Objective: Chronic cough (CC) symptoms can persist as refractory or unexplained CC (RCC). We sought to characterize the clinical and economic burden of RCC.
Methods: In this retrospective US cohort study using data from Optum's de-identified CDM Database (01/2015-03/2022), CC was identified as ≥1 CC diagnosis or ≥3 cough events (with ≥8 weeks and ≤120 days between the first and third events and ≥3 weeks between any 2 events). The index date was set as the earliest date of meeting the CC definition. The baseline period was defined as the 364 days prior to and including the index date. Adults with CC at baseline who met CC requirements (≥1 CC diagnosis, or ≥2 cough events occurring ≥8 weeks but ≤120 days apart) in both follow-up year 2 and follow-up year 3 were defined as having '3-year chronic cough' (3YCC), a proxy measure of RCC, and compared to adults with CC at baseline who did not meet CC requirements in follow-up years 2 and 3 (non-3YCC). A propensity score weighting approach was used to adjust for baseline differences between the 3YCC and non-3YCC groups to compare clinical characteristics and healthcare resource use and costs in the two groups during the follow-up period.
Results: At baseline, the 3YCC group (N = 3,338) had significantly more comorbidities and higher all-cause healthcare resource use and costs than the non-3YCC group (N = 43,122) in unweighted analyses. After weighting, the groups (N = 3,338 with 3YCC and N = 3,145 without) were compared during a 3-year follow-up period. The 3YCC group had significantly more comorbidities, higher levels of all-cause healthcare resource use, and higher all-cause healthcare costs during the follow-up period compared to the non-3YCC group, after adjusting for baseline differences. For example, the mean total healthcare costs (in 2022 US dollars) were significantly higher among the 3YCC group than the non-3YCC group in each follow-up year, at $49,454 versus $42,144 in follow-up year 1, $49,339 versus $36,939 in follow-up year 2, and $51,737 versus $36,503 in follow-up year 3 (p<0.001 for each comparison).
Conclusions: After adjusting for baseline differences, persistent symptoms of CC were associated with significantly higher comorbidity, healthcare resource use, and healthcare costs compared to CC that resolved. Effective treatments for RCC would thus be expected to result in improved health as well as substantial healthcare cost offsets.
Keywords: Chronic cough; healthcare costs; healthcare resource use; refractory or unexplained chronic cough.
Chronic cough (CC), defined as daily cough for ≥8 weeks, is a common condition that negatively affects physical and mental health, work, and participation in other daily activities. CC that continues following treatment of a diagnosed underlying condition is termed refractory chronic cough, while ongoing symptoms of CC in cases where no underlying condition can be identified are classified as unexplained chronic cough. Due to difficulties in differentiating between these conditions, they are often grouped together based on their shared characteristic of CC that persists for an extended period of time. In this study, we adopted a previously published approach and studied the clinical and economic burden of refractory and unexplained chronic cough using a nationwide US administrative claims database and found that after adjusting for baseline differences, persistent symptoms of CC were associated with significantly higher comorbidity, healthcare resource use, and healthcare costs compared to CC that resolved.