Researchers Find 2 Patterns of Coexisting Disorders in Patients

Neurological and psychological disorders that often coexist in patients with chronic obstructive pulmonary disease (COPD) may be grouped into two distinct clusters or patterns, according to a recent study.

Investigators noted these clusters and disease patterns may be helpful for physicians caring for these patients in clinical practice, as their identification may help guide patient care.

The study, “Neurological and Psychiatric Comorbidities in Chronic Obstructive Pulmonary Disease,” was published in the International Journal of Chronic Obstructive Pulmonary Disease. 

COPD can be complicated by multiple comorbid conditions, including hypertension (high blood pressure), diabetes, and neurological and psychological disorders, which all contribute to the overall disease burden.

Research indicates that COPD comorbidities tend to appear in disease-specific clusters, such as those involving cardiovascular or metabolic conditions.

In the study, researchers at Vilnius University in Lithuania sought to evaluate the frequency of neurological and psychiatric comorbidities in patients with COPD, and to explore potential associations between them.

Investigators extracted patient data spanning January 2012 to June 2014 from an electronic database of the National Health Insurance Fund of Lithuania.

In total, data from 4,834 COPD patients (median age of 69 and 69.1% male) were selected to be included in the study.

A total of 2,767 (57.2%) patients had at least one comorbid neurological or psychiatric condition, with the most frequent being nerve disorders (29.8%), followed by sleep disorders (13.8%), transient ischemic attack (11.3%), depression (7.5%), and ischemic stroke (7.2%). A transient ischemic attack is a type of stroke that lasts a few minutes and is not associated with permanent brain damage. However, an ischemic stroke lasts longer and is normally associated with permanent brain damage.

Alcohol-related disorders and ischemic stroke were both more frequent in men, while depression, anxiety, transient ischemic attack, sleep, headache, and nerve disorders were more frequent in women.

Both transient ischemic attacks and ischemic strokes were found to be correlated with hypertension, and the latter was also associated with arrhythmias (heart rhythm disorders).

Analyses also showed the likelihood of developing epilepsy was significantly higher in patients who also had Parkinson’s disease, dementia, transient ischemic attack, and ischemic stroke. 

Exploratory factor analysis was also used to identify comorbidity patterns. In the overall population, this analysis revealed the existence of two comorbidity groups.

The first group included disorders that, with the exception of epilepsy, tend to become more frequent as people age. These were mainly neurodegenerative and cerebrovascular conditions, which included Parkinson’s disease and all types of strokes. The second group included psychiatric and sleep disorders like depression and anxiety.

While a second analysis revealed that male patients showed distinct comorbidity patterns similar to those observed in the overall patient population, no such patterns were seen in female patients. 

Researchers also noted that future exploration of these comorbidity patterns may yield important therapeutic insights.

“The psychiatric-sleep pattern of COPD comorbidities could be relevant from a purely practical standpoint: targeting poor sleep in COPD might be directly beneficial in reducing the patient’s psychiatric symptoms,” they wrote.

Yet, they acknowledged the study may have been limited by its retrospective nature, potential selection bias for patients with less severe COPD, and the use of medical records not originally intended to be used in an observational study.

The researchers also emphasized that these comorbidity associations should be interpreted with caution, as these findings do not allow for causal relationships to be established between them. 

Nevertheless, they noted their study provided “novel insights into the neurological and psychiatric comorbidities in COPD by outlining an association among cerebrovascular, neurodegenerative disorders and epilepsy, and psychiatric and sleep disorders. Future studies could substantiate the discrete pathological [disease] mechanism that underlie these comorbidity groups.”