English summary: CLOSTRIDIUM DIFFICILE INFECTION IN PATIENTS DISCHARGED FROM FINNISH HEALTH CARE FACILITIES IN 1996-2004

Several reports from individual hospitals suggest that both the incidence and the severity of Clostridium difficile-associated disease (CDAD) may be increasing. Few nationwide, population-based studies on CDAD epidemiology have previously been published. We wished to determine whether the rate of CDAD and CDAD-related deaths had increased in Finland during 1996-2004. The National Care Register (HILMO) contains comprehensive healthcare records provided by all hospitals and municipal health centers in Finland (population 5.3 million). Each report to HILMO includes patient identifying information, admission and discharge dates, healthcare provider, type of service, medical specialty, the place (home or institution) from which the patient was transferred to the facility, and data on surgical procedures and discharge diagnoses. HILMO data were used to determine the number of discharges and persons with the International Classification of Diseases (ICD-10) codes specific for CDAD - "enterocolitis due to Clostridium difficile" (A04.7) and "pseudomembranous enterocolitis associated with antimicrobial therapy" (K52.80) - listed as the primary or as any discharge diagnosis. CDAD-related deaths were identified from death certificates of the National Causes of Death Register in which underlying and immediate causes of death and contributory factors are coded according to the ICD-10. From 1996 through 2004, a total of 7,946 and 10,958 discharges for which CDAD was listed as the primary or as any diagnosis, respectively, were identified among 8,093 patients; 5,239 (65%) were 65 years of age and 5,005 (62%) female. Discharges for which CDAD was listed as any diagnosis doubled from 810 or 16/100,000 population in 1996 to 1787 or 34/100,000 in 2004. The overall rate during this period was many times higher in persons 65 years of age (108/100,000) than in those of 45-64 years of age (16/100,000). A total of 761 CDAD-related deaths (range per year 70-143) were identified; 733 (96%) occurred in persons aged 65 years (age-standardized mortality rate 76-146 per million population) and in 81 cases (range by year 7-13) CDAD was considered an underlying cause of death. Although the rates of CDAD and CDAD-related deaths are still at lower levels than the national estimates reported from the US and UK, Finnish clinicians should be aware of the increasing risk for CDAD, especially among elderly patients.