Racial differences in estimated GFR decline, ESRD, and mortality in an integrated health system.

BACKGROUND: Current evidence does not clearly identify the contribution of kidney function decline and mortality to racial disparities in end-stage renal disease (ESRD) incidence. We used observed estimated glomerular filtration rate (eGFR) to project the time of onset of kidney failure and examined mortality to better understand these racial disparities. STUDY DESIGN: Retrospective cohort. SETTING & PARTICIPANTS: Adult members of Kaiser Permanente Southern California in 2003-2009 with more than 2 serum creatinine tests and more than 180 days between tests: 526,498 whites, 350,919 Hispanics, 136,923 blacks, and 105,476 Asians. PREDICTOR: Race/ethnicity. OUTCOMES: ESRD (dialysis or transplantation); mortality. MEASUREMENTS: eGFR decline was modeled using linear regression. Kidney failure was projected based on predicted eGFR <15 mL/min/1.73 m² at specified times. Racial differences in projected kidney failure and mortality in those with projected kidney failure were estimated with adjustment for age, sex, and entry eGFR. RESULTS: Blacks had more extreme rates of eGFR decline (1st percentile, -23.6 mL/min/1.73 m² per year), followed by Hispanics (-20.9 mL/min/1.73 m² per year), whites (-20.1 mL/min/1.73 m² per year), and Asians (-17.6 mL/min/1.73 m² per year; P < 0.001). There were 25,065 whites, 11,368 Hispanics, 6,785 blacks, and 3,176 Asians with projected kidney failure during the study period. The ORs for projected kidney failure versus whites during CKD stages 3 and 4 were 1.54 (95% CI, 1.46-1.62) in blacks, 1.49 (95% CI, 1.42-1.56) in Hispanics, and 1.41 (95% CI, 1.32-1.51) in Asians. For those with projected kidney failure, the HRs of death versus whites during CKD stages 3 and 4 were 0.82 (95% CI, 0.77-0.88) in blacks, 0.67 (95% CI, 0.63-0.72) in Hispanics, and 0.58 (95% CI, 0.52-0.65) in Asians. LIMITATIONS: Results may not generalize to the uninsured or subgroups within a race. Projected kidney failure was based on linear trends from clinically obtained eGFR. CONCLUSIONS: We found more extreme rates of eGFR decline in blacks. Projected kidney failure during CKD stages 3 and 4 was high in blacks, Hispanics, and Asians relative to whites. Mortality for those with projected kidney failure was highest in whites. Differences in eGFR decline and mortality contributed to racial disparities in ESRD incidence.

Surgical outcomes of total knee replacement according to diabetes status and glycemic control, 2001 to 2009.

BACKGROUND: Poor glycemic control in patients with diabetes may be associated with adverse surgical outcomes. We sought to determine the association of diabetes status and preoperative glycemic control with several surgical outcomes, including revision arthroplasty and deep infection. METHODS: We conducted a retrospective cohort study in five regions of a large integrated health-care organization. Eligible subjects, identified from the Kaiser Permanente Total Joint Replacement Registry, underwent an elective first primary total knee arthroplasty during 2001 through 2009. Data on demographics, diabetes status, preoperative hemoglobin A1c (HbA1c) level, and comorbid conditions were obtained from electronic medical records. Subjects were classified as nondiabetic, diabetic with HbA1c < 7% (controlled diabetes), or diabetic with HbA1c ≥ 7% (uncontrolled diabetes). Outcomes were deep venous thrombosis or pulmonary embolism within ninety days after surgery and revision surgery, deep infection, incident myocardial infarction, and all-cause rehospitalization within one year after surgery. Patients without diabetes were the reference group in all analyses. All models were adjusted for age, sex, body mass index, and Charlson Comorbidity Index. RESULTS: Of 40,491 patients who underwent total knee arthroplasty, 7567 (18.7%) had diabetes, 464 (1.1%) underwent revision arthroplasty, and 287 (0.7%) developed a deep infection. Compared with the patients without diabetes, no association between controlled diabetes (HbA1c < 7%) and the risk of revision (odds ratio [OR], 1.32; 95% confidence interval [CI], 0.99 to 1.76), risk of deep infection (OR, 1.31; 95% CI, 0.92 to 1.86), or risk of deep venous thrombosis or pulmonary embolism (OR, 0.84; 95% CI, 0.60 to 1.17) was observed. Similarly, compared with patients without diabetes, no association between uncontrolled diabetes (HbA1c ≥ 7%) and the risk of revision (OR, 1.03; 95% CI, 0.68 to 1.54), risk of deep infection (OR, 0.55; 95% CI 0.29 to 1.06), or risk of deep venous thrombosis or pulmonary embolism (OR, 0.70; 95% CI, 0.43 to 1.13) was observed. CONCLUSIONS: No significantly increased risk of revision arthroplasty, deep infection, or deep venous thrombosis was found in patients with diabetes (as defined on the basis of preoperative HbA1c levels and other criteria) compared with patients without diabetes in the study population of patients who underwent elective total knee arthroplasty.