Intestinal bacterial overgrowth in CAPD patients with hypokalaemia

We have previously demonstrated that hypokalaemia is a risk factor for enteric peritonitis in CAPD patients. The underlying mechanism is unclear, and there have been no similar reports. We hypothesized that hypokalaemia may result in dysmotility of the intestinal tract and in turn cause bacterial overgrowth and subclinical translocation of enteral bacteria.

Uraemic patients undergoing CAPD in our hospital were enrolled in the study. Hypokalaemia was defined as a serum potassium (K) level < or = 3.5 mEq/L despite treatment for 1 month. A breath hydrogen test (BHT) was performed to detect if intestinal bacterial overgrowth was present. Blood samples were also collected for the study of inflammatory cytokines, including interleukin 1 (IL1), IL2, IL6, IL8, TNF-alpha and gamma-IFN.

A total of 68 patients were recruited. Hypokalaemia was present in 18 cases (26.5%, group 1), while 50 cases (group 2) had normal serum K levels. A higher prevalence of abnormal BHT was found in group 1 (27.8%), compared with group 2 (8.0%, P = 0.048). There was a trend towards a higher prevalence of abnormal BHT in diabetes mellitus (DM) patients with hypokalaemia (80.0%) compared with normal kalaemia (22.2%, P = 0.09), while no similar trends were found in non-DM hypokalaemic patients (7.7 versus 4.9%). When comparisons were made among different subgroups, patients with DM and hypokalaemia had a significantly higher prevalence of abnormal BHT compared to non-DM, normokalaemic patients (P < 0.0004) and non-DM, hypokalaemic patients (P = 0.008). Multivariate logistic regression analysis revealed that DM was an independent risk factor for abnormal BHT (odds ratio: 12.39, 95% CI: 2.25-68.20, P = 0.004). There was no significant difference in serum albumin, Kt/V, weekly creatinine clearance, pattern of peritoneal equilibrium test, C-reactive protein and various inflammatory cytokines between the two groups.

CAPD patients with hypokalaemia may have intestinal bacterial overgrowth. While both DM and hypokalaemia might contribute to this abnormality, only DM appeared to be the independent risk factor.