Individuals with a prior diagnosis of pneumonia were significantly more likely to develop chronic otitis media (COM) than were those without a history of pneumonia, based on data from a nationwide cohort study of more than 100,000 patients.
“Recently, middle ear diseases, including COM, have been recognized as respiratory tract diseases beyond the pathophysiological concepts of ventilation dysfunction, with recurrent infection that occurs from anatomically adjacent structures such as the middle ear, mastoid cavity, and eustachian tube,” but the potential link between pneumonia and chronic otitis media and adults in particular has not been examined, wrote Sung Kyun Kim, MD, of Hallym University, Dongtan, South Korea, and colleagues.
In a study recently published in the International Journal of Infectious Diseases, the researchers identified 23,436 adults with COM and 93,744 controls aged 40 years and older from a Korean health insurance database between 2002 and 2015.
The overall incidence of pneumonia in the study population was significantly higher in the COM group compared with controls (9.3% vs. 7.2%, P <.001). The odds ratios of pneumonia were significantly higher in the COM group compared with controls, and a history of pneumonia increased the odds of COM regardless of sex and across all ages.
Pneumonia was defined as when a patient had a diagnosis of pneumonia based on ICD-10 codes and underwent a chest x-ray or chest CT scan. Chronic otitis media was defined as when a patient had a diagnosis based on ICD-10 codes at least two times with one of the following conditions: chronic serous otitis media, chronic mucoid otitis media, other chronic nonsuppurative otitis media, unspecified nonsuppurative otitis media, chronic tubotympanic suppurative otitis media, chronic atticoantral suppurative otitis media, other chronic suppurative otitis media, or unspecified suppurative otitis media.
Age groups were divided into 5-year intervals, and patients were classified into income groups and rural vs. urban residence.
In a further sensitivity analysis, individuals who were diagnosed with pneumonia five or more times before the index date had a significantly higher odds ratio for COM compared with those with less than five diagnoses of pneumonia (adjusted odds ratio, 1.34; P < .001).
Microbiome dysbiosis may explain part of the connection between pneumonia and COM, the researchers wrote in their discussion. Pathogens in the lungs can prompt changes in the microbiome dynamics, as might the use of antibiotics, they said. In addition, “Mucus plugging in the airway caused by pneumonia induces hypoxic conditions and leads to the expression of inflammatory markers in the eustachian tube and middle ear mucosa,” they noted.
The study findings were limited by several factors, including the retrospective design and lack of data on microbiological cultures for antibiotic susceptibility, radiologic findings on the severity of pneumonia, results of pulmonary function tests, and hearing thresholds, the researchers noted. Other limitations were the exclusion of the frequency of upper respiratory infections and antibiotic use due to lack of data, they said.
However, the results show an association between pneumonia diagnoses and increased incidence of COM, which suggests a novel perspective that “infection of the lower respiratory tract may affect the function of the eustachian tube and the middle ear to later cause COM,” they concluded.
The study received no outside funding. The researchers have disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.