Introduction
AKI is recognised as one of the major complications in hospitalised
individuals imposing a substantial burden on patients and health care
systems. The syndrome is associated with an increased risk of morbidity
and mortality (1), progressive deterioration of renal
function (2) and reduced quality of life(3-5). High costs of AKI-related inpatient care result
from prolonged hospitalisations, additional examinations and
complications such as the need for renal replacement therapy (RRT), and
readmissions (6, 7). Strata of AKI severity have
significant prognostic implication (2); however, the
direct contribution of AKI to adverse events is difficult to establish.
Studies over the last decade have identified complex and bidirectional
interactions between the kidney and other remote organ systems,
including heart, lungs, brain liver in the settings of AKI(8). As a result, the syndrome is often seen as a
proxy of the underlying severity of illness (9)involving a spectrum of differing etiologies, pathophysiologies and
clinical scenarios (10). Its epidemiological profile
is highly dependent on patient characteristics and the setting in which
occurs. Studies on AKI in specific clinical cohorts allow understanding
the magnitude, clinical features and outcomes in local circumstances,
thus providing essential information for prevention and treatment
strategies. The objective of this study was to describe the occurrence
of AKI in a general population of hospitalised patients and to
characterise them with a distinction between AKI apparent at admission
and acquired later during hospitalisation. We studied whether the two
groups differed in baseline characteristics, AKI severity and short-term
outcomes, namely the length of hospital stay, in-hospital and 6-month
post-discharge mortality. Besides, in patients free of AKI at admission,
we assessed how the risk of the development of the syndrome changes over
hospital stay.