Hemodialysis patients had higher perforation rate

The incidence of colonic perforation during colonoscopy was significantly higher in hemodialysis patients than in controls in a retrospective analysis, Clinical Gastroenterology and Hepatology.

“Hemodialysis patients more commonly have lower gastro-intestinal bleeding, due not only to cancer, but also to diverticulitis or vascular abnormalities,” wrote the authors. This makes colonoscopy a common diagnostic tool for hemodialysis patients with positive fecal occult blood tests or iron-deficiency anemia.

The new-data — from the “first report that shows an increased incidence of this complication in patients on [hemodialysis]” — suggest that “reconsideration of the indications for colonoscopy in patients on hemodialysis is needed, especially for screening colonoscopy.”

The department of gastroenterology at Nagoya Kyoritsu Hospital, Aichi, Japan, and their colleagues looked at records for 15,098 consecutive patients who underwent colonoscopy at that institution during 2001-2008. There were 1,106 hemodialysis patients and 13,992 nonhemodialysis patients.

In the hemodialysis group, 59 percent were male, versus 64 percent in the nonhemodialysis group, a significant difference. Hemodialysis were also significantly older, with a mean age of 66 years, compared with 60 years in the nonhemodialysis patients. The mean duration of hemodialysis was 7.4 years.

Polypectomy was performed in 250 hemodialysis patients (23 percent), compared with 3,569 nonhemodialysis patients (26 percent), a significant difference (P = 03). Colonic perforations occurred in five hemodialysis patients and in three hemodialysis patients, for an incidence of 0.45 percent and 0.02 percent, respectively. That amounted to an odds ratio for perforation in the hemodialysis group of 21.17, with a 95 percent confidence interval of 5.05-88.73 (P less than .0001).

Mechanical causes were suspected in two cases in the hemodialysis group, and barotraumas in one, while the remaining two perforations among the hemodialysis patients had unknown etiologies. Mechanical perforation was also the cause of two perforations in the nonhemodialysis group, with electrocauterization after polypectomy responsible for the third case.

In the hemodialysis group, there were two perforations at the cecum, one of the descending colon, one at the transverse colon, and one at the rectum. In the control group, there was perforation at the descending colon and two at the sigmoid. One hemodialysis patients died of sepsis on the first postoperative day. There were no other perforation-related mortalities.

The speculation that the tissue elasticity and rupture strength of colonic mucosa in hemodialysis patients may be lower than in the nonhemodialysis patients, possibly because of beta-microglobulin amyloidosis — a common side effect in dialysis patients. While the condition normally affects musculoskeletal tissue, “visceral involvement also occurs.”

Indeed, “beta 2-microglobulin deposition was seen in specimens at perforated sites obtained from three hemodialysis patients, whilst no such deposition was seen in nonhemodialysis patients.”

The authors pointed out that they did not control for other comorbidities among the hemodialysis population, and that “consequently, hemodialysis may be surrogate for another risk factor.”