Supplementary Material for: Acute Kidney Injury and Mortality in Hospitalized Patients

<i>Background:</i> The objective of this study was to determine the incidence of acute kidney injury (AKI) and its relation with mortality among hospitalized patients. <i>Methods:</i> Analysis of hospital discharge and laboratory data from an urban academic medical center over a 1-year period. We included hospitalized adult patients receiving two or more serum creatinine (sCr) measurements. We excluded prisoners, psychiatry, labor and delivery, and transferred patients, ‘bedded outpatients’ as well as individuals with a history of kidney transplant or chronic dialysis. We defined AKI as (a) an increase in sCr of ≥0.3 mg/dl; (b) an increase in sCr to ≥150% of baseline, or (c) the initiation of dialysis in a patient with no known history of prior dialysis. We identified factors associated with AKI as well as the relationships between AKI and in-hospital mortality. <i>Results:</i> Among the 19,249 hospitalizations included in the analysis, the incidence of AKI was 22.7%. Older persons, Blacks, and patients with reduced baseline kidney function were more likely to develop AKI (all p < 0.001). Among AKI cases, the most common primary admitting diagnosis groups were circulatory diseases (25.4%) and infection (16.4%). After adjustment for age, sex, race, admitting sCr concentration, and the severity of illness index, AKI was independently associated with in-hospital mortality (adjusted odds ratio 4.43, 95% confidence interval 3.68–5.35). <i>Conclusions:</i> AKI occurred in over 1 of 5 hospitalizations and was associated with a more than fourfold increased likelihood of death. These observations highlight the importance of AKI recognition as well as the association of AKI with mortality in hospitalized patients

Supplementary Material for: A Risk Score to Guide Cystatin C Testing to Detect Occult-Reduced Estimated Glomerular Filtration Rate

<strong><em>Background/Aims:</em></strong> Persons with occult-reduced estimated glomerular filtration rate (eGFR <60 ml/min/1.73 m² detected by serum cystatin C but missed by creatinine) have high risk for complications. Among persons with preserved kidney function by creatinine-based eGFR (eGFRcreat >60 ml/min/1.73 m²), tools to guide cystatin C testing are needed. <b><i>Methods:</i></b> We developed a risk score to estimate an individual's probability of reduced eGFR by cystatin C (eGFRcys <60 ml/min/1.73 m²) in The Reasons for Geographic and Racial Differences in Stroke (REGARDS) study and externally validated in the Third National Health and Nutrition Examination Survey (NHANES III). We used logistic regression with Bayesian model averaging and variables available in practice. We assessed performance characteristics using calibration and discrimination measures. <b><i>Results:</i></b> Among 24,877 adults with preserved kidney function by creatinine, 13.5% had reduced eGFRcys. Older and Black participants, current smokers and those with higher body mass index, lower eGFRcreat, diabetes, hypertension and history of cardiovascular disease were more likely to have occult-reduced eGFR (p < 0.001). The final risk function had a c-statistic of 0.87 in REGARDS and 0.84 in NHANES. By risk score, 72% of occult-reduced eGFR cases were detected by screening only 22% of participants. <b><i>Conclusions:</i></b> A risk score using characteristics readily accessible in clinical practice can identify the majority of persons with reduced eGFRcys, which is missed by creatinine.<br

Supplementary Material for: Healthy Behaviors, Risk Factor Control and Awareness of Chronic Kidney Disease

<b><i>Background/Aims:</i></b> The association between chronic kidney disease (CKD) awareness and healthy behaviors is unknown. We examined whether CKD self-recognition is associated with healthy behaviors and achieving risk-reduction targets known to decrease risk of cardiovascular morbidity and CKD progression. <b><i>Methods:</i></b> CKD awareness, defined as a ‘yes’ response to ‘Has a doctor or other health professional ever told you that you had kidney disease?’, was examined among adults with CKD (eGFR <60 ml/min/1.73 m²) who participated in the REasons for Geographic And Racial Differences in Stroke (REGARDS) study. Odds of participation in healthy behaviors (tobacco avoidance, avoidance of regular nonsteroidal anti-inflammatory drug use, and physical activity) and achievement of risk-reduction targets (angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use, systolic blood pressure control and glycemic control among those with diabetes) among those aware versus unaware of their CKD were determined by logistic regression, controlling for sociodemographics, access to care and comorbid conditions. Systolic blood pressure control was defined as <130 mm Hg (primary definition) or <140 mm Hg (secondary definition). <b><i>Results:</i></b> Of 2,615 participants, only 6% (n = 166) were aware of having CKD. Those who were aware had 82% higher odds of tobacco avoidance compared to those unaware (adjusted OR = 1.82, 95% CI 1.02–3.24). CKD awareness was not associated with other healthy behaviors or achievement of risk-reduction targets. <b><i>Conclusions:</i></b> Awareness of CKD was only associated with participation in one healthy behavior and was not associated with achievement of risk-reduction targets. To encourage adoption of healthy behaviors, a better understanding of barriers to participation in CKD-healthy behaviors is needed