Cirrhosis is a risk factor for total hip arthroplasty for avascular necrosis: A Danish nationwide cohort study

Deleuran, Thomas; Overgaard, Søren; Vilstrup, Hendrik; Jepsen, Peter

We performed this registry-based historical cohort study in Denmark, which has 5.6 million inhabitants. All Danish residents are given universal, tax-paid access to hospitals. The Danish National Patient Registry (NPR) is a nationwide registry that has covered admissions to non-psychiatric hospitals since 1977 and outpatient and emergency room visits since 1995. The data include relevant dates and discharge diagnoses, coded in accordance with the International Classifi cation of Diseases, 10th edition (ICD-10) from 1994 and the ICD-8 before that (Lynge et al. 2011) . The Danish Hip Arthroplasty Registry (DHR) is a clinical database of all primary or revision total hip arthroplasties performed in Denmark since January 1, 1995. The data are entered by the operating surgeon immediately after the procedure and include the indication for arthroplasty (primary osteoarthritis, fracture, avascular necrosis, or other indication) (Pedersen et al. 2004 ). The indication for arthroplasty has been confi rmed by medical chart review and radiographs in 79 of 80 randomly selected AVN patients (Pedersen et al. 2004 ). The Danish Central Offi ce of Civil Registration continuously monitors the vital status of Danish residents, including dates of emigration or death, and it issues a unique personal identifi cation number to everyone at birth or immigration. This number enables linkage of individual-level data between the NPR, the DHR, and the civil registration system (Pedersen et al. 2006) .