Prevalence of Generalized Anxiety Disorder in Japan: A General Population Survey.

Purpose: Generalized anxiety disorder (GAD) is among the most prevalent and highly disabling mental health conditions that negatively impacts patient's quality of life (QOL) and disrupts activities of daily living. However, the recognition of GAD is difficult due to substantial overlap with other mental disorders. The purpose of this study was to estimate the prevalence of GAD, assess QOL of probable GAD patients in Japan, and gain insights on the status of visiting medical institutions as well as their recognition/awareness of the disorder. Patients and Methods: We conducted a web-based cross-sectional survey of 20,009 participants using a questionnaire with approximately 30 single/multiple choice or open-ended questions in Japanese. Results: Overall prevalence of GAD based on Generalized Anxiety Disorder 7-item (GAD-7) cutoff score of ≥10 and questionnaires developed with reference to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria was 7.6% (n=1530) and 6.0% (n=1197), respectively. The degree of coincidence between GAD diagnosis by DSM-5 criteria and GAD-7 scores was moderate (Cohen's Kappa=0.47, p<0.01). Younger people reported a substantially higher prevalence of GAD compared to older. QOL scores assessed using EuroQol 5 dimensions 5-level and EuroQol Visual Analog Scale were substantially lower in probable GAD patients than those with GAD-7<10. Anxiety/depression and pain/discomfort were the most prevalent issues and depression was the most reported comorbidity for the probable GAD patients. Probable GAD patients "currently visiting medical institutions" for anxiety or other mental issues were 27.6% (422/1530); a majority had seen specialists. Most of the probable GAD patients had never heard of the disease. Conclusion: We found higher prevalence of GAD and lower QOL of probable GAD patients in Japan. There is a need for creating awareness about GAD among the general population and developing clinical guidelines on GAD in Japan so that physicians can educate their patients.

Diagnosis and Treatment of Generalized Anxiety Disorder in Japan: Psychiatric Specialist Survey.

Purpose: Generalized anxiety disorder (GAD) is a suboptimally managed chronic recurring psychiatric condition with a lifetime prevalence of 2.6% in Japan. We assessed the current status of GAD management in Japan. Patients and Methods: This was an observational, cross-sectional study conducted through an anonymous web-based survey in Japan from December 12-16, 2022. Psychiatrists and psychosomatic medicine physicians who agreed to participate and saw ≥10 outpatients in the previous month were eligible. Survey questionnaire comprised 37 single/multiple choice, numerical entry, or open-ended questions in Japanese. Results: Among 509 participants (493 psychiatrists and 16 psychosomatic medicine physicians), 96.9% were aware of GAD. On average, 12.4 outpatients and 1.0 inpatient were diagnosed with GAD per physician per month. Of 433 physicians having patients diagnosed with GAD, 46.9% used operational diagnostic tools; among these, DSM-5 diagnostic criteria were used by 81.5% physicians. The majority (54.7%) of participants did not use a self-administered rating scale; depression scales were used more than anxiety scales. Among these 433 physicians, 96.8% used selective serotonin reuptake inhibitors for GAD management, and 79.2% used it as the first choice; of 431 physicians who prescribed drug therapy, 54.3% gave antidepressant monotherapy as first choice. The most frequent symptom in patients diagnosed with GAD was excessive anxiety/worry (96.5%); depression was the most commonly reported comorbidity (84.3%) as per physicians aware of GAD (N=508). Conclusion: This study illustrates that although GAD awareness is high among Japanese psychiatric specialists, GAD is not frequently diagnosed using operational diagnostic approaches. Due to a lack of Japanese guidelines for GAD diagnosis and treatment, diverse international guidelines are followed, with similar treatment paradigms as that of depression. This may not be an optimal approach given cultural/geographical differences. These findings highlight the need for uniform diagnosis and treatment recommendations for GAD management in Japan. Clinical Trial Registration: UMIN-CTR: UMIN000049572.

Clinical implication of children's depression rating scale-revised score: Linking the children's depression rating scale-revised score and clinical global impression using patients data from clinical trials.

Background and Aims: The Children's Depression Rating Scale-Revised (CDRS-R) score has been widely used to assess the severity of major depression in children and adolescents; however, the clinical implications of changes in the CDRS-R score remain unclear. We evaluated these clinical implications by assessing the relationship between changes in the CDRS-R score and changes in the Clinical Global Impression of Improvement (CGI-I), in clinical research on major depression. Methods: We used data from four clinical trials involving two antidepressants and evaluated the relationship between CDRS-R score changes and the CGI-I score using the equipercentile linking method. Results: CDRS-R score changes corresponding to a minimally improved (score of 3) CGI-I score was approximately 14 points. Conclusion: Our findings from the linking analyses are useful for interpreting the clinical implications of changes in the CDRS-R score.

Comparative effectiveness of early initiation of oral nonsteroidal anti-inflammatory drug and oral acetaminophen therapies on the time to knee replacement in patients with knee osteoarthritis in Japan.

BACKGROUND: Although disease-modifying properties of nonsteroidal anti-inflammatory drugs (NSAIDs) for osteoarthritis (OA) have been reported, the effects of NSAIDs on OA progression remain controversial. The purpose of this study was to investigate the effect of early initiation of oral NSAID therapy on the progression of knee OA. METHODS: In this retrospective cohort study, we extracted data of patients newly diagnosed with knee OA between November 2007 and October 2018 from a Japanese claims database. The primary outcome was the time to knee replacement (KR), and the secondary outcome was the time to composite event including joint lavage and debridement, osteotomy, or arthrodesis in addition to KR. Weighted Cox regression analysis with standardized mortality/morbidity ratio (SMR) weight was performed to compare the outcomes between patients prescribed oral NSAID (NSAID group) and those prescribed oral acetaminophen (APAP) (APAP group) early after a diagnosis of knee OA. Propensity scores were calculated using logistic regression conditioned on potential confounding factors, and SMR weights were calculated using the propensity scores. RESULTS: The study population comprised 14,261 patients, who were divided into two groups as follows: 13,994 in the NSAID group and 267 in the APAP group. The mean ages of patients in the NSAID and APAP groups were 56.9 and 56.1 years, respectively. Furthermore, 62.01% and 68.16% patients in the NSAID and APAP groups, respectively, were female. The NSAID group had a reduced risk of KR compared with the APAP group in the analysis using SMR weighting (SMR-weighted hazard ratio, 0.19; 95% confidence interval, 0.05-0.78). While no statistically significant difference was found for the risk of composite event between the two groups (SMR-weighted hazard ratio, 0.56; 95% confidence interval, 0.16-1.91). CONCLUSIONS: The risk of KR in the NSAID group was significantly lower than that in the APAP group after accounting for residual confounding using SMR weighting. This finding suggests that oral NSAID therapy early after the initial diagnosis is associated with a reduced risk of KR in patients with symptomatic knee OA.

Physician consultation rates and characteristics among workers with chronic pain or headache who participated in a behavioural change program: a retrospective database analysis using real-world healthcare data.

OBJECTIVE: To assess the potential benefit of a behavioural change programme in working individuals with chronic pain or headache, in the form of increased physician consultation. DESIGN: Retrospective observational database study. SETTING: Members of employment-based healthcare insurance in Japan. PARTICIPANTS: Individual-level data of working individuals aged <75 years from November 2019 through March 2020 were extracted from a database managed by MinaCare Co., Ltd. Included individuals had records of programme participation and chronic pain or headache (self-reported), and did not consult physicians for ≥3 months before programme participation. OUTCOME MEASURES: Physician consultation rates after participating in the programme were examined from December 2019 through March 2020, separately for chronic pain and headache. Baseline characteristics included age, pain numeric rating scale (NRS) score (for chronic pain), suspected migraine (for headache), labour productivity including absenteeism and presenteeism, and 4-month indirect costs in Japanese yen (JPY). RESULTS: The baseline mean age (±SD) of 506 individuals with chronic pain was 46.8±10.1 years; that of 352 individuals with headache was 43.6±9.9 years. Of those with chronic pain, 71.4% had an NRS score≥4, and 49.7% of those with headache had suspected migraine. Overall, 11.3% and 5.4% of those with chronic pain or headache consulted physicians, respectively. The mean baseline absenteeism and presenteeism were 1.5% and 19.1% in those with chronic pain, and 1.5% and 23.0% in those with headache. The baseline indirect costs were 586 941.6 JPY and 1 060 281.6 JPY among those with chronic pain or headache, respectively. CONCLUSION: Given that the individuals did not regularly consult physicians before the programme despite reporting substantial symptoms, our results suggest the potential benefit of educational programmes encouraging physician consultation. Further studies are required to evaluate how to effectively implement such educational programmes via healthcare insurers to reduce the burden of pain symptoms and overall medical costs.

The Use of a Network Analysis to Identify Associations and Temporal Patterns Among Non-communicable Diseases in Japan Based on a Large Medical Claims Database.

BACKGROUND: Reducing the considerable non-communicable disease (NCD) burden in the aging Japanese population depends on better understanding of the comorbid and temporal relationships between different NCDs. OBJECTIVE: We aimed to identify associations between NCDs and temporal patterns of NCDs in Japan using data from a large medical claims database. METHODS: The study used three-digit International Classification of Diseases, Tenth Revision codes for NCDs for employees and their dependents included in the MinaCare database, which covers the period since 2010. Associations between pairs of NCDs were assessed by calculating risk ratios. The calculated risk ratios were used to create a network of closely associated NCDs (risk ratio > 15, statistically significant) and to assess temporal patterns of NCD diagnoses (risk ratio ≥ 5). The Infomap algorithm was used to identify clusters of diseases for different sex and age strata. RESULTS: The analysis included 4,200,254 individuals (age < 65 years: 98%). Many of the temporal associations and patterns of the diseases of interest identified in this study were previously known. Regarding the diseases of interest, these associations can be classified as comorbidities, early manifestations initially diagnosed as something else, diseases attributable to or that cause the disease of interest, or caused by pharmacological treatment. International Classification of Diseases, Tenth Revision chapters that were most associated with other chapters included L Diseases of the skin and subcutaneous tissue. In the age-stratified and gender-stratified networks, clusters with the highest numbers of International Classification of Diseases, Tenth Revision codes included I Diseases of the circulatory system and F Mental and behavioral disorders. CONCLUSIONS: Our findings reinforce established associations between NCDs and underline the importance of comprehensive NCD care.

Item Response Analyses of the Children's Depression Rating Scale-Revised Using Data from Clinical Studies.

Objective: We aimed to identify which of the 17 items comprising the Children's Depression Rating Scale-Revised (CDRS-R) can sensitively capture changes in depression severity. Methods: We used data from four studies involving two antidepressants. For each of the 17 CDRS-R items, we conducted item response analyses to identify and evaluate those that reflect changes in depression severity. We created plots of the item characteristic curves (ICCs) estimated by the graded response model, and option characteristic curves and ICCs using nonparametric item response theory. The change from baseline in the CDRS-R subscale score with specified reflective items by item response analyses and the effect size between the treatment group and placebo group were calculated and compared with those of the CDRS-R total score. Results: CDRS-R items #2 (difficulty having fun), #3 (social withdrawal), #10 (low self-esteem), #11 (depressed feelings), and #15 (depressed facial expression) have favorable profiles that reflect disease severity. Changes from baseline in the CDRS-R total score (least square mean ± standard error) at week 8 were -22.3 ± 0.7 and -23.9 ± 0.7 in the placebo group and treatment group, respectively (difference, -1.5; estimated effect size, -0.113), changes from baseline in the CDRS-R5 (CDRS-R subscale consisting of the specified reflective items [#2, #3, #10, #11, and #15]) score at week 8 were -8.4 ± 0.3 and -9.6 ± 0.3 in each group, respectively (difference, -1.2; effect size, -0.202). Conclusions: The item response analyses clarified the properties of 17 items of the CDRS-R for major depressive disorder in children and adolescents. The CDRS-R5 might optimize the assessment of changes in overall depression severity and differentiation of treatment responses.

Inverse Association Between Persistence With Antidepressant Medication and Onset of Chronic Pain in Patients With Depression: A Retrospective Cohort Study.

PURPOSE/BACKGROUND: Despite the known involvement of depression in chronic pain, the association between persistence with and adherence to antidepressant medication and onset of chronic pain in patients with depression remains unclear. METHODS/PROCEDURES: This retrospective cohort study used a Japanese claims database to extract data for adult patients with depression who were prescribed antidepressants between April 2014 and March 2020. Patients were divided into groups according to duration of continuous prescription of antidepressants (≥6 months [persistent group] and <6 months [nonpersistent group]) and medication possession ratio (≥80% [good adherence group] and <80% [poor adherence group]). The outcome was onset of chronic pain, which was defined as continuous prescription >3 months of analgesics and diagnosis of pain-related condition after discontinuation of the first continuous antidepressant prescription. The risk of onset of chronic pain was compared between the paired groups. FINDINGS/RESULTS: A total of 1859 patients were selected as the study population and categorized as the persistent (n = 406) and nonpersistent (n = 1453) groups, and good adherence (n = 1551) and poor adherence (n = 308) groups. Risk of onset of chronic pain was significantly lower in the persistent group than in the nonpersistent group after controlling for confounding via standardized mortality ratio weighting (hazard ratio, 0.38; 95% confidence interval, 0.18-0.80; P = 0.011). There was no significant difference between the good and poor adherence groups. IMPLICATIONS/CONCLUSIONS: Antidepressant persistence for ≥6 months is recommended and may reduce the onset of chronic pain in patients with depression.

Antidyslipidemic Drug Prescriptions and Lipid Control Status After Unfavorable Annual Health Checkup Results: A Retrospective Cohort Study Using a Health Insurance Database.

BACKGROUND: Japanese employers are obligated to offer employees annual health checkups and guidance programs for their health promotion and maintenance to prevent cardiovascular (CV) and lifestyle-related diseases. Under these programs, checkup recipients are notified of the checkup results, and in case of abnormal findings, employers are expected to provide employees with follow-up encouragement to change their behavior; for example, with medical consultations or lifestyle modifications. However, the effect of these programs on behavioral changes and their subsequent clinical outcomes has not been clearly assessed. OBJECTIVE: The aim of this study was to investigate changes in CV risk management behaviors after receiving unfavorable health checkup results on serum lipid levels among subjects without antidyslipidemic drug prescription and uncontrolled lipid levels and at elevated risk of CV events in a real-world setting. PATIENTS AND METHODS: This retrospective cohort study used a Japanese employment-based health insurance database managed by MinaCare Co., Ltd. This study analyzed the data from the annual health checkups of recipients aged 20-74 years with data on their low-density lipoprotein-cholesterol (LDL-c), high-density lipoprotein-cholesterol (HDL-c), and triglyceride (TG) values from 2015 to 2017, who had uncontrolled lipid levels based on their checkup results at baseline in 2015, and without prescription records of antidyslipidemic drugs. Lipid status was considered uncontrolled if any of the following were detected: LDL-c ≥ 140 mg/dL, HDL-c < 40 mg/dL, or TG ≥ 150 mg/dL. Changes in antidyslipidemic drug prescription, as a primary CV risk management behavior measure, and in lipid control status in 2016 and 2017 were investigated. Potential factors associated with lipid control were also explored using logistic regression analysis. RESULTS: Among 154,421 subjects without antidyslipidemic drug prescription and with uncontrolled lipid levels in 2015, 93.6% remained without antidyslipidemic drug prescription in both 2016 and 2017. Of these subjects, 76.8% and 76.4% continued having uncontrolled lipid levels in 2016 and 2017, respectively. Fewer subjects without prescription achieved lipid control than those with prescription. Various factors were associated with lipid control, with high LDL-c as the greatest risk factor for uncontrolled lipid levels. CONCLUSIONS: These results suggest that most health checkup recipients may not have changed their behaviors; that is, they may have not sought medical treatment and continued having uncontrolled lipid levels in the years following the unfavorable health checkup results. To encourage subjects to initiate desirable behavioral changes, more practical support may be essential.

Relationship of Annual Health Checkups with the Subject's Subsequent Behavior of Cardiovascular Risk Management in a Real-World Setting in Japan: A Retrospective Cohort Study on Changes in Antihypertensive Drug Prescription and Blood Pressure from 2015 to 2017.

BACKGROUND: In Japan, workers receive a health checkup annually, and based on the results, a follow-up health guidance or intervention is provided when deemed necessary. However, it remains unclear whether the current real-world health checkup and guidance programs in Japan successfully lead to behavioral changes or improvement of clinical outcomes in individuals who require cardiovascular (CV) risk management. OBJECTIVE: This study aimed to explore the association between health checkup and the subsequent behavior change in CV risk management in subjects with uncontrolled blood pressure (BP) without antihypertensive drug prescription, who can have increased risk of CV events. PATIENTS AND METHODS: This was a retrospective cohort study that used health-checkup and claims data from a Japanese healthcare database managed by MinaCare Co., Ltd. Of those aged 20-74 years with available data on systolic and diastolic BP from 2015 to 2017, data from individuals with uncontrolled BP who were not prescribed antihypertensive drugs within 6 months before their baseline health checkup in 2015 were extracted and analyzed. The primary outcome measures were changes in antihypertensive drug prescription and BP control status based on health-checkup results from the baseline year (2015) to 2017. CV risk-management behavior was also assessed using body mass index (BMI) and smoking status, as these are the major modifiable CV risk factors. RESULTS: Among 39,242 subjects with uncontrolled BP without antihypertensive drug prescription at baseline, 88.9% remained without prescription in 2016. Of the subjects without prescription, 62.9% continued to have uncontrolled BP. Both statuses of the major modifiable CV risk factors remained unchanged in 2016: 92.1% of obese subjects (BMI ≥ 25 kg/m2) at baseline remained obese, and 93.8% of smokers at baseline aged ≥ 40 years continued to smoke. Logistic regression analysis revealed that age 60-69 years (vs. 40-49 years), hypertension (HT) stage II (vs. stage I), HT stage III (vs. stage I), and BMI ≥ 25.0 kg/m2 (vs. < 25.0 kg/m2) were factors associated with uncontrolled BP in 2016 (subsequent year), regardless of antihypertensive drug prescription. CONCLUSIONS: Untreated HT for years increases the risk of CV events. These results suggest that current health-checkup and guidance programs are inadequately effective for behavioral change. Further practices for committing to lifestyle modifications and seeking medical advice based on their health-checkup results need to be undertaken to improve health behavior.

Validation of novel identification algorithms for major adverse cardiovascular events in a Japanese claims database.

Predicting clinical outcomes can be difficult, particularly for life-threatening events with a low incidence that require numerous clinical cases. Our aim was to develop and validate novel algorithms to identify major adverse cardiovascular events (MACEs) from claims databases. We developed algorithms based on the data available in the claims database International Classification of Diseases, Tenth Revision (ICD-10), drug prescriptions, and medical procedures. We also employed data from the claims database of Jichi Medical University Hospital, Japan, for the period between October 2012 and September 2014. In total, we randomly extracted 100 potential acute myocardial infarction cases and 200 potential stroke cases (ischemic and hemorrhagic stroke were analyzed separately) based on ICD-10 diagnosis. An independent committee reviewed the corresponding clinical data to provide definitive diagnoses for the extracted cases. We then assessed the algorithms' accuracy using positive predictive values (PPVs) and apparent sensitivities. The PPVs of acute myocardial infarction, ischemic stroke, and hemorrhagic stroke were low only by diagnosis (81.6% [95% CI 72.5-88.7]; 31.0% [95% CI 22.8-40.3]; and 45.5% [95% CI 34.1-57.2], respectively); however, the PPVs were elevated after adding the prescription and procedure data (87.0% [95% CI 78.3-93.1]; 44.4% [95% CI 32.7-56.6]; and 46.1% [95% CI 34.5-57.9], respectively). When we added event-specific prescription and procedure data to the algorithms, the PPVs for each event increased to 70%-98%, with apparent sensitivities exceeding 50%. Algorithms that rely on ICD-10 diagnosis in combination with data on specific drugs and medical procedures appear to be valid for identifying MACEs in Japanese claims databases.

A Retrospective, Cross-Sectional Study on the Prevalence of Hyperuricemia Using a Japanese Healthcare Database.

OBJECTIVES: This study aims to evaluate the prevalence of hyperuricemia (HU) considering both serum uric acid (SUA) levels and medication status of urate-lowering drugs (ULDs), and the association between HU and its comorbidities using a Japanese healthcare database. MATERIALS AND METHODS: The study population consisted of 60,828 subjects who had at least one serum uric acid measurement between the fiscal years (FYs) 2010 and 2014 in a Japanese employment-based health insurance database (MinaCare Co., Ltd., Tokyo, Japan), which includes mutually linked medical/pharmaceutical claims data and health check-up data. Hyperuricemia was defined as a SUA level >7.0 mg/dL of the health check-up data and/or a prescription for a ULD. The association between HU and comorbidities were analyzed by comparing the prevalence of HU of each subgroup defined by presence or absence of comorbidity. RESULTS: The prevalence of HU in FY 2014 was 26.8% [95% confidence interval (CI): 26.2 to 27.3%] in male subjects and 0.9% (95% CI: 0.7 to 1.0%) in female subjects. According to the analyses by sex and age, a trend of increasing prevalence with age was observed in both males and females. The prevalence of HU remained stable both in males and females from FYs 2010 to 2014. The positive association between HU and well-known comorbidities were confirmed with the exception of diabetes mellitus and smoking status in male subjects. CONCLUSION: Our results provided a more accurate prevalence of HU in Japanese population. It is important to increase the awareness on HU in the society to reduce the burden of HU-related diseases.

The effects of topiroxostat on vascular function in patients with hyperuricemia.

Xanthine oxidoreductase (XOR) inhibitors, such as allopurinol and febuxostat, inhibit the catalysis of serum uric acid (SUA) synthesis. In doing so, they are thought to improve vascular endothelial function in patients with hyperuricemia and cardiovascular risk by reducing increases in SUA and reactive oxygen species levels. We performed a retrospective cohort study to evaluate the effects of topiroxostat, a novel XOR inhibitor, on vascular function measured by flow-mediated dilation (FMD) on ultrasonography. In total, 23 patients with hyperuricemia were enrolled. After approximately 8 weeks, topiroxostat was associated with a significant increase in the peak percentage change in diameter (∆FMD) from 4.53% ± 2.09% to 5.54% ± 3.08% (P = .045). It also significantly reduced the SUA levels from 7.31 ± 1.43 to 5.44 ± 1.11 mg/dL (P < .001). Although further studies are needed to validate these results, it appears that topiroxostat improves vascular endothelial function in patients with hyperuricemia.

Association of genes involved in bile acid synthesis with the progression of primary biliary cirrhosis in Japanese patients.

BACKGROUND: Patients with primary biliary cirrhosis (PBC) exhibit a variety of clinical manifestations and patterns of disease progression. The aim of this study was to identify genetic determinants of PBC progression. METHODS: A total of 52 tag single nucleotide polymorphisms (SNPs) of 11 candidate genes involved in regulating bile acid synthesis were analyzed by polymerase chain reaction (PCR)-restriction fragment length polymorphism, -high resolution melting curve analysis, or -direct DNA sequencing in 315 Japanese patients with PBC. RESULTS: In this study, four tag SNPs of CYP7A1 (rs1457043, rs8192870, rs3808607, and rs3824260), two tag SNPs of HNF4A (rs6017340 and 6031587), and one SNP of PPARGC1A (rs8192678) showed a significant association with PBC progression. In addition, a dual luciferase assay revealed that the polymorphism of rs3808607 in CYP7A1 altered the expression of CYP7A1 in HepG2. Specifically, the CYP7A1 promoter carrying the risk G allele for PBC progression induced higher expression of CYP7A1 under both the normal and cholestatic conditions in vitro as compared to another promoter carrying the non-risk T allele. CONCLUSION: These results suggested that the genetic variants of CYP7A1 and its transcriptional activators (HNF4A and PPARGC1A) may activate bile acid synthesis, resulting in the accumulation of bile acids in hepatocytes and eventually leading to the predisposition to PBC progression. Thus, the regulation of CYP7A1 expression may represent an attractive therapeutic target for cholestatic liver diseases including PBC.

Single-nucleotide polymorphism analysis of the multidrug resistance protein 3 gene for the detection of clinical progression in Japanese patients with primary biliary cirrhosis.

UNLABELLED: Primary biliary cirrhosis (PBC) is a multifactorial disease in which genetic factors rather than environmental factors may predominantly contribute to the pathogenesis. In order to identify the genetic determinants of the disease severity and progression of PBC, we examined an association of seven tag single-nucleotide polymorphisms (SNPs) in the multidrug resistance protein 3 (MDR3/ABCB4) gene in 148 Japanese PBC patients and 150 age- and sex-matched healthy control subjects. SNPs were detected via polymerase chain reaction (PCR) restriction fragment length polymorphism and PCR direct DNA sequencing methods. Subsequently, haplotypes were constructed from three tag SNPs (rs31658, rs31672, and rs1149222) that were significantly associated with progression of PBC. Logistic regression analyses revealed that a Hap 2 haplotype and its homozygous diplotype, Hap 2/Hap 2, in MDR3 were closely associated with the susceptibility to jaundice-type progression of PBC [P = 0.004, odds ratio (OR) 3.93, 95% confidence interval (CI) 1.56-9.90 and P = 0.0003, OR 17.73, 95% CI 3.77-83.42, respectively]. Conversely, another haplotype, Hap 1, and its homozygous diplotype, Hap 1/Hap 1, were associated with the insusceptibility to the progression to late-stage PBC (P = 0.021, OR 0.55, 95% CI 0.33-0.91 and P = 0.011, OR 0.24, 95% CI 0.08-0.71, respectively). CONCLUSION: The present study is the first report of an association of MDR3 haplotypes and diplotypes with progression of PBC. The Hap 2/Hap 2 diplotype in MDR3 could therefore be potentially applied to DNA-based diagnosis in Japanese patients with PBC as a strong genetic biomarker for predicting the progression and prognosis of PBC.