Choose the prognostic index for patients with dialytic acute renal failure in the intensive care unit

Objective

To study APACHE II and Acute Tubular Necrosis Individual Severity Score (ATN-ISS) discrimination and calibration with the aim of choosing the prognostic rate for patients in dialytic acute renal failure (ARF), for routine use in our intensive care unit (ICU).

Method

A retrospective study was carried out, based on data collected from patient's records (those treated in the ICU of Israeli Hospital Albert Einstein). The study comprised 81 patients with dialytic ARF, treated from 1 January 1996 to 31 December 1998. Age, sex, origin, length and type of internment, associated chronic pathologies, intervals for dialysis indication, APACHE II and ATN-ISS scores and the hospital mortality were all analyzed.

Outcome

The prognostic scores APACHE II and ATN-ISS were carried out on the day of the realization of the first dialysis. The average age was 69, 14.72% were men and the mortality rate was 69%. In the survivors group there were 25 patients and 56 patients evolved for death internment. Both groups presented very similar characteristics, regarding the average prognostic scores and demographic data, differing only in time of hospital stay which was significantly longer in the survivors. Out of the evaluated prognostic scores, only the risk of death (APACHE II) presented a statistically significant difference among the survivors and non-survivors. The risk of death (APACHE II) and the ATN-ISS presented good discrimination. For the calibration, the risk of death underestimated the mortality in the lower tierces of seriousness significantly, while the ATN-ISS underestimated the mortality in all tierces of seriousness, although without significant difference.

Conclusion

It is possible to use both scores in our ICU, however by its easy obtainment we have opted to use the ATN-ISS score.