CRP and idiopathic pulmonary fibrosis: The unadjusted Cox proportional hazards model showed that age, smoking status, higher C-reactive protein levels, lower DLCO and TLC, a shorter six-minute walk test distance (6MWD), a UIP pattern on the HRCT, and a higher level of KL-6 (> 53.5 pg/mL) were significantly associated with 10-year mortality (Table 3).