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

Abstract

Background We previously have shown that chronic kidney disease (CKD) is associated with cardiovascular and all-cause mortality in community-dwelling people 75 years and older. The present study addresses the hypothesis 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 health assessment between 1994 and 1999. Predictor Data for estimated glomerular filtration rate (eGFR, derived from creatinine levels using the CKD Epidemiology Collaboration [CKD-EPI] study equation) and dipstick proteinuria were available for 12,371 participants. Outcomes Hospital admissions collected from hospital discharge letters for 2 years after assessment. Measurements Age, sex, cardiovascular risk factors, possible biochemical and health consequences of kidney 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 for age, 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 m 2 for hospitalizations during <6 months of follow-up. HRs were weaker for follow-up of 6-18 months. Dipstick-positive proteinuria was associated with an increased 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 more hospital admissions during the 2-year follow-up. Adjustment for other health factors and laboratory measurements attenuated 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 for potential covariates, and single noncalibrated measurements from multiple laboratories. Conclusions The study indicates that community-dwelling older people who have dipstick-positive proteinuria and/or eGFR <30 mL/min/1.73 m2 are at increased risk of hospitalization. © 2011 National Kidney Foundation, Inc.