Response to Letter Regarding Article, “Heart Failure Is a Risk Factor for Orthopedic Fracture: A Population-Based Analysis of 16 294 Patients”
Reeder and Anderson suggest that hyponatremia and falls may be responsible for the observed association between heart failure (HF) and fractures.1 Whereas it is certainly possible that hyponatremia may explain some of the observed association between HF and fracture, the studies they cite either did not report the prevalence of HF2 or specifically excluded patients with HF.3 Thus, whether an association between hyponatremia and falls exists in patients with chronic HF is unknown.
Our study adds to published basic and clinical research implicating hyperaldosteronism, elevated parathyroid hormone, and low vitamin D levels in patients with HF with low bone-mineral density.4–5 A limitation of studies using administrative datasets such as ours is a lack of laboratory values and direct information on the cause of falls. Thus, we cannot examine the association between serum sodium levels and fall risk. We excluded or controlled for fall risk factors, and a matching analysis was performed in our study in an attempt to control for unmeasured variables; the results remain unaltered, strengthening the conclusions of our study. Nevertheless, Reeder and Anderson’s suggestion is worthy of evaluation in subsequent studies.
van Diepen S, Majumdar SR, Bakal JA, McAlister FA, Ezekowitz JA. Heart failure is a risk factor for orthopedic fracture: a population-based analysis of 16 294 patients. Circulation. 2008; 118: 1946–1952.
Gankam Kengne F, Andres C, Sattar L, Melot C, Decaux G. Mild hyponatremia and risk of fracture in the ambulatory elderly. QJM. 2008; 101: 583–588.
Chhokar VS, Sun Y, Bhattacharya SK, Ahokas RA, Myers LK, Xing Z, Smith RA, Gerling IC, Weber KT. Hyperparathyroidism and the calcium paradox of aldosteronism. Circulation. 2005; 22: 111: 871–878.