CHOLECYSTECTOMY IS A RISK FACTOR FOR MICROSCOPIC COLITIS: A NATIONWIDE POPULATION-BASED MATCHED CASE CONTROL STUDY.

Abstract

Background and aims: Studies have linked bile-acid malabsorption and microscopic colitis (MC), with some MC patients responding to treatment with bile-acid sequestrants. However, the literature on cholecystectomy as a risk factor for MC is inconclusive. Therefore, we investigated the relationship between cholecystectomy and MC on a nationwide scale to provide more definitive insights.

Methods: We conducted a nationwide matched case-control study involving 13,554 patients diagnosed with MC between 1981 and 2017 in Sweden who were matched to 64,886 controls. Data on MC were obtained from Swedish pathology registers, and controls were randomly selected from the general population and matched according to birth year, sex, county of residence and calendar year. Moreover, MC-free full siblings to patients with MC were identified. Information on cholecystectomy was collected from the Swedish National Patient Register. Adjusted odds ratios (aORs) were calculated using multivariable-adjusted conditional logistic regression.

Results: The median age at diagnosis was 63.5 years (interquartile range [IQR]=51.0-73.4), and 72.3% of MC patients were women. Among MC patients, 342 (2.5%) had undergone a cholecystectomy before diagnosis, compared to 687 (1.1%) in the control group. This yielded an aOR of 2.36 (95% CI=2.07-2.69) for earlier cholecystectomy in MC patients. The corresponding aORs for collagenous colitis and lymphocytic colitis were 1.87 (95% CI=1.48-2.36) and 2.65 (95% CI=2.26-3.12), respectively. When compared to siblings, the aOR was 1.49 (95% CI=1.21-1.85).

Conclusions: Cholecystectomy is associated with an increased risk of subsequent MC. These findings have implications for surgeons and general practitioners and underscore the need for further research into the underlying association between bile-acid and microscopic colitis.