BACKGROUND

This study aimed to validate self-reported fractures in the Japan Multi-Institutional Collaborative Cohort (J-MICC).

METHODS

Of the 10,332 participants who were followed up for 10 years, 1,137 individuals with self-reported fractures were included. Among them, 201 individuals were randomly selected, and 192 individuals with available medical records were analyzed. A false-positive fracture was defined as a self-reported fracture without a clinical diagnosis or record. We calculated the positive predictive value (PPV) stratified by the number of years from injury to response. Multivariate logistic regression analysis was used to elucidate the factors influencing false-positive fractures and to calculate the odds ratios (ORs) with 95% confidence intervals (CIs). The dependent variable was false-positive fractures, and the independent variables included factors such as fracture site, age, sex, body mass index, education, multisite fractures, multiple fractures, and number of years from injury to response.

RESULTS

The average age at the time of injury was 69.6 years (range, 50–80 years), and 48 individuals (25.0%) were male. Fractures were reported in the spine (41 individuals, 21.4%), upper limbs (57 individuals, 29.7%), lower limbs (71 individuals, 37.0%), and other locations (23 individuals, 11.9%), respectively. The PPV was 85.4% (164/192 individuals; 95% CI, 79.7–89.7) and was >90% if the period from injury to response was within 3 years. False-positive fractures were significantly associated with a period from injury to response >3 years (OR, 3.46; 95% CI, 1.43–8.37).

CONCLUSIONS

elf-reported fractures are useful outcomes; however, recall periods >3 years may increase the risk of misclassification.

BACKGROUND

This study aimed to evaluate the association of the initial body weight-stratified cefazolin antimicrobial prophylaxis (AMP) dose and surgical-site infection (SSI) in major orthopedic implant surgery.

METHODS

This nationwide, retrospective cohort study used data from the Diagnosis Procedure Combination database. We included patients (age ≥18 years) who underwent major orthopedic implant surgery between July 2010 and March 2022. Patients underwent surgery with an initial cefazolin dose of either 1 g (1 g cefazolin group) or 2 g (2 g cefazolin group). Primary outcome was in-hospital SSI. Restricted cubic spline functions were used to estimate the nonlinear association of body weight-stratified cefazolin dose with the outcome and between cefazolin dose per weight and the outcome.

RESULTS

Among the 408,487 participants, 394,731 and 13,756 were in the 1 g and 2g cefazolin groups, respectively. The 1 g cefazolin group, but not the 2 g cefazolin group, showed a J-shaped relationship between body weight and SSI, which increased continuously beyond 50 kg, in an increased risk of SSI with body weight. A reverse J-shaped relationship was observed between cefazolin dose per weight and SSI, with an increased risk of SSI at <20 mg/kg.

CONCLUSION

An increased risk of SSI was observed with 1 g cefazolin, but not with 2 g cefazolin, as an initial AMP with higher body weight among adults weighing >50 kg.

BACKGROUND

In 1986, a strategy of vaccinating infants at 2, 3, and 5 months of age was implemented in Japan to prevent the vertical transmission of the hepatitis B virus. This strategy was revised in 2013 to vaccinate infants at birth, 1 month, and 6 months of age. We aimed to evaluate the effect of this policy change on the vaccination status of infants born to mothers with positive hepatitis B surface antigen.

METHODS

We identified infants born between April 2009 and March 2021 from the JMDC Claims Database. Administration of hepatitis B immunoglobulin at birth was used to identify infants who received preventive measures against vertical transmission. The timing of hepatitis B vaccine administration within 12 months of birth was compared between old (born between April 2009 and September 2013) and new (born between October 2013 and March 2021) groups.

RESULTS

Among the 77,797 and 510,584 infants born before and after October 1 2013, respectively, 190 (0.24%) and 732 (0.14%) were analyzed. The proportion of infants receiving at least one dose of the vaccine increased from 63% to 96% (p < 0.001). The proportion of infants who received timely first, second, and third doses of vaccines changed from 54% to 90% (p < 0.001), 46% to 59% (p = 0.002), and 39% to 31% (p = 0.034), respectively.

CONCLUSIONS

The change in strategy against the vertical transmission of hepatitis B virus resulted in an increased rate of receiving the first dose of the vaccine and a decreased rate of timely completion of the recommended doses.

The DeSC database, launched in 2020 by DeSC Healthcare Co., Ltd. is a commercially available Japanese administrative medical claims and health checkup database. Recently, long-term care insurance (LTCI) claims data—covering care-need levels, monthly care benefits, service utilization, and cost information—have been integrated into the database. We showed that the distributions of the seven care-need levels were highly similar between the DeSC database and the official report by the Ministry of Health, Labour and Welfare. This similarity supports the representativeness and reliability of the DeSC database for epidemiological analyses using care-need status, particularly in the Advanced Elderly Medical Service System. This integrated dataset bridges critical information gaps and offers substantial advantages for health services research and epidemiological studies through individual-level linkage of medical, pharmacy, and LTCI claims. This study provides an overview of the LTCI claims data and available data items in the DeSC database and discusses future research prospects, with a particular focus on the linkage between medical and LTCI claims.