Prevalence of chronic kidney disease stages 3-5 among acute medical admissions: another opportunity for screening.

BACKGROUND: Early identification of chronic kidney disease (CKD) can help delay or prevent its progression, but the opportunities for systematic screening of patients are not well defined.

AIM: To define the prevalence of CKD Stages 3-5 and related anaemia among acute medical admissions.

DESIGN: Retrospective analysis.

METHODS: We studied all acute medical admissions to a major London teaching hospital during one year. The lowest creatinine, highest haemoglobin (Hb) and average mean corpuscular volume (MCV) were determined for 3 months before and after admission. Patients were categorized as CKD Stages 3-5 if the highest estimated GFR (eGFR) was <60 ml/min/1.73 m2. CKD-related anaemia was diagnosed if these patients had Hb <11 g/dl with normal MCV.

RESULTS: A total of 6073 patients were studied: male 49.0%, age 65.4 +/- 19.6 years (mean +/- SD), creatinine 82.7 +/- 46.7 micromol/l, eGFR 89.1 +/- 32.5 ml/min/1.73 m2, Hb 13.6 +/- 1.73 g/dl, MCV 87.7 +/- 7.2 fl. There was an inverse correlation between eGFR and age (r2 = 0.5; P < 0.001). Males were younger than females (63.5 +/- 18.4 years vs. 67.3 +/- 20.5) and had higher eGFR (93.6 +/- 34.1 vs. 84.7 +/- 30.2 ml/min/1.73 m2; P < 0.001). A total of 743 patients (12.2%) had raised creatinine >110 micromol/l, however using eGFR <60 ml/min/1.73 m2, 1075 patients (17.7%) were identified. The patients were categorized as follows: Stage 3: 950 (15.6%), Stage 4: 100 (1.7%), Stage 5: 25 (0.4%). Ninety-nine (9.2%) of the 1075 patients had normocytic anaemia.

CONCLUSION: We have found a high prevalence of CKD Stages 3-5 (17.7%) among acute medical admissions, of whom 9.2% had a related anaemia. Our findings highlight an important opportunity (amongst the 1.9 million acute medical admissions annually in England) for detecting patients with CKD.