RESUMEN
BACKGROUND: It has been reported that elderly outpatients take at least 6 different kinds of medication. PURPOSE: To know which formula will best predict creatinine clearance, because 24-hour urine collection is difficult for elderly outpatients. PATIENTS AND METHODS: We compared four types of formulae (Cockcroft and Gault, Yasuda, Orita, Walser) to estimate creatinine clearance using serum creatinine of 143 elderly inpatients (73 men, 70 women, mean age 82.9 +/- 8.6 years old) including 67 extremely elderly people with various underlying diseases. RESULT: The formula of Cockcroft and Gault showed the best correlation with creatinine clearance in the extremely elderly subjects (r = 0.74) as well as in people under 85 years (r = 0.76). However, the estimated values of the extremely elderly women were lower than actual creatinine clearance. CONCLUSION: The formula of Cockcroft and Gault is the best predictive equation of creatinine clearance, except in the extremely elderly women.