Post-surgical acromegaly patients show 19.5% biochemical discordance, predominantly elevated IGF-1 with normal GH
Background
The clinical management of acromegaly relies heavily on monitoring growth hormone (GH) and insulin-like growth factor-1 (IGF-1) levels. A significant challenge arises from biochemical discordance, where one hormone is within the reference range while the other is elevated. This discrepancy complicates the interpretation of disease activity, making it difficult to determine if a patient is truly in remission or requires further intervention. Understanding the prevalence and clinical correlates of this discordance is crucial for improving diagnostic accuracy and guiding treatment strategies.
Study Design
This retrospective cohort study analyzed 82 patients who underwent pituitary surgery for acromegaly at Sahlgrenska University Hospital between 1994 and 2019. Medical records were reviewed, and all patients were examined with an oral glucose tolerance test (OGTT) post-surgery. The study compared patients exhibiting postoperative biochemical discordance (one hormone normal, one elevated) with those showing concordant hormone levels (both normal or both elevated) to identify clinical correlates and implications.
Results
In a cohort of 82 patients surgically treated for acromegaly, 16 (19.5%) exhibited biochemical discordance between GH and IGF-1 levels. The predominant pattern observed in 14 of 16 discordant patients was elevated IGF-1 with normal nadir GH. This finding highlights a common scenario where IGF-1 remains high despite GH normalization, complicating remission assessment. The IGF-1 levels at diagnosis were significantly higher in patients who later developed discordance compared with the controlled concordant group, suggesting a potential predisposition. However, no significant differences were observed between the discordant and concordant groups regarding baseline variables at diagnosis, including age, gender, invasive tumor status, micro/macro-adenoma presence, or BMI. Similarly, hypertensive treatment at the time of surgery and postoperative radiotherapy or reoperation did not differ between the groups. This indicates that while initial disease severity (higher IGF-1) may play a role, other common clinical factors do not strongly predict postoperative discordance. The prevalence of 19.5% underscores the clinical relevance of this phenomenon.
The discordant group had significantly higher
IGF-1levels at diagnosis compared with the controlled concordant group, suggesting that greater preoperative disease activity may predispose to postoperative biochemical discordance.
Key Findings
- Biochemical discordance occurred in 19.5% of patients after surgical treatment for acromegaly.
- The predominant pattern was elevated IGF-1 with normal nadir GH in 14 of 16 discordant cases.
- Patients with postoperative discordance had significantly higher
IGF-1levels at acromegaly diagnosis. - No differences were found in age, gender, tumor characteristics, BMI, or other treatments between discordant and concordant groups.
Why It Matters
Identifying patients at risk for postoperative biochemical discordance is crucial for optimizing acromegaly management and preventing undertreatment. This study reveals that nearly one-fifth of surgically treated patients may present with elevated IGF-1 despite normalized GH, challenging the traditional definition of remission. Clinicians should consider higher IGF-1 levels at diagnosis as a potential indicator for increased vigilance post-surgery, even if GH appears controlled. This finding suggests that a more nuanced approach to interpreting biochemical markers is needed, potentially leading to revised follow-up protocols or earlier consideration of adjunctive medical therapies for patients with persistent IGF-1 elevation, even in the absence of elevated GH.
acromegaly
gh
igf-1
biochemical discordance
pituitary surgery
endocrinology