Association of Preventive Health Care with Atherosclerotic Heart Disease and Mortality in CKD

Chronic kidney disease (CKD, stages 1 to 4) affects approximately 13.1% of United States adults and leads to ESRD, cardiovascular disease, and premature death. Here, we assessed adherence to a subset of Kidney Disease Outcomes Quality Initiative preventive health care guidelines and identified associations between adherence and incident atherosclerotic heart disease (ASHD). Using the Medicare 5% data set, 1999 to 2005 (about 1.2 million patients per year), we created 3-yr rolling cohorts. We classified CKD and diabetes during year 1, assessed preventive care during year 2, and evaluated ASHD outcomes during year 3. We defined preventive care by the receipt of laboratory measurements (serum creatinine, lipids, calcium and phosphorus, parathyroid hormone, and, for patients with diabetes, hemoglobin A1c), influenza vaccination, and by at least one outpatient visit to a nephrologist. Among patients with CKD, 80% received ≥2 serum creatinine tests during the year, and only 11% received parathyroid hormone testing. Cumulative incidence of the combined ASHD outcome was 25% and 11% for patients with and without prevalent cardiovascular disease, respectively. Except for serum creatinine testing, preventive care associated with lower ASHD rates in the subsequent year, ranging from 10% lower for those who received influenza vaccinations and ≥2 A1c tests, to 43% lower for calcium-phosphorus assessment. Receiving ≥2 serum creatinine tests associated with a 13% higher rate of ASHD. A higher number of preventive measures associated with lower rates of ASHD. In summary, these data support an association between preventive measures and reduced cardiovascular morbidity and mortality.Chronic kidney disease (CKD, stages 1 to 4) is estimated to affect 13.1% (12.0% to 14.1%) of the adult noninstitutionalized civilian United States population, or 26.3 million adults according to the 2000 census.¹ The prevalence rate increased approximately 30% between the early 1990s and the early 2000s.¹ In 2002, the Kidney Disease Outcomes Quality Initiative (KDQOI) Clinical Practice Guidelines committee, organized by the National Kidney Foundation (NKF), noted that the three primary adverse consequences of CKD are kidney failure, cardiovascular disease (CVD), and premature death.² The committee further noted that CVD is common, treatable, and potentially preventable in CKD patients, and that CKD appears to be a risk factor for CVD.² In 1998, the NKF Task Force on Cardiovascular Disease in Chronic Renal Disease recommended that CKD patients be considered in the highest risk group for CVD events.³Two recent studies demonstrate increasing incidence of cardiovascular events⁴ and increasing prevalence of cardiovascular risk factors⁵ with decreasing GFR. An analysis of secondary cardiovascular events following myocardial infarction demonstrates increasing probability of subsequent cardiovascular events with decreasing GFR.⁶ United States Renal Data System (USRDS) analyses demonstrate hospitalization rates for congestive heart failure (CHF), ischemic heart disease, and arrhythmias two to seven times higher for Medicare patients with CKD than for those without CKD,⁷ and that CKD patients with no prior evidence of CVD were 60% more likely to develop CVD during the subsequent year than non-CKD patients.^8,9The USRDS notes that CKD patients are three to five times more likely to die than to reach ESRD¹⁰ and that nearly half of CKD patient deaths occur out of the hospital, presumably sudden cardiac death.⁸ A recent meta-analysis found that the relative risk of all-cause mortality comparing CKD to non-CKD patients ranged from 0.94 to 5.00 in all cohorts analyzed and was significantly more than 1.0 in 93% of the cohorts; it also found an increasing risk of all-cause mortality with decreasing GFR.¹¹The Healthy People 2010 initiative of the Centers for Disease Control and Prevention includes objectives intended to preserve renal function and slow CKD progression through early detection and intervention.¹² The NKF has published numerous clinical practice guidelines addressing ESRD and CKD,^2,13–15 with the goals of identifying CKD early, slowing its progression, and reducing associated morbidity and mortality.Our objectives were to assess adherence to KDOQI recommendations for CKD care and subsequent associations between preventive care and incident atherosclerotic heart disease (ASHD) in the general Medicare population with evidence of CKD. Preventive care measures assessed include monitoring of serum creatinine, lipids, calcium-phosphorus, parathyroid hormone (PTH), glycated hemoglobin (A1c) in diabetic patients; influenza vaccinations; and outpatient nephrologist office visits. Subsequent ASHD outcomes studied include acute ischemic heart disease events, angina pectoris, cardiac arrest, coronary revascularization procedures, and all-cause death. Data were from the 5% Medicare 1999 to 2005 random sample limited data set standard analytic files.