STATISTICAL STUDY OF 5473 RESULTS OF 9 PHARMACOLOGICAL STIMULATION TESTS - A PROPOSED WEIGHTING INDEX

A total of 5473 pharmacological stimulation tests were carried out in 3143 children and subjected to statistical analysis. The mean chronological age of the children was 9 years 9 months (range 3 years to 16 years 6 months) and mean bone age was 7 years 6 months (range 2 years to 14 year's). Nine pharmacological tests were used: (1) arginine (n = 625); (2) clonidine (n = 339); (3) insulin (n = 198); (4) ornithine (n = 162); (5) insulin and arginine (n = 203); (6) clonidine and betaxolol (n = 2003); (7) L-dopa (n = 685); (8) glucagon and propranolol (n = 443); and (9) glucagon and betaxolol (n = 815). Measurement of plasma growth hormone was always performed using the same method. The distribution of values in each test was of the gausso-logarithmic type. The results of the mean peak and the 95% confidence limit were as follows: (1) 10.2, 0.45; (2) 11.5, 0.7; (3) 11.8, 0.8; (4) 14.2, 1.2; (5) 14.3, 0.9; (6) 15.7, 1.1; (7) 19.8, 2.1; (8) 20.8, 2.3; (9) 21, 2.5. These results lead to the following conclusions: the specificity of these tests is low, the mean peak may vary two-fold from one test to another, and the percentage of peaks < 10 ng/ml ranges from 69% for test 1 to 29% for tests 8 and 9. The proportion of growth hormone deficiencies thus varies considerably according to the test used. To avoid these disparities, we propose a weighting index to adjust values according to the tests used: weighting index (1) 1.9; (2) 1.48; (3) 1.4; (4) 1.16; (5) 1.06; (6) 1.01; (7) 0.73; (8) 0.69; (9) 0.66.