Development of a decision support tool to facilitate primary care management of patients with abnormal liver function tests without clinically apparent liver disease [HTA03/38/02]. Abnormal Liver Function Investigations Evaluation (ALFIE)

Real-World Primary Care Data Comparing ALT and FIB-4 in Predicting Future Severe Liver Disease Outcomes

BACKGROUND

Alanine aminotransferase (ALT) has long provided a cue for chronic liver disease (CLD) diagnostic evaluation, but the Fibrosis-4 Index (FIB-4), a serologic score used for predicting advanced fibrosis risk in CLD, may provide an alternative signal.

OBJECTIVE

Compare the predictive performance of FIB-4 with ALT for severe liver disease (SLD) events while adjusting for potential confounders.

DESIGN

Retrospective cohort study of primary care electronic health record data from 2012 to 2021.

PATIENTS

Adult primary care patients with at least two sets of ALT and other lab values necessary for calculating two unique FIB-4 scores, excluding those patients with an SLD prior to their index FIB-4 value.

MAIN MEASURES

The occurrence of an SLD event, a composite of cirrhosis, hepatocellular carcinoma, and liver transplantation, was the outcome of interest. Categories of ALT elevation and FIB-4 advanced fibrosis risk were the primary predictor variables. Multivariable logistic regression models were developed to evaluate the association of FIB-4 and ALT with SLD, and the areas under the curve (AUC) for each model were compared.

KEY RESULTS

The cohort of 20,828 patients included 14% with an abnormal index ALT (≥40 IU/L) and 8% with a high-risk index FIB-4 (≥2.67). During the study period, 667 (3%) patients suffered an SLD event. Adjusted multivariable logistic regression models demonstrated an association between high-risk FIB-4 (OR 19.34; 95%CI 15.50-24.13), persistently high-risk FIB-4 (OR 23.85; 95%CI 18.24-31.17), abnormal ALT (OR 7.07; 95%CI 5.81-8.59), and persistently abnormal ALT (OR 7.58; 95%CI 5.97-9.62) with SLD outcomes. The AUC of the index FIB-4 (0.847, p < 0.001) and combined FIB-4 (0.849, p < 0.001) adjusted models exceeded the index ALT adjusted model (0.815).

CONCLUSIONS

High-risk FIB-4 scores demonstrated superior performance compared to abnormal ALT in predicting future SLD outcomes.

How to interpret and manage abnormal liver blood test results in older people

Ageing impairs liver function and reduces the liver's regenerative capacity. With the predicted increase in the older population, the burden of liver disease will proportionally rise in this age group. Elevated levels of liver enzymes in an otherwise asymptomatic older individual (≥65 years) are a common observation and positively associated with the metabolic syndrome, whereas a decline in albumin levels is linked with a rise in all-cause and liver-specific mortality. Deranged liver function tests do not always indicate liver disease, nor do normal liver function tests exclude liver disease. Therefore, clinicians need to consider individual patient risk factors during the assessment of abnormal liver function tests. This article discusses various liver function tests, their pathophysiology, and the approach to interpret and manage common abnormalities in liver function test results and liver disease in the older population.

Clinical Ontologies Improve Case Finding of Primary Biliary Cholangitis in UK Primary and Secondary Care

INTRODUCTION

PBC registries in the UK focus on data from secondary care without clear coordinated contribution from primary care. The Royal College of General Practitioners (RCGP) Research and Surveillance Centre (RSC) receives data from > 500 primary care practices (PCPs). Notably, the Lancet commissioning group is extracting data from the RCGP RSC database to shape UK policy on liver disease.

AIMS

To create a novel ontology to facilitate PBC case finding from primary care provider (PCP) records.

METHODS

RCGP RSC data were collected from participating PCPs in the county of Surrey, UK. PBC diagnostic criteria of the AASLD and EASL guidelines were used to develop 725 data codes to facilitate patient record searches. A scoring system built into the ontology allowed categorization of cases as PBC definite, PBC probable, and PBC unlikely.

RESULTS

A total of 218,099 records were searched from participating PCPs. Of these, there were 58 PBC definite, 2317 PBC probable, and 215,724 PBC unlikely patients. There were 32 PBC definite patients who did not match to our regional PBC database and were henceforth included as new-found cases. Two of these cases were not labeled as PBC by the PCP. From the PBC unlikely group, 7/215,724 (0.003%) patients were labeled as PBC in secondary care records; however, none of them were coded as having PBC by their PCPs.

CONCLUSIONS

Utilization of the UK National RCGP RSC database supported by novel ontology score has successfully helped us identify (i) new cases of PBC not known to local/regional secondary care providers and (ii) de novo PBC cases. There are many PBC probable cases whose data merit further careful evaluation.

Transaminases: oldies but goldies. A narrative review

Worldwide, patients are tested for acute and chronic diseases using a series of basic blood assays. The most common liver tests are serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST), also called transaminases. These tests are indicators of hepatocellular injury and their increase requires further investigations. The aim of this descriptive review is to highlight and remind the importance of liver transaminases in daily practice. A systematic literature search of the main international databases was performed. We looked for papers that involved transaminases, either in the normal range or in case of increased level and focused on their use in clinical practice. A narrative review of this topic was written. Multiple studies have demonstrated that the presence of an elevated ALT was associated with increased liver-related mortality. The normal ALT level ranges from 29 to 33 IU/L in males and 19 to 25 IU/L in females. The investigations imposed by a high level of transaminases includes testing for viral hepatitis A, B, C and E, assessment for nonalcoholic fatty liver disease and alcoholic liver disease, screening for autoimmune hepatitis, hemochromatosis, Wilson's disease and alpha-1 antitrypsin deficiency. Hepatotoxic drugs consumption also should be excluded. Furthermore, the utility of transaminases is evident in the assessment of the outcome after treatment of each specific liver disease. Beside the role in the first diagnostic step of liver injuries, the utility of liver transaminases is also maintained during the follow-up of liver diseases and in their prognostic assessment.

Intelligent liver function testing (iLFT): A trial of automated diagnosis and staging of liver disease in primary care

BACKGROUND & AIMS

Liver function tests (LFTs) are frequently requested blood tests which may indicate liver disease. LFTs are commonly abnormal, the causes of which can be complex and are frequently under investigated. This can lead to missed opportunities to diagnose and treat liver disease at an early stage. We developed an automated investigation algorithm, intelligent liver function testing (iLFT), with the aim of increasing the early diagnosis of liver disease in a cost-effective manner.

METHODS

We developed an automated system that further investigated abnormal LFTs on initial testing samples to generate a probable diagnosis and management plan. We integrated this automated investigation algorithm into the laboratory management system, based on minimal diagnostic criteria, liver fibrosis estimation, and reflex testing for causes of liver disease. This algorithm then generated a diagnosis and/or management plan. A stepped-wedged trial design was utilised to compare LFT outcomes in general practices in the 6 months before and after introduction of the iLFT system. Diagnostic outcomes were collated and compared.

RESULTS

Of eligible patients with abnormal LFTs, 490 were recruited to the control group and 64 were recruited to the intervention group. The primary diagnostic outcome was based on the general practitioner diagnosis, which agreed with the iLFT diagnosis in 67% of cases. In the iLFT group, the diagnosis of liver disease was increased by 43%. Additionally, there were significant increases in the rates of GP visits after diagnosis and the number of referrals to secondary care in the iLFT group. iLFT was cost-effective with a low initial incremental cost-effectiveness ratio of £284 per correct diagnosis, and a saving to the NHS of £3,216 per patient lifetime.

CONCLUSIONS

iLFT increases liver disease diagnoses, improves quality of care, and is highly cost-effective. This can be achieved with minor changes to working practices and exploitation of functionality existing within modern laboratory diagnostics systems.

LAY SUMMARY

There is a growing epidemic of advanced liver disease, this could be offset by early detection and management. Checking liver blood tests (LFTs) should be an opportunity to diagnose liver problems, but abnormal results are often incompletely investigated. In this study we were able to substantially increase the diagnostic yield of the abnormal LFTs using the automated intelligent LFT system. With the addition of referral recommendations and management plans, this strategy provides optimum investigation and management of LFTs and is cost saving to the NHS.

When Do Clinicians Follow-up Abnormal Liver Tests in Primary Care?

BACKGROUND

Many guidelines addressing the approach to abnormal liver chemistries, including bilirubin, transaminases and alkaline phosphatase, recommend repeating the tests. However, when clinicians repeat testing is unknown.

MATERIAL AND METHODS

This retrospective study followed adult patients with abnormal liver chemistries in a patient-centered medical home (PCMH) from 2007 to 2016. All PCMH patients possessing at least 1 abnormal liver test (total bilirubin, aminotransferases and alkaline phosphatase) were included. Patients were followed from the index abnormal liver chemistry until the next liver test result, or the end of the study period. The primary predictor variable of interest was the number of abnormal chemistries (out of 4) on index testing. Demographic and clinical variables served as other potential predictors of outcome. A Cox proportional hazards model was applied to investigate associations between the predictor variables and the time to repeat liver chemistry testing.

RESULTS

Of 9,545 patients with at least 2 PCMH visits and 1 liver test abnormality, 6,489 (68%) obtained repeat testing within 1 year, and 80% of patients had follow-up tests within 2 years. Patients with multiple abnormal liver tests and those with higher degrees of abnormality were associated with shorter time to repeat testing.

CONCLUSIONS

A large proportion of patients with abnormal liver tests still lack repeat testing at 1 year. The number of liver abnormal liver tests and degree of elevation were inversely associated with the time to repeat testing.

Evaluation of abnormal liver tests in the adult asymptomatic patient

PURPOSE OF REVIEW

Liver blood tests, including bilirubin, aminotransferases, and alkaline phosphatase, are among the most commonly encountered tests in medicine. With roles including the investigation of symptoms, medication monitoring, assessment of chronic disease, and routine assessment, these tests serve many purposes and result in abnormality in up to 40% of patients.

RECENT FINDINGS

The toll of liver disease continues to rise and abnormal liver tests offer an opportunity to identify hepatic disease early, when treatment is most effective and before patients suffer the potential downstream consequences of cirrhosis, portal hypertension, and hepatocellular carcinoma. By utilizing diagnostic strategies including detailed history gathering, alcohol use assessment, recognition of metabolic syndrome, and identifying patterns of liver test abnormalities, clinicians can develop a systematic approach to address abnormal liver tests. For these reasons, developing an evidence-based, systematic approach to handling abnormal liver tests is critically important.

SUMMARY

This review seeks to synthesize key elements of the best evidence, presently available guidelines, and expert opinion in drafting a strategy to aid clinicians and patients in the timely and accurate diagnosis of liver disease for the adult asymptomatic patient with abnormal liver tests.

Evaluation of liver test abnormalities in a patient-centered medical home: do liver test patterns matter?

Abnormal liver tests are extremely common in clinical practice, present with varying patterns and degrees of elevation, and can signal liver injury from a variety of causes. Responding to these abnormalities requires complex medical decision-making and merits investigation in primary care. This retrospective study investigates the association of patterns of liver test abnormality with follow-up in primary care. Using administrative data, this study includes patients with abnormal liver tests seen between 2007 and 2016 in a patient-centered medical home. Liver tests examined include serum bilirubin, aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase. Patients entered the cohort on the first liver test elevation. The outcome examined was completion of repeat testing, and the proportions of patients without follow-up were compared by patterns of index abnormality. 9545 patients met the inclusion criteria. Of these, 6155 (64.5%) possessed one liver test abnormality and 3390 (35.5%) possessed multiple abnormalities on index testing. Overall 1119 (11.7%) patients did not have repeat testing performed during the study period. A greater proportion of patients with lone abnormalities lacked repeat testing compared with those patients with multiple abnormalities. Differences in repeat testing appeared when comparing clinical patterns of abnormality, with higher proportions of follow-up in patients with testing suggestive of cholestasis. Over 11% of patients with abnormal liver tests did not undergo repeat testing during the study period. Repeat testing occurred more often in patients with multiple abnormalities and in clinical patterns suggestive of cholestasis. This study highlights a potential opportunity to improve quality of care.

Identification of risk factors for elevated transaminases in methotrexate users through an electronic health record

OBJECTIVE

To determine the predictors of elevated transaminases in an incident user cohort of older adult patients with rheumatic diseases receiving methotrexate (MTX) using elements derived from an electronic health record.

METHODS

Using a national, administrative database of patients seen through the Veterans Health Administration that included pharmacy and laboratory data, we performed an observational cohort study of veterans ages ≥65 years who were new users of MTX to identify risk factors for elevated transaminases.

RESULTS

We studied 659 incident users of MTX. We found a 6% incidence of moderate (≥1.5 × the upper limit of normal) elevations in aspartate aminotransferase or alanine aminotransferase over a mean followup period of 7 months. We identified predictors of moderate transaminase elevations to include obesity (per body mass index ≥30 kg/m(2) ), total cholesterol >240 mg/dl, pre-MTX liver function test (LFT) elevations, use of biologic agents, and lack of folic acid supplementation. A patient with these characteristics and >3 comorbid conditions would be predicted to have a 90% chance of developing a moderate transaminase elevation in the 7 months after starting MTX.

CONCLUSION

Moderate LFT abnormalities were uncommon in the first 7 months of MTX use, but were more likely to occur in patients with obesity, untreated high cholesterol, pre-MTX LFT elevations, biologic agent use, and lack of folic acid supplementation. Future work should aim to develop a robust, automated prediction rule for identifying patients at high risk for MTX-related liver toxicity.

The utility of liver function tests for mortality prediction within one year in primary care using the algorithm for liver function investigations (ALFI)

Background

Although liver function tests (LFTs) are routinely measured in primary care, raised levels in patients with no obvious liver disease may trigger a range of subsequent expensive and unnecessary management plans. The aim of this study was to develop and validate a prediction model to guide decision-making by general practitioners, which estimates risk of one year all-cause mortality in patients with no obvious liver disease.

Methods

In this population-based historical cohort study, biochemistry data from patients in Tayside, Scotland, with LFTs performed in primary care were record-linked to secondary care and prescription databases to ascertain baseline characteristics, and to mortality data. Using this derivation cohort a survival model was developed to predict mortality. The model was assessed for calibration, discrimination (using the C-statistic) and performance, and validated using a separate cohort of Scottish primary care practices.

Results

From the derivation cohort (n = 95 977), 2.7% died within one year. Predictors of mortality included: age; male gender; social deprivation; history of cancer, renal disease, stroke, ischaemic heart disease or respiratory disease; statin use; and LFTs (albumin, transaminase, alkaline phosphatase, bilirubin, and gamma-glutamyltransferase). The C-statistic for the final model was 0.82 (95% CI 0.80–0.84), and was similar in the validation cohort (n = 11 653) 0.86 (0.79–0.90). As an example of performance, for a 10% predicted probability cut-off, sensitivity = 52.8%, specificity = 94.0%, PPV = 21.0%, NPV = 98.5%. For the model without LFTs the respective values were 43.8%, 92.8%, 15.6%, 98.1%.

Conclusions

The Algorithm for Liver Function Investigations (ALFI) is the first model to successfully estimate the probability of all-cause mortality in patients with no apparent liver disease having LFTs in primary care. While LFTs added to the model's discrimination and sensitivity, the clinical utility of ALFI remains to be established since LFTs did not improve an already high NPV for short term mortality and only modestly improved a very low PPV.

Health outcomes following liver function testing in primary care: a retrospective cohort study

BACKGROUND

patients who present with abnormal liver function tests (LFTs) in primary care and no obvious symptoms can be difficult to manage.

OBJECTIVE

The objective is to follow-up a cohort of liver function tested patients to determine their outcome.

METHODS

This population-based retrospective cohort study was conducted in Tayside, Scotland, from 1989 to 2003. Subjects were patients with no clinically obvious liver disease at initial liver function testing in primary care. Main outcomes were diagnosed liver disease and mortality. Record linkage of databases ascertained risk factors and outcomes. Measures of performance were calculated and Weibull regression analysis from initial LFT date was performed on all outcomes by level of abnormality.

RESULTS

In total, 95 977 patients had 364 194 incident initial LFTs, with median follow-up 3.7 years. A total of 21.7% had at least one abnormal LFT and 1108 (1.15%) developed liver disease. Elevated transaminase was strongly associated with diagnosed liver disease, hazard ratio (HR) = 4.23 (95% confidence interval 3.55, 5.04) for mild levels and HR = 12.67 (95% CI 9.74, 16.47) for severe levels versus normal. For gamma-glutamyl transferase, these hazards were 2.54 (95% CI 2.17, 2.96) and 13.44 (95% CI 10.71, 16.87), respectively. Low albumin was strongly associated with all-cause mortality, HR = 2.65 (95% CI 2.47, 2.85) for mild levels and HR = 4.99 (95% CI 4.26, 5.84) for severe levels. Sensitivity for predicting events over 5 years was low and specificity high.

CONCLUSIONS

All LFTs were predictive markers for liver disease as well as general ill health, although sensitivity was poor. Most patients with abnormal LFTs had no later formal diagnosis of liver disease within the study period. The time taken to develop liver disease in these patients provides opportunity to intervene.