Optimal follow-up time after continuous renal replacement therapy in actual renal failure patients stratified with the RIFLE criteria.

BACKGROUND We wished to determine the optimal duration of follow-up for patients with acute renal failure (ARF) treated with continuous renal replacement therapy (CRRT) and tested the hypothesis that a 6 month follow-up would be the minimum to catch most of the mortalities. In addition, we evaluated the association between mortality and the RIFLE classification in the same patients. METHODS We analysed the data of 8152 consecutive patients who had been admitted to the intensive care unit (ICU) of a Swedish university hospital between 1995 and 2001. Of that population, 207 patients were treated with CRRT, excluding 16 treated for non-renal indications. RESULTS ICU mortality in this cohort was 34.8% and 30 day and in-hospital mortalities were 45.9% and 50.2%, respectively. The cohort's all-cause mortality 6 months after inclusion was 59.9%, but 54.6% died as early as after 60 days. Patients in the more severe RIFLE category, F (failure), had a 30 day mortality of 57.9% compared with 23.5% for those in the RIFLE-R (risk) category and 22.0% for RIFLE-I (injury) patients. CONCLUSIONS In our opinion, a 60 day follow-up is sufficient to catch the majority of deaths in ARF patients treated with CRRT. The patients in the RIFLE-F category had a significantly higher mortality than RIFLE-R and -I patients.