How are glycosuria and hypoglycemia related?

No. Glycosuria means blood in the urine, most commonly associated with diabetes, whereas hypolglycemia means low blood sugar, seen if subjects have administered too much Insulin or have an insulinoma. (insulin producing tumor) they are not related as a result of sugar in the urine leaking from the kidney causing the blood sugar to fall. Good question but the two are not related.
Diabetes. People with diabetes commonly have glycosuria (excess glucose in the urine usually associated with high blood sugar) and/or experience episodes of hypoglycemia (low blood sugar) especially in diabetic pts being treated with Insulin or oral medications.