Cynthia W. Ko

Complications of Colonoscopy: Magnitude and Management

Although complications of colonoscopy are rare, they are potentially serious and life threatening. In addition, less serious adverse events may occur frequently and may have an impact on a patients willingness to undergo future procedures. This article reviews the magnitude of and risk factors for major and minor colonoscopy complications, discusses management of complications, and suggests ways to design quality improvement programs to reduce the risk of complications.

Persistent demographic differences in colorectal cancer screening utilization despite Medicare reimbursement.

BackgroundColorectal cancer screening is widely recommended, but often under-utilized. In addition, significant demographic differences in screening utilization exist. Insurance coverage may be one factor influencing utilization of colorectal cancer screening tests.MethodsWe conducted a retrospective analysis of claims for outpatient services for Washington state Medicare beneficiaries in calendar year 2000. We determined the proportion of beneficiaries utilizing screening fecal occult blood tests, flexible sigmoidoscopy, colonoscopy, or double contrast barium enema in the overall population and various demographic subgroups. Multiple logistic regression analysis was used to determine the relative odds of screening in different demographic groups.ResultsApproximately 9.2% of beneficiaries had fecal occult blood tests, 7.2% had any colonoscopy, flexible sigmoidoscopy, or barium enema (invasive) colon tests, and 3.5% had invasive tests for screening indications. Colonoscopy accounted for 41% of all invasive tests for screening indications. Women were more likely to receive fecal occult blood test screening (OR 1.18; 95%CI 1.15, 1.21) and less likely to receive invasive tests for screening indications than men (OR 0.80, 95%CI 0.77, 0.83). Whites were more likely than other racial groups to receive any type of screening. Rural residents were more likely than urban residents to have fecal occult blood tests (OR 1.20, 95%CI 1.17, 1.23) but less likely to receive invasive tests for screening indications (OR 0.89; 95%CI 0.85, 0.93).ConclusionReported use of fecal occult blood testing remains modest. Overall use of the more invasive tests for screening indications remains essentially unchanged, but there has been a shift toward increased use of screening colonoscopy. Significant demographic differences in screening utilization persist despite consistent insurance coverage.

Fecal occult blood testing in a general medical clinic: comparison between guaiac-based and immunochemical-based tests

PURPOSE Guaiac-based fecal occult blood tests are limited by poor patient compliance, and low sensitivity, specificity, and positive predictive value. Newer immunochemical-based tests are designed to improve accuracy and patient compliance. We compared patient compliance and the test characteristics of these two types of tests. METHODS The laboratory outcomes associated with use of different fecal occult blood tests were examined in a Veterans Affairs-based general medicine clinic that was divided into two firms with similar patient and provider characteristics. Tests were ordered for colorectal cancer screening or for symptom evaluation. Patients were given one of the two tests depending on their firm. The completion and positivity rates, time to test completion, completion of diagnostic follow-up, and positive predictive values were compared. RESULTS The percentage of returned test cards was similar between the two groups (47% [1369/2964] for guaiac-based tests vs. 48% [1410/2965] for immunochemical-based tests) as was the positivity rate (9.0% [122/1396] and [128/1410] for both groups). In patients with positive tests who underwent further colon evaluation, the proportion with adenomas was similar between groups (59% [38/64] vs. 58% [40/69]). However, 17% (12/69) with a positive immunochemical-based test had an adenoma >1 cm or a colorectal malignancy, versus 30% (19/64) for guaiac-based tests (P = 0.09). CONCLUSION Overall, immunochemical-based and guaiac-based fecal occult blood tests had comparable performance. However, although immunochemical-based testing is reported to be easier for patients than guaiac-based testing, we found that patients were no more likely to return cards for analysis. The similar positive predictive value and additional cost of immunochemical-based tests call into question their utility in general practice.

Risk factors for gallstone-related hospitalization during pregnancy and the postpartum.

OBJECTIVES:Gallbladder disease is a leading nonobstetrical cause for hospitalization in the first year postpartum. The aim of this study was to define the incidence and risk factors for postpartum hospitalization as a result of gallstone-related disease.METHODS:We identified 6,670 women with discharge diagnoses related to biliary disease from linked birth certificate and hospital discharge databases for Washington State from 1987 through 2001. Cases were women with gallstone-related diagnoses at delivery or as primary diagnosis in the postpartum. Four controls who were within 1 yr postpartum were randomly selected for each case and matched for year of delivery. From the birth certificates, we obtained data about patient demographics, reproductive history, and pregnancy-related risk factors. In a retrospective case-control study, we developed multiple logistic regression models to identify independent risk factors for hospitalization.RESULTS:We identified 6,211 women as cases (0.5% of all births) during the study period. The median time to hospitalization was 95 days (interquartile range 46–191 days), with a median length of stay of 3 days. Seventy-six percent were diagnosed with uncomplicated cholelithiasis, 16% with pancreatitis, 9% with acute cholecystitis, and 8% with cholangitis. Seventy-three percent of hospitalized women underwent cholecystectomy, and 5% underwent endoscopic retrograde cholangiopancreatography (ERCP). On multivariate analysis, independent risk factors for hospitalization included maternal race, age, being overweight or obese prepregnancy, pregnancy weight gain, and estimated gestational age.CONCLUSIONS:Hospitalization for gallstone-related disease is common in the first year postpartum, most commonly for uncomplicated cholelithiasis. Risk factors for hospitalization include prepregnancy body mass index, race, Hispanic ethnicity, and maternal age.

Gallstone formation: Local factors

Bile supersaturation is necessary for cholesterol gallstones to form. Not all people with supersaturated bile form gallstones, however, and additional factors must be present. The role of pronucleating substances has been extensively studied. Of these, proteins, especially mucin, are best understood. Mucin is secreted by the gallbladder epithelium and may act as a nidus for crystal nucleation. Other proteins that may act as pronucleators include alpha 1-acid glycoprotein, alpha 1-antichymotrypsin, phospholipase C, and a small calcium binding protein. The role of antinucleating factors is less well understood. Certain drugs, including octreotide and ceftriaxone, may also predispose to stone formation. Another local factor is gallbladder stasis, a well-known risk factor for pigment stone formation. More recent research has focused on the role of bacterial infection, which has long been believed to be a factor in pigment gallstone formation. Newer data also support a role for infection in cholesterol gallstone pathogenesis. Additionally, genetic factors that may predispose a patient to cholesterol gallstones have been identified in mice and in humans.

Specialty differences in polyp detection, removal, and biopsy during colonoscopy.

BACKGROUND Colonoscopy is a technically complex procedure commonly performed to detect and remove colorectal pathology. This study examined the influence of provider characteristics on polyp detection, polyp removal, and diagnostic biopsy rates. METHODS We conducted a retrospective cross-sectional study using a 20% sample of 2003 Medicare claims. Primary outcome measures were use of diagnostic biopsy, polyp detection, and polyp removal. We used generalized estimating equations to identify independent predictors of the outcomes, adjusting for patient and provider characteristics. RESULTS Among 328,167 outpatient colonoscopies, polyp detection and removal rates were significantly lower for nongastroenterologists than gastroenterologists, with adjusted relative risk for polyp detection between 0.80 (95% confidence interval [CI], 0.77-0.83) for general surgeons and 0.93 (95% CI, 0.89-0.98) for internists. Compared with gastroenterologists, diagnostic biopsy was significantly less likely for general (relative risk [RR] 0.69; 95% CI, 0.65-0.74) or colorectal surgeons (RR 0.58; 95% CI, 0.52-0.65). The likelihood of polyp detection and removal was higher for physicians in the middle 2 quartiles of annual colonoscopy volume, but similar for physicians in the highest and lowest volume quartiles. Polyp detection and removal were significantly less likely for examinations in ambulatory surgery centers or offices than hospital outpatient settings, while diagnostic biopsy was significantly less likely in office settings. CONCLUSIONS Physician specialty, annual colonoscopy volume, and site of service are significant predictors of polyp detection, polyp removal, and diagnostic biopsy. These findings may have important implications for the effectiveness of colonoscopy.

Severe gastrointestinal bleeding after hematopoietic cell transplantation, 1987-1997: incidence, causes, and outcome.

Severe gastrointestinal bleeding after hematopoietic cell transplantation, 1987–1997: incidence, causes, and outcome

Racial discrepancies in the association between paternal vs. maternal educational level and risk of low birthweight in Washington State

BackgroundThe role of paternal factors in determining the risk of adverse pregnancy outcomes has received less attention than maternal factors. Similarly, the interaction between the effects of race and socioeconomic status (SES) on pregnancy outcomes is not well known. Our objective was to assess the relative importance of paternal vs. maternal education in relation to risk of low birth weight (LBW) across different racial groups.MethodsWe conducted a retrospective population-based cohort study using Washington state birth certificate data from 1992 to 1996 (n = 264,789). We assessed the associations between maternal or paternal education and LBW, adjusting for demographic variables, health services factors, and maternal behavioral and obstetrical factors.ResultsPaternal educational level was independently associated with LBW after adjustment for race, maternal education, demographic characteristics, health services factors; and other maternal factors. We found an interaction between the race and maternal education on risk of LBW. In whites, maternal education was independently associated with LBW. However, in the remainder of the sample, maternal education had a minimal effect on LBW.ConclusionsThe degree of association between maternal education and LBW delivery was different in whites than in members of other racial groups. Paternal education was associated with LBW in both whites and non-whites. Further studies are needed to understand why maternal education may impact pregnancy outcomes differently depending on race and why paternal education may play a more important role than maternal education in some racial categories.

Biliary Sludge Is Formed by Modification of Hepatic Bile by the Gallbladder Mucosa

BACKGROUND & AIMS We studied 22 patients with symptomatic microlithiasis to determine whether a contributory role of the gallbladder in the early stage of cholesterol gallstone formation exists. We compared the merits of different methods (ultrasonography and microscopy) and sources (hepatic or gallbladder) of bile samples for diagnosing microlithiasis. METHODS Paired hepatic and gallbladder bile samples were studied with polarizing microscopy. Nucleation time, bile salts, phospholipid, cholesterol, cholesterol saturation index (CSI), bilirubin, total protein, albumin and mucin concentration were measured. All patients had abdominal ultrasound examination. RESULTS With polarizing microscopy as the standard, ultrasonography was positive in 13 patients (59%) and negative in 9 (41%). All gallbladder bile samples were positive for microlithiasis by microscopy. Only one hepatic bile sample was positive (P < .0001). There was a disproportional enrichment of total protein, albumin, and mucin (P < .05) in the gallbladder bile and a conversion of bilirubin diglucuronide to monoglucuronide (P < .01). Gallbladder samples had lower CSI but a faster nucleation time (P < .001), which correlates inversely with CSI, total protein, and mucin concentration. CONCLUSION Biochemical composition and physical chemical behavior of hepatic bile are modified during residence in the gallbladder, contributing to sludge formation. Gallbladder bile has a lower calculated CSI, higher deconjugation of bilirubin, protein and mucin concentration and crystals were present. Hepatic bile samples are inappropriate for microscopic detection of microlithiasis.

Physician specialty and the outcomes and cost of admissions for end-stage liver disease

OBJECTIVES: Chronic liver disease is a frequent cause of morbidity and mortality. The aim of this study was to characterize the effects of physician specialty on length of stay, mortality, and costs during hospitalizations for end-stage liver disease. METHODS: We used data from the HBS International EXPLORE database. Patients hospitalized for treatment of variceal hemorrhage, spontaneous bacterial peritonitis, or hepatic encephalopathy were identified from primary discharge diagnoses. Patients were characterized by the specialty of the attending physician and by whether a gastroenterology consultation was obtained. Procedures performed were identified using ICD-9CM procedure codes. Costs were computed using proprietary HBS International Standard Transaction Codes. Linear and logistic regression analyses were used to examine the effect of physician specialty and consultation on length of stay, in-hospital mortality, and costs. RESULTS: Attending gastroenterologist care was associated with a shorter length of stay compared to nongastroenterologist attending care (median 4 vs 5 days, p = 0.01), which persisted after adjustment for differences in patient age, comorbidity, and number of procedures performed. There was a strong trend toward greater in-hospital mortality for patients without a gastroenterology attending or consultant (adjusted OR 1.72; 95% CI = 0.99, 2.98) compared to patients with a gastroenterology attending. Costs of hospital care were not significantly different between physician groups. CONCLUSIONS: Gastroenterologist involvement in inpatient care for end-stage liver disease was associated with shorter length of stay and a strong trend toward improved survival. Hospital costs were similar for patients cared for by the different physician groups.