Prevalence and associated factors of catastrophic health expenditure among adults with chronic pain in an urban slum of Delhi: a community-based cross-sectional study.

Background: Chronic pain is a major and growing public health challenge with a disproportionate burden across sex, age, and socioeconomic groups. As its prevalence continues to rise, it imposes substantial financial hardship on affected households, particularly in low- and middle-income countries (LMICs) where healthcare is largely financed through out-of-pocket expenditure (OOPE). However, the risk of catastrophic health expenditure (CHE) among individuals with chronic pain remains poorly characterised. This study aimed to estimate the prevalence of CHE and identify its associated factors among community-dwelling adults with chronic pain in an urban slum of Delhi. Methods: A community-based cross-sectional analytical study was conducted among 151 adults with chronic pain (pain persisting >3 months on most or all days) residing in Gokalpuri, North-East Delhi. Participants were recruited by simple random sampling from a household register. CHE was defined as OOPE exceeding 10% of annual household income. Sociodemographic, clinical, and healthcare utilisation variables were assessed using a semi-structured questionnaire. Multivariable logistic regression was used to explore factors associated with CHE. Results: The prevalence of catastrophic health expenditure was 28.5% (95% CI: 21.4-36.4), with an overshoot of 5.3 percentage points and a mean positive overshoot of 18.4 percentage points (95% CI: 11.6-25.3). Nearly all participants (96.0%) incurred some out-of-pocket expenditure (OOPE), with a median annual direct expenditure of ₹6,000 (IQR: ₹2,400-24,000). Direct medical costs constituted 89.5% of total direct OOPE, with medications being the single largest component. Among the 16 working participants, the median number of workdays lost was 72 days per year (IQR: 60-132), with a range of 24-240 days, corresponding to a mean of 100.5 workdays per participant per year (SD: 58.6). Nearly three-quarters (72.2%) delayed treatment due to financial reasons. Borrowing from family members or relatives was the most common coping strategy to meet treatment expenses (80.1%). On multivariable analysis, daily pain (aOR 7.30; 95% CI: 2.73-19.55) and lower socioeconomic status (aOR 0.05; 95% CI: 0.005-0.41), were significantly associated with CHE, while married status was associated with lower odds of CHE (aOR 0.24; 95% CI: 0.08-0.73). Conclusions: More than one in four adults with chronic pain in this urban community experienced catastrophic health expenditure. Out-of-pocket spending was dominated by medication costs. Daily pain, lower socioeconomic status, and unmarried/separated/widowed status were associated with greater financial vulnerability. Strengthening public sector pain management capacity, expanding essential medicines availability, and extending social protection schemes may help to reduce the financial hardship chronic pain imposes on India's most vulnerable households.