This retrospective cohort study aimed to examine the relationship between herpes zoster ophthalmicus (HZO) and the subsequent risk of dementia using a population-based database. We retrieved the study sample from the Taiwan Longitudinal Health Insurance Database 2005. The study group included 846 patients with HZO, and the comparison group included 2538 patients without HZO. Each patient was individually followed for a 5-year period to identify those patients who subsequently received a diagnosis of dementia. We performed a Cox proportional hazards regression to calculate the hazard ratios (HRs) along with 95% confidence intervals (CIs) for dementia during the follow-up period between patients with HZO and comparison patients. The respective incidence rates of dementia per 1000 person-years were 10.15 (95% CI: 7.22~13.87) and 3.61 (95% CI: 2.61~4.89) for patients with HZO and comparison patients. The Cox proportional analysis showed that the crude HR of dementia during the 5-year follow-up period was 2.83 (95% CI: 1.83–4.37) for patients with HZO than comparison patients. After adjusting for patients’ characteristics and comorbidities, HZO patients were still at a 2.97-fold greater risk than comparison patients for developing dementia. Furthermore, we found that of sampled male patients, the crude HR of dementia for patients with HZO was as high as 3.35 (95% CI = 1.79–6.28) compared to comparison patients. This study demonstrated an association between HZO and dementia. Clinicians must be alert to suspect dementia in patients with cognitive impairment who had prior HZO.

Sleep disturbances are among the most common nonmotor symptoms of Parkinson disease. However, no large epidemiological data regarding the association between obstructive sleep apnea (OSA) and Parkinson disease have been reported. The goal of this study was to investigate the risk for Parkinson disease during a 5-y follow-up period after a diagnosis of OSA using a population-based dataset. The data for this retrospective longitudinal cohort study were retrieved from the Taiwan Longitudinal Health Insurance Database 2000. We identified 1,532 patients with OSA as the study cohort and randomly selected 7,660 patients as the comparison cohort. Each subject was individually followed up for a 5-y period to identify those in whom Parkinson disease subsequently developed. Stratified Cox proportional hazard regressions were performed as a means of comparing the 5-y risk of subsequent Parkinson disease between the study cohort and comparison cohort. Of the 9,192 total patients, Parkinson disease developed in 0.73% during the 5-y follow-up period: 1.24% and 0.63% in the OSA and control cohorts, respectively. After censoring patients who died during the follow-up period and adjusting for socio-demographic characteristics, the hazard ratio (HR) of Parkinson disease during the 5-y follow-up period for patients with OSA was 2.26 (95% confidence interval [CI] = 1.32-3.88) compared with comparison patients. In addition, among females, the adjusted HR of Parkinson disease was 3.54 (95% CI = 1.50-8.34) for patients with OSA compared to patients without OSA. However, among males, there was no significantly increased hazard of Parkinson disease for patients with OSA compared to those without OSA. Female patients with OSA were found to be at a significant risk of subsequent Parkinson disease during a 5-y follow-up period.

Psoriasis is a prevalent autoimmune disorder. Various studies have reported on the relationship between psoriasis and chronic diseases but very few have explored the association between psoriasis and subsequent acute infection. This retrospective cohort study aimed to compare the risk of pneumonia between subjects with and those without psoriasis. The medical records of 14,022 patients with psoriasis and 14,022 without psoriasis were obtained from the Taiwan Longitudinal Health Insurance Database 2000. Each patient was followed-up for a three-year period. Cox proportional hazard regressions were performed to compare difference of subsequent pneumonia incidence between subjects with and those without psoriasis. There were 206 (1.47%) subjects with psoriasis and 138 (0.98%) without psoriasis hospitalized for pneumonia. By Cox proportional hazard regressions analysis, the HR (hazard ratio) of pneumonia requiring hospitalization for patients with psoriasis was 1.50 (95% confidence interval [CI]: 1.21–1.86) compared to patients without psoriasis. The adjusted HR was 1.40 (95% CI: 1.12–1.73). The adjusted HR of pneumonia hospitalization for subjects with mild and severe psoriasis was 1.36 (95% CI: 1.09–1.70) and 1.68 (95% CI: 1.12–2.52), respectively, compared to those without psoriasis. Patients with psoriasis have significantly higher incidence of pneumonia compared to those without psoriasis.

Although obstructive sleep apnea (OSA) is not a life-threatening disease, very few studies have compared differences in healthcare service utilization between patients with and those without OSA in an Asian population according to different age groups. This study attempted to investigate differences in healthcare service utilization between patients with and those without OSA in different age groups in Taiwan. Sampled subjects and data on their health service utilization were retrieved from the Taiwan Longitudinal Health Insurance Database 2005. We included 568 patients with OSA and 2840 subjects without OSA. Each subject was followed for a 1-year period to evaluate their healthcare resource utilization. Wilcoxon-Mann-Whitney tests were performed to compare differences in healthcare utilization between patients with and those without OSA during the 1-year follow-up period. As to all healthcare service utilization, patients with OSA had significantly more outpatient visits (30.3 vs. 18.6), outpatient costs (US$1231.2 vs. US$764.8), inpatient days (1.8 vs. 1.2), inpatient costs (US$563.6 vs. US$276.7), and total costs (US$1794.8 vs. US$1041.5) than comparison subjects during the 1-year follow-up period. Moreover, patients with OSA aged 40~49 and 50~59 years respectively incurred 2.11- and 2.02-fold higher total costs compared to patients without OSA. However, patients with OSA aged over 70 years did not have higher total costs compared to those without OSA. This study found that patients with OSA had greater healthcare service utilization than those without OSA. Additionally, patients with OSA in the 40~49- and 50~59-year age groups had about 2-fold higher total costs of healthcare services than those without OSA.