Adjustment for Comorbidity in Studies on Health Status in ESRD Patients

Abstract

ABSTRACT. Health status can be an important outcome in studies on patients with end-stage renal disease (ESRD). In these studies, adjustment for prognostic factors, such as comorbidity, often has to be made. None of the comorbidity indices that are commonly used in research on ESRD patients has been validated for studies on health status. This study evaluated three existing indices (Khan, Davies, and Charlson) and four indices specifically developed for use in studies on health status. In a large prospective multi-center study (NECOSAD-2), new ESRD patients were included (n = 1041). Comorbidity was assessed at the start of dialysis. Health status was assessed with the physical and mental component summary score of the SF-36 (PCS and MCS), the symptoms dimension of the KDQOL-SF, and the Karnofsky Scale. Patient data were randomly allocated to a modeling or a testing set. The new indices were developed in the modeling set. The three existing indices explained about the same percentage of variance in the PCS (7 to 8%), MCS (1 to 3%), symptoms (2 to 4%), and Karnofsky (10 to 12%). The new indices performed better than the existing indices in the modeling population (13% PCS, 10% MCS, 10% symptoms, 18% Karnofsky), but not in the testing population (8% PCS, 1% MCS, 3% symptoms, 8% Karnofsky). Individual comorbidities explained more variance in PCS (10 to 15%), MCS (1 to 7%), symptoms (6 to 11%), and Karnofsky (11 to 18%) than comorbidity indices. The Khan, Davies, and the Charlson indices will adjust to the same extent for the potential confounding effect of comorbidity in studies with health status as an outcome. Separate comorbidity diagnoses will adjust best for comorbidity. E-mail: j.g.vanmanen@amc.uva.nl

Combining Near-Subject Absolute and Relative Measures of Longitudinal Hydration in Hemodialysis

“…The clinical dry weight of patients was assessed and regularly reviewed as part of their routine care by clinicians who were blinded to the body composition data. The patients' comorbidities were recorded using the Stoke comorbidity score (8), a validated tool that predicts survival in HD patients (9). The score is an arithmetic sum of up to seven comorbidities: Ischemic heart disease, peripheral vascular disease (includes cerebrovascular), left ventricular dysfunction, diabetes, connective tissue disorder, active noncutaneous malignancy, and another life threatening illness.…”

Reliability and Validity of the Korean Version of Kidney Disease Quality of Life Instrument (KDQOL-SFTM)

“…The KDQOL-SF TM has been used extensively to assess and evaluate the health-related quality of life among patients with kidney disease and on dialysis in clinical trial studies, validation studies, evaluation studies and multinational studies (Green et al 2001;Korevaar et al 2002;Walters et al 2002;Fukuhara et al 2003;Mapeds et al 2003;Van Maden et al 2003;Aqarwal et al 2006 ) as a generic core to measure functioning and well-being of patients on dialysis. The SF-36 includes eight multi-item scales that summarize physical component scale (PCS) and mental component scale (MCS): physical functioning (10 items), role limitations caused by physical health problems (4 items), bodily pain (2 items), general health (5 items), vitality (energy/fatigue) (4 items), social functioning (2 items), role limitations due to emotional problems (3 items), and mental health (psychological distress and psychological well-being) (5 items) (Ware 2001).…”

Evaluation of Anemia Management by Algorithms in Patients with Chronic Kidney Disease Who Are Not Receiving Dialysis

“…2,3 Erythropoietin deficiency is common among patients with anemia related to chronic kidney disease, and the use of erythropoiesis-stimulating agents (specifically epoetin or darbepoetin) has been shown to reduce the need for blood transfusions. 4 However, these therapies do carry risks of adverse outcomes, including increased blood pressure and thrombotic complications, and therefore should be administered at the lowest possible dose.…”

“…In this situation, appropriate iron supplementation is required before initiation of therapy with erythropoiesis-stimulating agents. 3 Transferrin saturation is an appropriate indicator of the iron that is effectively available for erythropoiesis.…”