Beneficial Effects of Long-term GH Replacement Therapy on Quality of Life in Adults with GH Deficiency

Objective: Quality of life tends to be adversely affected in adults with GH deficiency. The aim of this study was to examine changes in quality of life in a large group of GH-deficient adults receiving long-term GH replacement therapy.

Design: The study was conducted in two stages. The first stage was a prospective, open trial of GH replacement therapy in 71 GH-deficient adults, during which GH was administered for 20-50 months. For the second stage, a further 90 patients were recruited to create a population of 161 GH-deficient adults, all of whom had received GH replacement therapy for more than 12 months. This population was investigated retrospectively, using a questionnaire designed specifically for this study.

Patients: All patients were GH deficient and showed a peak GH response of less than 3.0 micrograms/l during an insulin tolerance test in which blood glucose levels dropped to 2.2 mmol/l or below.

Measurements: The quality of life of patients in the prospective stage was assessed using the Nottingham Health Profile (NHP) parts I and II, and the Psychological General Well-Being (PGWB) index. In the retrospective study patients completed a specially developed questionnaire, designed to determine whether changes in quality of life were sudden or gradual, and whether quality of life continued to change after GH had been administered for more than 12 months.

Results: In the prospective stage, mean overall score on the NHP I improved significantly during the first 6 months of GH therapy, and remained at its new level thereafter. Scores in all areas of the NHP II improved significantly between baseline and 20-50 months, as did the total score and five of six area scores on the PGWB index. The total PGWB score and three area scores improved significantly between 6 or 12 months and 20-50 months. In the retrospective stage, 92.7% of the patients reported that they had experienced positive effects of GH therapy. In 30.3% of patients, however, such effects did not become apparent until GH had been administered for more than 6 months. Almost 60% of patients felt that their condition was still improving.

Conclusions: These results indicate that the previously reported beneficial effects of GH therapy on quality of life in GH-deficient adults are sustained during long-term therapy. In addition, they suggest that, once started, GH therapy should be continued for at least 6 months before judgements are made regarding its efficacy in improving quality of life.