Spironolactone and colitis: increased mortality in rodents and in humans

Abstract

Background: Crohn's disease causes intestinal inflammation leading to intestinal fibrosis. Spironolactone is an antifibrotic medication commonly used in heart failure to reduce mortality. We examined whether spironolactone is antifibrotic in the context of intestinal inflammation.

Methods: In vitro, spironolactone repressed fibrogenesis in transforming growth factor beta (TGF-β)-stimulated human colonic myofibroblasts. However, spironolactone therapy significantly increased mortality in two rodent models of inflammation-induced intestinal fibrosis, suggesting spironolactone could be harmful during intestinal inflammation. Since inflammatory bowel disease (IBD) patients rarely receive spironolactone therapy, we examined whether spironolactone use was associated with mortality in a common cause of inflammatory colitis, Clostridium difficile infection (CDI).

Results: Spironolactone use during CDI infection was associated with increased mortality in a retrospective cohort of 4008 inpatients (15.9% vs. 9.1%, n = 390 deaths, P < 0.0001). In patients without liver disease, the adjusted odds ratio (OR) for inpatient mortality associated with 80 mg spironolactone was 1.99 (95% confidence interval [CI]: 1.51-2.63) In contrast to the main effect of spironolactone mortality, multivariate modeling revealed a protective interaction between liver disease and spironolactone dose. The adjusted OR for mortality after CDI was 1.96 (95% CI: 1.50-2.55) for patients without liver disease on spironolactone vs. 1.28 (95% CI: 0.82-2.00) for patients with liver disease on spironolactone when compared to a reference group without liver disease or spironolactone use.

Conclusions: We propose that discontinuation of spironolactone in patients without liver disease during CDI could reduce hospital mortality by 2-fold, potentially reducing mortality from CDI by 35,000 patients annually across Europe and the U.S.

Figure 1. Consolidated Standards of Reporting Trials (CONSORT) flow diagram

Selection of inpatient subjects for modeling among patients with a discharge diagnosis of CDI. Re-admissions for recurrent CDI within 30 days of discharge were treated as a single admission for this analysis.

Figure 2. Results of in vitro studies

(A) Spironolactone inhibits TGFβ induction of αSMA protein expression in colonic myofibroblasts. A representative Western blot of αSMA expression in protein extracts from CCD-18co colonic myofibroblasts stimulated for 24 h with TGFβ is shown. Increasing amounts of spironolactone (SPIR) from 10 μM to 100 μM reduce αSMA expression to levels comparable to unstimulated cells (no Tx). GAPDH expression serves as the loading control for the amount of protein. (B) Treatment of TGFβ stimulated CCD-18co cells with spironolactone (SPIR) represses expression of Acta2, Col1a1, and Ctgf. A metabolite of spironolactone, canrenone (CAN) partially represses pro-fibrotic gene expression. (C) The role of the RAAS pathway in fibrosis and the relationship of pathway inhibitors. (D) Inhibitors of the RAAS pathway aliskiren (ALK), enalaprilat (ENT), and losartan (LOR) partially repress TGFβ induction of fibrotic genes with partial repression of Acta2 expression but have minimal effect on Col1a1 expression (E). Results are from 9 independent experiments. Asterisks denote statistically significant comparisons between untreated control cells (no Tx) and the treatment groups. Brackets denote comparisons between TGFβ treated and other treatment groups. * P <0.05, *** P <0.001

Figure 3. Results of rodent colitis studies

(A) Increased mortality in rats with chronic TNBS colitis treated with spironolactone. Kaplan-Meier mortality estimates of rats with chronic TNBS and 20mg/kg/day SPIR (TNBS+SP) compared to no mortality with TNBS alone and in untreated rats (no Tx). Data are from three rats per experimental group. (B) Increased mortality in rats with chronic TNBS colitis treated with spironolactone is dose-dependent. The Kaplan-Meier curve demonstrates increased mortality in rats with chronic TNBS colitis treated with doses of 10 or 20 mg/kg/day SPIR (T+SP 20, T+SP 10) compared to low doses of SPIR (T+SP 0.5, T+SP 2.5), TNBS alone, or rats with no treatment (noTx). Data are from three rats per experimental group. (C) Spironolactone treatment increases mortality in the S. typhimurium mouse model of colitis. Mortality occurred in mice with S. typhimurium-induced colitis treated with 0.7 mg/kg/day SPIR (SP +St), compared to mice infected with S. typhimurium without SPIR (St), uninfected mice (no Tx), or mice receiving 0.7 mg/kg/day SPIR alone (SP). Uninfected mice which received SPIR treatment over 15 days had 0% mortality until subsequent S. typhimurium induction of colitis (SP→SP + St) at day 16 (vertical arrow) which produced 100% mortality by day 5 post-infection. Data are from five mice per experimental group.

Figure 4. Single Predictor Odds Ratios for Inpatient Mortality in Patients with C. difficile Colitis

For each predictor, the odds ratio from a logistic model for inpatient mortality was adjusted for hospitalization number (≤ 2 vs. > 2) and is presented with 95% confidence intervals. A vertical dashed line at 1 represents the point of no effect.

Figure 5. Adjusted Odds Ratios for and Predicted Probabilities of Inpatient Mortality in Patients with C. difficile Colitis

(A) The adjusted odds ratios for inpatient mortality in a multivariable model containing spironolactone, liver disease, heart failure, the interaction between spironolactone and liver disease, ACE-I use, ARB use, total bilirubin, albumin, BUN, and hospitalization number (≤ 2 vs. > 2). The OR for liver diseases with and without spironolactone and the OR of liver disease with spironolactone are compared to patients without liver disease not taking spironolactone (Reference group). (B) The predicted probability (with 95%CI) of inpatient mortality in patients with liver disease, heart failure and neither liver disease nor heart failure while using 3 possible doses of spironolactone for that disease state. For each disease state, the average total bilirubin, albumin and BUN were used in conjunction with the proportion of patients on ACE-I and ARB medications. Details for each disease state are located in the appendix. In all groups, the probability is shown for hospitalization number ≤2. This demonstrates that spironolactone use is associated with increased mortality in patients without liver disease.