Causes of death after total hip arthroplasty: a nationwide cohort study with 24,638 patients.

Based on the nationwide registration of the total hip arthroplasties (THAs) in Finland since 1980, a cohort of 24,638 patients with primary THA was gathered and followed for causes of death until December 31, 1996. The causes of death were divided into 20 main categories according to the classification of diseases ICD-10. The number of person-years was 153,410, and the mean length of follow-up of a person was 6.2 years. During the follow-up, 4,626 patients died; the expected number was 6,746. The standardized mortality ratio (SMR) was 0.69 (95% confidence interval; 0.67-0.70), without any difference between men and women. The total risk increased during the follow-up, with the highest being 0.84 (95% confidence interval, 0.81-0.87). Among the ICD categories, there were significantly low SMRs for cancers (0.54), accidents (0.74), cardiovascular diseases (0.70), and respiratory diseases (0.46). Among the diseases, there was a constant and significant decline of the SMR for dementia and Alzheimer's disease (0.50), diabetes (0.40), myocardial infarction (0.73), hypertension (0.68), other ischemic diseases (0.70), other heart diseases (0.57), and cerebrovascular diseases (0.70). The explanation for the decreased SMRs seems to be attributed to factors other than the THA per se, such as preoperative patient selection, more active lifestyle after THA, and possibly the use of anti-inflammatory drugs.