Patient Age, Sex, and Inflammatory Bowel Disease Phenotype Associate With Course of Primary Sclerosing Cholangitis

BACKGROUND & AIMS

Primary sclerosing cholangitis (PSC) is an orphan hepatobiliary disorder associated with inflammatory bowel disease (IBD). We aimed to estimate the risk of disease progression based on distinct clinical phenotypes in a large international cohort of patients with PSC.

METHODS

We performed a retrospective outcome analysis of patients diagnosed with PSC from 1980 through 2010 at 37 centers in Europe, North America, and Australia. For each patient, we collected data on sex, clinician-reported age at and date of PSC and IBD diagnoses, phenotypes of IBD and PSC, and date and indication of IBD-related surgeries. The primary and secondary endpoints were liver transplantation or death (LTD) and hepatopancreatobiliary malignancy, respectively. Cox proportional hazards models were applied to determine the effects of individual covariates on rates of clinical events, with time-to-event analysis ascertained through Kaplan-Meier estimates.

RESULTS

Of the 7121 patients in the cohort, 2616 met the primary endpoint (median time to event of 14.5 years) and 721 developed hepatopancreatobiliary malignancy. The most common malignancy was cholangiocarcinoma (n = 594); patients of advanced age at diagnosis had an increased incidence compared with younger patients (incidence rate: 1.2 per 100 patient-years for patients younger than 20 years old, 6.0 per 100 patient-years for patients 21-30 years old, 9.0 per 100 patient-years for patients 31-40 years old, 14.0 per 100 patient-years for patients 41-50 years old, 15.2 per 100 patient-years for patients 51-60 years old, and 21.0 per 100 patient-years for patients older than 60 years). Of all patients with PSC studied, 65.5% were men, 89.8% had classical or large-duct disease, and 70.0% developed IBD at some point. Assessing the development of IBD as a time-dependent covariate, Crohn's disease and no IBD (both vs ulcerative colitis) were associated with a lower risk of LTD (unadjusted hazard ratio [HR], 0.62; P < .001 and HR, 0.90; P = .03, respectively) and malignancy (HR, 0.68; P = .008 and HR, 0.77; P = .004, respectively). Small-duct PSC was associated with a lower risk of LTD or malignancy compared with classic PSC (HR, 0.30 and HR, 0.15, respectively; both P < .001). Female sex was also associated with a lower risk of LTD or malignancy (HR, 0.88; P = .002 and HR, 0.68; P < .001, respectively). In multivariable analyses assessing the primary endpoint, small-duct PSC characterized a low-risk phenotype in both sexes (adjusted HR for men, 0.23; P < .001 and adjusted HR for women, 0.48; P = .003). Conversely, patients with ulcerative colitis had an increased risk of liver disease progression compared with patients with Crohn's disease (HR, 1.56; P < .001) or no IBD (HR, 1.15; P = .002).

CONCLUSIONS

In an analysis of data from individual patients with PSC worldwide, we found significant variation in clinical course associated with age at diagnosis, sex, and ductal and IBD subtypes. The survival estimates provided might be used to estimate risk levels for patients with PSC and select patients for clinical trials.

Mapping chronic liver disease questionnaire scores onto SF-6D utility values in patients with primary sclerosing cholangitis

PURPOSE

The chronic liver disease questionnaire (CLDQ) is a frequently used liver-specific quality of life instrument, but it does not provide information on preference-adjusted health status, which is essential for cost-utility analysis. We aimed to develop a mapping function deriving utilities from the CLDQ in primary sclerosing cholangitis (PSC).

METHODS

Short form-6D (SF-6D) utilities were calculated from SF-36 data collected in a recent prospective study in which unselected patients with PSC also completed the CLDQ. Ordinary least squares (OLS), generalized linear, median, and kernel regression analyses were employed to devise a mapping function predicting utilities. This was validated in three random subsamples of the cohort and in a separate sample of PSC patients following liver transplantation. Adjusted R (2) and root-mean-square error (RMSE) as well as Pearson's r coefficients and mean absolute errors between predicted and observed values were used to determine model performance.

RESULTS

Decompensated liver disease and fatigue, systemic symptoms, and emotional distress, assessed with the CLDQ, were related to worse SF-6D utilities. The final OLS prediction model explained 66.3 % of the variance in the derivation sample. Predicted and observed utilities were strongly correlated (r = 0.807, p < 0.001), but the mean absolute error (0.0604) and adjusted RMSE (10.6 %) were of intermediate size. Similar model characteristics were observed after employment of generalized linear and median regression models and at validation.

CONCLUSIONS

A model has been constructed, showing good validity predicting SF-6D utilities from CLDQ scores at the group level in PSC. Further testing is required to externally validate the model.

Association Between HLA Haplotypes and Increased Serum Levels of IgG4 in Patients With Primary Sclerosing Cholangitis

Increased serum levels of IgG4 have been reported in 9%-15% of patients with primary sclerosing cholangitis (PSC); it is not clear whether this increase contributes to pathogenesis. We performed genetic analyses of the HLA complex in patients with PSC from Norway, Sweden, and from the United States. We found an association between levels of IgG4 above the upper reference limit and specific HLA haplotypes. These patients had a significantly lower frequency of the strongest PSC risk factor, HLA-B*08, than patients without increased IgG4, and significantly higher frequencies of HLA-B*07 and HLA-DRB1*15. HLA genotype therefore might affect the serum concentration of IgG4, and increased IgG4 might be a marker of a distinct phenotype of PSC.

The impact of elevated serum IgG4 levels in patients with primary sclerosing cholangitis

BACKGROUND

Elevated IgG4 levels have been reported among patients with primary sclerosing cholangitis. Epidemiological data has only been provided from tertiary centres.

AIMS

To investigate the prevalence of elevated IgG4 levels and to compare prognosis between patients with and without elevated IgG4 levels in serum in two European cohorts of patients with primary sclerosing cholangitis.

METHODS

Serum IgG4-levels were measured in a consecutive series of patients from Berlin, and retrospectively collected in a population-based cohort from Sweden (total N=345). Cox's proportional hazard analysis was used to calculate relative risks for liver-related death or liver transplantation and cholangiocarcinoma.

RESULTS

Elevated IgG4 values were demonstrated in 10% of patients. A previous history of pancreatitis, combined intra- and extrahepatic biliary involvement and jaundice were independently associated with elevated IgG4 in multivariate analysis. IgG4 status was not associated with an increased risk for the combined endpoint liver-related death or liver transplantation or cholangiocarcinoma.

CONCLUSION

The prevalence of elevated IgG4 values among European patients with primary sclerosing cholangitis is similar to what previously has been reported from the United States. Elevated IgG4 was not associated with an increased risk of liver transplantation or liver-related death or cholangiocarcinoma.

Factors that reduce health-related quality of life in patients with primary sclerosing cholangitis

BACKGROUND & AIMS

Health-related quality of life (HRQL) is frequently reduced in patients with chronic liver disease, but there are limited data from patients with primary sclerosing cholangitis (PSC). We aimed to evaluate HRQL and its potential determinants in 2 population-based cohorts of patients with PSC and to study the prevalence of fatigue among these patients.

METHODS

Validated questionnaires were used to measure quality of life (the Short-Form 36 [SF-36] and the chronic liver disease questionnaire), fatigue (the fatigue impact scale), and psychological distress (the hospital anxiety and depression scale) in 182 PSC patients residing in Sweden or England. Results were compared with those from the general population (controls). Regression analysis was performed to identify factors independently associated with HRQL.

RESULTS

Patients with PSC had significantly lower scores from several areas of the SF-36, compared with controls (P < .05). Age (β = -0.62 to -0.21, P < .05) and systemic symptoms (β = 3.84-15.94, P < .05) such as pruritus were associated with lower scores from specific areas of the SF-36; serum level of alkaline phosphatase (β =-1.12 to -0.75, P < .05), and large-duct PSC (β = -15.35 to -10.05, P < .05) were associated with lower scores on mental health questionnaires. The proportion of patients with significant fatigue, depression, or anxiety did not differ between patients and controls (P > .05).

CONCLUSIONS

Quality of life is impaired in unselected patients with PSC. Fatigue does not seem to be a specific symptom of PSC. Older age, large-duct disease, and systemic symptoms seem to reduce HRQL in patients with PSC.

Mortality and cancer risk related to primary sclerosing cholangitis in a Swedish population-based cohort

BACKGROUND

Population-based studies on the epidemiology of primary sclerosing cholangitis (PSC) are sparse.

AIMS

To investigate mortality and risk of cancer, and to identify risk factors for hepatobiliary cancer and the combined end-point liver related death or liver transplantation (OLT) in a population-based PSC cohort in Västra Götaland, Sweden.

METHODS

Primary sclerosing cholangitis cases were identified in diagnostic registries. Case validation and follow up was provided through individual review of case files and linkage to the Swedish Cancer and Cause of Death registries. Standardized mortality ratio (SMR) and standardized incidence ratio (SIR) for cancer were calculated in relation to the background population. Cox's proportional hazards analysis was used to calculate crude and adjusted relative risks (RRs).

RESULTS

A total of 199 PSC patients were identified between 1992 and 2005. SMR in the PSC cohort was 4.20 (95% confidence interval (CI), 3.01-5.69). SIR for hepatobiliary cancer, cholangiocarcinoma and colorectal cancer were 177 (110-271), 868 (505-1390) and 2.87 (0.33-10.4) respectively. Age (RR=1.25 (1.01-1.53) per decade), female gender (RR=2.01 (1.09-3.72)), cholangitis (RR=2.56 (1.20-5.64)) and bilirubin (RR=3.95 (1.96-10.75) highest vs lowest quartile) were associated with the risk of liver related death or OLT. Age was associated with the risk of hepatobiliary cancer (RR 1.40 (1.01-1.95) per decade).

CONCLUSIONS

Primary sclerosing cholangitis was associated with a four-fold increase in mortality in this population-based study. In accordance with previous studies, the risk of hepatobiliary cancer was dramatically increased. However, the increased risk of colorectal cancer reported in previous studies could not be confirmed.

Incidence and prevalence of primary sclerosing cholangitis in a defined adult population in Sweden

Population-based studies on the epidemiology of primary sclerosing cholangitis (PSC) are sparse. The aim of the present study was to investigate prevalence and temporal trends in the incidence of PSC 1992-2005 in an adult population in Västra Götaland, a region in southern Sweden with a defined population of about 1.5 million. Patients with PSC aged 18 years or above were identified through a computerized search for diagnostic codes. A total number of 199 incident cases fulfilling Mayo criteria for PSC were identified through retrospective validation of clinical records. Temporal trends in the incidence of PSC were investigated by Poisson regression and expressed as average annual percent change (AAPC) with a 95% confidence interval (CI). The point prevalence of PSC on December 31, 2005, was 16.2/100,000 in the total adult population (men, 23.7/100,000; women, 8.9/100,000). The annual incidence was 1.22/100,000 in the total adult population (men, 1.78/100,000; women, 0.69/100,000). The overall incidence rate of PSC increased significantly over the investigation period (AAPC 3.06, 95% CI 0.01-6.20). Stratified analysis revealed significantly increasing trends for inflammatory bowel disease (IBD)-associated PSC (AAPC 7.01, 95% CI 0.24-14.24) and large duct PSC (AAPC 6.32, 95% CI 0.03-13.02) in women and for PSC without IBD (AAPC 9.69, 95% CI 0.82-19.33) and small duct PSC (AAPC 17.88, 95% CI 0.95-40.25) in men.

CONCLUSION

This is the first study to report a significantly increasing trend in the incidence of PSC. The prevalence of PSC at the end of the study period is the highest reported to date. This implies that the medical burden of PSC may be higher than estimated previously.