Concomitant Oral Potassium Chloride and Anticholinergic Therapy is Associated with Upper Gastrointestinal Bleeding: A Cohort Study.

AimTo determine whether oral potassium chloride (KCI) therapy with concomitant anticholinergic exposure among hospitalized patients is associated with an excess risk for upper gastrointestinal bleeding (UGIB).MethodsA retrospective controlled study among hospitalized patients between January 2007 and April 2019 who were treated with oral KCI. Patients were divided into two groups: with or without concomitant exposure to agents with anticholinergic activity. Outcome was defined as any UGIB.ResultsThe final sample included 13 728 subjects who received oral KCI treatment, of them 3542 (25.8%) had at least one documented overlap with an anticholinergic agent. Mean age was 67.6 (±17.2) and 6893 (50.2%) were females. Median KCI dose was 2.4 g (interquartile range [IQR] 1.2‐5.4, n = 9416) with the majority (90.4%) being treated with the wax‐matrix form (Slow‐K). Twenty‐six (0.2%) patients experienced an UGIB event. Univariate analysis demonstrated a significantly higher rate of UGIB among patients concomitantly treated with oral KCI and anticholinergics (0.3%) compared to those without anticholinergic exposure (0.1%, P = 0.018), with median 7 days (IQR 3‐16.8) from first KCI dose to bleeding event. Multivariate analysis demonstrated that concomitant anticholinergic exposure (Odds Ratio 2.48, 95% Confidence Interval 1.11‐6.51, P = 0.022) and anticoagulation treatment among patients with hemato‐oncologic disease (OR 6.61, 95% CI 1.96‐22.25, P = 0.002) were significantly associated with UGIB.ConclusionHospitalized patients treated concomitantly with oral KCI and anticholinergic agents have significantly increased risk for UGIB.