.


Studies have shown that up to 90% of patients with misdiagnosed COPD regularly receive COPD treatments, which can cause adverse events and add costs to the health care system. Additionally, some researchers have estimated that between 5% and 62% of patients with COPD have received a misdiagnosis.

“Diagnostic errors cause patients to suffer from unnecessary harm from tests and treatments, but misdiagnosed patients might also suffer from a true underlying disease, which is delayed or completely missed, causing harm or earlier death,” the investigators wrote.

The retrospective, population-based study included data on 284,154 patients with diagnosed COPD that were entered in the registry from 1994 to 2015. Two other database records from 2009 to 2016 were used to compare patterns of conducted laboratory tests between misdiagnosed patients, patients with COPD, and patients with lung cancer.

Overall, 192,997 had a primary diagnosis of COPD; 91,156 had a secondary diagnosis of COPD; and 34,088 followed a COPD trajectory in a less strict order.

Of the remaining 42,459 patients with a COPD diagnosis who did not follow a COPD trajectory, 9597 were identified as the “most dissimilar” and often received their diagnosis at a younger age and were less frequently given a lung function test.

On average, this group had a 96% greater risk of mortality. A subgroup of the most dissimilar patients (n = 2185) died within the first 3 months after receiving a COPD diagnosis, suggesting that patients who do not display the typical comorbidity patterns associated with COPD could be at risk for misdiagnosis.

Additionally, 10.5% (n = 226) of the patients who ended up dying faster after their COPD diagnosis had eventually received a lung cancer diagnosis, suggesting that lung cancer is generally underdiagnosed.

A separate subgroup of the most dissimilar patients (n = 2368) survived longer than 5.5 years after receiving a COPD diagnosis but did not experience the typical complications associated with COPD, suggesting they were overdiagnosed.

The investigators found that patients who do not follow a COPD trajectory had an HR of 1.96 compared with patients who do follow a trajectory, despite having less comorbidities.

In total, 17.2% of patients following a COPD trajectory were offered access to pulmonary rehabilitation programs compared with 10.4% of overdiagnosed patients and 0% of misdiagnosed patients.

Only 3.8% of patients with a potential misdiagnosis received a spirometry test to assess lung function compared with 40% who followed a COPD trajectory. Spirometry tests are essential to evaluating airway obstructions and diagnosing COPD but are generally underutilized in Denmark.

“Unfortunately, we cannot validate by additional work-up whether these patients are actually mis- or overdiagnosed, as the majority of them have already passed away. However, we can create awareness of these patient groups where diagnoses appear without the most common comorbidity context,” concluded the authors.


Jørgensen IF, Brunak S. Time-ordered comorbidity correlations identify patients at risk of mis- and overdiagnosis. npj Digit Med. Published online January 29, 2021. doi:10.1038/s41746-021-00382-y