Key Clinical Updates in Diabetes Mellitus
In a 2019 study of 4744 patients with NYHA class II, III, IV heart failure and ejection fraction of less 40%, dapagliflozin (a sodium-glucose co-transporter 2 inhibitor) reduced the cumulative incidence of worsening heart failure or cardiovascular death.
In addition to their cardioprotective effects, the sodiumglucose linked transporter (SGLT) inhibitors, eg, canagliflozin and empagliflozin, slow progression of early diabetic nephropathy. Use of these agents may require reduction in diuretic dosing in those patients requiring natriuresis, and they should not be used in advanced chronic kidney disease.
ESSENTIALS OF DIAGNOSIS
Type 1 diabetes
Polyuria, polydipsia, and weight loss associated with random plasma glucose of 200 mg/dL (11.1 mmol/L) or more.
Plasma glucose of 126 mg/dL (7.0 mmol/L) or more after an overnight fast, documented on more than one occasion.
Ketonemia, ketonuria, or both.
Islet autoantibodies are frequently present.
Type 2 diabetes
Many patients are over 40 years of age and are obese.
Polyuria and polydipsia. Ketonuria and weight loss are uncommon at time of diagnosis. Candidal vaginitis may be an initial manifestation.
Plasma glucose of 126 mg/dL or more after an overnight fast on more than one occasion. Two hours after 75 g oral glucose, diagnostic values are 200 mg/dL (11.1 mmol) or more.
HbA1c 6.5% or more.
Hypertension, dyslipidemia, and atherosclerosis are often associated.
An estimated 34.2 million people (10.5%) in the United States have diabetes mellitus, of which approximately 5–10% have type 1 diabetes and most of the rest have type 2 diabetes. A third group designated as “other specific types” by the American Diabetes Association (ADA) (Table 27–1) number in the thousands. Among these are the monogenic defects of either B cell function or of insulin action, primary diseases of the exocrine pancreas, endocrinopathies, and medication-induced diabetes. Current statistics about diabetes in the United States are available from the Centers for Disease Control and Prevention (https://www.cdc.gov/diabetes/data/statistics/statistics-report.html).
Table 27–1.Other specific types of diabetes mellitus. ||Download (.pdf) Table 27–1. Other specific types of diabetes mellitus.
Genetic defects of pancreatic B cell function
MODY 1 (HNF-4alpha); rare
MODY 2 (glucokinase); less rare
MODY 3 (HNF-1alpha); accounts for two-thirds of all MODY
MODY 4 (PDX1); very rare
MODY 5 (HNF-1beta); very rare
MODY 6 (neuroD1); very rare
Genetic defects in insulin action
Type A insulin resistance
Diseases of the exocrine pancreas
Drug- or chemical-induced diabetes
Other genetic syndromes (Down, Klinefelter, Turner, others) sometimes associated with diabetes
CLASSIFICATION & PATHOGENESIS
Diabetes mellitus is a syndrome with disordered metabolism and inappropriate hyperglycemia due to either a deficiency of insulin secretion or to a combination of insulin resistance and inadequate insulin secretion to compensate for the resistance.