Change of symptoms and perceived health in acromegalic patients on pegvisomant therapy: a retrospective cohort study within the German Pegvisomant Observational Study (GPOS)

Abstract

This study aimed at investigating how symptoms and perceived health changes in acromegalic patients during pegvisomant treatment in respect to IGF-1 levels and disease characteristics. Retrospective, multicentre cohort study in 131 acromegalic patients within the German Pegvisomant Observational Study (GPOS). Outcome measure was the change of perceived health evaluated by the Patient-Assessed Acromegaly Symptom Questionnaire (PASQ) between baseline and after 1 year of pegvisomant therapy. Predictors were change in IGF-1 levels, maximal pegvisomant dosage, adverse events and comorbidities. Perspiration, soft tissue swelling and perceived health improved after 1 year of pegvisomant therapy while other symptoms such as headache, fatigue and joint pain remained largely unchanged over time. The highest mean IGF-1/upper limit of normal (ULN) values before pegvisomant therapy were found in those patients with a reported amelioration in perspiration and soft tissue swelling after 1 year of pegvisomant treatment. The highest mean decrease of IGF-1/ULN was found in those patients with reported amelioration of numbness and tingling of limbs. Other factors such as decrease in fasting glucose may play a role as independent predictor for some symptoms such as the improvement of headache, perspiration and perceived health, while other factors such as maximal pegvisomant dosage, occurrence of adverse events, tumour growth, or liver enzyme elevation did not play a predictive role. Patients' symptoms and perceived health are in part an independent construct, not merely reflecting IGF-1 status or biochemical control. Subjective measures should therefore be regularly documented in acromegalic patients as a patient-oriented indicator for treatment success.