Adherence in chronic hepatitis B: associations between medication possession ratio and adverse viral outcomes

Social, clinical and biological barriers to hepatitis B virus suppression with nucleos/tide analogue therapy: who is at risk and what should we do about it?

Optimising treatment outcomes for people living with hepatitis B virus (HBV) is key to advancing progress towards international targets for the elimination of viral hepatitis as a public health threat. Nucleos/tide analogue agents (most commonly tenofovir or entecavir) are well-tolerated and suppress viraemia effectively in the majority of those who are offered therapy. However, outcomes are not consistent, and we explore the factors that may contribute to incomplete therapeutic responses. We discuss situations in which therapy is not accessible, affordable or acceptable, reflecting the impact of social, cultural and economic barriers, stigma and discrimination, low awareness, poor access to health systems and comorbidity. These challenges are amplified in certain vulnerable populations, increasing the risk of adverse outcomes-which include liver cirrhosis and hepatocellular carcinoma-among people who already experience marginalisation and health inequities. We also tackle the physiological and biological mechanisms for incomplete virological suppression in individuals receiving HBV treatment, considering the possible impact of inadequate tissue drug levels, poor drug-target avidity and genomic resistance. These factors are interdependent, leading to a complex landscape in which socioeconomic challenges increase the challenge of consistent daily therapy and set the scene for selection of drug resistance. By putting a spotlight on this neglected topic, we aim to raise awareness, prompt dialogue, inform research and advocate for enhanced interventions. As criteria for HBV treatment eligibility relax, the population receiving therapy will expand, and there is a pressing need to optimise outcomes and close the equity gap.

Epidemiological trends and outcomes of primary biliary cholangitis in South Korea between 2009 and 2019

BACKGROUND

There are no longitudinal studies on the epidemiology of primary biliary cholangitis (PBC) in Korea. This study aimed to elucidate the temporal trends in the epidemiology and outcomes of PBC in South Korea between 2009 and 2019.

METHODS

The epidemiology and outcomes of PBC were estimated using data from the Korean National Health Service database. Temporal trends in the PBC incidence and prevalence were analyzed using join-point regression. Transplant-free survival was analyzed according to age, sex, and ursodeoxycholic acid (UDCA) treatment using Kaplan-Meier and Cox regression analyses.

RESULTS

The age and sex-standardized incidence between 2010 and 2019 (total patients, 4230) was 1.03 per 100,000 per year on average and increased from 0.71 to 1.14 per 100,000 with an annual percent change (APC) of 5.5. The age and sex-standardized prevalence between 2009 and 2019 was 8.21 per 100,000 on average and increased from 4.30 to 12.32 per 100,000 with an APC of 10.9. The increasing trend in prevalence was prominent in males and elderly individuals. Among patients with PBC, 98.2% received UDCA with 77.3% adherence. The 5-year transplant-free overall survival rate was 87.8%. Male sex and low adherence to UDCA were associated with all-cause death or transplantation (hazard ratios of 1.59 and 1.89, respectively), and liver-related death or transplantation (hazard ratios of 1.43 and 1.87, respectively).

CONCLUSIONS

The incidence and prevalence of PBC in Korea increased significantly between 2009 and 2019. Male sex and low adherence to UDCA were poor prognostic factors for PBC.

The risk of drug resistance during long-acting antimicrobial therapy

The emergence of drug resistance during antimicrobial therapy is a major global health problem, especially for chronic infections like human immunodeficiency virus, hepatitis B and C, and tuberculosis. Sub-optimal adherence to long-term treatment is an important contributor to resistance risk. New long-acting drugs are being developed for weekly, monthly or less frequent dosing to improve adherence, but may lead to long-term exposure to intermediate drug levels. In this study, we analyse the effect of dosing frequency on the risk of resistance evolving during time-varying drug levels. We find that long-acting therapies can increase, decrease or have little effect on resistance, depending on the source (pre-existing or de novo) and degree of resistance, and rates of drug absorption and clearance. Long-acting therapies with rapid drug absorption, slow clearance and strong wild-type inhibition tend to reduce resistance caused by partially resistant strains in the early stages of treatment even if they do not improve adherence. However, if subpopulations of microbes persist and can reactivate during sub-optimal treatment, longer-acting therapies may substantially increase the resistance risk. Our results show that drug kinetics affect selection for resistance in a complicated manner, and that pathogen-specific models are needed to evaluate the benefits of new long-acting therapies.

Association between medication adherence and disease outcomes in patients with hepatitis B-related cirrhosis: a population-based case-control study

OBJECTIVE

To evaluate medication adherence among patients with hepatitis B-related cirrhosis who developed decompensation and mortality, and to examine the association between medication adherence and patients' disease outcomes.

DESIGN

In this retrospective case-control study, patients aged over 20 years old and diagnosed with both chronic hepatitis B and cirrhosis from 2007 to 2016 are identified using a population-based medical claims database. Two prognosis endpoints (decompensation and mortality) are used, respectively, to classify subjects into two different case-control sets. Study groups are propensity-score matched. Medication possession ratio (MPR) is used as a measure of treatment adherence for oral antiviral drugs, and conditional logistic regression models are used to estimate the odds of decompensation and mortality after accounting for MPR and other covariates.

RESULTS

Between decompensated and compensated patients, longer term treatment adherence is seen higher in the compensated group versus the decompensated group: 1-year MPR (0.65±0.43 vs 0.57±0.53) and 6-month MPR (0.79±0.52 vs 0.76±0.79). On the contrary, 3-month adherence is higher in the decompensated group (1.00±1.15 vs 0.96±0.79). For patients with and without mortality, drug adherence is ubiquitously higher in the alive group regardless of follow-up length: 1-year MPR (0.62±0.44 vs 0.50±0.51), 6-month MPR (0.78±0.62 vs 0.69±0.72) and 3-month MPR (0.97±0.91 vs 0.96±1.12). After accounting for confounding variables, we find that the likelihood of complicated cirrhosis is significantly lower in more adherent patients and the benefit increases with more persistent adherence (log 1-year MPR OR: 0.75, 95% CI: 0.73 to 0.77). Similar results are observed for the adjusted likelihood of mortality (log 1-year MPR OR: 0.70, 95% CI: 0.68 to 0.72).

CONCLUSIONS

Long-term patient adherence to oral antiviral therapy remains inadequate in patients with hepatitis B virus-related cirrhosis. Their adherence to oral antiviral therapy appears to be inversely associated with decompensation and mortality.

High level of medication adherence is required to lower mortality in patients with chronic hepatitis B taking entecavir: A nationwide cohort study

It is unclear whether suboptimal adherence contributes to adverse clinical outcomes in patients with chronic hepatitis B (CHB). Moreover, there is no consensus regarding the optimal level of drug adherence. This was a population-based historical cohort study including 51 975 adult CHB patients treated with entecavir (0.5 mg/d orally). Data were obtained from the Korean national health insurance service claims database, which covers >99% of the entire population, between 2007 and 2015. Medication adherence was categorized as high (proportion of days covered [PDC], ≥90%; n = 32 089), intermediate (PDC, 80%-89%; n = 10 197) and low (PDC, <80%; n = 9689). During a median 4.5 years (maximal 9 years) of follow-up in 51 975 CHB patients treated with entecavir, multivariable analyses revealed that the risk of mortality/transplantation was significantly greater in the low-adherers (adjusted hazard ratio [HR], 1.38; P < .001) and intermediate-adherers (adjusted HR, 1.44; P < .001) than the high-adherers (P for trend < 0.001). The risk of renal failure in the low- and intermediate-adherence groups was also significantly higher than the high-adherence group (P for trend < 0.001). By contrast, the risk of hepatocellular carcinoma (HCC) was not significantly different between groups (P for trend = 0.70). The higher risk of mortality/transplantation and renal failure but similar risk of HCC for low- and intermediate-adherers compared with high-adherers was consistent in inverse probability treatment weighting analysis of the entire cohort and subcohorts with or without cirrhosis. In conclusion, high medication adherence (≥90%) is required to significantly lower risk of mortality and renal failure in patients with CHB during long-term treatment with entecavir.