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

To investigate the association between proton pump inhibitor (PPI) use and the presence and severity of calcinosis in SSc.

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).

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.

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.