High prevalence of unlabeled chronic kidney disease among inpatients at a tertiary-care hospital.

BACKGROUND: Although awareness of chronic kidney disease (CKD) is low in outpatient settings, the prevalence of unrecognized CKD in the inpatient setting is unknown.
METHODS: We examined the extent of unlabeled CKD among adults admitted to a tertiary-care hospital in North Carolina, based upon a combination of web-based medical record review, chart review, ICD-9 codes and laboratory information from 2000 to 2005.
RESULTS: A total of 9772 patients had 2 or more serum creatinine measures at least 6 months apart and demographic variables for race and sex; 431 met criteria for stage 5 CKD (estimated glomerular filtration rate<15 mL/min/1.73 m2) and 6851 patients had stage 2 to 4 CKD (estimated glomerular filtration rate between 15 and 89 mL/min/1.73 m2). Within the latter groups, 3002 had stage 3 to 4 CKD, and 3849 had stage 2 CKD. Forty-three percent were male, 37% had a minority race/ethnicity. The number of patients not labeled as having CKD by ICD-9 code was 2176 (72.5%). Women and whites were less likely than men and minorities to be labeled as having CKD by ICD-9 codes. Medical record review of 600 randomly selected patients identified 399 patients with stage 3 or 4 CKD diagnosis. ICD-9 codes had a sensitivity of 0.50, specificity of 0.88, and positive predictive value of 0.39.
CONCLUSIONS: A large proportion of individuals with CKD are going unrecognized in the hospital setting. Automatic laboratory reporting of GFR and education about CKD may help increase awareness in both the inpatient settings.