Many studies have reported a possible association of an appendectomy with rheumatoid arthritis (RA). However, findings of the relationship between an appendectomy and RA remain inconsistent. Furthermore, all such studies were conducted in Western societies, and relevant studies on the relationship between an appendectomy and RA in Asian countries are still lacking. In this study, we investigated the relationship between an appendectomy and the subsequent risk of RA using a population-based dataset. We retrieved data for this retrospective cohort study from the Taiwan “Longitudinal Health Insurance Database 2005”. We included 4,294 subjects who underwent an appendectomy in the study cohort and 12,882 matched subjects in the comparison cohort. We individually tracked each subject for a 5-year period from their index date to identify those who developed RA. A stratified Cox proportional hazard regression was performed to calculate the hazard ratio (HR) and its corresponding 95% confidence interval (CI) for the subsequent development of RA during the 5-year follow-up period between subjects who underwent an appendectomy and comparison subjects. Of the sampled subjects, 93 (0.54%) received a diagnosis of RA during the 5-year follow-up period: 33 from the study cohort (0.77% of subjects who underwent an appendectomy) and 60 from the comparison cohort (0.47% of comparison subjects) (p<0.001). After censoring individuals who died during the follow-up period and adjusting for subjects’ monthly income and geographic region, the HR of RA during the 5-year follow-up period was 1.61 (95% CI = 1.05~2.48) for subjects who underwent an appendectomy compared to comparison subjects. We found that among females, the adjusted HR of RA was 1.76 (95% CI = 1.04~2.96) for subjects who underwent an appendectomy compared to comparison subjects. However, there was no increased hazard of RA for males who underwent an appendectomy compared to comparison subjects. We concluded that female subjects who undergo an appendectomy have a higher risk of RA than comparison female subjects.

This study aimed to investigate differences in healthcare service utilization between patients with and those without benign prostatic hyperplasia (BPH) using Taiwan's National Health Insurance population-based database. A total of 7413 patients with BPH and 7413 age-matched patients without BPH were included. The outcome variable was 1-year utilization of healthcare services including the number of outpatient visits, inpatient days, and the costs of outpatient and inpatient treatments. In addition, we separated healthcare services into urology services and nonurology services for analysis. We found that as to the utilization of outpatient urological services, patients with BPH had more outpatient services (7.84 vs 0.52, P < 0.001), higher outpatient costs (US$372 vs US$34, P < 0.001), a longer length of inpatient stay (0.55 vs 0.11, P < 0.001), higher in-patients costs (US$149 vs US$32, P < 0.001), and higher total costs (US$521 vs US$67, P < 0.001) than the comparison group. As for nonurological services, patients with BPH also had more outpatient services (49.11 vs 24.79, P < 0.001), higher outpatient costs (US$1794 vs US$1014, P < 0.001), a longer length of in-patient stay (3.72 vs 2.04, P < 0.001), higher inpatient costs (US$874 vs US$486, P < 0.001), and higher total costs (US$2668 vs US$1500, P < 0.001) compared to comparison patients. We also found that the average total cost was about 2-fold greater for patients with BPH than comparison patients. We concluded that patients with BPH had higher healthcare utilization than comparison patients without BPH.