Pediatric otitis media in Japan: A nationwide longitudinal study of the pre- and post-pneumococcal conjugate vaccine eras born in 2001 and 2010.

BACKGROUND: Otitis media (OM) is a prevalent respiratory disease in children and poses significant public health challenges due to its impact on child health and economic burdens. However, there have no nationwide epidemiological studies conducted in Japan. This study investigates the epidemiological trends of OM in Japan, taking into account the impact of the 7-valent pneumococcal conjugate vaccine (PCV7) introduction. METHOD: This study was retrospective cohort study using secondary data on the nationwide longitudinal birth cohort. This survey followed two cohorts born in 2001 (pre-PCV era) and 2010 (post-PCV era) until the age of 9. Every year, parents were surveyed about their children's health status, including occurrences of OM. The annual period prevalence and cumulative incidence of OM were assessed in this study, and the two cohorts were compared using a modified Poisson regression model adjusted environmental factors with the 2001 cohort as reference. RESULT: The study included 47,015 children from the 2001 cohort and 38,554 from the 2010 cohort. Peak annual period prevalence of OM varied by era. Cumulative incidence was 13.8 % for the 2001 cohort and 18.5 % for the 2010 cohort by 1.5 years of age and 28.9 % and 33.3 %, respectively, by 3.5 years of age. In particular, from the fourth survey onward, covering ages 2.5-3.5 years, a shift was observed from an increased risk to a decreased risk of OM. CONCLUSION: This nationwide longitudinal study emphasizes variations in OM epidemiology across Japan over time, with changes potentially influenced by the introduction of PCV7. In this study, due to the absence of individual PCV7 vaccination data, the effect of PCV7 was estimated based on the vaccination rate at the population level. The results suggest a notable decrease in the incidence of OM in later years, aligning with the increased uptake of PCV7.

Effect of COVID-19 Infection on Presenteeism: Cohort Study Using Large Health Insurance-Based Data in Japan.

OBJECTIVE: Presenteeism occurs when employees attend work despite experiencing problems and ill-health that require sick leave. This study examined whether presenteeism worsened following COVID-19 infection. METHODS: We used the DeSC, a large health insurance claims database. Participants were 9,241 individuals who responded to questionnaires at baseline (June 2020) and 6 months later, had been continuously insured for at least 6 months prior to baseline, and reported being employed. Propensity score matching was performed. Adjusted multiple logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) of worsening presenteeism from baseline according to COVID-19 infection compared with non-infection. RESULTS: Conditional logistic regression analysis showed that the adjusted OR for presenteeism in the COVID-19 infected group was 1.555 (95% CI, 1.086-2.225). CONCLUSION: The findings suggest that COVID-19 infection affected worsening of presenteeism.

Antibody titers and the risk of infection during the SARS-CoV-2 Omicron phase in Bizen City, Japan.

BACKGROUND: Understanding the association between the immune response and the risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has implications for forthcoming prevention strategies. We evaluated the association between antibody titers and the risk of infection for the general population during the Omicron-dominant phase. METHODS: This was a prospective cohort study of residents or people affiliated with institutions in Bizen City, which included 1,899 participants. We measured the titers of antibodies against SARS-CoV-2 repeatedly every 2 months from June 2022 to March 2023. Infection status was obtained from self-reported questionnaires and the official registry. We estimated risk ratios (RRs) for infection within 2 months of the date of each antibody measurement with 95% confidence intervals (CIs) based on antibody titer categories and spline functions. RESULTS: Compared with the <2,500 arbitrary unit (AU)/mL category, the 2,500-5,000, 5,000-10,000, and ≥10,000 AU/mL categories had adjusted RRs (95% CI) of 0.81 (0.61-1.08), 0.51 (0.36-0.72), and 0.41 (0.31-0.54), respectively. The spline function showed a non-linear relationship between antibody titer and risk. CONCLUSIONS: Higher antibody titers were associated with a lower risk. We demonstrate the usefulness of measuring an antibody titers to determine the appropriate timing for future vaccination.

Longitudinal changes in antibody titers in a nursing home in which COVID-19 clusters occurred.

BACKGROUND: Many outbreaks of coronavirus disease 2019 have occurred in Japanese nursing homes in which residents and staff are in close daily contact. This study evaluated longitudinal changes in antibody titers in nursing homes in which clusters occurred and examined the association between antibody titer and the severe acute respiratory syndrome coronavirus 2 infection or severity. METHODS: This cohort study included 171 participants who had provided at least one antibody titer test between June 2022 and March 2023. A descriptive analysis estimated the association between the risk of infection and antibody titer level. RESULTS: The facility experienced 2 clusters during the study period that involved facility staff as the initial source of infection. Noninfected participants had less variation in antibody titer levels and a higher level of preinfection antibodies than infected participants. The risk of infection and severity was lower in participants with higher antibody titers than in those with lower titers. CONCLUSIONS: We showed the changes in antibody titers over time and the association between antibody titer and severe acute respiratory syndrome coronavirus 2 infection or severity. Vaccination schedules may need to be tailored to the dynamics of decreasing antibody titers over time and the occurrence of infectious diseases in facilities.

Impact of COVID-19 Infection on Health-Related Quality of Life in the Japanese Population: A Large Health-Insurance-Based Database Study.

Evidence for acute or long-term coronavirus disease 2019 (COVID-19) infection is relatively limited. We aimed to evaluate the impact of COVID-19 infection on health-related quality of life (HRQoL) in the Japanese population. Eligible study participants were 13,365 employees and their dependents who answered questionnaires at baseline and 18 months later and who had at least 6 months of continuous enrolment before and after baseline. Of the 711 study participants who developed COVID-19 infection, 29.0% reported a decline in HRQoL, whereas 25.2% of uninfected participants reported a decline. The adjusted odds ratios (95% confidence intervals) for the association between COVID-19 infection and declines in HRQoL in the age categories of less than 30 years, 30s, 40s, 50s, and 60 years or higher were 0.54 (0.15-1.92), 1.70 (1.03-2.81), 1.14 (0.82-1.57), 1.05 (0.77-1.42), and 0.87 (0.46-1.64), respectively. This study demonstrates a differential association between COVID-19 infection and declines in HRQoL by age group. A 1.7-fold increase in the odds of negative changes in HRQoL was observed in only those in their 30s. Further studies are needed to elucidate differences in the impact of COVID-19 infection on HRQoL between younger people such as those in their 30s and the older population.

Longitudinal antibody dynamics after COVID-19 vaccine boosters based on prior infection status and booster doses.

Global concern over COVID-19 vaccine distribution disparities highlights the need for strategic booster shots. We explored longitudinal antibody responses post-booster during the Omicron wave in a Japanese cohort, emphasizing prior infection and booster doses. This prospective cohort study included 1763 participants aged 18 years and older with at least three vaccine doses (7376 datapoints). Antibody levels were measured every 2 months. We modeled temporal declines in antibody levels after COVID-19 vaccine boosters according to prior infection status and booster doses using a Bayesian linear mixed-effects interval-censored model, considering age, sex, underlying conditions, and lifestyle. Prior infection enhanced post-booster immunity (posterior median 0.346, 95% credible interval [CrI] 0.335-0.355), maintaining antibody levels (posterior median 0.021; 95% CrI 0.019-0.023) over 1 year, in contrast to uninfected individuals whose levels had waned by 8 months post-vaccination. Each additional booster was correlated with higher baseline antibody levels and slower declines, comparing after the third dose. Female sex, older age, immunosuppressive status, and smoking history were associated with lower baseline post-vaccination antibodies, but not associated with decline rates except for older age in the main model. Prior infection status and tailored, efficient, personalized booster strategies are crucial, considering sex, age, health conditions, and lifestyle.

Regression of Necrotic Lesions after Methotrexate Withdrawal in Patients with Methotrexate-Associated Lymphoproliferative Disorders: A Retrospective CT Study.

This retrospective study investigated whether necrotic lesions detected on a computed tomography (CT) scan are more regressive than non-necrotic lesions after methotrexate withdrawal in patients pathologically diagnosed with methotrexate-associated lymphoproliferative disorders (MTX-LPD). In total, 89 lesions extracted from 24 patients on CT scans were included in the analysis. All patients had been evaluated for the presence of necrosis within lesions via CT scan upon first suspicion of MTX-LPD (baseline CT scan). The percentage lesion size reduction between the baseline and initial follow-up CT scan was calculated. The association between necrosis within lesions and size changes was estimated via linear regression analyses using both crude and adjusted models. Necrosis was significantly more common in extranodal lesions (27 out of 30 lesions, 90%) than in nodal lesions (9 out of 59 lesions, 15%, p<0.001). In the crude model, the regression of necrotic lesions was 58.5% greater than that of non-necrotic lesions; the difference was statistically significant (p<0.001). Additionally, the longest diameter of necrotic lesions at the baseline CT scan was significantly greater than that of non-necrotic lesions (p<0.001). Based on the adjusted model, necrotic lesions showed 49.3% greater regression than non-necrotic lesions (p=0.017). Necrosis detected on a CT scan was found to be an independent predictor of regression after MTX withdrawal in patients with MTX-LPD.

Significance of Continuous Low-Dose Lenvatinib for the Treating of the Patients with Unresectable Thyroid Carcinoma.

The tyrosine kinase inhibitor lenvatinib has been confirmed as an effective treatment option for patients with unresectable thyroid carcinoma. We conducted a retrospective analysis of the significance of the effect of continued lenvatinib treatment for the longest duration possible at a reasonable daily dose and with a minimum discontinuation period in 42 patients with unresectable thyroid carcinoma treated with lenvatinib between 2015 and 2020. A Cox proportional hazard model-based analysis revealed that the overall survival of the patients treated with a <8 mg/day mean dose of lenvatinib was significantly better than that of the patients treated with 8-24 mg/day (hazard ratio [HR] 0.38 for 1.14-4.54 mg/day, and HR 0.01 for 4.56-7.97 mg/day) adjusted for various factors (e.g., sex, age, drug interruption period). The cumulative dose of lenvatinib administered tended to be higher in the patients treated with low doses (< 8 mg/day) than in the patients treated with relatively high doses (8-24 mg/day). Considering its adverse events, the continuation of lenvatinib treatment with an adequate daily dose and drug interruption may help prolong the survival of patients with unresectable thyroid carcinoma.

Complementary and Alternative Medicine Use, Cancer Screening, and Medical Checkups in Japan from 2001 to 2013: A Repeated Cross-Sectional Study.

Introduction: The association between complementary and alternative medicine (CAM) use and other health-related behaviors is an important issue. A previous study reported that complementary medicine use is related to greater use of cancer screening, whereas alternative medicine use is related to lower use of cancer screening. Given the sparse evidence from Japan, we aimed to examine the association of CAM use with cancer screening and medical checkups. We used a repeated cross-sectional survey of a nationally representative sample of Japanese people and conducted age-period-cohort analysis. Methods: The study population was 68,217 of 83,827 individuals observed from 2001 to 2013 who received cancer screening. CAM users were defined as individuals who received acupuncture, moxibustion, anma/massage/shiatsu, or judo therapy for their most worrisome symptom. The outcomes of interest were receiving stomach, lung, colorectal, uterine, and breast cancer screenings and medical checkups. Using crossclassified multilevel logistic regression models, we estimated odds ratios (ORs) and 95% credible intervals (CIs) for cancer screening and medical checkups. Results: For CAM users of complementary medicine, the adjusted ORs for stomach, lung, and colorectal cancer screening were 1.40 (95% CI: 1.35-1.44), 1.37 (95% CI: 1.34-1.40), and 1.52 (95% CI: 1.49-1.54), respectively. We found similar results for uterine and breast cancer screening, and medical checkups. Conclusions: Irrespective of whether they use CAM, CAM users in Japan tend to receive a variety of cancer screenings and medical checkups.

Association Between Clinical Remission of Infantile-Onset Allergic Rhinitis During the School-Age Period and the Type of Housing: A Longitudinal Population-Based Japanese Study.

This study investigated the association between housing type and clinical remission of infantile-onset allergic rhinitis (AR) in 53,575 children born in 2001 in Japan. Infantile-onset AR was defined as the presence of AR symptoms reported between ages 1.5 and 4.5 years, and remission was assessed between ages 10 and 12. The type of housing was categorized into detached houses and multi-unit residential buildings with 1-2, 3-5, or ≥6 floors. Among the 4,352 infantile-onset AR, 42.9% experienced remission. Notably, living in multi-unit residential buildings, particularly those with 1-2 and ≥6 floors, was positively associated with AR remission.

Review of a Series of Surveys on Adverse Reactions to the COVID-19 mRNA-1273 Vaccine at Okayama University.

This paper presents the results of a series of surveys conducted from July 2021 to March 2023 to investigate the post-vaccination adverse reactions to the mRNA-1273 (Moderna) vaccine among faculty, staff, and students at Okayama University. These studies complement the official surveys conducted by the Ministry of Health, Labour and Welfare (MHLW) and provide a more representative picture of adverse reactions in the general population including large numbers of healthy young people. Pain, swelling, redness at the injection site, fever, headache, and malaise were the main adverse reactions reported. The proportion of adverse reactions was generally higher after the second vaccination and decreased with each additional vaccination. No statistically significant differences in the adverse reactions were found for males and females and those with/without a history of allergy, but a lower proportion of fever was observed in older participants and those with underlying medical conditions. We also evaluated the association between adverse reactions and antibody titers after the third vaccination and found no significant differences in antibody levels one month after vaccination. This series of studies highlights the importance of conducting surveys in diverse populations to provide a more representative picture of post-vaccination adverse reactions during a pandemic.

Fine Particulate Matter and Diabetes Prevalence in Okayama, Japan.

Many studies have shown an association between long-term exposure to particulate matter having an aerodynamic diameter of 2.5 µm or less (PM2.5) and diabetes mellitus (DM), but few studies have focused on Asian subjects. We thus examined the association between long-term exposure to PM2.5 and DM prevalence in Okayama City, Japan. We included 76,591 participants who had received basic health checkups in 2006 and 2007. We assigned the census-level modeled PM2.5 data from 2006 and 2007 to each participant and defined DM using treatment status and the blood testing. PM2.5 was associated with DM prevalence, and the prevalence ratio (95% confidence interval) was 1.10 (1.00-1.20) following each interquartile range increase (2.1 µg/m3) in PM2.5. This finding is consistent with previous results and suggests that long-term exposure to PM2.5 is associated with an increased prevalence of DM in Okayama City, Japan, where the PM2.5 level is lower than in other cities in Asian countries.

Effectiveness of the Original COVID-19 Vaccine against COVID-19 Exacerbations during the Omicron Wave: A Population-based Study in Okayama, Japan.

Introduction: In Japan, approximately 97 million individuals have received their primary two doses of coronavirus disease 2019 (COVID-19) vaccine at the end of 2022. In this study, we aim to examine the effectiveness of the primary vaccines and compare its efficacy to booster vaccine shots in terms of preventing COVID-19 exacerbations during the Omicron-predominant period in Japan. Methods: For this analysis, we have collected all the confirmed COVID-19-positive cases from different medical institutions in Okayama City and have also utilized the information from the public Vaccination Record System. Taking the number of vaccinations into consideration, we then conducted a population-based study to assess the effectiveness of the two primary vaccine doses in preventing COVID-19 exacerbations during the Omicron waves. Our primary and secondary outcomes were COVID-19 exacerbations with respiratory failure (i.e., oxygen saturation on room air ≤ 93%, requiring supplemental oxygen), intensive care unit admission and/or mechanical ventilator requirement, or death, in accordance with the Japanese COVID-19 guidelines, and pneumonia during the course of COVID-19 infection, respectively. Results: In total, 95,329 COVID-19-positive individuals, aged 5 years and above, were included in this analysis (study period from January 1 to September 10, 2022). As per our findings, the effectiveness of the primary two doses against COVID-19 exacerbations compared with those who had never been vaccinated was 55.5% (95% confidential interval [CI]: 32.6-71.7), whereas it was higher after the third dose (76.9%; 95% CI: 66.7-84.0) and the fourth dose (75.7%; 95% CI: 58.8-85.7). Effectiveness was sustained for ≥ 5 months after the third vaccination, and preventive effectiveness was observed in individuals aged ≥ 65 years. Conclusions: As per the results of this study, we can conclude that the efficacy of the primary two doses of SARS-CoV-2 vaccine can be further strengthened in terms of preventing COVID-19 exacerbations by administering third and fourth booster vaccine shots. The additional bivalent vaccine is anticipated to further increase its efficacy against the Omicron strain, suggesting that individuals who have not received their booster shots yet should consider getting them to prevent COVID-19 exacerbations.

Childcare and Child Development in Japan.

For decades, the notion has persisted in developed countries that exclusive care by the mothers is best for the development of children up to 3 years of age. To examine the veracity of this "myth of the first three years" in Japan, we examined the effects of childcare facility use for children younger than 3 years on their development using the cohorts of the Longitudinal Survey of Newborns in the 21st Century conducted in Japan. Of the 47,015 respondents to the survey, we studied the children of 5,508 mothers with university/professional education to evaluate the relationships between primary early (< 2.5 years) childcare providers during weekday daytime hours and specific development indices for the ages of 2.5, 5.5, and 8 years. At the age of 2.5 and 5.5 years, children attending childcare facilities were judged as having more advanced developmental behaviors by their parents, such as being able to compose a two-word sentence (adjusted odds ratio [aOR]: 0.22) or to express emotions (aOR: 0.81), compared with those cared for by mothers. However, at the age of 8 years, children who attended childcare facilities as infants < 2.5 years showed more aggressive behavior in interrupting people (aOR: 1.20) and causing disturbances in public (aOR: 1.26) than those cared for by mothers (after adjustment for numerous child and parental factors). Although these results are generally consistent with previous studies, issues potentially involved with problem behavior such as quality of childcare require further investigation, as does the case of children of mothers with more modest educational attainment.

Participation in the Setouchi Triennale and the Health of Residents in Naoshima: A Cross-Sectional Study.

Arts festivals have become increasingly popular in various parts of Japan in recent years. The purpose of this study was to investigate the relationships between arts festival activities participation at the Setouchi Triennale and the health of residents in the town of Naoshima. This was a cross-sectional study. Questionnaires were distributed to all residents of Naoshima who were 20 years old or older (n=2,588). We analyzed responses from 708 people. The associations between arts festival activities participation and health (measured by self-rated health) were analyzed using logistic regression analysis as the primary outcome. Kessler's psychological distress scale scores were also analyzed in the same manner as the primary outcome. The participating group had an adjusted odds ratio of 1.86 (95% confidence interval: 1.03-3.33) for higher self-rated health compared with those who did not participate. Kessler's psychological distress scale results showed that the participating group had an adjusted odds ratio of 3.23 (95% confidence interval: 1.19-8.81) for lower psychological distress compared with those who did not participate. In conclusion, arts festival activities participation was associated with higher self-rated health and lower psychological distress. However, caution must be taken in regard to generalizability and causality when interpreting these results.

Does Participation in the Setouchi Triennale Foster Social Capital? : A Cross-Sectional Study.

This study examined whether participation in an art project was associated with higher social capital (SC). We conducted a questionnaire survey from November 2021 to March 2022 among residents aged 20 years or older of Naoshima, an island in Kagawa Prefecture, Japan. Before the survey, the Setouchi Triennale had been held on Naoshima four times, starting in 2010. We calculated propensity scores for Triennale participation and performed propensity score matching. We then compared cognitive and structural SC by Triennale participation and found significant differences, respectively. We adopted a conditional ordered logistic regression analysis with propensity score matching for cognitive or structural SC, and found adjusted odd ratios of 2.913 (95%CI, 1.846-4.596) for cognitive SC and 4.535 (95%CI, 2.839-7.244) for structural SC. Our findings suggest that Triennale participation enhanced the cognitive aspect of SC while also building structural SC.

Association between Radon Hot Spring Bathing and Health Conditions: A Cross-Sectional Study in Misasa, Japan.

No epidemiological studies have examined the health effects of daily bathing in radon hot springs. In this cross-sectional study, we investigated the associations between radon hot spring bathing and health conditions. The target population was 5,250 adults ≥ 20 years old in the town of Misasa, Japan. We collected information about the participants' bathing habits and alleviation of a variety of disease symptoms, and their self-rated health (SRH). Unadjusted and adjusted odds ratios (ORs) and 95% confidence intervals (CI) were calculated. In both the adjusted and unadjusted models of hypertension, significant associations between the > 1×/week hot spring bathing and the alleviation of hypertension symptoms were observed compared to the group whose hot spring bathing was <1×/week: adjusted model, OR 5.40 (95%CI: 1.98-14.74); unadjusted model, 3.67 (1.50-8.99) and for gastroenteritis: adjusted model, 9.18 (1.15-72.96); unadjusted model, 7.62 (1.59-36.49). Compared to the no-bathing group, higher SRH was significantly associated with both bathing < 1×/week: unadjusted model, 2.27 (1.53-3.37) and > 1×/week: adjusted model, 1.91 (1.15-3.19). These findings suggest that bathing in radon hot springs is associated with higher SRH and the alleviation of hypertension and gastroenteritis.

Obesity, overweight, and severe prognosis in COVID-19 patients in Japan.

INTRODUCTION: Obesity (i.e., body mass index [BMI] of 30 kg/m2 or more) is one of the risk factors for severe COVID-19, but the findings may not be directly applicable to Asians, who have a different cutoff point for defining obesity. We thus examined the association between obesity/overweight (BMI of 25 kg/m2 or more and less than 30 kg/m2) and the risk of COVID-19 severity. METHODS: The study population included COVID-19 patients who had been enrolled in the registry of the Okayama City Public Health Center in Okayama, Japan, between March 2020 and June 2022. We included 27 820 patients who had information on BMI and prognosis, and we conducted Poisson regression analysis with robust error variance to estimate risk ratios (RRs) with 95% confidence intervals (CIs) for severe outcomes. RESULTS: Obesity and overweight were associated with the increased risk of severe COVID-19 in all age categories. The RRs (95% CI) for COVID-19 induced respiratory failure compared to the normal weight category were 1.57 (1.31-1.88) for overweight and 2.45 (1.90-3.15) for obesity. CONCLUSIONS: Both obesity and overweight were associated with increased risk of severe COVID-19. This study suggests the importance of the overweight category to predict the risk of severe COVID-19 in Asians.

Association between handwashing and gargling education for children and prevention of respiratory tract infections: a longitudinal Japanese children population-based study.

PURPOSE: A longitudinal study was conducted to examine the effects of handwashing and gargling education for children on the prevention of respiratory tract infections (RTIs) in children in Japan. METHODS: The study included 38,554 children born in 2010 who were enrolled in a longitudinal study. Information on children's hygiene education regarding handwashing and gargling was collected in a survey at the age of 3.5 years. Based on parents' reports of doctors' diagnoses, airway infections and influenza events in the 12-month duration before the survey were evaluated for RTIs at the ages of 4.5 and 9 years. Poisson regression with robust variance was performed to examine the effects of hygiene education on RTIs prevention. The supplementary analysis was stratified by household income. RESULTS: Children were categorized into different groups: 38% in the handwashing and gargling group, 29% in the handwashing group, 0.1% in the gargling group, and 9.7% in the no-education group. Exclusions were made for non-respondent children (23%) and those in the gargling group. Hygiene education was associated with decreased influenza at the age of 4.5 years in the handwashing (adjusted RR [aRR] = 0.8; 95% CI, 0.8-0.9) and handwashing and gargling groups (aRR = 0.8; 95% CI, 0.8-0.9) compared with no education. However, no preventive effects on airway infections at the age of 4.5 and 9, influenza at the age of 9, or hospitalization between the ages of 3.5 and 9 years were detected. Handwashing and gargling could significantly prevent influenza in low-income households (aRR = 0.7; 95% CI, 0.6-0.8).     Conclusions: Gargling education was widespread and mostly combined with handwashing education in Japan. Hygiene education significantly affected prevention of influenza infections at the age of 4.5 years, especially in low-income households. WHAT IS KNOWN: • Previous intervention studies showed handwashing and gargling are effective in preventing respiratory tract infections. WHAT IS NEW: • We conducted a longitudinal study on handwashing and gargling education in Japanese children and found that handwashing and gargling were widely practiced together. • Handwashing and gargling education were related to a reduction in influenza, particularly in low-income households.

Comparison between olanzapine and aripiprazole treatment for 104 weeks after hospital discharge in schizophrenia spectrum disorders: a multicenter retrospective cohort study in a real-world setting.

RATIONALE: The long-term effectiveness of olanzapine and aripiprazole in real clinical conditions at flexible doses in patients after hospital discharge has not been evaluated yet. OBJECTIVES: This study was a multicenter retrospective cohort study. Patients with schizophrenia (n = 398) were prescribed olanzapine (n = 303) or aripiprazole (n = 95) at hospital discharge. The continuation of olanzapine or aripiprazole at 26, 52, or 104 weeks after the hospital discharge were compared using a Cox proportional hazards model and adjusted for possible confounders. RESULTS: The Kaplan-Meier survival curves revealed that the continuation of olanzapine at 26 (P = 0.001) and 52 weeks (P = 0.018) was significantly higher than that of aripiprazole but not at 104 weeks. Olanzapine was better than aripiprazole in efficacy at 26 (hazard ratio: 0.321, 95% confidence interval: 0.159-0.645, P = 0.001), 52 (hazard ratio: 0.405, 95% confidence interval: 0.209-0.786, P = 0.008), and 104 weeks (hazard ratio: 0.438, 95% confidence interval: 0.246-0.780, P = 0.005). Aripiprazole was better than olanzapine in tolerability at 104 weeks (hazard ratio: 4.574, 95% confidence interval: 1.415-14.787, P = 0.011). Rates after two years continuation of olanzapine and aripiprazole were not significantly different in patients with less than five years' duration of illness, but olanzapine was more commonly maintained for more than two years in those patients who had been ill for over five years' due to its greater efficacy. CONCLUSION: Olanzapine treatment showed better continuation rates at 26 and 52 after hospital discharge than aripiprazole, whereas maintenance with the two antipsychotics did not differ significantly at 104 weeks, due reduced tolerability of long-term olanzapine treatment.