The risk of infection-related hospitalization with decreased kidney function

Background: Moderate kidney disease may predispose to infection. We sought to determine whether decreased kidney function, estimated by serum cystatin C level, was associated with the risk of infection-related hospitalization in older individuals.

Study design: Cohort study.

Setting & participants: 5,142 Cardiovascular Health Study (CHS) participants with measured serum creatinine and cystatin C and without estimated glomerular filtration rate (eGFR) <15 mL/min/1.73 m(2) at enrollment.

Predictor: The primary exposure of interest was eGFR using serum cystatin C level (eGFR(SCysC)).

Outcome: Infection-related hospitalizations during a median follow-up of 11.5 years.

Results: In adjusted analyses, eGFR(SCysC) categories of 60-89, 45-59, and 15-44 mL/min/1.73 m(2) were associated with 16%, 37%, and 64% greater risk of all-cause infection-related hospitalization, respectively, compared with eGFR(SCysC) ≥90 mL/min/1.73 m(2). When cause-specific infection was examined, eGFR(SCysC) of 15-44 mL/min/1.73 m(2) was associated with an 80% greater risk of pulmonary and 160% greater risk of genitourinary infection compared with eGFR(SCysC) ≥90 mL/min/1.73 m(2).

Limitations: No measures of urinary protein, study limited to principal discharge diagnosis.

Conclusions: Lower kidney function, estimated using cystatin C level, was associated with a linear and graded risk of infection-related hospitalization. These findings highlight that even moderate degrees of decreased kidney function are associated with clinically significant higher risks of serious infection in older individuals.