Anemia in diabetics may flag kidney disease, heart risks.
This link in diabetics between anemia and chronic kidney disease (CKD) arises because, as diabetes progresses, the kidneys become damaged and there is a decrease in the production of erythropoietin, which can also cause anemia, said Dr. Pandya.
He recommended routinely checking diabetics for anemia and noted that the severity of anemia correlates with the severity of underlying disease, which often exists along with other causes of anemia, particularly iron deficiency.
In stressing the importance of checking high-risk patients, Dr. Pandya cited the findings in a study of Medicare patients, which suggested that anemia is a mortality multiplier when combined with another disease.
Anemia of CKD is now also considered a nontraditional risk factor for cardiovascular disease. Erythropoietin deficiency and the resulting reduction in the concentration of hemoglobin causes tissue hypoxia and increased cardiac work, which results in left ventricular hypertrophy and ischemic heart disease.
That, in turn, increases the risk for heart failure, angina pectoris, heart attack, and poor health-related outcomes, explained Dr. Pandya, chair of the department of geriatrics at Nova Southeastern University's College of Osteopathic Medicine in Fort Lauderdale, Fla.
Study findings indicate that anemia doubles the risk for hospitalization for a comorbid condition and significantly increases the risk of premature death in older adults with diabetes, CKD, and heart failure, as well as the risk of stroke in patients with CKD, he noted.
Anemia of CKD is defined by a hemoglobin level of less than 12 g/dL in men and postmenopausal women, and a glomerular filtration rate of 60 mL/min per 1.73 [m.sup.2] of body surface area for 3 months with or without kidney damage, or kidney damage for 3 months as shown by pathologic abnormalities or markers such as proteinuria.
Dr. Pandya said that anemic adults experience a decline in functioning because of lower exercise tolerance, muscle wasting, decreased mobility and cardiovascular fitness, greater physical instability and frailty, and an increase in the number of falls. CKD patients, however, have even lower functioning scores than do patients with other comorbid conditions. For example, CKD patients have a mean physical functioning score of 41.2 (0 denotes total disability and 100 denotes full functioning), compared with a mean score of 47.5 in heart failure patients, 67.7 in diabetics without CKD, and 73.4 in hypertensives.
Anemia is effectively a diagnosis of exclusions, because its signs and symptoms, such as weight loss, erectile dysfunction, and often feeling cold, are nonspecific, said Dr. Pandya.
The National Kidney Foundation advises assessing for anemia when the glomerular filtration rate is less than 60 mL/min per 1.73 [m.sup.2]. The evaluation consists of checking hemoglobin and/or hematocrit, red blood indices, reticulocyte count, and iron parameters, and for occult blood. A test for iron, total iron-binding capacity, percentage saturation of iron-binding capacity, ferritin and soluble transferrin receptor levels will distinguish anemia of chronic disease (ACD) from iron-deficiency anemia (IDA). A high ferritin level is the hallmark of ACD, whereas ferritin is normal in IDA; transferrin is normal in ACD but elevated in IDA.
A more extensive work-up, dictated by clinical and laboratory circumstances, and which may include bone marrow aspiration or biopsy, may be needed to determine the cause of anemia.
Dr. Pandya emphasized that it is imperative to identify the cause, because cause directs therapy.
ACD is treated with erythropoietic stimulatory proteins, which are peptide hormones and their derivatives, manufactured by recombinant DNA technology.
The two major products are epoetin alfa (Eprex, Ortho Biologics) and darbepoetin alfa (Aranesp, Amgen Inc.). Darbepoetin's half-life is three times longer than epoetin's half-life. Epoetin alfa is given subcutaneously or intravenously one to three times weekly, whereas 0.45 mcg/kg, given once every 2 weeks, usually maintains a target hemoglobin level of 11-12 g/dL.
BY PATRICIA L. KIRK
DATA WATCH Top Inpatient Cardiovascular Procedures (in thousands) Diagnostic cardiac catheterization 1,414 Open heart surgery 666 Percutaneous coronary intervention 664 Cardiac revascularization 467 Stenting 387 Pacemaker 197 Carotid endaterectomy 117 Valve surgery 95 Defibrillator implantation 64 Note: Based on 2003 estimates from the National Center for Health Statistics. Source: American Heart Association Note: Table made from bar graph.
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|Title Annotation:||Cardiovascular Medicine; care and treatment|
|Author:||Kirk, Patricia L.|
|Publication:||Family Practice News|
|Date:||Sep 15, 2006|
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