Effects of growth hormone (GH) replacement with recombinant human GH on bone and mineral metabolism were studied in 36 GH-deficient children. Several outcomes, including serum ionized calcium levels, were assessed at pretherapy (zero months) and 1, 3, 6, 9 and 12 months after the beginning of therapy. Simple linear regression was used to determine if changes in ionized calcium levels could be predicted from length of therapy. Each patient’s ionized calcium level was employed in the analysis.
Is the use of simple linear regression appropriate?
c. The investigators should have used logistic regression instead