severe insulin resistance, dyslipidemia, and hepatic steatosis.35 Interestingly, insulin resistance but not hyperglycemia is the norm in those patients with lipodystrophy related to protease inhibitors. Conversely, congenital generalized lipodystrophy usually is associated with severe hypertriglyceridemia prone to pancreatitis.
Other Forms of Diabetes Often Seen in the Hospital
The etiology of the diabetes is multifactorial. As noted, other conditions are associated with diabetes, and one that often is seen in the hospital is diabetes associated with hepatitis C infection.36 These patients are at high risk for stress hyperglycemia or already may have undiagnosed T2D when admitted.
Conclusion
The classification of diabetes remains a work in progress. Attempts to classify our patients will lead to better understanding of the pathophysiology of the common diabetes types, the genetic mutations causing diabetes in rare forms of diabetes, and greater recognition of the vast heterogeneity in this disease. It is clear that for some patients, accurately classifying diabetes in the hospital may not be possible, whereas for others, more sophisticated lab testing may be required to confirm both diagnosis as well as classification. Occasional patients will be difficult to classify. Nevertheless, while in the hospital, the primary goal will remain to thoughtfully consider classification of diabetes and to treat the hyperglycemia to accepted targets, and this usually will require insulin therapy.
We acknowledge that the various subtypes of autoimmune diabetes have an evolving consensus in their classification. Figure 2.1 illustrates our conceptualization for how a health-care provider in the hospital can think about the classification of diabetes, taking into account what is now accepted by the ADA and what often is used clinically.
Figure 2.1—A conceptual classification for diabetes mellitus. Above the dark line are those classes not included in the 2015 ADA classification; below the line are those that are included. Moving left to right moves to greater degrees of insulin resistance.
*Depending on etiology, may have different degrees of insulin resistance and does not include CFRD; **wide degrees of insulin resistance depending on etiology.
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