Chronic cough is a significant risk factor for the development of chronic pain, according to the results of a large, prospective, population-based study published in the European Respiratory Journal.
Studies have shown that individuals with chronic cough and those with chronic pain share similar clinical features that have common underlying mechanisms, but the relationship between chronic cough and chronic pain has not yet been determined.
To examine the association between chronic cough and chronic pain in adult subjects, data from 7141 participants (58% women; mean age, 69.9 years) were analyzed. Participants filled out a baseline survey and underwent clinical examinations every 4 to 5 years. Chronic cough was defined as daily coughing lasting 3 months or more, and chronic pain was defined as pain in the past 6 months — either daily, weekly, or several times per month.
At baseline, 54% of participants reported chronic pain; the coprevalence of daily chronic pain and chronic cough was 4.4%. Among the participants with chronic pain at baseline, 83% had musculoskeletal conditions, including arthrosis (35.4%), rheumatoid arthritis (3.6%), sciatica (0.9%), ankylosing spondylitis (0.2%), gout (0.2%), or an unspecified musculoskeletal condition (29.2%).
Among participants with chronic pain at baseline, 59% experienced pain daily, 17% experienced pain weekly, and 24% experienced pain monthly.
Patients with daily and weekly or monthly chronic pain were more likely to have chronic cough compared with those without chronic pain (P <.001). After adjusting for confounders, prevalent chronic pain was “significantly associated” with incident chronic cough (odds ratio [OR], 1.47; 95% CI, 1.08-1.99).
Patients with chronic pain at baseline were more likely to develop unexplained chronic cough compared with those without chronic pain (OR, 1.60; 95% CI, 1.02-2.51). Those with chronic cough at baseline were also significantly more likely to develop chronic pain compared with those without chronic cough (OR, 1.96; 95% CI, 1.08-3.56).
The results of this study demonstrated that chronic cough and chronic pain are significantly associated and have a bidirectional association over time. The association between the conditions was observed even in individuals without risk factors for chronic cough, showing that the relationship is independent of common risk factors.
One limitation to this study was the phrasing of the questionnaire question regarding chronic pain. Respondents were asked if they had been in pain in the last 6 months, which may not require subjects to have been in pain for any minimal duration. Additionally, the self-reported nature of the data may result in recall bias, and pain intensity was not captured.
Future research including intensity of chronic pain, history of chronic pain, and clarification of the minimal duration of pain to be considered chronic is warranted.
“[O]ur study shows that chronic cough and chronic pain are interrelated in middle-aged and older [people], thereby suggesting that both conditions might share common risk factors and/or pathogenic mechanisms,” the researchers concluded. “Therefore, a history of chronic pain may be relevant in the clinical evaluation of patients presenting with chronic cough and vice versa.”
Arinze JT, Verhamme KMC, Luik AI, Stricker B, van Meurs JBJ, Brusselle GG. The interrelatedness of chronic cough and chronic pain. Published online October 29, 2020. Eur Respir J. doi: 10.1183/13993003.02651-2020