Impact of primary medical or surgical therapy on prolactinoma patients' BMI and metabolic profile over the long-term

Abstract

Objectives: High prolactin levels have been associated with weight gain and impaired metabolic profiles. While treatment with dopamine agonists (DAs) has been shown to improve these parameters, there is a lack of surgical series on its comparative effect in prolactinoma patients.

Methods: In this retrospective, comparative study, consecutive patients with a prolactinoma were enrolled if treated with first-line transsphenoidal surgery (TSS) or with DAs. Patients with prolactinomas of Knosp grade >2 and those with a follow-up <24 months were excluded, as were patients with missing laboratory metabolic parameters at baseline and over the long-term. Effects of either treatment on BMI and the metabolic profile were analyzed, and independent risk factors for long-term obesity were calculated.

Results: Primary treatment was TSS for 12 patients (40%) and DAs for 18 patients (60%). At diagnosis, no significant differences between the two cohorts were observed with regard to adenoma size, Knosp grading, baseline prolactin (PRL) levels, prevalence of hypogonadism, or laboratory metabolic parameters. Mean follow-up was 51.9 months (range, 24-158). Over the long-term, both TSS and DAs led to the control of hyperprolactinemia (92% vs. 72%) and hypogonadism (78% vs. 83%) in the majority of patients. While a significant decrease in patients' BMI and fasting glucose were observed, changes in the lipid profile were marginal and independent of the treatment modality. At baseline, increased BMI-but not the primary treatment strategy-was an independent predictor of long-term obesity.

Conclusions: Over the long-term, patients' BMI and FG improve, but changes in the metabolic profile are marginal and independent of the primary treatment. It is presumable that not DAs per se, but rather the control of hyperprolactinemia plays a role in patients' metabolic profile alterations.

Keywords: BMI; Dopamine agonist; Metabolic profile; Prolactinoma; Surgery.

Fig. 1

Flow chart of patient selection process Out of 162 patients with a prolactinoma, first therapy was TSS in 84 patients and DA in 78 patients. 30 patients met the final inclusion criteria.

Fig. 2

Patients’ BMI as a function of their adenoma size and their relation with PRL levels (A) Patients with a macroprolactinoma vs. those with a microprolactinoma showed significant differences in their BMI at diagnosis, (31.5 ± 4.4 vs. 26.8 ± 7.5, p = 0.04), but not over the long-term (29.4 ± 5.1 vs. 26.5 ± 6.0, p = 0.18). (B) Scatterplot showing a significant positive correlation between all patients’ PRL and BMI values (r = 0.4, p = 0.03).

Fig. 3

Changes in PRL levels, metabolic parameters and patients’ BMI over the long-term (A) PRL levels significantly decreased at long-term follow-up (p = 0.03), independent of the primary treatment strategy; i.e. surgery (p = 0.05) and DA therapy (p = 0.01). (B) Over the long-term, a significant reduction in levels of TG (p = 0.02), TC (p = 0.01), and FG (p = 0.003), but not HDL-C (p = 0.16) or LDL-C (p = 0.07), was noted. (C) Patients’ BMI significantly decreased over the long-term (p = 0.05), and was significant in the surgical (p = 0.02) but not the medical (p = 0.34) cohort.