Endocrine, Metabolic, and Renal Disorders
What to know
Diabetes in older adults: individualized A1c targets (looser, e.g., <8% or higher with comorbidity) because hypoglycemia is dangerous. Avoid sulfonylureas and insulin regimens that risk hypoglycemia; metformin is first-line if renal function permits. Thyroid disease is common and often subtle-hypothyroidism can masquerade as depression or cognitive decline; hyperthyroidism may present as AF or weight loss. Renal physiology: GFR declines with age; use Cockcroft-Gault or CKD-EPI and adjust doses. Hyponatremia is frequent (SIADH, thiazides, SSRIs) and can cause falls and confusion. Hypercalcemia (hyperparathyroidism, malignancy) can cause confusion and constipation.
Traps
Overly tight glycemic control in frail elders causes hypoglycemia-a major fall and delirium risk. Serum creatinine "normal" does not mean normal GFR. Thiazides and SSRIs are common hyponatremia culprits. Atypical thyroid presentations are frequently tested. Don't miss drug-induced hyperkalemia (ACEi, potassium-sparing diuretics) in CKD.
Rule of thumb
"Looser is safer" in frail elders: relax glycemic targets and prioritize avoiding hypoglycemia.
Worked example
A 79-year-old on glyburide has recurrent confusion and falls. Check glucose; hypoglycemia is likely. Switch to a low-hypoglycemia agent (e.g., metformin if renal function allows) and relax A1c target.
Worked example 2
New confusion and constipation in an older adult: check calcium; hypercalcemia is a reversible cause.