High proton pump inhibitor exposure increases risk of calcinosis in systemic sclerosis.

Objective: To investigate the association between proton pump inhibitor (PPI) use and the presence and severity of calcinosis in SSc.
Methods: We analysed data from two SSc cohorts from a single centre. Cohort 1 included 199 patients reviewed over 10 years, for whom retrospective data on PPI use and calcinosis were available. Cohort 2 was recruited prospectively and included 215 consecutive patients, who underwent clinical assessment. Outcomes of interest were presence of current calcinosis (CC) or calcinosis at any time (CAT).
Results: The cohort 1 data analysis showed that among patients on standard dose PPI 20% had calcinosis, while in those on high doses of PPI calcinosis was present in 39% (P = 0.003). Analysis of the data from cohort 2 confirmed these findings, demonstrating that the odds of CAT increased significantly with longer PPI exposure [odds ratio (OR) 1.04, 95% CI: 1.02, 1.06; P < 0.001], longer disease duration (OR 1.08, 95% CI: 1.05, 1.12; P < 0.001) and greater age (OR 1.03, CI: 1.01, 1.05; P = 0.010). Multivariable logistic regression showed that higher exposure to PPI remained a significant predictor of calcinosis, with PPI exposure >10 years increasing the risk of CAT >6-fold, compared with no PPI (OR 6.37, 95% CI: 1.92, 21.17; P = 0.003) after adjusting for disease duration and antibodies.
Conclusion: We confirm a significant association between high PPI exposure with severity of calcinosis in SSc. Given the clinical impact of calcinosis and reflux in SSc, PPI exposure as a potentially modifiable risk factor for calcinosis requires further evaluation.
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