Assessment of the longitudinal changes in bone mineral density in patients receiving home parenteral nutrition

Background: Low bone mineral density (BMD) is commonly reported in patients receiving home parenteral nutrition (HPN), but it remains unclear whether or not an accelerated bone loss occurs during HPN therapy. We evaluated the spinal, hip, and forearm bone mass density longitudinally in a cohort of 75 patients receiving HPN. Methods: A total of 943 regional dual-energy x-ray absorptiometry scans, 335 spinal, 318 hip, and 290 forearm, obtained between 1995 and 2003 in 75 patients receiving HPN, were used for the analysis of the annual changes in BMD. The average (SD) number of scans per patients was 4.4 (2.9), and follow-up time was 4.1 (1.9) years. Diagnoses were Crohn's disease (n = 35) and other conditions (non-Crohn's diseases; n = 40). Data were analyzed using a linear random coefficient model. Results: There was a statistically significant overall decline over time in spinal, hip, and forearm BMD, corresponding roughly to a 1% annual loss (p < .005); however, the loss was not significantly larger than that of age and sex-matched healthy subjects. In Crohn's disease patients, model estimates of spinal and hip BMD on the initiation of HPN therapy were significantly reduced compared with normal, whereas values were not significantly reduced in non-Crohn's disease patients. Conclusions: With the current protocols for HPN treatment, the annual decline in BMD is moderate and not significantly larger than in age- and sex-matched healthy subjects. A considerable part of the metabolic bone disease in these patients is related to the underlying disease for which the HPN was indicated.