Secondary Hyperparathyroidism Among Bariatric Patients: Unraveling the Prevalence of an Overlooked Foe

Abstract

Introduction: Bariatric surgery (BS) is an effective therapeutic approach for obese patients. It is associated with important gastrointestinal anatomic changes, predisposing these subjects to altered nutrient absorption that impact phosphocalcium metabolism. This study aims to clarify the prevalence of secondary hyperparathyroidism (SHPT) and its predictors in patients submitted to BS. Methods: Retrospective unicentric study of 1431 obese patients who underwent metabolic surgery between January/2010 and June/2017 and who were followed for, at least, a year. In this group, 185 subjects were submitted to laparoscopic adjustable gastric banding (LAGB), 830 underwent Roux-en-Y gastric bypass (RYGB) and 416 sleeve gastrectomy (SG). Data comprising 4 years of follow-up were available for 333 patients. We compared the clinical and analytical characteristics of patients with and without secondary hyperparathyroidism (considering SHPT a PTH˃69pg/mL), taking also into account the type of surgery. A multiple logistic regression was performed to study the predictors of SHPT after BS. Results: The overall prevalence of SHPT before surgery was 24.9%, 11.2% one year after surgery and 21.3% four years after surgery. At 12 months after surgery, LAGB had the highest prevalence of patients with SHPT (19.4%, N=36), RYGB had 12.8% (N=274) and SG 5.3% (N=131). At 48 months after surgery, RYGB had the highest prevalence of SHPT (27.0%, N=222), LAGB had 13.2% (N=53) and SG 6.9% (N=58). Multi-variate logistic analysis showed that increased body mass index and age, decreased levels of vitamin D and RYGB were independent predictors of SHPT one year after surgery. The only independent predictor of SHPT four years after surgery was RYGB. Conclusion: The prevalence of SHPT is considerably higher before and four years after BS than 1 year after surgery. This fact raises some questions about the efficacy of the implemented follow-up plans of vitamin D supplementation on the long term, mainly among patients submitted to RYGB.

Prevalence and associated factors of secondary hyperparathyroidism after Roux‐en‐Y gastric bypass: A meta‐analysis

“…After the exclusion of ineligible studies, our final sample was 30 studies. 4,5,[7][8][9][10][11][14][15][16][17][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] Among them, four studies had two arms, these arms were analyzed separately in this meta-analysis 14,31,34,39 (Figure 1). The characteristics of included studies are presented in Table 1.…”

“…The study quality assessment is also displayed in this table. Of all included studies, 30 were considered inadequate for vitamin D and calcium supplementation, [7][8][9][10]14,16,17,[21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] and 4 were assessed as adequate supplementation 4,5,11,15 (Table 2). Of the 30 studies with inadequate supplementation, 6 reported data for ≤1 year of follow-up, 19 for >1 and ≤5 years, 3 for >5 and ≤10 years, and 2 for >10 years.…”

“…Compared with sleeve gastrectomy, Roux-en-Y gastric bypass (RYGB) has a higher risk of developing SHPT. 4,5 This may be explained by the unique exclusion of the upper small intestine with RYGB. Bypassing the duodenum and upper jejunum hinders the effective absorption of orally administered calcium supplementation.…”

“…[7][8][9] As for SHPT prevalence after RYGB, it was found to be as high as 69%, 10 but others reported it to be only 12.8%-15%. 4,5 Some studies have even shown a reduction in the prevalence of SHPT after surgery compared with before surgery. 4,5,11 These results do not seem to have been well explained.…”

“…4,5 Some studies have even shown a reduction in the prevalence of SHPT after surgery compared with before surgery. 4,5,11 These results do not seem to have been well explained. In any case, if SHPT is neglected for a long time, it may lead to bone loss and osteopenia, which may increase the risk of fracture.…”