gms | German Medical Science

Objectives: The objective was to estimate the impact of one week oral corticosteroid dose for the risk of femoral head osteonecrosis (ONF).

Methods: Cases were defined as patients who received a diagnosis of ONF after first oral corticosteroid prescription (methylprednisolone) for one week during the three previous years before the diagnosis of osteonecrosis and without other evident cause of osteonecrosis (as alcohol abuse, lupus, sickle cell disease and so on...). Patients who had received any other glucocorticoid product prior to this oral prescription were excluded. Matched controls were selected among patients who had MRI demonstrating absence of osteonecrosis on both hips, and also had had first oral corticosteroid prescription for one week during the three previous years preceding 6 months the MRI. A total of 1218 cases patients with hip osteonecrosis and first oral corticosteroid prescription during the three previous years before the diagnosis of osteonecrosis were identified between 1984 and 2014 among 9234 patients with hip osteonecrosis; for these 1218 patients the diagnosis of osteonecrosis was obtained at average 9 months (range 6 to 25 months) from the corticosteroid prescription. 5148 matched controls were identified with an oral administration of corticosteroid that occurred average 15 months (range 6 to 36 months) before the normal MRI.

Results and Conclusion: Among the 1218 patients with osteonecrosis 474 (39%) received between 800 and 500 mg methylprednisolone, 395 (32%) > 400 mg, 186 (15%) > 300 mg, 90 (7%)> 200mg, 64 (5%) >100 mg and 9 (1%) patients had received less than 100 mg methylprednisolone. Among the 5148 patients without osteonecrosis 140 (3%) had received between 800 and 500 mg methylprednisolone, 125 (3%) > 400 mg, 255 (5%)> 300 mg, 363 (6%) > 200mg, 1635 (32%) >100 mg and 2630 (51%) patients had received less than 100 mg methylprednisolone. 80% of the patients had received their corticosteroid dose within 5or 6-day period. In absence of hyperlipidaemia, short-term (one week or less) oral corticosteroid administration is associated with a statisti¬cally significant increased incidence of osteonecrosis when the dose is more than 300 mg. A positive association of history of hyperlipidemia (67 patients; 40%) for ONF was observed for the 167 patients who received doses below 300 mg, while this association was only found in 4% of the patients presenting with absence of osteonecrosis. The relative risk of osteonecrosis after the prescription of methylprednisolone increased from 1.4 with less than 100 mg to 10 when the dose was > 300 mg with a threshold dose of more than 1mg/kg per day during 5 days. Short-term (one week or less) oral corticosteroid administration is associated with a statisti¬cally significant increased incidence of osteonecrosis when the dose is more than 300 mg, which roughly represents 1mg/kg per day during at least five days for a person of 60 kg.