Determinants of parathyroid hormone levels in nursing home residents.
BACKGROUND
Elevated parathyroid hormone (PTH) levels contribute to age-related bone loss. Practitioners should be aware of iatrogenic and/or correctable determinants of PTH elevation.


METHODS
We performed a cross-sectional study including 302 of 609 eligible residents at a state veterans home. Multiple regression analysis was used to determine the effect of 25-OH-D level, glomerular filtration rate (GFR), calcium supplements, diuretics, and mobility status on PTH levels. The dose of calcium carbonate and diuretics was determined as milligram per kilogram of body weight.


RESULTS
The multiple regression process identified GFR, 25-OH-D level, as well as the dose of furosemide and calcium per kilogram of body weight as significant contributors to PTH. In a 70-kg resident, a daily dose of 40 mg of furosemide was associated with an increase of 22.8 pg/mL in PTH, while 500 mg of elemental calcium carbonate (in the absence of a proton pump inhibitor) was associated with a decrease of 8.7 pg/mL in PTH. An increase of 10 ng/mL in 25-OH-D was associated with a decrease of 5.7 pg/mL in PTH.


CONCLUSIONS
Clinicians should be aware of the adverse effects of loop diuretics on urinary calcium excretion and PTH levels. Residents who ingest furosemide should be targeted to receive recommended doses of vitamin D and calcium.
Drinka
Paul J
PJ
Wisconsin Veterans Home, King, WI 54946-0620, USA. Paul.Drinka@dva.state.wi.us
Krause
Peggy F
PF
Nest
Lori J
LJ
Goodman
Brian M
BM
D000368:Aged; D000369:Aged, 80 and over; D000863:Antacids / Q000627:therapeutic use; D002112:Calcifediol / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002119:Calcium Carbonate / Q000627:therapeutic use; D015984:Causality; D015897:Comorbidity; D003430:Cross-Sectional Studies; D004232:Diuretics / Q000627:therapeutic use; D005260:Female; D005919:Glomerular Filtration Rate; D006707:Homes for the Aged / Q000706:statistics & numerical data*; D006801:Humans; D006961:Hyperparathyroidism / Q000097:blood* / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D009735:Nursing Homes / Q000706:statistics & numerical data*; D012044:Regression Analysis; D051437:Renal Insufficiency / Q000453:epidemiology / Q000378:metabolism; D014922:Wisconsin / Q000453:epidemiology
D000863:Antacids; D004232:Diuretics; D002119:Calcium Carbonate; D002112:Calcifediol; D002118:Calcium