CKD and risk of hospitalization and death with pneumonia

Abstract

Background: The effects of kidney disease on the risk of hospitalization or death from specific noncardiovascular causes, including pneumonia, are unclear. The objective of this study is to determine the associations between estimated glomerular filtration rate (eGFR) and hospitalization or death with pneumonia.

Study design: Retrospective cohort study.

Setting & participants: Community-based study from a Canadian health region of 252,516 participants with 1 or more outpatient serum creatinine measurements from July 1, 2003, to June 30, 2004, who were not receiving dialysis or kidney transplantation.

Predictor: eGFR calculated by using the 4-variable Modification of Diet in Renal Disease Study equation.

Outcomes: Hospitalization with pneumonia or death within 30 days after pneumonia hospitalization.

Measurements: Cox proportional hazards models adjusted for age, sex, socioeconomic status, and comorbidities with censoring at death, initiation of renal replacement therapy, or emigration.

Results: Lower eGFR was associated with increased risk of hospitalization with pneumonia, although the magnitude of effect varied with age. The risk associated with decreased eGFR was greatest in participants 18 to 54 years old; compared with participants with an eGFR of 60 to 104 mL/min/1.73 m(2), adjusted hazard ratios for hospitalization with pneumonia were 3.23 (95% confidence interval, 2.40 to 4.36) in those with eGFR of 45 to 59 mL/min/1.73 m(2), 9.67 (95% confidence interval, 6.36 to 14.69) for eGFR of 30 to 44 mL/min/1.73 m(2), and 15.04 (95% confidence interval, 9.64 to 23.47) for eGFR less than 30 mL/min/1.73 m(2). Associations became weaker with increasing age, although the graded inverse association between lower eGFR and risk remained for older participants. An age-dependent inverse relationship also was observed between eGFR and risk of death within 30 days of hospitalization with pneumonia.

Limitations: Residual confounding caused by severity of illness or unmeasured comorbidities may be present.

Conclusion: The risk of hospitalization and death with pneumonia is greater at lower eGFRs, especially in younger adults. This association may contribute to excess mortality in people with chronic kidney disease.