Continuous PPI Treatment After Gastric Bypass Increases the Risk of Pathological PTH Levels at 10 Years Postoperatively

Abstract

Background: Apart from massive weight loss, metabolic and bariatric surgery, especially gastric bypass (Roux-en-Y gastric bypass [RYGB]), can cause nutritional deficiencies. Proton pump inhibitors (PPI), relatively often used after RYGB, are associated with reduced calcium absorption. We have studied the long-term impact of PPI upon calcium homeostasis among RYGB patients.

Methods: In the Scandinavian Obesity Surgery Registry (SOReg), 550 primary RYGB patients, with eGFR > 60 mL/min/1.73 m², had PTH and 25-OH D levels registered at 10 years. To avoid the impact of hypovitaminosis D, those with 25-OH D > 75 nmol/L were selected.

Results: At 10 years, 10.3% of patients reported continuous PPI treatment, i.e., daily use during the last month. In an age adjusted logistic regression model, continuous PPI treatment was associated with a quadruple risk (OR: 4.65 [1.54-14.04]) of having a pathological PTH level (> 7 pmol/L).

Conclusion: This unique study has shown a correlation between continuous PPI use and pathological PTH levels, thereby inferring that the medication may have detrimental effects upon calcium homeostasis among gastric bypass patients. The risk of having pathological PTH levels was more than tripled among those with PPI treatment, highlighting the importance of specialized follow-up while also suggesting that a limited duration of PPI treatment is preferable.

Keywords: Bariatric surgery; Gastric bypass; Parathyroid hormone; Proton-pump inhibitors.

Fig. 1

Proportion of patients with pathological PTH (PTH ≥ 7.0 pmol/L) depending upon PPI treatment