Endocrine and neuroanatomic features associated with weight gain and obesity in adult patients with hypothalamic...

Obesity is a common consequence in patients with tumors of the hypothalamic region and of related treatment in children. Much less information is available on adult patients and long-term survivors. The aims of this study were to estimate the prevalence of obesity in adult patients with acquired structural hypothalamic damage and to define the characteristics of patients at greatest risk of obesity.

A retrospective study was conducted of 52 patients (25 women; median age at diagnosis, 44 years; range, 17 to 78 years) with tumors involving the hypothalamic region. These included 22 craniopharyngiomas, 24 pituitary adenomas, and six other hypothalamic tumors. Changes in body mass index were determined, magnetic resonance imaging scans were scored by a radiologist for tumor size and the extent of involvement of the hypothalamus, and current hormone replacement therapy was recorded, to identify possible features associated with new or worsened obesity (defined as a body mass index > or =30 kg/m(2) at the latest follow-up, which had increased by at least 2 kg/m(2) since diagnosis of the tumor).

Serial body mass index data from diagnosis to the latest follow-up were available for 42 patients. After a median of 5 years (range, 1 to 19 years) of follow-up, most patients with hypothalamic damage were obese (52% [n = 22] vs. 24% [n = 10] at the time of diagnosis, P < 0.0001). In a multivariate model, use of desmopressin (odds ratio [OR] = 13; 95% confidence interval [CI]: 2.0 to 86; P = 0.007) and growth hormone replacement (OR = 7.6; 95% CI: 1.1 to 51; P = 0.04) were associated with new or worsened obesity during follow-up. No correlation was found between the initial size or location of the tumor and subsequent weight gain.

Obesity is highly prevalent in adult survivors of hypothalamic tumors. Use of desmopressin and growth hormone therapy, but not size or location of the tumor, were associated with weight gain and obesity following diagnosis. These findings may be helpful in identifying patients at increased risk of obesity, to whom earlier intervention could be offered.