Prevalence of Chronic Cough Following COVID-19 Infection: A Cross Sectional Study

Abstract

Rationale: SARS CoV-2 infection has been associated with long-term sequelae, including cough. The clinical course of chronic cough following SARS CoV-2 infection and therapies are not known. This study examined the prevalence and characteristics of chronic cough following SARS CoV-2 infection, aiming to assess its course, impact on patient well-being and predisposing factors. Methods: 113 patients were analysed as part of PREDICT UK follow up (NHS HRA: 20/HRA/2344) at 3 to 6 months (mean 152 days) after admission for a PCR positive SARS CoV2 infection. The baseline clinical and demographic characteristics were examined to assess contributing mechanisms that may predispose to chronic cough (defined as >8 weeks following SARS CoV2 infection). Results: 41.5% patients did not have a cough. In contrast, 24% of patients had an acute cough (<3 weeks), 10.6% had subacute cough (3 to 8 weeks), and 21.6% had chronic cough (>8 weeks). 1.7% of patients had a pre-existing cough, unchanged following COVID-19. The demographic and clinical characteristics of the study population are summarised in Table 1.50% of the cough group had a pre-existing lung disease (mainly airways disease), compared to 16% of patients without cough (P < 0.001). No differences in hypoxia, inflammation or infection markers (CRP) were noted between the 2 groups at admission. Diffusion Capacity for Carbon Monoxide (DLCO) was significantly reduced in those with cough compared with the non-cough group (32.2% vs 57.7%;P = 0.02). No significant differences in cough was noted between patients treated with different ventilator support strategies i.e. ITU and CPAP vs simple oxygen supplementation. Conclusions: This study notes a prevalence of chronic cough in 21.6% of patients post COVID-19. This was not associated with airway obstruction, reducing the likelihood of post infective bronchoconstriction. There was a significant reduction in DLCO consistent with post-infective interstitial lung disease (ILD). This study has looked at first-wave patients where dexamethasone was minimally used. Future studies reviewing cough with steroids therapy in patients requiring oxygen supplementation may note reduced levels of chronic cough. The use of cough as marker of post- COVID ILD warrants investigation. The current findings are in keeping with previous reports in SARS and MERS, where DLCO impairments were noted with time resolution of up to two years.