Nephrology referral and outcomes in critically ill acute kidney injury patients.

BACKGROUND: Delayed nephrology consultation (NC) seems to be associated with worse prognosis in critically ill acute kidney injury (AKI) patients. DESIGN SETTING PARTICIPANTS & MEASUREMENTS: The aims of this study were to analyze factors related with timing of NC and its relation with AKI patients' outcome in intensive care units of a tertiary hospital. AKI was defined as an increase ≥50% in baseline serum creatinine (SCr). Early NC and delayed NC were defined as NC performed before and two days after AKI diagnosis day. Multivariable logistic regression and propensity scores (PS) were used to adjust for confounding and selection biases. Hospital mortality and dialysis dependence on hospital discharge were the primary outcomes. RESULTS: A total of 366 AKI patients were analyzed and NCs were carried out in 53.6% of the patients. Hospital mortality was 67.8% and dialysis required in 31.4% patients (115/366). Delayed NCs (34%) occurred two days after AKI diagnosis day. This group presented higher mortality (OR: 4.04/CI: 1.60-10.17) and increased dialysis dependence (OR: 3.00/CI: 1.43-6.29) on hospital discharge. Four variables were retained in the PS model for delayed NC: diuresis (1000 ml/24 h--OR: 1.92/CI: 1.27-2.90), SCr (OR: 0.49/CI: 0.32-0.75), surgical AKI (OR: 3.67/CI: 1.65-8.15), and mechanical ventilation (OR: 2.82/CI: 1.06-7.44). After correction by PS, delayed NC was still associated with higher mortality (OR: 3.39/CI: 1.24-9.29) and increased dialysis dependence (OR: 3.25/CI: 1.41-7.51). Delayed NC was associated with increased mortality either in dialyzed patients (OR: 1.54/CI: 1.35-1.78) or non-dialyzed patients (OR: 2.89/CI: 1.00-8.35). CONCLUSION: Delayed NC was associated with higher mortality and increased dialysis dependence rates in critically ill AKI patients at hospital discharge. Further studies are necessary to ascertain whether this effect is due to delayed nephrology intervention or residual confounding factors.

Performance of the third-generation models of severity scoring systems (APACHE IV, SAPS 3 and MPM-III) in acute kidney injury critically ill patients.

BACKGROUND: Severity scores are useful to guarantee similar disease severity among groups in clinical trials and to enable comparison between different studies. The aim of this study was to assess the performance of the third generation models of severity scoring systems [simplified acute physiology score (SAPS) 3, acute physiology and chronic health evaluation (APACHE) IV and mortality probability model (MPM)-III] in acute kidney injury (AKI) patients in the intensive care unit (ICU). METHODS: Three hundred and sixty-six consecutive AKI critically ill patients were prospectively assessed in six ICUs of an academic tertiary care center. Scores were applied on AKI diagnosis day (DD) and on the day of nephrology consultation (NCD). Discrimination was assessed by area under the receiver operating characteristic curve (AUCROC) and calibration by Hosmer-Lemeshow (HL) goodness-of-fit test. RESULTS: Hospital mortality rate was 67.8%. SAPS 3 general and Central and South America (CSA) customized equations presented identical good discrimination (AUCROC curve: 0.80 on NCD) and satisfactory HL tests on both analyzed days (P > 0.100). CSA SAPS 3 equation predicted mortality more accurately [standardized mortality ratio (SMR) on NCD = 1.00 (95% confidence interval (CI) 0.84-1.34)]. APACHE IV and MPM-III scores presented similar discrimination compared to SAPS 3 on both analyzed days (P > 0.05). APACHE IV presented satisfactory HL tests over time (P > 0.100) but underestimated mortality [SMR on DD = 1.92 (95% CI 1.61-2.23); SMR on NCD = 1.46 (95% CI 1.48-1.96)]. MPM-III showed unsatisfactory HL test results (P = 0.027 on DD; P = 0.045 on NCD) and underestimated mortality [SMR on NCD = 2.09 (95% CI 1.48-1.96)]. CONCLUSIONS: SAPS 3, especially the geographical customized equation, presented good discrimination and calibration performances, accurately predicting mortality in this group of AKI critically ill patients.

Sequential evaluation of prognostic models in the early diagnosis of acute kidney injury in the intensive care unit.

General and specific severity scores for patients with acute kidney injury have significant limitations due in part to the diversity of methods that have been used. Here we prospectively validated five general (APACHE II, SAPS II, SOFA, LODS, and OSF) and three specific (SHARF, Liaño, and Mehta) scoring systems in 366 critically ill patients who developed acute kidney injury in the intensive care unit. Sequential scores in each system were determined on the day that acute kidney injury was diagnosed, on the day when acute kidney injury-specific score criteria were achieved, and on the day of initial nephrology consultation. Acute kidney injury, defined as an increase of 50% or more in the baseline serum creatinine, was mainly due to sepsis, and had an incidence of 19% and an overall 68% mortality. A progressive improvement in score performance was found. On the day of initial nephrology consultation, most scores showed a good performance and two indices (SAPS II and SHARF) achieved an area under the receiver operating characteristic curve above 0.80. Calibration was good on all three defining days, except for OSF when score criteria were achieved, and Mehta at the time of nephrology consultation. Our study shows that early and sequential evaluation is a better approach for prognostic scoring in critically ill patients who develop acute kidney injury.