Objective: We previously noted secondary hyperparathyroidism (SHPT) in African-American patients hospitalized during February, 2005 with either untreated or treated congestive heart failure (CHF) due to ischemic or idiopathic cardiomyopathy. Herein, we hypothesized that housebound African-American patients hospitalized during the period of June 1 through August 31, 2005, with CHF would have SHPT and hypovitaminosis D.
Methods: Twenty-five African-American patients with an ejection fraction (EF) less than 35% due to ischemic or dilated (idiopathic) cardiomyopathy were monitored: 20 were hospitalized with CHF, stratified on historical grounds as of 4 weeks' or longer duration or of 1 to 2 weeks' duration in 11 and 9 patients, respectively, despite medical care that included furosemide; serum parathyroid hormone (PTH) and 25(OH)D at the time of admission in these patients were compared to five asymptomatic outpatients seen during the summer with stable, compensated failure.
Results: Serum PTH was elevated (127 +/- 13; 82-243 pg/mL) in all patients with CHF of 4 weeks' or longer duration (normal, 12-65 pg/mL) and was elevated in three of nine patients (59 +/- 8; 18-99 pg/mL) with CHF of 1 to 2 weeks' duration. Ionized hypocalcemia (1.09 +/- 0.03 and 1.08 +/- 0.02 mmol/L; normal, 1.12-1.30) and hypomagnesemia (0.47 +/- 0.02 and 0.46 +/- 0.03 mmol/L; normal, 0.53-0.67) were respectively found in long- or short-duration CHF. No compensated patient had elevated PTH (42 +/- 5; 17-53). Hypovitaminosis D (< or =30 ng/mL) was universally present in patients with CHF of 4 weeks' or longer duration (15.1 +/- 1.4; 7.0-23.8 ng/mL) and was also prevalent in the other groups (20.3 +/- 5.1, 7.0-54.1 ng/mL in CHF of 1 to 2 weeks' duration and 23.1 +/- 4.9; 17.2-42.7 ng/mL in compensated failure).
Conclusions: In African-American patients with CHF, hypovitaminosis D, aldosteronism, and loop diuretic treatment each exaggerate Ca and Mg losses to stress a fragile Ca balance leading to ionized hypocalcemia and hypomagnesemia with SHPT.