Adult growth hormone deficiency in Japan: Results of investigation by questionnaire

Adult GH deficiency (AGHD) has been established as a syndrome associated with various metabolic disturbances such as hyperlipidemia, impaired glucose tolerance and protein catabolism, in addition to changes in body composition such as increased visceral fat, decreased muscle mass and bone density. We investigated the clinical findings, complications and prognosis of AGHD in Japan. The questionnaire was sent to various expert facilities of endocrinology and metabolism to gather cross-sectional information as well as longitudinal follow-up data on adult patients with hypopituitarism. We received answers on 422 subjects, of which number the GH stimulation test was performed in only 63% of them. An age- and sex-matched group of 259 adults with hypopituitarism (125 male and 134 female subjects) was finally selected for this investigation. Of them 185 subjects (81 male and 104 females) were diagnosed as AGHD with plasma peak GH levels less than 3 ng/ml after GH stimulation test. Male adult patients with GHD had significantly lower ratio of smoking and drinking in their life style compared with those without GHD. Male adult patients with GHD revealed significantly higher BMI on physical examination, and significantly higher plasma ALT, AST, total cholesterol, and LDL cholesterol in blood chemistry compared with those without GHD (P<0.05). Though patients with ischemic heart disease were more frequent in female patients than male patients, the rate of frequency was not different between female adult patients with and without GHD. Clinical characteristics found in especially male adult patients with GHD in Japan were consistent with findings reported so far in foreign countries. However, consequent complications such as atherosclerosis seemed less severe than expected. Moreover, GH stimulation test for the diagnosis of AGHD as well as clinical test to perform when AGHD was suspected is still less frequently carried out. Therefore, the clinical outcome of AGHD in our country requires further investigation.