Temporal trends in hypersensitivity pneumonitis–coded mortality: a multinational analysis of 32 countries, 1999–2019

Contemporary evidence on hypersensitivity pneumonitis (HP) mortality trends remains limited. Using World Health Organization Mortality Database data (ICD-10: J67) from 32 countries, we analyzed 7,581 deaths in adults aged ≥ 20 years between 1999 and 2019. Age-standardized mortality rates (ASMRs) were calculated using the WHO World Standard Population; joinpoint regression estimated annual and average annual percent changes (APC, AAPC), and Kitagawa decomposition separated the contributions of population age structure and age-specific mortality rates. The pooled ASMR was 0.0394 per 100,000 (95% CI 0.0385–0.0403). HP-coded mortality was stable from 1999 to 2004 and rose thereafter (APC 7.34%; 95% CI 6.66–8.02), giving an AAPC of 5.43% (95% CI 4.35–6.52). HP-coded mortality was higher in men (0.0496 versus 0.0317 per 100,000), increased more steeply in women (AAPC 6.40% versus 4.45%) and rose with age to 0.2977 per 100,000 at ≥ 80 years. Among the 25 countries with ≥ 30 deaths, eight showed a significant increase and two a significant decrease. Population aging accounted for 12.2% of the increase in crude mortality among adults aged ≥ 40 years. HP-coded mortality increased across this multinational sample with substantial between-country heterogeneity, which may reflect changes in diagnostic recognition and certification practice as well as in disease occurrence.