BACKGROUND

Reoperation after lumbar spine surgery is a major issue for both patients and physicians. It is uncertain whether fusion is superior to decompression alone for lumbar degenerative disease regarding reoperation rate. We aim to evaluate the reoperation rate after fusion surgery for lumbar degenerative disease compared with decompression alone.

METHODS

This study was conducted under a retrospective cohort design in patients undergoing fusion or decompression alone in one or two levels for lumbar degenerative disease using a Japanese claims-based database. Primary outcome was reoperation incidence during the follow-up period, and secondary outcome was reoperation incidence within 90 days postoperatively. Confounding factors were handled using propensity score overlap weighting. Cumulative incidence of reoperation was calculated from the Kaplan-Meier curve and hazard ratios (HRs) and 95% confidence intervals (CIs) for reoperation were estimated using Cox proportional hazards regression models.

RESULTS

8497 patients (2051 patients in the fusion group and 6446 in the decompression alone group) were included in the study. There was no difference in reoperation rate between fusion and decompression alone (weighted HR 0.85 [95% CI 0.69 to 1.04]; p = 0.11).

CONCLUSIONS

Among patients with lumbar degenerative disease who underwent fusion or decompression alone, no significant difference was observed between the two groups.

BACKGROUND

Polycythemia often develops in the highland areas. However, it remains to be clarified whether blood hemoglobin levels in the general population are affected by elevations above sea level of <1,000 m.

METHODS

This ecological study targeting secondary medical areas in Japan considered residential altitude at 0–800 m as the exposure and the mean hemoglobin level of the inhabitants aged between 40–44 years as the main outcome, based on the data extracted from the nationwide Special Health Checkup for 2021. The secondary outcome was the proportion of examinees with low hemoglobin levels. The results were validated using a 2018 dataset.

RESULTS

Individual data from approximately 1.21 million women and 1.93 million men in 335 secondary medical areas were summarized. When these areas were categorized into four groups by their altitude, the mean hemoglobin level at 600–800 m was elevated with a mean difference of 0.27 g/dL in women (p for trend <0.01) and with a mean difference of 0.21 g/dL in men (p for trend <0.01), compared to that at 0–200 m in 2021 dataset. Moreover, the proportion of women examinees with hemoglobin level <12.0 g/dL was 21.3% at 0–200 m and 17.6% at 600–800 m in 2021 (p for trend <0.01). These results were confirmed using the 2018 dataset.

CONCLUSIONS

As the residential altitude increased from sea level to 800 m, blood hemoglobin levels were slightly elevated, and anemia prevalence in women decreased, implying caution in hemoglobin measurements.

BACKGROUND

The current report shows a comparison of changes in pre- and in-hospital procedures, treatments and outcomes of patients with out-of-hospital cardiac arrest (OHCA) during the SOS-KANTO study periods.

METHOD

This study included patients aged ≥18 years who experienced bystander-witnessed OHCA of cardiac etiology, which was confirmed by emergency medical service (EMS) providers at the scene, received cardiopulmonary resuscitation (CPR) from EMS providers, and were subsequently transported to the participating institutions.

The primary outcome measure was patient survival with favorable neurological outcomes at 1 month from cardiac arrest. The secondary outcomes were the proportions of bystander CPR cases, advanced CPR procedures performed by EMS providers, pre-hospital return of spontaneous circulation (ROSC) rates, and post-resuscitation treatment administration.

RESULTS

Data of 1,515 patients from the SOS-KANTO 2017 study and 2,189 patients from the 2012 study were analyzed. Bystander CPR and advanced CPR procedures were performed more frequently and reliably by EMS providers in the 2017 than in the 2012 study. The rate of pre-hospital ROSC to total ROSC was higher in the 2017 study (35.7% vs 29.0%), and in-hospital treatments and post-resuscitation care was provided more frequently in the 2017 study. However, the 2017 study showed no significant difference in the survival rate with favorable neurological outcomes at 1 month, compared with the 2012 study. (9.0% vs 8.5%).

CONCLUSION

High quality of prior to ROSC and post-resuscitation care following ROSC was maintained in the 2017 study. However, the 2017 study showed no significant difference in the survival rate with favorable neurological outcomes at 1 month, compared with the 2012 study.

Mendelian randomization (MR), i.e. instrumental variable analysis using genetic instruments, is an approach that incorporates population genetics to improve causal inference. Given that genetics are randomly allocated at conception, this resembles the randomization process in randomized controlled trials and hence is more resistant to unobserved confounding compared to conventional observational studies (e.g. cohort studies). The seminar paper briefly described the origin of MR and its underlying assumptions (relevance, independence, and exclusion restriction). This was followed by introducing one sample MR designs (in which instrument-exposure and instrument-outcome associations are derived from the same sample) and one sample MR design (in which instrument-exposure and instrument-outcome associations are derived from different samples). The seminar paper then summarized key aspects of MR studies, such as instrument selection, data sources for conducting MR studies, and statistical analyses. Variations of MR design were also introduced, such as how this design can inform the effect of drug targets (drug target MR). The STROBE-MR checklist and relevant MR guidelines were introduced. The seminar paper concluded by discussing the credibility crisis of MR studies.