In Reply In our study, we demonstrated a significant relationship between the use of loop diuretics and serum parathyroid hormone (PTH) level in individuals with a preserved renal function.1 We hypothesized that this relationship was the result of the well-known increase in urinary calcium excretion associated with loop diuretic use and that the rise in serum PTH level was a compensatory response to maintain serum calcium within the normal range. This relationship has been seen in specific patient populations, including those with chronic kidney disease2 or congestive heart failure.3 Thus, in selecting covariates we included both estimated glomerular filtration rate and a history of congestive heart failure in our final model.