Measurement of basal growth hormone (GH) is a useful test of disease activity in treated acromegalic patients

@article{citeulike:2112632, author = {Jayasena and C. N. and Wujanto and C. and Donaldson and M. and Todd and J. F. and Meeran and K.}, citeulike-article-id = {2112632}, comment = {To define disease remission in treated patients with acromegaly, the consensus guidelines state that nadir serum GH levels should be less than 1 µg/l after 75-g oral glucose tolerance test (OGTT) and serum IGF-I levels within age- and sex-matched normal range. In order to perform an OGTT, multiple blood samples are required for the measurement of nadir GH levels. This can sometimes be cumbersome is a busy clinical practice. Furthermore, the OGTT is an inconsistent test because variables such as the rate of glucose absorption, neural activation and incretins are potential confounders; not to mention the fact that the optimal dose of whether 75-g or 100-g of oral glucose that should be used is unclear. This article aims to address the very practical issue as to whether a single blood test without glucose loading would be advantageous to the OGTT in monitoring disease activity. The authors found a tight correlation between basal GH and nadir GH after OGTT, and that basal GH was highly predictive of nadir GH for GH levels below 1 mcg/l and above 2 mcg/l in patients treated and not treated with radiotherapy. Interestingly, the negative predictive value for basal GH less than 1 µg/l with respect to nadir GH more than 1 µg/l was 100\%, and the positive predictive value for basal GH above 2 µg/l with respect to nadir GH less than 1 µg/l for patients treated and not treated with radiotherapy were 96•7\% and 95•2\%, respectively. This suggests that radiotherapy did not appear to affect the prediction of nadir GH to basal GH. This study is indeed clinically relevant to practicing clinicians and a welcome alternative to patients as a single measurement of ‘fasting’ basal GH is probably sufficient in assessing disease remission rather than subjecting patients to the OGTT if basal GH is less than 1 µg/l or more than 2 µg/l. However, the single basal GH level should still be taken into consideration in the context of the clinical assessment, the patient’s overall symptoms and serum IGF-I levels before deciding on the disease status of the patient. David M. Cook, MD }, doi = {10.1111/j.1365-2265.2007.02996.x}, issn = {0300-0664}, journal = {Clinical Endocrinology}, keywords = {acromegaly, diagnosis}, month = {January}, number = {1}, pages = {36--41}, posted-at = {2008-04-15 21:42:26}, priority = {2}, publisher = {Blackwell Publishing}, title = {Measurement of basal growth hormone (GH) is a useful test of disease activity in treated acromegalic patients}, url = {http://dx.doi.org/10.1111/j.1365-2265.2007.02996.x}, volume = {68}, year = {2008} }

TY - JOUR ID - citeulike:2112632 TI - Measurement of basal growth hormone (GH) is a useful test of disease activity in treated acromegalic patients JF - Clinical Endocrinology VL - 68 IS - 1 SP - 36 EP - 41 PB - Blackwell Publishing SN - 0300-0664 KW - acromegaly KW - diagnosis N1 - To define disease remission in treated patients with acromegaly, the consensus guidelines state that nadir serum GH levels should be less than 1 µg/l after 75-g oral glucose tolerance test (OGTT) and serum IGF-I levels within age- and sex-matched normal range. In order to perform an OGTT, multiple blood samples are required for the measurement of nadir GH levels. This can sometimes be cumbersome is a busy clinical practice. Furthermore, the OGTT is an inconsistent test because variables such as the rate of glucose absorption, neural activation and incretins are potential confounders; not to mention the fact that the optimal dose of whether 75-g or 100-g of oral glucose that should be used is unclear. This article aims to address the very practical issue as to whether a single blood test without glucose loading would be advantageous to the OGTT in monitoring disease activity. The authors found a tight correlation between basal GH and nadir GH after OGTT, and that basal GH was highly predictive of nadir GH for GH levels below 1 mcg/l and above 2 mcg/l in patients treated and not treated with radiotherapy. Interestingly, the negative predictive value for basal GH less than 1 µg/l with respect to nadir GH more than 1 µg/l was 100%, and the positive predictive value for basal GH above 2 µg/l with respect to nadir GH less than 1 µg/l for patients treated and not treated with radiotherapy were 96•7% and 95•2%, respectively. This suggests that radiotherapy did not appear to affect the prediction of nadir GH to basal GH. This study is indeed clinically relevant to practicing clinicians and a welcome alternative to patients as a single measurement of ‘fasting’ basal GH is probably sufficient in assessing disease remission rather than subjecting patients to the OGTT if basal GH is less than 1 µg/l or more than 2 µg/l. However, the single basal GH level should still be taken into consideration in the context of the clinical assessment, the patient’s overall symptoms and serum IGF-I levels before deciding on the disease status of the patient. David M. Cook, MD AU - Jayasena AU - Wujanto AU - Donaldson AU - Todd AU - Meeran PY - 2008/01// UR - http://dx.doi.org/10.1111/j.1365-2265.2007.02996.x ER -