CKD and hospitalization in the elderly: a community-based cohort study in the United Kingdom

Background: we previously have shown that chronic kidney disease (CKD) is associated with cardiovascularand all-cause mortality in community-dwelling people 75 years and older. The present study addresses thehypothesis that CKD is associated with a higher rate of hospital admission at an older age.Study Design: cohort study.Setting & Participants: 15,336 participants from 53 UK general practices underwent comprehensive healthassessment between 1994 and 1999.Predictor: data for estimated glomerular filtration rate (eGFR, derived from creatinine levels using the CKDEpidemiology Collaboration [CKD-EPI] study equation) and dipstick proteinuria were available for 12,371participants.Outcomes: hospital admissions collected from hospital discharge letters for 2 years after assessment.Measurements: Age, sex, cardiovascular risk factors, possible biochemical and health consequences ofkidney disease (hemoglobin, phosphate, and albumin levels; physical and mental health problems).Results: 2,310 (17%) participants had 1 hospital admission, and 981 (7%) had 2 or more. After adjusting forage, sex, and cardiovascular risk factors, HRs were 1.66 (95% CI, 1.21-2.27), 1.17 (95% CI, 0.95-1.43), 1.08(95% CI, 0.90-1.30), and 1.11 (95% CI, 0.91-1.35) for eGFRs ?30, 30-44, 45-59, and ?75 mL/min/1.73 m2,respectively, compared with eGFRs of 60-74 mL/min/1.73 m2 for hospitalizations during ?6 months offollow-up. HRs were weaker for follow-up of 6-18 months. Dipstick-positive proteinuria was associated with anincreased HR throughout follow-up (HR, 1.29 [95% CI, 1.11-1.49], adjusting for cardiovascular risk factors).Dipstick-positive proteinuria and eGFR ?30 mL/min/1.73 m2 were independently associated with 2 or morehospital admissions during the 2-year follow-up. Adjustment for other health factors and laboratory measurementsattenuated the effect of eGFR, but not the effect of proteinuria.Limitations: follow-up limited to 2 years, selection bias due to nonparticipation in study, missing data forpotential covariates, and single noncalibrated measurements from multiple laboratories.Conclusions: the study indicates that community-dwelling older people who have dipstick-positive proteinuriaand/or eGFR ?30 mL/min/1.73 m2 are at increased risk of hospitalization