Postoperative complications following colectomy for ulcerative colitis: a validation study.

BACKGROUND: Ulcerative colitis (UC) patients failing medical management require colectomy. This study compares risk estimates for predictors of postoperative complication derived from administrative data against that of chart review and evaluates the accuracy of administrative coding for this population. METHODS: Hospital administrative databases were used to identify adults with UC undergoing colectomy from 1996-2007. Medical charts were reviewed and regression analyses comparing chart versus administrative data were performed to assess the effect of age, emergent operation, and Charlson comorbidities on the occurrence of postoperative complications. Sensitivity, specificity, and positive/negative predictive values of administrative coding for identifying the study population, Charlson comorbidities, and postoperative complications were assessed. RESULTS: Compared to chart review, administrative data estimated a higher magnitude of effect for emergent admission (OR 2.52 [95% CI: 1.80-3.52] versus 1.49 [1.06-2.09]) and Charlson comorbidities (OR 2.91 [1.86-4.56] versus 1.50 [1.05-2.15]) as predictors of postoperative complications. Administrative data correctly identified UC and colectomy in 85.9% of cases. The administrative database was 37% sensitive in identifying patients with ≥ 1Charlson comorbidity. Restricting analysis to active comorbidities increased the sensitivity to 63%. The sensitivity of identifying patients with at least one postoperative complication was 68%; restricting analysis to more severe complications improved the sensitivity to 84%. CONCLUSIONS: Administrative data identified the same risk factors for postoperative complications as chart review, but overestimated the magnitude of risk. This discrepancy may be explained by coding inaccuracies that selectively identifying the most serious complications and comorbidities.

Postoperative complications and mortality following colectomy for ulcerative colitis.

BACKGROUND & AIMS: Complications after colectomy for ulcerative colitis (UC) have not been well characterized in large, population-based studies. We characterized postoperative in-hospital complications, stratified them by severity, and assessed independent clinical predictors, including use of immunosuppressants. METHODS: We performed population-based surveillance using administrative databases to identify all adults (≥18 y) who had an International Classification of Diseases-9th/10th revisions code for UC and a colectomy from 1996 to 2009. All medical charts were reviewed. The primary outcome was severe postoperative complications, including in-hospital mortality. Logistic regression was used to assess predictors of complications after colectomy and then restricted to patients undergoing emergent or elective surgeries. RESULTS: Of the 666 UC patients who underwent a colectomy, a postoperative complication occurred in 27.0% and the mortality rate was 1.5%. Independent predictors of postoperative complications were age (for patients >64 vs 18-34 y: odds ratio [OR], 1.95; 95% confidence interval [CI], 1.07-3.54), comorbidities (>2 vs none: OR, 1.89; 95% CI, 1.06-3.37), and admission status (emergent vs elective colectomy: OR, 1.62; 95% CI, 1.14-2.30). Significant risk factors for an emergent colectomy included time from admission to colectomy (>14 vs 3-14 d: OR, 3.32; 95% CI, 1.62-6.80) and a preoperative complication (≥1 vs 0: OR, 3.04; 95% CI, 1.33-6.91). A prescription of immunosuppressants before colectomies did not increase the risk for postoperative complications. CONCLUSIONS: Postoperative complications frequently occur after colectomy for UC, predominantly among elderly patients with multiple comorbidities. Patients who were admitted to the hospital under emergency conditions and did not respond to medical treatment had worse outcomes when surgery was performed 14 or more days after admission.

The reconstitution of unfolded myoglobin with hemin dicyanide is not accelerated by fly-casting.

This study explores how the kinetics of a coupled folding/binding reaction depend on the initial conformation of the protein. Stopped-flow spectroscopy is used to monitor the reaction of apo-myoglobin (aMb) with hemin dicyanide at pH 7.2. Different initial aMb conformations are tested. In the case of acid-denatured aMb, the observed kinetics are consistent with a "fly-casting" scenario [Shoemaker et al., Proc. Natl. Acad. Sci. USA 97 (2000) 8868-8873]. However, the formation of a compact complex proceeds more rapidly in the case of prefolded aMb. This finding is opposite to what would be expected based on predictions of the fly-casting model.