Cath Lab Digest

S evere catabolism, resulting in a rapid loss of lean body mass, is a well recognized complication of major burns. Significant involuntary weight loss is a predictable occurrence despite optimum nutrition and early wound closure.1-5 The majority of lost weight is lean body mass, due to the overwhelming catabolic response that leads to the use of body protein for energy.3 Complications of lost lean mass are of particular concern for the older patient who already is likely to have sustained pre-injury loss of body protein as the result of decreased endogenous anabolism and decreased physical activity,5-7 including a decrease in healing for any remaining surgical procedures. Also, the restoration of body weight and lean mass occurs at a much slower rate than the rate of loss.6-8 This process of weight and lean mass restoration is even slower in the elderly, as decreased levels of the anabolic hormones, human growth hormone, and testosterone occur with aging.6,7,9
Providing an exogenous anabolic agent, such as the testosterone analog oxandrolone, has been shown to significantly increase the rate of restoration of lost lean mass after injury.10 The restoration of lean mass correlates with improved wound healing and musculoskeletal function.11 However, the effect of anabolic agents on weight and lean mass gain has not been specifically determined for the older burn patient.12 This information would be of value, as a more rapid restoration of function is essential in the older patient to avoid a permanent disability.13, 14
The results of previous report10 on the rate of weight gain in a smaller population of older burn patients have been expanded in this larger study to include the rate of healing of a new skin graft donor site. To determine the effect of the potent anabolic agent oxandrolone combined with optimum nutrition and exercise on restoration of lean mass and function in the older versus young burn patient, a randomized, controlled clinical study was conducted among patients in the post-catabolic or recovery phase when wounds were nearly closed and endogenous anabolic activity was returning to normal. During this phase, investigators tested the effect of increasing anabolism on the rate of restoration of lost lean mass.

Methods
Study design. Using a randomized, prospective study design, patients with deep burns not exceeding 55% of total body surface (TBS) were studied. Participants included major burn patients admitted to the Brigham and Women's Hospital Burn Center between 1998 and 2001. Of all burn patients, 90% have burns less than 50% of TBS; a more severe burn in an older population would result in a very high morbidity and mortality rate, making an assessment of age-related anabolism very difficult.12 In addition, all patients in this category of burn size were considered candidates if they were at least 17 years old and their burn size was sufficient to produce a severe catabolic state. A burn of 20% of body surface is large enough to produce a rate of catabolism and hypermetabolism which exceeds 50% of normal.3
Standard care protocols were used on all patients during the acute care phase of injury, including early debridement and wound closure, along with optimum nutrition.14 Patients included in the study were anticipated to require at least 4 weeks of inpatient rehabilitation care during the recovery phase to restore sufficient lost lean mass and musculoskeletal function before discharge.
Although somewhat arbitrary, the beginning of the recovery period was determined to be a stable cardiopulmonary status, no active infection, and metabolic rate at rest (indirect calorimeter) less than 130% of normal. Patients also needed to be on adequate nutrition with supplements (or tube feeding), as well as have the ability to actively participate in a physical therapy program.
All study patients were determined to have met recovery phase criteria before entry into the study.