Impact of urinary tract infection requiring hospital admission on short-term, mid-term and long-term renal outcomes in adult CKD patients - A potentially modifiable factor for CKD progression

Abstract

Background: Urinary tract infection (UTI) or acute pyelonephritis can lead to renal scarring and impact the subsequent renal function progression. The aims of this study were to investigate the changes in renal function related to UTI requiring hospital admission (UTI/HA) and the association between UTI/HA and long-term renal outcomes in patients with chronic kidney disease (CKD).

Methods: This was a multicenter, retrospective observational study. Renal events and renal function before and after UTI/HA in CKD patients were analyzed for short-term and mid-term renal outcomes. A case-control study with multivariate logistic regression analysis was used to investigate the association between clinical characteristics and risk of long-term renal outcomes (kidney replacement therapy or death, KRT/death) in adult CKD patients.

Results: This study included 1062 adult CKD patients, with 340 KRT and 76 deaths identified during a median follow-up of 105 months. Among 174 patients with UTI/HA, 59 (33.9 %) had bacteremia, 90 (51.7 %) acute kidney injury (AKI), and one in-hospital mortality. There was a faster decline rate of estimated glomerular filtration rate (eGFR) after UTI/HA compared to the pre-UTI/HA period [median (IQR) 0.37 (0.17-0.72) versus 0.19 (0.06-0.36) ml/min/1.73 m² per month, P < 0.0001]. The incidence of UTI/HA was similar between the KRT/death and the CKD non-dialysis groups. Multivariate logistic regression analysis showed that baseline eGFR, baseline eGFR decline rate and number of hospital admission were significantly associated with an increased risk of KRT/death.

Conclusions: This study highlights the impact of UTI/HA on renal function and renal outcomes in adult CKD patients. It demonstrates a high incidence of in-hospital AKI but low mortality, and accelerated deterioration of renal function following UTI/HA. Long-term renal outcomes were influenced by the baseline renal function and progression rate, and the frequency of hospital admission. UTI/HA may be regarded as a potentially modifiable factor for CKD progression. However, there is a need for further analysis to isolate the impact of UTI/HA from pre-existing renal function decline on long-term renal outcomes.

Keywords: Acute kidney injury; Chronic kidney disease; Estimated glomerular filtration rate; Kidney replacement therapy; Urinary tract infection.