Specialized healthcare diagnostic events within one year preceding colorectal cancer diagnosis

Patients/material and methodsIncident CRC cases with International Classification of Diseases and Related Health Problems, 10 th revision (ICD-10) codes C18-C20 [14] diagnosed in 2015 were retrieved from the Finnish Cancer Registry (FCR) [15,16].All HS events (outpatient visits or inpatient stays in specialized HS) within 1 year before CRC diagnosis were retrieved from the Care Register for Health Care (Hilmo) [17].Sex, date of diagnosis, stage, and age of patient at the time of CRC diagnosis were available from the FCR, and the dates of HS events with diagnostic ICD-10-codes from Hilmo.The individual data from FCR and Hilmo were linked using the unique personal identity number.Diagnostic codes for HS events were classified into diagnostic ICD-10 groups according to the first character of each code, forming homogeneous groups that represent diseases with shared characteristics or a single defined condition [14] (Table 1).We focus on ICD-10 diagnostic groups with at least one visit by 15% or more of the patients: Malignant neoplasms (C), Neoplasms and diseases of the blood (D), Diseases of the digestive system (K), Symptoms, signs and abnormal clinical and