Santos Wilson J Q, Zanetta Dirce M T, Pires Antonio C, Lobo Suzana M A, Lima Emerson Q, Burdmann Emmanuel A
Intensive Care Unit, Hospital de Base, São José do Rio Preto Medical School, São Paulo, Brazil.
Crit Care. 2006;10(2):R68. doi: 10.1186/cc4904.
Acute tubular necrosis (ATN) is usually studied as a single entity, without distinguishing between ischaemic, nephrotoxic and mixed aetiologies. In the present study we evaluated the characteristics and outcomes of patients with ATN by aetiological group.
We conducted a retrospective comparison of clinical features, mortality rates and risk factors for mortality for the three types of ATN in patients admitted to the general intensive care unit of a university hospital between 1997 and 2000.
Of 593 patients with acute renal failure, 524 (88%) were classified as having ATN. Their mean age was 58 years, 68% were male and 52% were surgical patients. The overall mortality rate was 62%. A total of 265 patients (51%) had ischaemic ATN, 201 (38%) had mixed ATN, and 58 (11%) had nephrotoxic ATN. There were no differences among groups in terms of age, sex, APACHE II score and reason for ICU admission. Multiple organ failure was more frequent among patients with ischaemic (46%) and mixed ATN (55%) than in those with nephrotoxic ATN (7%; P < 0.0001). The complications of acute renal failure (such as, gastrointestinal bleeding, acidosis, oliguria and hypervolaemia) were more prevalent in ischaemic and mixed ATN patients. Mortality was higher for ischaemic (66%; P = 0.001) and mixed ATN (63%; P = 0.0001) than for nephrotoxic ATN (38%). When ischaemic ATN patients, mixed ATN patients and all patients combined were analyzed by multivariate logistic regression, the independent factors for mortality identified were different except for oliguria, which was the only variable universally associated with death (odds ratio [OR] 3.0, 95% confidence interval [CI] 1.64-5.49 [P = 0.0003] for ischaemic ATN; OR 1.96, 95% CI 1.04-3.68 [P = 0.036] for mixed ATN; and OR 2.53, 95% CI 1.60-3.76 [P < 0.001] for all patients combined]).
The frequency of isolated nephrotoxic ATN was low, with ischaemic and mixed ATN accounting for almost 90% of cases. The three forms of ATN exhibited different clinical characteristics. Mortality was strikingly higher in ischaemic and mixed ATN than in nephrotoxic ATN. Although the type of ATN was not an independent predictor of death, the independent factors related to mortality were different for ischaemic, mixed and all patients combined. These data indicate that the three types of ATN represent different patient populations, which should be taken into consideration in future studies.
急性肾小管坏死（ATN）通常作为一个单一实体进行研究，未区分缺血性、肾毒性和混合性病因。在本研究中，我们按病因分组评估了ATN患者的特征和预后。
我们对1997年至2000年期间入住一所大学医院综合重症监护病房的三种类型ATN患者的临床特征、死亡率及死亡危险因素进行了回顾性比较。
在593例急性肾衰竭患者中，524例（88%）被归类为患有ATN。他们的平均年龄为58岁，68%为男性，52%为外科患者。总死亡率为62%。共有265例患者（51%）患有缺血性ATN，201例（38%）患有混合性ATN，58例（11%）患有肾毒性ATN。各组在年龄、性别、急性生理与慢性健康状况评分系统II（APACHE II）评分及入住重症监护病房的原因方面无差异。多器官功能衰竭在缺血性（46%）和混合性ATN患者（55%）中比在肾毒性ATN患者（7%）中更常见（P<0.0001）。急性肾衰竭的并发症（如胃肠道出血、酸中毒、少尿和血容量过多）在缺血性和混合性ATN患者中更普遍。缺血性（66%；P = 0.001）和混合性ATN（63%；P = 0.0001）的死亡率高于肾毒性ATN（38%）。当对缺血性ATN患者、混合性ATN患者及所有患者进行多因素逻辑回归分析时，除少尿外，确定的死亡独立因素各不相同，少尿是唯一普遍与死亡相关的变量（缺血性ATN的比值比[OR]为3.0，95%置信区间[CI]为1.64 - 5.49[P = 0.0003]；混合性ATN的OR为1.96，95%CI为1.04 - 3.68[P = 0.036]；所有患者合并的OR为2.53，95%CI为1.60 - 3.76[P<0.001]）。
单纯肾毒性ATN的发生率较低，缺血性和混合性ATN占病例的近90%。ATN的三种形式表现出不同的临床特征。缺血性和混合性ATN的死亡率显著高于肾毒性ATN。虽然ATN的类型不是死亡的独立预测因素，但缺血性、混合性及所有患者合并的与死亡率相关的独立因素各不相同。这些数据表明，三种类型的ATN代表不同的患者群体，在未来的研究中应予以考虑。
