A211 INCIDENCE OF PRIMARY SCLEROSING CHOLANGITIS: A META-ANALYSIS OF POPULATION-BASED STUDIES

Background

Primary sclerosing cholangitis (PSC) is a chronic liver disease associated with significant morbidity, mortality and healthcare utilization. Understanding the incidence of PSC is important in defining the burden of disease and planning for allocation of healthcare resources.

Aims

To conduct a systematic review and meta-analysis of population-based studies of the incidence of PSC and to assess temporal trends of incidence overtime.

Methods

Medline and Embase (from inception to May 10, 2021) were systematically searched to identify studies via the following inclusion criteria: 1) original articles, 2) population-based study of defined geographic area, 3) reported the incidence of PSC or provided data to calculate the incidence of PSC. Studies that assessed specific populations (e.g., pediatric-only, IBD-only) or reported less than 1 year of data were excluded. Abstracts and full texts were reviewed for inclusion and data was extracted independently in duplicate by two individuals (JC, AM). Meta-analyses were performed to calculate overall and country-specific incidence rates (per 100,000 persons) with 95% confidence intervals (CI). Meta-regression calculated the Average Annual Percentage Change (AAPC) of PSC incidence rates overtime.

Results

The initial search returned 3,958 abstracts. After duplicates were removed, abstracts (3,443) were screened, and full texts were reviewed (317), 17 studies met the criteria for inclusion and underwent data extraction. Meta-analysis included 6 studies with annual data contributing to the calculation of AAPC. Studies originated from 10 countries from North America, Europe, and Oceania; however, no population-based studies were published in Asia, Africa, or Latin America (Figure 1). Overall, the incidence rates of PSC was 0.82 per 100,000 (95% CI: 0.62, 1.02) (Figure 1). Incidence rates of PSC were significantly increasing overtime (AAPC: 4.56%; 95% CI: 0.45, 8.68).

Conclusions

The incidence of PSC is low at 0.82 per 100,000 but has been significantly increasing over time. Future studies on the incidence of PSC should be directed at Asia, Africa of Latin America to assess the global epidemiology of PSC.

Figure 1: Pooled incidence rate estimates of PSC per 100,000 person-years at risk.

Funding Agencies

None

A202 IMPACT OF THE COVID-19 PANDEMIC ON THE EPIDEMIOLOGY OF ALCOHOL-RELATED HEPATITIS

Background

Alcohol-related hepatitis (AH) is the most severe form of alcohol-related liver disease, with rising incidence. Stay-at-home orders for the COVID-19 pandemic were associated with increased alcohol consumption. Online sales reported a 262% increase from March 2019 to 2020.

Aims

The purpose of this study was to track the epidemiology of hospitalizations for AH by sex before and after the COVID-19 pandemic. We hypothesized that AH would be more severe in females and younger individuals during the pandemic.

Methods

Using the Discharge Abstract Database, we identified all hospitalizations in Alberta with international classification of disease-10 codes for AH between March 2018 and September 2020. We merged this dataset with provincial laboratory data to identify all inpatient lab values. We calculated Model for End-Stage Liver Disease (MELD) and Maddrey scores and validated a laboratory-based algorithm for AH. Severe AH was defined as Maddrey score > 32. Onset of the pandemic was defined as March 2020. Stratified by pandemic onset, descriptive statistics were done with Chi-squared and Kruskal Wallis tests. Inpatient mortality was assessed as a primary outcome. Binomial regression was used to assess changes in frequency of admission for AH with the denominator as all cirrhosis-related admissions over the same time-period.

Results

We identified 991 hospitalizations for AH prior to the pandemic (n=381, 38.5% female) and 417 during the pandemic (n=144, 34.5% female). Hospitalizations for AH significantly increased during the pandemic (p = 0.04) (Figure 1). Median Maddrey score for females (30.5) before the pandemic was significantly higher than for males (22.9), p < 0.01. During the pandemic, median Maddrey for females (28.7) was higher than males 21.4, p = 0.07. Median age at admission was significantly lower for both males and females during the pandemic (age 44 and 41, respectively) as compared to prior (age 47 and 45, respectively) p < 0.05. There was no significant difference in MELD between sexes before (13.5 for females, 14.0 for males, p = 0.15) and during the pandemic (13.3 for females, 13.0 for males, p = 0.75). Additionally, there was no significant difference in mortality between sexes before (10.4% in females, 11.5% in males, p = 0.22) and after the pandemic (9.2% in females, 9.9% in males, p = 0.67).

Conclusions

Hospitalizations for AH rose during the pandemic and occurred at younger ages. There was no significant difference in disease severity or mortality before and during the pandemic. Overall, females have more severe AH than males. Public health efforts should continue to be made to educate about the harms of alcohol excess and offer community support. Future studies will expand the trend through multiple pandemic waves.

Funding Agencies

None

A141 ENDOSCOPIST PROCEDURAL VOLUME AND COLONOSCOPY OUTCOMES: A SYSTEMATIC REVIEW AND META-ANALYSIS

Background

In addition to monitoring adverse events (AEs) and post-colonoscopy colorectal cancers (PCCRC), several indicators are used to assess the overall quality of colonoscopy performance, including adenoma detection rate (ADR) and cecal intubation rate (CIR). It is unclear whether there is an association between an endoscopist’s annual colonoscopy volumes and ADR, CIR, AEs or PCCRC.

Aims

We performed a systematic review and meta-analysis to determine whether there is an association between annual colonoscopy volume and colonoscopy quality indicators, or between annual volume and colonoscopy outcomes.

Methods

A comprehensive electronic search was performed through March of 2019 for any studies assessing the potential association between annual colonoscopy volume and outcomes, or quality indicators, including ADR, CIR, AEs or PCCRC. Pooled odds ratios (OR) were calculated using DerSimonian and Laird random effects models. Subgroup and sensitivity analyses were also performed to assess for any potential methodological or clinical factors associated with outcomes. These included dividing procedural volume into total procedures or screening procedures performed.

Results

Out of an initial 9,235 studies, 27 were included in our systematic review, representing 11,276,244 colonoscopies performed by over 530 endoscopists. There was no association between procedural volume and ADR (OR 1.00, 95% confidence intervals, CI, 0.98 to 1.02 per additional 100 annual total colonoscopy procedures performed by an endoscopist). CIR was improved with each additional 100 annual colonoscopy procedures (OR 1.17, 95% CI 1.08 to 1.28). There was a trend toward decreased overall adverse events per additional 100 annual procedures that did not meet significance (OR 0.95, 95% CI 0.90 to 1.00), although there was a decreased incidence of colonic perforations with increasing colonoscopy volume. Figure 1 - Forest plots demonstrating the odds of A) detecting an adenoma, B) intubating the cecum, and C) incurring an overall or specific adverse event, per additional 100 annual procedures, for total and screening procedures.

Conclusions

In this meta-analysis, higher annual colonoscopy volumes correlated with higher CIR, but not with ADR or PCCRC. Trends toward lower AE rates were also demonstrated with higher volumes. All studies included in this review examined endoscopists performing above respective recommended minimum volume thresholds for their health region. Thus, data are lacking on endoscopists performing very low numbers or very high numbers of colonoscopies annually. Future studies should focus on measuring colonoscopy quality metrics and outcomes among these extreme performers to more clearly determine associations between annual volume and colonoscopy outcomes.

Funding Agencies

Alberta Health Services Digestive Health Strategic Care Network

A62 CANADIAN POPULATION-BASED EVALUATION OF THE NATURAL HISTORY OF PRIMARY BILIARY CHOLANGITIS OVER THE LAST DECADE

Background

Few studies have evaluated the epidemiology of primary biliary cirrhosis (PBC) in North America. Ursodeoxycholic acid (URSO) improves outcomes amongst PBC patients.

Aims

Therefore, we undertook this study to determine the epidemiology of PBC in Canada, and impact of URSO on clinical outcomes, two decades after URSO approval in North America.

Methods

We used our previously validated coding algorithm to identify PBC patients in population based administrative databases in the Calgary Health Zone (population ~1.5 million) from 2005–2015. Multiple sources of data including inpatient, ambulatory, physician billing, laboratory, and pharmaceutical were linked. Annual prevalence and incidence were estimated using Poisson regression. Age/sex adjusted rate ratios were calculated. We used Cox regression models to estimate: all-cause mortality, liver transplant and decompensated cirrhosis free survival. In our models, we adjusted for demographic and clinical variables including response to URSO.

Results

During the study period over 11 years, the overall annual age/sex adjusted PBC incidence was 29.5 cases per million (48.3 and 9.9 per million for women and men, respectively). The highest incidence rate was observed among women aged 60–79 (90.9 per million) with an incidence rate ratio of 10.4 (95%: 6.83–15.9) compared to those aged 20–39. While incidence rate remained stable, prevalence rate increased significantly from 242 to 343 cases/ million, between 2005 and 2015 (P&lt;0.01). Prevalence rate was highest at 965 cases/ million amongst women aged 60–79. We identified 299 incident PBC cases with a median follow up of 5.1 years (IQR 2.9–8.3). 87 (29.1%) of these incident cases developed decompensated cirrhosis or HCC, 10 patients (3.4%) underwent liver transplantation, and 44 (14.7%) patients died. The annual mortality rate was 2.9% (95%CI: 2.1- 3.8) compared to 3.4% (2.3–4.9%) a decade ago (P=0.04). The estimated 5-year survival rate was 87.6% (82.6- 91.3). Standardized mortality rate was 3.2 (95%CI: 2.2–4.1). Overall, 25% of our incident cohort were not prescribed URSO. Patients not prescribed URSO were more likely to be male, older age, have normal ALP and had decompensated cirrhosis at diagnosis (P&lt;0.01 for all). Among those who used URSO, response rate was 86%. Response to URSO was an independent predictor of reduced risk of decompensated cirrhosis and liver transplant, and higher survival (aHR: 0.46, 0.29–0.74).

Conclusions

PBC prevalence is increasing in this North American population. While mortality rate decreases in our PBC cohort, survival was suboptimal compared to the general population, mainly due to late presentation at diagnosis. Therefore, better surveillance and early detection of possible PBC patients in the primary care setting are essential to improve PBC outcomes.

Funding Agencies

None

Patient, visitor, and nurse evaluations of visitation for adult postanesthesia care unit patients

Although PACU visitation for children is sometimes encouraged, most families of adult postoperative patients continue to be excluded from PACUs in this country. At an academic medical center, an open visitation policy for adult postoperative patients was evaluated by eliciting patient, visitor, and nurse evaluations of visitation for adult patients from 181 families. Commonly cited reasons for restricting PACU visitation were not identified as problems by the vast majority of respondents. Even when some aspect of a PACU visit was disturbing, patients and families expressed a desire for visitation. The results of this evaluation of a change in practice led to permanent implementation of an open visitation policy in this PACU.

Expression of the genes encoding the rat renal insulin-like growth factor-I system

Insulin-like growth factor-I (IGF-I) modulates renal function, growth, and repair. IGF-I produced in the kidney is one component of the intrarenal IGF-I system comprising the IGF-I receptor (IGF-IR) and six IGF-binding proteins (IGFBP). Because of the physiologic importance of IGF-I and its potential therapeutic properties, the renal sites of mRNA synthesis for IGF-I, IGF-IR, and IGFBP-I through IGFBP-5 were characterized in rat kidney by in situ hybridization. Anatomical heterogeneity was prominent. IGF-I mRNA was present in the thick ascending limb of Henle in the outer medulla, whereas IGF-IR mRNA was diffusely present at low levels throughout the kidney. IGFBP-I mRNA was localized to cells within the distal convoluted tubules as well as the thick ascending limb of Henle. IGFBP-2 mRNA was expressed in glomeruli, medullary ray collecting ducts, pelvic smooth muscle and uroepithelium, and the papilla tip; IGFBP-3 mRNA was localized to the cortical interstitium, whereas IGFBP-4 mRNA was expressed in proximal tubules, medullary ray collecting ducts, and glomeruli. IGFBP-5 was strongly positive throughout the medulla with lesser expression in the distal convoluted tubules and glomeruli. This study highlights the complexity of the intrarenal IGF-I system. The striking heterogeneity of IGFBP gene expression suggests that the various IGFBP may have diverse modulatory effects on the action of IGF-I or discrete effects of their own.

Radio-immuno assay estimation of plasma endothelin levels in patients with bilharzial and post viral liver cirrhosis: a possible new additive factor in aggravation of portal hypertension

Radio immunoassay estimation of plasma endothelin level was carried out in 90 patients with bilharzial and post viral chronic liver diseases with portal hypertension associated with bleeding and non bleeding oesophageal varices as well as 10 normal control subjects. It was found that plasma endothelin level was significantly elevated in such patients when compared to normal controls. Moreover, there was a positive correlation between the elevated levels of plasma endothelin and portal vein diameter as well as bleeding oesophageal varices. It may be concluded that plasma endothelin, which is a very potent vasoconstrictor for both systemic and portal circulation, plays an important role in aggravation of portal hypertension in liver cirrhosis.

The effects of an atherogenic diet on macrophage/biomaterial interactions

We previously reported that biomaterials differentially induced macrophages to secrete growth factors that mediate reendothelialization. The present study evaluates the effect of an atherogenic diet on macrophage/biomaterial interactions. Female New Zealand white rabbits were fed an atherogenic diet. Peritoneal macrophages were harvested from these as well as rabbits fed a normal diet and cultured in Minimum Essential Medium with platelet-poor serum. Dacron or polyglactin 910 were added to two of three conditions of both cell groups in passage 2. Conditioned media were collected weekly through week 15. Mitogenicity assays were performed with quiescent mouse embryonal (BALB/c3T3) fibroblasts, atherosclerotic rabbit aortic smooth muscle cells, and murine capillary lung (LE-II) endothelial cells. Mitogenic activity was assayed by scintillation counting of tritiated thymidine incorporation into deoxyribonucleic acid (DNA). Results showed increased mitogenic activity released by macrophages from atherosclerotic rabbits, in the absence of prosthetic material, when assayed against every cell line. In normal diet macrophages, polyglactin 910 stimulated mitogen release for every cell line, and Dacron yielded minimal mitogen release. In lipid diet macrophages polyglactin 910 slightly increased mitogen release for all three cell lines, whereas Dacron resulted in stimulation of DNA synthesis in smooth muscle cells and BALB/c3T3 cells but less DNA synthesis in LE-II cells than in control, no graft material, media. Western blotting demonstrated immunoreactivity to basic fibroblast growth factor in media from normal diet macrophages but only in the presence of polyglactin 910 or Dacron. Radioimmunoassay for platelet-derived growth factor B chain was negative in all groups, and polymerase chain reaction techniques to amplify transforming growth factor-beta messenger ribonucleic was negative. These data demonstrate the effect of in vivo dietary manipulation on macrophage activation as well as the effect of an atherogenic diet in modulating macrophage/biomaterial interactions. Additionally, different biomaterials differentially induce macrophages to release factors that stimulate and inhibit growth.

Structure-function studies of heparin-binding (acidic fibroblast) growth factor-1 using site-directed mutagenesis

The heparin-binding or fibroblast growth factors (HBGFs) modulate cell growth and migration, angiogenesis, wound repair, neurite extension, and mesoderm induction. Relatively little is known regarding the precise mechanism of action of these growth factors or the structural basis for their action. A better understanding of the structural basis for the different activities of these proteins should lead to the development of agonists and antagonists of specific HBGF activities. In this report, we summarize evidence that indicates that the heparin-binding and mitogenic activities of HBGF-1 can be dissociated from the receptor-binding activities of the growth factor by site-directed mutagenesis of a single lysine residue. Thus, the mutant HBGF-1 has normal receptor-binding activity and is capable of stimulating tyrosine kinase activity and proto-oncogene expression but is not able to elicit a mitogenic response. A similar dissociation of early events such as proto-oncogene expression from the mitogenic response is observed when the human wild-tupe HBGF-1 is used in the absence of added heparin. These results indicate that intracellular sites of action by the growth factor may be required to complete the mitogenic response. Further evidence for this idea is provided by transfection experiments where NIH 3T3 cells are engineered to produce large quantities of wild-type or mutant HBGF-1. Production of wild-type induces a transformed phenotype, whereas over-production of the mutant does not. The majority of both forms of the protein is found in the nuclear fraction of the transfected cells. Additional site-directed mutagenesis of putative nuclear translocation sequences in the wild-type protein do not affect mitogenic activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Possible dissociation of the heparin-binding and mitogenic activities of heparin-binding (acidic fibroblast) growth factor-1 from its receptor-binding activities by site-directed mutagenesis of a single lysine residue

The fibroblast or heparin-binding growth factors (HBGFs) are thought to be modulators of cell growth and migration, angiogenesis, wound repair, neurite extension, and mesoderm induction. A better understanding of the structural basis for the different activities of these proteins should facilitate the development of agonists and antagonists of specific HBGF activities and identification of the signal transduction pathways involved in the mechanisms of action of these growth factors. Chemical modification studies of Harper and Lobb (Harper, J. W., and R. R. Lobb. 1988. Biochemistry. 27:671-678) implicated lysine 132 in HBGF-1 (acidic fibroblast growth factor) as being important to the heparin-binding, receptor-binding, and mitogenic activities of the protein. We changed lysine 132 to a glutamic acid residue by site-directed mutagenesis of the human cDNA and expressed the mutant protein in Escherichia coli to obtain sufficient quantities for functional studies. Replacement of this lysine with glutamic acid reduces the apparent affinity of HBGF-1 for immobilized heparin (elutes at 0.45 M NaCl vs. 1.1 M NaCl for wild-type). Mitogenic assays established two points: (a) human recombinant HBGF-1 is highly dependent on the presence of heparin for optimal mitogenic activity, and (b) the change of lysine 132 to glutamic acid drastically reduces the specific mitogenic activity of HBGF-1. The poor mitogenic activity of the mutant protein does not appear to be due to a reduced affinity for the HBGF receptor. Similarly, the mutant HBGF-1 can stimulate tyrosine kinase activity and induce protooncogene expression. Differences in the biological properties of the wild-type and mutant proteins were observed in transfection studies. Mutant HBGF-1 expression in transfected NIH 3T3 cells did not induce the same transformed phenotype characteristic of cells expressing wild-type HBGF-1. Together these data indicate that different functional properties of HBGF-1 may be dissociated at the structural level.