Osteoporosis in Tube‐Fed Bed‐Ridden Elderly Female Patients

To the Editor: Tube-fed, bedridden, elderly patients, despite being confined to bed, undergo fractures from accidental falls from bed and slipping during bathing and even during repositioning and getting out of bed. It is important to quantify the prevalence of osteoporosis in such patients to reduce the incidence of fractures.1 Tube feeding is increasingly common in elderly patients who are unable to swallow.2 A point-prevalence study of bone mineral density (BMD) was conducted in patients hospitalized in the Skilled Nursing Department, Herzog Hospital, Jerusalem, Israel. The purpose of the study was to determine the prevalence and severity of osteoporosis in tube-fed female patients. The assumption was, because they are immobilized and not exposed to the sun, they would have severe levels of osteoporosis. After approval from the ethical committee of the hospital, 27 tube-fed women were checked for BMD at the L2–L4 level using dual X-ray absorptiometry (DXA; Dual Photon Absorptiometry Lunar Prodigy, GE Healthcare USA, Madison, WI). The BMD was measured only in the lumbar vertebrae because of muscular contracture of the hip joint. The results were evaluated using the T-score and Z-score. Osteoporosis was defined according to the World Health Organization–based BMD T-score of −2.5 or less. Osteopenia was defined as a T-score between −1.0 and −2.5. All subjects received prepared formula, Osmolite or Jevity (Abbott, Chicago, IL) containing 37.1 and 44 g of protein, 528 and 907 mg of calcium, and 211 and 304 IU of vitamin D, respectively, per liter. On average, patients received 1,500 mL, each mL equal to 1.06 kcal per day. The allocation of protein was at least 1 g/kg of body weight. Continuous variables are represented by means and standard deviations and categorical variables by count and percentage and compared using the Kruskal-Wallis test. Categorical variables were compared using the Mantel-Haenszel chi-square test. P≤.05 was considered statistically significant. Nineteen patients (70.4%) were found to have a T-score greater than −2.5, with a mean T-score of −3.8 ± 0.88. Three patients (11.1%) had osteopenia, with a T-score between −1.0 and −2.5, and the remaining five (18.5%) had a T-score greater than −1.0, which is considered normal. The group with osteoporosis was aged 86.1 ± 8.1, the group with osteopenia 84.3 ± 4.2, and the group with normal BMD was aged 82.8 ± 7.4 (Kruskal-Wallis test P=.30). Subjects with osteoporosis had hospitalized for an average of 2.56 ± 2.13 years, those with osteopenia for an average of 1.15 ± 1.16 years, and those with normal BMD for an average of 2.31 ± 1.37 (Kruskal-Wallis test P=.46). The average total duration of being confined to a wheelchair or bed was 3.84 ± 3.47 years in those with osteoporosis, 2.65 ± 0.40 years in those with osteopenia, and 3.41 ± 2.13 years in those with normal BMD (Kruskal-Wallis test P=.90). Average Norton scores3 were 8.19 ± 1.07, 8.00 ± 0.00, and 8.40 ± 1.34, and average Glasgow Coma scores4 were 9.79 ± 3.10, 9.33 ± 1.15, and 10.8 ± 1.92 for those with osteoporosis, those with osteopenia, and those with normal BMD, respectively. No differences were found in body mass index, level of education, or rate of comorbid conditions (dementia, persistent vegetative state, pressure ulcers, and hip fracture preceding hospitalization) between the three groups. Four patients (21.1%) with osteoporosis and none with osteopenia or normal BMD had a hip fracture preceding their hospitalization. Blood cholesterol, calcium, phosphate, vitamin D, and parathyroid hormone did not differ between the three groups and were within normal limits (Table 1). Serum alkaline phosphatase levels were higher in those with osteoporosis but this was not statistically significant. Albumin and hemoglobin levels were low, as would be expected in bed-ridden patients. BMD was low in 19 patients with osteoporosis and three with osteopenia and was significantly different from those with normal BMD (Kruskal-Wallis test P<.001). The mean Z-score of the patients with osteoporosis was −1.7, which was significantly different from that of the group with normal BMD. A limitation of the study was that DXA was performed only on the lumbar spine; it was not possible to perform DXA of the hip because of severe limitation of movement as a result of muscular contractures. Only 19 (70.4%) patients suffered from osteoporosis. This was attributed to the tube feeding–ready formulas, which contain proteins, calcium, and vitamin D.5,6 Adequate daily administration of calcium and vitamin D can explain the normal blood levels of calcium and vitamin D in both groups. The patients who had been hospitalized longer, as well as bed ridden longer, had lower BMD even if they received tube feeding. No fractures were recorded during hospitalization in those patients. We would like to thank Dr. Sheva Mann for her help in editing the letter, Dr. Lisa Deutsch, for statistical analysis, and Professor Josef Wisman for the vitamin D determinations. Conflict of Interest: The editor in chief has reviewed the conflict of interest checklist provided by the authors and has determined that the authors have no financial or any other kind of personal conflict with this letter. Author Contributions: All of the authors took part in every aspect of this letter including data analysis and manuscript preparation. Sponsor's Role: No sponsors.