Biochemical Recovery Time Scales in Elderly Patients with Osteomalacia

Abstract

Osteomalacia is not rare in the UK and climatically similar countries, particularly in elderly people and those of Asian descent. Overt clinical osteomalacia is usually treated with a loading dose of vitamin D, followed by a regular supplement. However, little is known of the time taken to reach a stable biochemical state after starting treatment. Such information would shed light on the duration of the bone remineralization phase and guide decisions on the length of follow-up. To address this we conducted a 2-year follow-up study of 42 patients (35 female, mean age 80.8 years) with biopsy proven osteomalacia treated with a standard replacement regimen and general nutritional support. Although normocalcaemia was attained within 4 weeks the mean values continued to rise, to a mid-range plateau at 52 weeks. The phosphate and alkaline phosphatase values also took at least a year to reach a stable mean, with a slight further trend towards the mid-range for the entire 104 weeks. The mean serum albumin also rose throughout the first 52 weeks, indicating an effective response to the general nutritional support measures. Our observations suggest that the dynamic relationship between calcium, phosphate and bone requires at least a year, and probably longer, to reach an equilibrium after treatment for osteomalacia in elderly patients. The findings emphasize the need for close medical and social follow-up in this clinical context.