Evaluating the association between avascular necrosis of femoral head and oral corticosteroids use in Taiwan.

The aim of this study was to assess a correlation between avascular necrosis of femoral head and oral corticosteroids use in the general population in Taiwan. A population-based case-control study was performed to analyze the database of Taiwan National Health Insurance Program. The study consisted of 3002 subjects aged 20 to 84 with newly diagnosed avascular necrosis of femoral head between 2000 and 2013 as the cases and 11279 sex-matched and age-matched subjects without avascular necrosis of femoral head as the matched controls. Use of oral corticosteroids was defined as subjects who had at least a prescription for oral corticosteroids before the index date. No use of oral corticosteroids was defined as subjects who did not have a prescription for oral corticosteroids before the index date. The logistic regression model revealed that subjects with avascular necrosis of femoral head were 1.65 times more likely to be exposed to oral corticosteroids than those subjects without avascular necrosis of femoral head (OR 1.65, 95% CI = 1.51-1.80). A sub-analysis revealed that there was a significant association between avascular necrosis of femoral head and increasing cumulative duration of oral corticosteroids for each additional month of use (OR 1.03, 95% CI = 1.02-1.03). A significant association is detected between avascular necrosis of femoral head and oral corticosteroids use in the general population in Taiwan. There is a duration-dependent effect of oral corticosteroids use on the risk of avascular necrosis of femoral head. Clinicians should be aware of the risk of avascular necrosis of femoral head when oral corticosteroids are prescribed for a long time.