Assessment of statin-induced interstitial pneumonia in patients treated for hyperlipidemia using a health insurance claims database in Japan

This study aimed to determine the frequency and risk factors for statin-induced interstitial pneumonia (IP). We conducted a retrospective cohort study using a large Japanese health insurance claims database. We determined the statin-induced IP incidence in patients treated with statins for hyperlipidemia (n = 194,814) with 12-month screening and 3-month observation periods. Statin-induced IP was defined as: (1) diagnosis with IP (ICD-10 codes: J70.2-J70.4, J84.1, and J84.9) within 3 months after starting statins; (2) steroid administration starts after starting statins; (3) undergoing laboratory tests for sialylated carbohydrate antigen Krebs von den Lungen-6 or pulmonary surfactant protein-D; and (4) undergoing high-resolution computed tomography (HRCT). Risk factors for IP were defined as presence of lung-related diseases including lung cancer and IP (ICD-10 codes: A15-16, J12-18, 43-46, 60-70, and 80-99) that were known to the risk factors inducing IP during the screening period. Cohort 1 had no IP-inducing risk factors; based on lung-related disease history, we identified 4 cases (male/female: 0/4, 61 ± 2.5 years) and 46,574 controls (male/female: 29,677/16,897, 51.3 ± 9.5 years). In cohort 1, all cases were female and average age was older than that of controls (p