Low Diastolic Blood Pressure and Risk of Ischemic Colitis in the Women's Health Initiative Cohort.

INTRODUCTION

To identify risk and protective factors in older women for incidence of ischemic colitis (IC) and 30-day mortality.

METHODS

We conducted a prospective study of 100,825 women in the Women's Health Initiative, with an average of 13.1-year follow-up and extensive phenotypic and outcomes data in diverse race and ethnic groups. Lasso Cox regression selected variables related to incidence of IC from multiple domains (demographic, comorbidities, risk factors, biomarkers, psychosocial factors, and dietary factors). Cox regressions modelled the selected variables to obtain adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs).

RESULTS

The incidence rate of IC was twice as high among those with a history of cardiovascular disease (55.7 per 10,000 person-years) compared with those with no such history (27.3 per 10,000 person-years). After adjustment for multiple covariates, higher risk was associated with diastolic blood pressure below 90 mm Hg, using 2 or more types of antihypertensive medications compared with none (aHR 1.62, 95% CI 1.47-1.78), having gastrointestinal symptoms (aHR 1.31, 95% CI 1.20-1.42 highest vs lowest quartile). Higher fiber intake was associated with lower risk (aHR per increase of 10 g/d 0.93, 95% CI 0.89-0.97), and Black women had lower adjusted risk of IC than White women (aHR 0.73, 95% CI 0.63-0.83). Post-IC 30-day all-cause mortality was 10.6%, and sepsis was an important cause of death.

DISCUSSION: The incidence rate of IC in older women was twice as high in those with a history of cardiovascular disease and was associated with low diastolic blood pressure and multiclass antihypertensive treatment. Dietary fiber intake was associated with lower risk. Black women had lower risk of IC compared with White women.