Sleep-disordered breathing in acromegalics - Relation of mormonal levels and quantitative sleep study by means of bedside oximeter

Sleep-disordered breathing (SDB) is common in patients with growth hormone (GH) secreting pituitary adenomas. Since long-term untreated SDB aggravates systemic conditions (hypertension and arrhythmia etc.), the therapeutic ou tcome of SDB is important in reducing morbidity and mortality rates. But th e results of a quantitative analysis of the lowered GH and IGF-1 levels in SDB in a relatively large number of patients are not detailed. Ten consecut ive acromegalic patients were studied with a bedside oximeter. Preoperative ly they were divided into two groups based on the presence (SDB group=6 pat ients) or absence (non-SDB group=4 patients) of clinical symptoms of SDB su ch as habitual snoring, excessive daytime somnolence and nocturnal apneic e pisodes. The serum IGF-1 averaged 931.7 ng/ml in SDB group and 898.3 ng/ml in non-SDB group. The oxygen desaturation index (ODI) (the number of oxygen desaturations exceeding 4% from the base line) was 29.1+/-15.4 in the SDB group and 2.5+/-1.8 in the non- SDB group (P=0.01). Other oximeter paramete rs such as the percent of the time spent at O-2 saturation<90% and the mean and the lowest O-2 saturations closely correlated with the degree of the c linical symptoms. A postoperative sleep study was conducted in 5 patients i n the preoperative SDB group, 4 months or more after the surgery. The serum GH and IGF-1 levels normalized in 3 patients but remained slightly high in 2. ODI became 9.1+/-5.6, which was significantly lower than the preoperati ve value (P=0.026). One patient had a complete clinical resolution. The oth er 4 obtained slight to moderate improvement clinically and oximetrically d espite normalized or decreased hormonal levels. This study clarified that t he response of SDB to lowering of the GH level varies from one patient to a nother and persisting SDB despite the normalization of the hormonal levels suggests the involvement of other factors in the production of SDB.